‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. DEFINITIONS DWELLING UNIT . A single unit consisting of one or more habitable rooms and occupied or arranged to be occu- pied as a unit separate from all other units within a dwelling. ELECTRIC HEATING APPLIANCE. An appliance that produces heat energy to create a warm environment by the application of electric power to resistance elements, refrigerant compressors or dissimilar material junctions. ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air - to - air heat exchangers to recover energy from or reject energy to exhaust ai r for the purpose of preheating, precooling , humidifying or dehumidifying outdoor ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. ENGINEERED SMOKE CONTROL SYSTEM. Refer to Smoke Control System in Sectio n 909 of the New York City Building Code . ENVIRONMENTAL AIR. Air that is conveyed to or from occupied areas through ducts that are not part of the heating or air - conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bath room exhaust, and domestic clothes dryer exhaust. EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for bu ildings. This definition shall also include other systems specifically regulated in this code. EQUIPMENT, EXISTING. Any equipment regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install h as been issued. EVAPORATIVE COOLER. A device used for reducing the sensible heat of air for cooling by the process of evap- oration of water into an airstream. EVAPORATIVE COOLING SYSTEM. The equipment and appliances intended or installed for the purpose of environmental cooling by an evaporative cooler from which the conditioned air is distributed through ducts or plenums to the conditioned area. EVAPORATOR. That part of the system in which liquid refrigerant is vaporized to produce refrigeration. EXCESS AIR. The amount of air provided in addition to theoretical air to achieve complete combustion of a fuel, thereby preventing the formation of dangerous produc ts of combustion . EXFILTRATION. Uncontrolled outward air leakage from conditioned spaces through unintentional openings in ceilings, floors and walls to unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stack effect create d by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. EXHAUST SYSTEM. An assembly of connected ducts, plenums , fittings, registers, grilles and hoods through which air is conducted from a space or spaces and exhausted to the outdoor atmosphere. EXTRA - HEAVY - DUTY COOKING APPLIANCE. Extra - heavy - duty cooking appliances are those utilizing open flame combustion of solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or pa rt of the heat source for cooking at any time. FIELD ERECTED BOILER. A boiler where the pressure vessel is constructed partially or totally in the field. Field erected boilers do not include cast iron sectional boilers that are considered factory built sin ce each section is a separate pressure vessel. FIRE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon detection of heat and to restrict the passage of flame. Fire dampers are classified for use in eit her static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. FIREPLACE. An assembly con sisting of a hearth and fire chamber of noncombustible material and provided with a chimney, for use with solid fuels. A fireplace shall be considered an appliance. Factory - built fireplace. A listed and labeled fireplace and chimney system composed of fact ory - made compo- nents, and assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. DEFINITIONS DWELLING UNIT . A single unit consisting of one or more habitable rooms and occupied or arranged to be occu- pied as a unit separate from all other units within a dwelling. ELECTRIC HEATING APPLIANCE. An appliance that produces heat energy to create a warm environment by the application of electric power to resistance elements, refrigerant compressors or dissimilar material junctions. ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air - to - air heat exchangers to recover energy from or reject energy to exhaust ai r for the purpose of preheating, precooling , humidifying or dehumidifying outdoor ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. ENGINEERED SMOKE CONTROL SYSTEM. Refer to Smoke Control System in Sectio n 909 of the New York City Building Code . ENVIRONMENTAL AIR. Air that is conveyed to or from occupied areas through ducts that are not part of the heating or air - conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bath room exhaust, and domestic clothes dryer exhaust. EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for bu ildings. This definition shall also include other systems specifically regulated in this code. EQUIPMENT, EXISTING. Any equipment regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install h as been issued. EVAPORATIVE COOLER. A device used for reducing the sensible heat of air for cooling by the process of evap- oration of water into an airstream. EVAPORATIVE COOLING SYSTEM. The equipment and appliances intended or installed for the purpose of environmental cooling by an evaporative cooler from which the conditioned air is distributed through ducts or plenums to the conditioned area. EVAPORATOR. That part of the system in which liquid refrigerant is vaporized to produce refrigeration. EXCESS AIR. The amount of air provided in addition to theoretical air to achieve complete combustion of a fuel, thereby preventing the formation of dangerous produc ts of combustion . EXFILTRATION. Uncontrolled outward air leakage from conditioned spaces through unintentional openings in ceilings, floors and walls to unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stack effect create d by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. EXHAUST SYSTEM. An assembly of connected ducts, plenums , fittings, registers, grilles and hoods through which air is conducted from a space or spaces and exhausted to the outdoor atmosphere. EXTRA - HEAVY - DUTY COOKING APPLIANCE. Extra - heavy - duty cooking appliances are those utilizing open flame combustion of solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or pa rt of the heat source for cooking at any time. FIELD ERECTED BOILER. A boiler where the pressure vessel is constructed partially or totally in the field. Field erected boilers do not include cast iron sectional boilers that are considered factory built sin ce each section is a separate pressure vessel. FIRE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon detection of heat and to restrict the passage of flame. Fire dampers are classified for use in eit her static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. FIREPLACE. An assembly con sisting of a hearth and fire chamber of noncombustible material and provided with a chimney, for use with solid fuels. A fireplace shall be considered an appliance. Factory - built fireplace. A listed and labeled fireplace and chimney system composed of fact ory - made compo- nents, and assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. DEFINITIONS DWELLING UNIT . A single unit consisting of one or more habitable rooms and occupied or arranged to be occu- pied as a unit separate from all other units within a dwelling. ELECTRIC HEATING APPLIANCE. An appliance that produces heat energy to create a warm environment by the application of electric power to resistance elements, refrigerant compressors or dissimilar material junctions. ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air - to - air heat exchangers to recover energy from or reject energy to exhaust ai r for the purpose of preheating, precooling , humidifying or dehumidifying outdoor ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. ENGINEERED SMOKE CONTROL SYSTEM. Refer to Smoke Control System in Sectio n 909 of the New York City Building Code . ENVIRONMENTAL AIR. Air that is conveyed to or from occupied areas through ducts that are not part of the heating or air - conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bath room exhaust, and domestic clothes dryer exhaust. EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for bu ildings. This definition shall also include other systems specifically regulated in this code. EQUIPMENT, EXISTING. Any equipment regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install h as been issued. EVAPORATIVE COOLER. A device used for reducing the sensible heat of air for cooling by the process of evap- oration of water into an airstream. EVAPORATIVE COOLING SYSTEM. The equipment and appliances intended or installed for the purpose of environmental cooling by an evaporative cooler from which the conditioned air is distributed through ducts or plenums to the conditioned area. EVAPORATOR. That part of the system in which liquid refrigerant is vaporized to produce refrigeration. EXCESS AIR. The amount of air provided in addition to theoretical air to achieve complete combustion of a fuel, thereby preventing the formation of dangerous produc ts of combustion . EXFILTRATION. Uncontrolled outward air leakage from conditioned spaces through unintentional openings in ceilings, floors and walls to unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stack effect create d by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. EXHAUST SYSTEM. An assembly of connected ducts, plenums , fittings, registers, grilles and hoods through which air is conducted from a space or spaces and exhausted to the outdoor atmosphere. EXTRA - HEAVY - DUTY COOKING APPLIANCE. Extra - heavy - duty cooking appliances are those utilizing open flame combustion of solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or pa rt of the heat source for cooking at any time. FIELD ERECTED BOILER. A boiler where the pressure vessel is constructed partially or totally in the field. Field erected boilers do not include cast iron sectional boilers that are considered factory built sin ce each section is a separate pressure vessel. FIRE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon detection of heat and to restrict the passage of flame. Fire dampers are classified for use in eit her static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. FIREPLACE. An assembly con sisting of a hearth and fire chamber of noncombustible material and provided with a chimney, for use with solid fuels. A fireplace shall be considered an appliance. Factory - built fireplace. A listed and labeled fireplace and chimney system composed of fact ory - made compo- nents, and assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. DEFINITIONS Masonry fireplace. A hearth and fire chamber of solid masonry units such as bricks, stones, listed masonry units or reinforced concrete, provided with a suitable chimney. FIREPLACE STOVE. A free - standing chimney - connected solid - fuel - burning heater, designed to be operated with the fire chamber doors in either the open or closed position. FLAME SAFEGUARD. A device that will automa tically shut off the fuel supply to a main burner or group of burners when the means of ignition of such burners becomes inoperative, and when flame failure occurs on the burner or group of burners. FLAME SPREAD INDEX. A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84 or UL 723. FLAMMABILITY CLASSIFICATION. Refrigerants shall be assigned to one of the three classes — 1, 2 or 3 — in ac cordance with ASHRAE 34. FLAMMABLE LIQUIDS. Any liquid that has a closed cup flash point below 100°F (37.8°C) , and has a vapor pressure not exceeding 40 psi (275.8 kPa) at 100°F (37.8°C ). Flammable liquids shall be known as Class I liquids and shall be div ided into the following classifications: Class IA. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point below 100°F (37.8°C). Class IB. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point at or above 100°F (37.8°C). Class IC. Liquids having a closed cup flash point at or above 73°F (22.8°C ) and below 100°F (37.8°C ). FLAMMABLE VAPOR OR FUMES. Mixtures of gases in air at concentrations equal to or greater than the LFL an d less than or equal to the upper flammability limit (UFL). FLASH POINT. The minimum temperature at which the application of a test flame causes the vapors of a portion of the sample to ignite under the conditions specified by the test procedures and appar atus . The flash point of a liquid shall be determined in accordance with ASTM D 56, ASTM D 93 or ASTM D 3278. FLEXIBLE AIR CONNECTOR. A conduit for transferring air between an air duct or plenum and an air terminal unit or between an air duct or plenum and an air inlet or air outlet. Such conduit is limited in its use, length and location. FLOOR AREA, NET. The actual occupied area, not including unoccupied accessory areas or thicknesses of walls. FLOOR FURNACE. A completely self - contained furnace suspended from the floor of the space being heated, taking air for combustion from outside such space and with means for observing flames and lighting the appliance from such space. Fan type. A floor furnace equipped with a fan that provides the primary means for ci rculating air. Gravity type. A floor furnace depending primarily on circulation of air by gravity. This classification shall also include floor furnaces equipped with booster - type fans that do not materially restrict free circulation of air by gravity flow when such fans are not in operation. FLUE. A passageway within a chimney or vent through which gaseous combustion products pass. FLUE CONNECTION (BREECHING). A passage for con - ducting the products of combustion from a fuel - fired appliance to the vent or c himney (see also “Chimney connector” and “Vent connector”). FLUE GASES. Products of combustion plus excess air in fireplace and appliance flues, or heat exchangers. FLUE LINER (LINING). A system or material used to form the inside surface of a flue in a ch imney or vent, for the purpose of protecting the surrounding structure from the effects of combustion products and conveying combustion products without leakage to the atmosphere. FUEL GAS. A natural gas, manufactured gas, liquefied petroleum gas or a mixt ure of these gases. FUEL OIL. Kerosene or any hydrocarbon oil having a flash point not less than 100°F (37.8°C). ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. DEFINITIONS DWELLING UNIT . A single unit consisting of one or more habitable rooms and occupied or arranged to be occu- pied as a unit separate from all other units within a dwelling. ELECTRIC HEATING APPLIANCE. An appliance that produces heat energy to create a warm environment by the application of electric power to resistance elements, refrigerant compressors or dissimilar material junctions. ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air - to - air heat exchangers to recover energy from or reject energy to exhaust ai r for the purpose of preheating, precooling , humidifying or dehumidifying outdoor ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. ENGINEERED SMOKE CONTROL SYSTEM. Refer to Smoke Control System in Sectio n 909 of the New York City Building Code . ENVIRONMENTAL AIR. Air that is conveyed to or from occupied areas through ducts that are not part of the heating or air - conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bath room exhaust, and domestic clothes dryer exhaust. EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for bu ildings. This definition shall also include other systems specifically regulated in this code. EQUIPMENT, EXISTING. Any equipment regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install h as been issued. EVAPORATIVE COOLER. A device used for reducing the sensible heat of air for cooling by the process of evap- oration of water into an airstream. EVAPORATIVE COOLING SYSTEM. The equipment and appliances intended or installed for the purpose of environmental cooling by an evaporative cooler from which the conditioned air is distributed through ducts or plenums to the conditioned area. EVAPORATOR. That part of the system in which liquid refrigerant is vaporized to produce refrigeration. EXCESS AIR. The amount of air provided in addition to theoretical air to achieve complete combustion of a fuel, thereby preventing the formation of dangerous produc ts of combustion . EXFILTRATION. Uncontrolled outward air leakage from conditioned spaces through unintentional openings in ceilings, floors and walls to unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stack effect create d by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. EXHAUST SYSTEM. An assembly of connected ducts, plenums , fittings, registers, grilles and hoods through which air is conducted from a space or spaces and exhausted to the outdoor atmosphere. EXTRA - HEAVY - DUTY COOKING APPLIANCE. Extra - heavy - duty cooking appliances are those utilizing open flame combustion of solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or pa rt of the heat source for cooking at any time. FIELD ERECTED BOILER. A boiler where the pressure vessel is constructed partially or totally in the field. Field erected boilers do not include cast iron sectional boilers that are considered factory built sin ce each section is a separate pressure vessel. FIRE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon detection of heat and to restrict the passage of flame. Fire dampers are classified for use in eit her static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. FIREPLACE. An assembly con sisting of a hearth and fire chamber of noncombustible material and provided with a chimney, for use with solid fuels. A fireplace shall be considered an appliance. Factory - built fireplace. A listed and labeled fireplace and chimney system composed of fact ory - made compo- nents, and assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. DEFINITIONS Masonry fireplace. A hearth and fire chamber of solid masonry units such as bricks, stones, listed masonry units or reinforced concrete, provided with a suitable chimney. FIREPLACE STOVE. A free - standing chimney - connected solid - fuel - burning heater, designed to be operated with the fire chamber doors in either the open or closed position. FLAME SAFEGUARD. A device that will automa tically shut off the fuel supply to a main burner or group of burners when the means of ignition of such burners becomes inoperative, and when flame failure occurs on the burner or group of burners. FLAME SPREAD INDEX. A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84 or UL 723. FLAMMABILITY CLASSIFICATION. Refrigerants shall be assigned to one of the three classes — 1, 2 or 3 — in ac cordance with ASHRAE 34. FLAMMABLE LIQUIDS. Any liquid that has a closed cup flash point below 100°F (37.8°C) , and has a vapor pressure not exceeding 40 psi (275.8 kPa) at 100°F (37.8°C ). Flammable liquids shall be known as Class I liquids and shall be div ided into the following classifications: Class IA. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point below 100°F (37.8°C). Class IB. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point at or above 100°F (37.8°C). Class IC. Liquids having a closed cup flash point at or above 73°F (22.8°C ) and below 100°F (37.8°C ). FLAMMABLE VAPOR OR FUMES. Mixtures of gases in air at concentrations equal to or greater than the LFL an d less than or equal to the upper flammability limit (UFL). FLASH POINT. The minimum temperature at which the application of a test flame causes the vapors of a portion of the sample to ignite under the conditions specified by the test procedures and appar atus . The flash point of a liquid shall be determined in accordance with ASTM D 56, ASTM D 93 or ASTM D 3278. FLEXIBLE AIR CONNECTOR. A conduit for transferring air between an air duct or plenum and an air terminal unit or between an air duct or plenum and an air inlet or air outlet. Such conduit is limited in its use, length and location. FLOOR AREA, NET. The actual occupied area, not including unoccupied accessory areas or thicknesses of walls. FLOOR FURNACE. A completely self - contained furnace suspended from the floor of the space being heated, taking air for combustion from outside such space and with means for observing flames and lighting the appliance from such space. Fan type. A floor furnace equipped with a fan that provides the primary means for ci rculating air. Gravity type. A floor furnace depending primarily on circulation of air by gravity. This classification shall also include floor furnaces equipped with booster - type fans that do not materially restrict free circulation of air by gravity flow when such fans are not in operation. FLUE. A passageway within a chimney or vent through which gaseous combustion products pass. FLUE CONNECTION (BREECHING). A passage for con - ducting the products of combustion from a fuel - fired appliance to the vent or c himney (see also “Chimney connector” and “Vent connector”). FLUE GASES. Products of combustion plus excess air in fireplace and appliance flues, or heat exchangers. FLUE LINER (LINING). A system or material used to form the inside surface of a flue in a ch imney or vent, for the purpose of protecting the surrounding structure from the effects of combustion products and conveying combustion products without leakage to the atmosphere. FUEL GAS. A natural gas, manufactured gas, liquefied petroleum gas or a mixt ure of these gases. FUEL OIL. Kerosene or any hydrocarbon oil having a flash point not less than 100°F (37.8°C). ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. DEFINITIONS DWELLING UNIT . A single unit consisting of one or more habitable rooms and occupied or arranged to be occu- pied as a unit separate from all other units within a dwelling. ELECTRIC HEATING APPLIANCE. An appliance that produces heat energy to create a warm environment by the application of electric power to resistance elements, refrigerant compressors or dissimilar material junctions. ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air - to - air heat exchangers to recover energy from or reject energy to exhaust ai r for the purpose of preheating, precooling , humidifying or dehumidifying outdoor ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. ENGINEERED SMOKE CONTROL SYSTEM. Refer to Smoke Control System in Sectio n 909 of the New York City Building Code . ENVIRONMENTAL AIR. Air that is conveyed to or from occupied areas through ducts that are not part of the heating or air - conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bath room exhaust, and domestic clothes dryer exhaust. EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for bu ildings. This definition shall also include other systems specifically regulated in this code. EQUIPMENT, EXISTING. Any equipment regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install h as been issued. EVAPORATIVE COOLER. A device used for reducing the sensible heat of air for cooling by the process of evap- oration of water into an airstream. EVAPORATIVE COOLING SYSTEM. The equipment and appliances intended or installed for the purpose of environmental cooling by an evaporative cooler from which the conditioned air is distributed through ducts or plenums to the conditioned area. EVAPORATOR. That part of the system in which liquid refrigerant is vaporized to produce refrigeration. EXCESS AIR. The amount of air provided in addition to theoretical air to achieve complete combustion of a fuel, thereby preventing the formation of dangerous produc ts of combustion . EXFILTRATION. Uncontrolled outward air leakage from conditioned spaces through unintentional openings in ceilings, floors and walls to unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stack effect create d by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. EXHAUST SYSTEM. An assembly of connected ducts, plenums , fittings, registers, grilles and hoods through which air is conducted from a space or spaces and exhausted to the outdoor atmosphere. EXTRA - HEAVY - DUTY COOKING APPLIANCE. Extra - heavy - duty cooking appliances are those utilizing open flame combustion of solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or pa rt of the heat source for cooking at any time. FIELD ERECTED BOILER. A boiler where the pressure vessel is constructed partially or totally in the field. Field erected boilers do not include cast iron sectional boilers that are considered factory built sin ce each section is a separate pressure vessel. FIRE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon detection of heat and to restrict the passage of flame. Fire dampers are classified for use in eit her static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. FIREPLACE. An assembly con sisting of a hearth and fire chamber of noncombustible material and provided with a chimney, for use with solid fuels. A fireplace shall be considered an appliance. Factory - built fireplace. A listed and labeled fireplace and chimney system composed of fact ory - made compo- nents, and assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. DEFINITIONS Masonry fireplace. A hearth and fire chamber of solid masonry units such as bricks, stones, listed masonry units or reinforced concrete, provided with a suitable chimney. FIREPLACE STOVE. A free - standing chimney - connected solid - fuel - burning heater, designed to be operated with the fire chamber doors in either the open or closed position. FLAME SAFEGUARD. A device that will automa tically shut off the fuel supply to a main burner or group of burners when the means of ignition of such burners becomes inoperative, and when flame failure occurs on the burner or group of burners. FLAME SPREAD INDEX. A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84 or UL 723. FLAMMABILITY CLASSIFICATION. Refrigerants shall be assigned to one of the three classes — 1, 2 or 3 — in ac cordance with ASHRAE 34. FLAMMABLE LIQUIDS. Any liquid that has a closed cup flash point below 100°F (37.8°C) , and has a vapor pressure not exceeding 40 psi (275.8 kPa) at 100°F (37.8°C ). Flammable liquids shall be known as Class I liquids and shall be div ided into the following classifications: Class IA. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point below 100°F (37.8°C). Class IB. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point at or above 100°F (37.8°C). Class IC. Liquids having a closed cup flash point at or above 73°F (22.8°C ) and below 100°F (37.8°C ). FLAMMABLE VAPOR OR FUMES. Mixtures of gases in air at concentrations equal to or greater than the LFL an d less than or equal to the upper flammability limit (UFL). FLASH POINT. The minimum temperature at which the application of a test flame causes the vapors of a portion of the sample to ignite under the conditions specified by the test procedures and appar atus . The flash point of a liquid shall be determined in accordance with ASTM D 56, ASTM D 93 or ASTM D 3278. FLEXIBLE AIR CONNECTOR. A conduit for transferring air between an air duct or plenum and an air terminal unit or between an air duct or plenum and an air inlet or air outlet. Such conduit is limited in its use, length and location. FLOOR AREA, NET. The actual occupied area, not including unoccupied accessory areas or thicknesses of walls. FLOOR FURNACE. A completely self - contained furnace suspended from the floor of the space being heated, taking air for combustion from outside such space and with means for observing flames and lighting the appliance from such space. Fan type. A floor furnace equipped with a fan that provides the primary means for ci rculating air. Gravity type. A floor furnace depending primarily on circulation of air by gravity. This classification shall also include floor furnaces equipped with booster - type fans that do not materially restrict free circulation of air by gravity flow when such fans are not in operation. FLUE. A passageway within a chimney or vent through which gaseous combustion products pass. FLUE CONNECTION (BREECHING). A passage for con - ducting the products of combustion from a fuel - fired appliance to the vent or c himney (see also “Chimney connector” and “Vent connector”). FLUE GASES. Products of combustion plus excess air in fireplace and appliance flues, or heat exchangers. FLUE LINER (LINING). A system or material used to form the inside surface of a flue in a ch imney or vent, for the purpose of protecting the surrounding structure from the effects of combustion products and conveying combustion products without leakage to the atmosphere. FUEL GAS. A natural gas, manufactured gas, liquefied petroleum gas or a mixt ure of these gases. FUEL OIL. Kerosene or any hydrocarbon oil having a flash point not less than 100°F (37.8°C). DEFINITIONS FUEL - OIL PIPING SYSTEM. A closed piping system that connects a combustible liquid from a source of supply to a fuel - oil - burning appliance. FURNACE. A completely self - contained heating unit that is designed to supply heated air to spaces remote from or adjacent to the appliance location. FURNACE ROOM. A room primarily utilized for the installation of fuel - burning, s pace - heating and water - heating appliances other than boilers (see also “Boiler room”). FUSIBLE PLUG. A device arranged to relieve pressure by operation of a fusible member at a predetermined tem- perature. GROUND SOURCE HEAT PUMP LOOP SYSTEM. Piping buried i n horizontal or vertical excavations or placed in a body of water for the purpose of transporting heat transfer liquid to and from a heat pump. Included in this definition are closed loop systems in which the liquid is recirculated and open loop systems in which the liquid is drawn from a well or other source. HAZARDOUS LOCATION. Any location considered to be a fire hazar d for flammable vapors, dust, combustible fibers or other highly combustible substances. The location is not necessarily categorized in the New York City Build- ing Code as a high - hazard use group classification. HEAT EXCHANGER. A device that transfers heat from one medium to another. HEAT PUMP. A refrigeration system that extracts heat from one substance and transfers it to another portion of the same substance or to a second substance at a higher temperature for a beneficial purpose. HEAT TRANSFER LIQUID. T he operating or thermal storage liquid in a mechanical system, including water or other liquid base, and additives at the concentration present under operating conditions used to move heat from one location to another. Refrigerants are not included as heat transfer liquids. HEAVY - DUTY COOKING APPLIANCE. Heavy - duty cooking appliances include electric under - fired broilers, electric chain (conveyor) broilers, gas under - fired broilers, gas chain (conveyor) broilers, gas open - burner ranges (with or without oven) , electric and gas wok ranges, smokers, smoker ovens, and electric and gas over - fired (upright) broil- ers and salamanders. HIGH - PROBABILITY SYSTEMS. A refrigeration system in which the basic design or the location of components is such that a leakage of ref rigerant from a failed connection, seal or component will enter an occupancy classified area, other than the machinery room. HIGH - SIDE PRESSURE. The parts of a refrigerating system subject to condenser pressure. HOOD. An air - intake device used to capture b y entrapment, impingement, adhesion or similar means, grease, mois- ture, heat and similar contaminants before they enter a duct system. Type I. A kitchen hood for collecting and removing grease vapors and smoke. Such hoods are equipped with a fire suppressi on system. Type II. A general kitchen hood for collecting and removing steam, vapor, heat, odors and products of combustion. HOOD, FUME. A hood used for hazardous exhaust systems. HYDROGEN GENERATING APPLIANCE. A self - contained package or factory - matched p ackages of integrated systems for generating gaseous hydrogen. Hydrogen generating appliances utilize electrolysis, reformation, chemical, or other processes to generate hydrogen. IGNITION SOURCE. A flame, spark or hot surface capable of igniting flammable vapors or fumes. Such sources include appliance burners, burner ignitors and electrical switching devices. IMMEDIATELY DANGEROUS TO LIFE OR HEALTH (IDLH). The concentration of airborne contaminants that poses a threat of death, immediate or delayed perman ent adverse health effects, or effects that could prevent escape from such an environment. This contaminant concentration level is established by the National Institute of Occupational Safety and Health (NIOSH) based on both toxicity and flammability. It i s generally expressed in parts per million by volume (ppm v/v) or milligrams per cubic meter (mg/m 3 ). DEFINITIONS INDIRECT REFRIGERATION SYSTEM. A system in which a secondary coolant cooled or heated by the refrig- erating system is circulated to the air or other substa nce to be cooled or heated. Indirect systems are distinguished by the following methods of application: Closed system. A system in which a secondary fluid is either cooled or heated by the refrigerating system and then circulated within a closed circuit in indirect contact with the air or other substance to be cooled or heated. Double - indirect open - spray system. A system in which the secondary substance for an indirect open - spray system is heated or cooled by an intermediate coolant circulated from a second enclosure. Open - spray system. A system in which a secondary coolant is cooled or heated by the refrigerating system and then circulated in direct contact with the air or other substance to be cooled or heated. Vented closed system. A system in which a secondary coolant is cooled or heated by the refrigerating system and then passed through a closed circuit in the air or other substance to be cooled or heated, except that the evaporator or con - denser is placed in an open or appropriately vented tank. ‡‡‡ INFILTRATION. Uncontrolled inward air leakage to conditioned spaces through unintentional openings in ceil- ings, floors and walls from unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stac k effect created by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. INTEGRAL VENT APPLIANCES. Appliances designed for outdoor installation that have built - in natural or me- chanical venti ng means and are constructed and installed so that all air for combustion is derived from the outdoor atmosphere and all flue gases are discharged to the outdoor atmosphere through an integral vent termination. INTERLOCK. A device actuated by another devic e with which it is directly associated, to govern succeeding oper- ations of the same or allied devices. A circuit in which a given action cannot occur until after one or more other actions have taken place. JOINT, FLANGED. A joint made by bolting together a pair of flanged ends. JOINT, FLARED. A metal - to - metal compression joint in which a conical spread is made on the end of a tube that is compressed by a flare nut against a mating flare. JOINT, MECHANICAL. A connection between pipes, fittings, or pipes and fittings, which is neither screwed, caulked, threaded, soldered, solvent cemented, brazed nor welded. Also, a joint in which compression is applied along the centerline of the pieces being joined. Some joi nts are part of a coupling, fitting or adapter. These joints include both the press - type and push - fit joining systems. JOINT, PLASTIC ADHESIVE. A joint made in thermoset plastic piping by the use of an adhesive substance that forms a continuous bond betwee n the mating surfaces without dissolving either one of them. JOINT, PLASTIC HEAT FUSION. A joint made in thermo - plastic piping by heating the parts sufficiently to permit fusion of the materials when the parts are pressed together. JOINT, PLASTIC SOLVENT C EMENT. A joint made in thermoplastic piping by the use of a solvent or solvent cement that forms a continuous bond between the mating surfaces. JOINT, SOLDERED. A gas - tight joint obtained by the joining of metal parts with metallic mixtures of alloys that melt at temperatures between 400°F (204.4°C ) and 1, 000°F (537.8°C ). JOINT, WELDED. A gas - tight joint obtained by the joining of metal parts in molten state. LIGHT - DUTY COOKING APPLIANCE. Light - duty cooking appliances include gas and electric ovens (includi ng standard , bake, roasting, revolving, retherm, convection, combination convection/steamer, countertop conveyorized baking/finishing, deck and pastry), electric and gas steam - jacketed kettles, electric and gas pasta cookers, electric and gas compartment steamers (both pressure and atmospheric ) and electric and gas cheesemelters. LIMIT CONTROL. A device responsive to changes in pressure , temperature or level for turning on, shutting off or throttling the gas supply to an appliance. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. DEFINITIONS DWELLING UNIT . A single unit consisting of one or more habitable rooms and occupied or arranged to be occu- pied as a unit separate from all other units within a dwelling. ELECTRIC HEATING APPLIANCE. An appliance that produces heat energy to create a warm environment by the application of electric power to resistance elements, refrigerant compressors or dissimilar material junctions. ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air - to - air heat exchangers to recover energy from or reject energy to exhaust ai r for the purpose of preheating, precooling , humidifying or dehumidifying outdoor ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. ENGINEERED SMOKE CONTROL SYSTEM. Refer to Smoke Control System in Sectio n 909 of the New York City Building Code . ENVIRONMENTAL AIR. Air that is conveyed to or from occupied areas through ducts that are not part of the heating or air - conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bath room exhaust, and domestic clothes dryer exhaust. EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for bu ildings. This definition shall also include other systems specifically regulated in this code. EQUIPMENT, EXISTING. Any equipment regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install h as been issued. EVAPORATIVE COOLER. A device used for reducing the sensible heat of air for cooling by the process of evap- oration of water into an airstream. EVAPORATIVE COOLING SYSTEM. The equipment and appliances intended or installed for the purpose of environmental cooling by an evaporative cooler from which the conditioned air is distributed through ducts or plenums to the conditioned area. EVAPORATOR. That part of the system in which liquid refrigerant is vaporized to produce refrigeration. EXCESS AIR. The amount of air provided in addition to theoretical air to achieve complete combustion of a fuel, thereby preventing the formation of dangerous produc ts of combustion . EXFILTRATION. Uncontrolled outward air leakage from conditioned spaces through unintentional openings in ceilings, floors and walls to unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stack effect create d by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. EXHAUST SYSTEM. An assembly of connected ducts, plenums , fittings, registers, grilles and hoods through which air is conducted from a space or spaces and exhausted to the outdoor atmosphere. EXTRA - HEAVY - DUTY COOKING APPLIANCE. Extra - heavy - duty cooking appliances are those utilizing open flame combustion of solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or pa rt of the heat source for cooking at any time. FIELD ERECTED BOILER. A boiler where the pressure vessel is constructed partially or totally in the field. Field erected boilers do not include cast iron sectional boilers that are considered factory built sin ce each section is a separate pressure vessel. FIRE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon detection of heat and to restrict the passage of flame. Fire dampers are classified for use in eit her static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. FIREPLACE. An assembly con sisting of a hearth and fire chamber of noncombustible material and provided with a chimney, for use with solid fuels. A fireplace shall be considered an appliance. Factory - built fireplace. A listed and labeled fireplace and chimney system composed of fact ory - made compo- nents, and assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. DEFINITIONS Masonry fireplace. A hearth and fire chamber of solid masonry units such as bricks, stones, listed masonry units or reinforced concrete, provided with a suitable chimney. FIREPLACE STOVE. A free - standing chimney - connected solid - fuel - burning heater, designed to be operated with the fire chamber doors in either the open or closed position. FLAME SAFEGUARD. A device that will automa tically shut off the fuel supply to a main burner or group of burners when the means of ignition of such burners becomes inoperative, and when flame failure occurs on the burner or group of burners. FLAME SPREAD INDEX. A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84 or UL 723. FLAMMABILITY CLASSIFICATION. Refrigerants shall be assigned to one of the three classes — 1, 2 or 3 — in ac cordance with ASHRAE 34. FLAMMABLE LIQUIDS. Any liquid that has a closed cup flash point below 100°F (37.8°C) , and has a vapor pressure not exceeding 40 psi (275.8 kPa) at 100°F (37.8°C ). Flammable liquids shall be known as Class I liquids and shall be div ided into the following classifications: Class IA. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point below 100°F (37.8°C). Class IB. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point at or above 100°F (37.8°C). Class IC. Liquids having a closed cup flash point at or above 73°F (22.8°C ) and below 100°F (37.8°C ). FLAMMABLE VAPOR OR FUMES. Mixtures of gases in air at concentrations equal to or greater than the LFL an d less than or equal to the upper flammability limit (UFL). FLASH POINT. The minimum temperature at which the application of a test flame causes the vapors of a portion of the sample to ignite under the conditions specified by the test procedures and appar atus . The flash point of a liquid shall be determined in accordance with ASTM D 56, ASTM D 93 or ASTM D 3278. FLEXIBLE AIR CONNECTOR. A conduit for transferring air between an air duct or plenum and an air terminal unit or between an air duct or plenum and an air inlet or air outlet. Such conduit is limited in its use, length and location. FLOOR AREA, NET. The actual occupied area, not including unoccupied accessory areas or thicknesses of walls. FLOOR FURNACE. A completely self - contained furnace suspended from the floor of the space being heated, taking air for combustion from outside such space and with means for observing flames and lighting the appliance from such space. Fan type. A floor furnace equipped with a fan that provides the primary means for ci rculating air. Gravity type. A floor furnace depending primarily on circulation of air by gravity. This classification shall also include floor furnaces equipped with booster - type fans that do not materially restrict free circulation of air by gravity flow when such fans are not in operation. FLUE. A passageway within a chimney or vent through which gaseous combustion products pass. FLUE CONNECTION (BREECHING). A passage for con - ducting the products of combustion from a fuel - fired appliance to the vent or c himney (see also “Chimney connector” and “Vent connector”). FLUE GASES. Products of combustion plus excess air in fireplace and appliance flues, or heat exchangers. FLUE LINER (LINING). A system or material used to form the inside surface of a flue in a ch imney or vent, for the purpose of protecting the surrounding structure from the effects of combustion products and conveying combustion products without leakage to the atmosphere. FUEL GAS. A natural gas, manufactured gas, liquefied petroleum gas or a mixt ure of these gases. FUEL OIL. Kerosene or any hydrocarbon oil having a flash point not less than 100°F (37.8°C). DEFINITIONS FUEL - OIL PIPING SYSTEM. A closed piping system that connects a combustible liquid from a source of supply to a fuel - oil - burning appliance. FURNACE. A completely self - contained heating unit that is designed to supply heated air to spaces remote from or adjacent to the appliance location. FURNACE ROOM. A room primarily utilized for the installation of fuel - burning, s pace - heating and water - heating appliances other than boilers (see also “Boiler room”). FUSIBLE PLUG. A device arranged to relieve pressure by operation of a fusible member at a predetermined tem- perature. GROUND SOURCE HEAT PUMP LOOP SYSTEM. Piping buried i n horizontal or vertical excavations or placed in a body of water for the purpose of transporting heat transfer liquid to and from a heat pump. Included in this definition are closed loop systems in which the liquid is recirculated and open loop systems in which the liquid is drawn from a well or other source. HAZARDOUS LOCATION. Any location considered to be a fire hazar d for flammable vapors, dust, combustible fibers or other highly combustible substances. The location is not necessarily categorized in the New York City Build- ing Code as a high - hazard use group classification. HEAT EXCHANGER. A device that transfers heat from one medium to another. HEAT PUMP. A refrigeration system that extracts heat from one substance and transfers it to another portion of the same substance or to a second substance at a higher temperature for a beneficial purpose. HEAT TRANSFER LIQUID. T he operating or thermal storage liquid in a mechanical system, including water or other liquid base, and additives at the concentration present under operating conditions used to move heat from one location to another. Refrigerants are not included as heat transfer liquids. HEAVY - DUTY COOKING APPLIANCE. Heavy - duty cooking appliances include electric under - fired broilers, electric chain (conveyor) broilers, gas under - fired broilers, gas chain (conveyor) broilers, gas open - burner ranges (with or without oven) , electric and gas wok ranges, smokers, smoker ovens, and electric and gas over - fired (upright) broil- ers and salamanders. HIGH - PROBABILITY SYSTEMS. A refrigeration system in which the basic design or the location of components is such that a leakage of ref rigerant from a failed connection, seal or component will enter an occupancy classified area, other than the machinery room. HIGH - SIDE PRESSURE. The parts of a refrigerating system subject to condenser pressure. HOOD. An air - intake device used to capture b y entrapment, impingement, adhesion or similar means, grease, mois- ture, heat and similar contaminants before they enter a duct system. Type I. A kitchen hood for collecting and removing grease vapors and smoke. Such hoods are equipped with a fire suppressi on system. Type II. A general kitchen hood for collecting and removing steam, vapor, heat, odors and products of combustion. HOOD, FUME. A hood used for hazardous exhaust systems. HYDROGEN GENERATING APPLIANCE. A self - contained package or factory - matched p ackages of integrated systems for generating gaseous hydrogen. Hydrogen generating appliances utilize electrolysis, reformation, chemical, or other processes to generate hydrogen. IGNITION SOURCE. A flame, spark or hot surface capable of igniting flammable vapors or fumes. Such sources include appliance burners, burner ignitors and electrical switching devices. IMMEDIATELY DANGEROUS TO LIFE OR HEALTH (IDLH). The concentration of airborne contaminants that poses a threat of death, immediate or delayed perman ent adverse health effects, or effects that could prevent escape from such an environment. This contaminant concentration level is established by the National Institute of Occupational Safety and Health (NIOSH) based on both toxicity and flammability. It i s generally expressed in parts per million by volume (ppm v/v) or milligrams per cubic meter (mg/m 3 ). DEFINITIONS INDIRECT REFRIGERATION SYSTEM. A system in which a secondary coolant cooled or heated by the refrig- erating system is circulated to the air or other substa nce to be cooled or heated. Indirect systems are distinguished by the following methods of application: Closed system. A system in which a secondary fluid is either cooled or heated by the refrigerating system and then circulated within a closed circuit in indirect contact with the air or other substance to be cooled or heated. Double - indirect open - spray system. A system in which the secondary substance for an indirect open - spray system is heated or cooled by an intermediate coolant circulated from a second enclosure. Open - spray system. A system in which a secondary coolant is cooled or heated by the refrigerating system and then circulated in direct contact with the air or other substance to be cooled or heated. Vented closed system. A system in which a secondary coolant is cooled or heated by the refrigerating system and then passed through a closed circuit in the air or other substance to be cooled or heated, except that the evaporator or con - denser is placed in an open or appropriately vented tank. ‡‡‡ INFILTRATION. Uncontrolled inward air leakage to conditioned spaces through unintentional openings in ceil- ings, floors and walls from unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stac k effect created by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. INTEGRAL VENT APPLIANCES. Appliances designed for outdoor installation that have built - in natural or me- chanical venti ng means and are constructed and installed so that all air for combustion is derived from the outdoor atmosphere and all flue gases are discharged to the outdoor atmosphere through an integral vent termination. INTERLOCK. A device actuated by another devic e with which it is directly associated, to govern succeeding oper- ations of the same or allied devices. A circuit in which a given action cannot occur until after one or more other actions have taken place. JOINT, FLANGED. A joint made by bolting together a pair of flanged ends. JOINT, FLARED. A metal - to - metal compression joint in which a conical spread is made on the end of a tube that is compressed by a flare nut against a mating flare. JOINT, MECHANICAL. A connection between pipes, fittings, or pipes and fittings, which is neither screwed, caulked, threaded, soldered, solvent cemented, brazed nor welded. Also, a joint in which compression is applied along the centerline of the pieces being joined. Some joi nts are part of a coupling, fitting or adapter. These joints include both the press - type and push - fit joining systems. JOINT, PLASTIC ADHESIVE. A joint made in thermoset plastic piping by the use of an adhesive substance that forms a continuous bond betwee n the mating surfaces without dissolving either one of them. JOINT, PLASTIC HEAT FUSION. A joint made in thermo - plastic piping by heating the parts sufficiently to permit fusion of the materials when the parts are pressed together. JOINT, PLASTIC SOLVENT C EMENT. A joint made in thermoplastic piping by the use of a solvent or solvent cement that forms a continuous bond between the mating surfaces. JOINT, SOLDERED. A gas - tight joint obtained by the joining of metal parts with metallic mixtures of alloys that melt at temperatures between 400°F (204.4°C ) and 1, 000°F (537.8°C ). JOINT, WELDED. A gas - tight joint obtained by the joining of metal parts in molten state. LIGHT - DUTY COOKING APPLIANCE. Light - duty cooking appliances include gas and electric ovens (includi ng standard , bake, roasting, revolving, retherm, convection, combination convection/steamer, countertop conveyorized baking/finishing, deck and pastry), electric and gas steam - jacketed kettles, electric and gas pasta cookers, electric and gas compartment steamers (both pressure and atmospheric ) and electric and gas cheesemelters. LIMIT CONTROL. A device responsive to changes in pressure , temperature or level for turning on, shutting off or throttling the gas supply to an appliance. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. DEFINITIONS DWELLING UNIT . A single unit consisting of one or more habitable rooms and occupied or arranged to be occu- pied as a unit separate from all other units within a dwelling. ELECTRIC HEATING APPLIANCE. An appliance that produces heat energy to create a warm environment by the application of electric power to resistance elements, refrigerant compressors or dissimilar material junctions. ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air - to - air heat exchangers to recover energy from or reject energy to exhaust ai r for the purpose of preheating, precooling , humidifying or dehumidifying outdoor ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. ENGINEERED SMOKE CONTROL SYSTEM. Refer to Smoke Control System in Sectio n 909 of the New York City Building Code . ENVIRONMENTAL AIR. Air that is conveyed to or from occupied areas through ducts that are not part of the heating or air - conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bath room exhaust, and domestic clothes dryer exhaust. EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for bu ildings. This definition shall also include other systems specifically regulated in this code. EQUIPMENT, EXISTING. Any equipment regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install h as been issued. EVAPORATIVE COOLER. A device used for reducing the sensible heat of air for cooling by the process of evap- oration of water into an airstream. EVAPORATIVE COOLING SYSTEM. The equipment and appliances intended or installed for the purpose of environmental cooling by an evaporative cooler from which the conditioned air is distributed through ducts or plenums to the conditioned area. EVAPORATOR. That part of the system in which liquid refrigerant is vaporized to produce refrigeration. EXCESS AIR. The amount of air provided in addition to theoretical air to achieve complete combustion of a fuel, thereby preventing the formation of dangerous produc ts of combustion . EXFILTRATION. Uncontrolled outward air leakage from conditioned spaces through unintentional openings in ceilings, floors and walls to unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stack effect create d by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. EXHAUST SYSTEM. An assembly of connected ducts, plenums , fittings, registers, grilles and hoods through which air is conducted from a space or spaces and exhausted to the outdoor atmosphere. EXTRA - HEAVY - DUTY COOKING APPLIANCE. Extra - heavy - duty cooking appliances are those utilizing open flame combustion of solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or pa rt of the heat source for cooking at any time. FIELD ERECTED BOILER. A boiler where the pressure vessel is constructed partially or totally in the field. Field erected boilers do not include cast iron sectional boilers that are considered factory built sin ce each section is a separate pressure vessel. FIRE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon detection of heat and to restrict the passage of flame. Fire dampers are classified for use in eit her static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. FIREPLACE. An assembly con sisting of a hearth and fire chamber of noncombustible material and provided with a chimney, for use with solid fuels. A fireplace shall be considered an appliance. Factory - built fireplace. A listed and labeled fireplace and chimney system composed of fact ory - made compo- nents, and assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. DEFINITIONS Masonry fireplace. A hearth and fire chamber of solid masonry units such as bricks, stones, listed masonry units or reinforced concrete, provided with a suitable chimney. FIREPLACE STOVE. A free - standing chimney - connected solid - fuel - burning heater, designed to be operated with the fire chamber doors in either the open or closed position. FLAME SAFEGUARD. A device that will automa tically shut off the fuel supply to a main burner or group of burners when the means of ignition of such burners becomes inoperative, and when flame failure occurs on the burner or group of burners. FLAME SPREAD INDEX. A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84 or UL 723. FLAMMABILITY CLASSIFICATION. Refrigerants shall be assigned to one of the three classes — 1, 2 or 3 — in ac cordance with ASHRAE 34. FLAMMABLE LIQUIDS. Any liquid that has a closed cup flash point below 100°F (37.8°C) , and has a vapor pressure not exceeding 40 psi (275.8 kPa) at 100°F (37.8°C ). Flammable liquids shall be known as Class I liquids and shall be div ided into the following classifications: Class IA. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point below 100°F (37.8°C). Class IB. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point at or above 100°F (37.8°C). Class IC. Liquids having a closed cup flash point at or above 73°F (22.8°C ) and below 100°F (37.8°C ). FLAMMABLE VAPOR OR FUMES. Mixtures of gases in air at concentrations equal to or greater than the LFL an d less than or equal to the upper flammability limit (UFL). FLASH POINT. The minimum temperature at which the application of a test flame causes the vapors of a portion of the sample to ignite under the conditions specified by the test procedures and appar atus . The flash point of a liquid shall be determined in accordance with ASTM D 56, ASTM D 93 or ASTM D 3278. FLEXIBLE AIR CONNECTOR. A conduit for transferring air between an air duct or plenum and an air terminal unit or between an air duct or plenum and an air inlet or air outlet. Such conduit is limited in its use, length and location. FLOOR AREA, NET. The actual occupied area, not including unoccupied accessory areas or thicknesses of walls. FLOOR FURNACE. A completely self - contained furnace suspended from the floor of the space being heated, taking air for combustion from outside such space and with means for observing flames and lighting the appliance from such space. Fan type. A floor furnace equipped with a fan that provides the primary means for ci rculating air. Gravity type. A floor furnace depending primarily on circulation of air by gravity. This classification shall also include floor furnaces equipped with booster - type fans that do not materially restrict free circulation of air by gravity flow when such fans are not in operation. FLUE. A passageway within a chimney or vent through which gaseous combustion products pass. FLUE CONNECTION (BREECHING). A passage for con - ducting the products of combustion from a fuel - fired appliance to the vent or c himney (see also “Chimney connector” and “Vent connector”). FLUE GASES. Products of combustion plus excess air in fireplace and appliance flues, or heat exchangers. FLUE LINER (LINING). A system or material used to form the inside surface of a flue in a ch imney or vent, for the purpose of protecting the surrounding structure from the effects of combustion products and conveying combustion products without leakage to the atmosphere. FUEL GAS. A natural gas, manufactured gas, liquefied petroleum gas or a mixt ure of these gases. FUEL OIL. Kerosene or any hydrocarbon oil having a flash point not less than 100°F (37.8°C). DEFINITIONS FUEL - OIL PIPING SYSTEM. A closed piping system that connects a combustible liquid from a source of supply to a fuel - oil - burning appliance. FURNACE. A completely self - contained heating unit that is designed to supply heated air to spaces remote from or adjacent to the appliance location. FURNACE ROOM. A room primarily utilized for the installation of fuel - burning, s pace - heating and water - heating appliances other than boilers (see also “Boiler room”). FUSIBLE PLUG. A device arranged to relieve pressure by operation of a fusible member at a predetermined tem- perature. GROUND SOURCE HEAT PUMP LOOP SYSTEM. Piping buried i n horizontal or vertical excavations or placed in a body of water for the purpose of transporting heat transfer liquid to and from a heat pump. Included in this definition are closed loop systems in which the liquid is recirculated and open loop systems in which the liquid is drawn from a well or other source. HAZARDOUS LOCATION. Any location considered to be a fire hazar d for flammable vapors, dust, combustible fibers or other highly combustible substances. The location is not necessarily categorized in the New York City Build- ing Code as a high - hazard use group classification. HEAT EXCHANGER. A device that transfers heat from one medium to another. HEAT PUMP. A refrigeration system that extracts heat from one substance and transfers it to another portion of the same substance or to a second substance at a higher temperature for a beneficial purpose. HEAT TRANSFER LIQUID. T he operating or thermal storage liquid in a mechanical system, including water or other liquid base, and additives at the concentration present under operating conditions used to move heat from one location to another. Refrigerants are not included as heat transfer liquids. HEAVY - DUTY COOKING APPLIANCE. Heavy - duty cooking appliances include electric under - fired broilers, electric chain (conveyor) broilers, gas under - fired broilers, gas chain (conveyor) broilers, gas open - burner ranges (with or without oven) , electric and gas wok ranges, smokers, smoker ovens, and electric and gas over - fired (upright) broil- ers and salamanders. HIGH - PROBABILITY SYSTEMS. A refrigeration system in which the basic design or the location of components is such that a leakage of ref rigerant from a failed connection, seal or component will enter an occupancy classified area, other than the machinery room. HIGH - SIDE PRESSURE. The parts of a refrigerating system subject to condenser pressure. HOOD. An air - intake device used to capture b y entrapment, impingement, adhesion or similar means, grease, mois- ture, heat and similar contaminants before they enter a duct system. Type I. A kitchen hood for collecting and removing grease vapors and smoke. Such hoods are equipped with a fire suppressi on system. Type II. A general kitchen hood for collecting and removing steam, vapor, heat, odors and products of combustion. HOOD, FUME. A hood used for hazardous exhaust systems. HYDROGEN GENERATING APPLIANCE. A self - contained package or factory - matched p ackages of integrated systems for generating gaseous hydrogen. Hydrogen generating appliances utilize electrolysis, reformation, chemical, or other processes to generate hydrogen. IGNITION SOURCE. A flame, spark or hot surface capable of igniting flammable vapors or fumes. Such sources include appliance burners, burner ignitors and electrical switching devices. IMMEDIATELY DANGEROUS TO LIFE OR HEALTH (IDLH). The concentration of airborne contaminants that poses a threat of death, immediate or delayed perman ent adverse health effects, or effects that could prevent escape from such an environment. This contaminant concentration level is established by the National Institute of Occupational Safety and Health (NIOSH) based on both toxicity and flammability. It i s generally expressed in parts per million by volume (ppm v/v) or milligrams per cubic meter (mg/m 3 ). DEFINITIONS INDIRECT REFRIGERATION SYSTEM. A system in which a secondary coolant cooled or heated by the refrig- erating system is circulated to the air or other substa nce to be cooled or heated. Indirect systems are distinguished by the following methods of application: Closed system. A system in which a secondary fluid is either cooled or heated by the refrigerating system and then circulated within a closed circuit in indirect contact with the air or other substance to be cooled or heated. Double - indirect open - spray system. A system in which the secondary substance for an indirect open - spray system is heated or cooled by an intermediate coolant circulated from a second enclosure. Open - spray system. A system in which a secondary coolant is cooled or heated by the refrigerating system and then circulated in direct contact with the air or other substance to be cooled or heated. Vented closed system. A system in which a secondary coolant is cooled or heated by the refrigerating system and then passed through a closed circuit in the air or other substance to be cooled or heated, except that the evaporator or con - denser is placed in an open or appropriately vented tank. ‡‡‡ INFILTRATION. Uncontrolled inward air leakage to conditioned spaces through unintentional openings in ceil- ings, floors and walls from unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stac k effect created by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. INTEGRAL VENT APPLIANCES. Appliances designed for outdoor installation that have built - in natural or me- chanical venti ng means and are constructed and installed so that all air for combustion is derived from the outdoor atmosphere and all flue gases are discharged to the outdoor atmosphere through an integral vent termination. INTERLOCK. A device actuated by another devic e with which it is directly associated, to govern succeeding oper- ations of the same or allied devices. A circuit in which a given action cannot occur until after one or more other actions have taken place. JOINT, FLANGED. A joint made by bolting together a pair of flanged ends. JOINT, FLARED. A metal - to - metal compression joint in which a conical spread is made on the end of a tube that is compressed by a flare nut against a mating flare. JOINT, MECHANICAL. A connection between pipes, fittings, or pipes and fittings, which is neither screwed, caulked, threaded, soldered, solvent cemented, brazed nor welded. Also, a joint in which compression is applied along the centerline of the pieces being joined. Some joi nts are part of a coupling, fitting or adapter. These joints include both the press - type and push - fit joining systems. JOINT, PLASTIC ADHESIVE. A joint made in thermoset plastic piping by the use of an adhesive substance that forms a continuous bond betwee n the mating surfaces without dissolving either one of them. JOINT, PLASTIC HEAT FUSION. A joint made in thermo - plastic piping by heating the parts sufficiently to permit fusion of the materials when the parts are pressed together. JOINT, PLASTIC SOLVENT C EMENT. A joint made in thermoplastic piping by the use of a solvent or solvent cement that forms a continuous bond between the mating surfaces. JOINT, SOLDERED. A gas - tight joint obtained by the joining of metal parts with metallic mixtures of alloys that melt at temperatures between 400°F (204.4°C ) and 1, 000°F (537.8°C ). JOINT, WELDED. A gas - tight joint obtained by the joining of metal parts in molten state. LIGHT - DUTY COOKING APPLIANCE. Light - duty cooking appliances include gas and electric ovens (includi ng standard , bake, roasting, revolving, retherm, convection, combination convection/steamer, countertop conveyorized baking/finishing, deck and pastry), electric and gas steam - jacketed kettles, electric and gas pasta cookers, electric and gas compartment steamers (both pressure and atmospheric ) and electric and gas cheesemelters. LIMIT CONTROL. A device responsive to changes in pressure , temperature or level for turning on, shutting off or throttling the gas supply to an appliance. DEFINITIONS LIMITED CHARGE SYSTEM. A system in which, with the compressor idle, the design pressure will not be ex- ceeded when the refrigerant charge has completely evaporated. LIMITED COMBUSTIBLE MATERIAL. A building construction material not complying with the definition of noncombustible material, which, in the form in which it is used, has a potential heat value not exceeding 3,500 Btu/lb (8141 kj/kg) and complies with the following: Materials, in the form and thickness used, having neit her a flame spread index/rating greater than 25 nor evidence of continued combustion, and of such composition that surfaces that would be exposed by cutting through the material on any place would have neither a flame spread index/rating greater than 25 no r evidence of continued progressive combustion. Materials subject to increase in combustibility or flame spread index/rating beyond the limits herein established through the effects of age, moisture, or other atmospheric condition shall be considered combu stible. LIVING SPACE. Space within a dwelling unit utilized for living , sleeping, eating, cooking, bathing, washing and sanitation purposes. LOWER EXPLOSIVE LIMIT (LEL). See “LFL.” LOWER FLAMMABLE LIMIT (REFRIGERANT) (LFL). The minimum concentration of re frigerant that is ca- pable of propagating a flame through a homogeneous mixture of refrigerant and air. LOWER FLAMMABLE LIMIT (LFL). The minimum concentration of vapor in air at which propagation of flame will occur in the presence of an ignition source. Th e LFL is sometimes referred to as LEL or lower explosive limit. LOW - PROBABILITY SYSTEMS. A refrigeration system in which the basic design or the location of components is such that a leakage of refrigerant from a failed connection, seal or component will n ot enter an occupancy - classified area, other than the machinery room. LOW - SIDE PRESSURE. The parts of a refrigerating system subject to evaporator pressure. MACHINERY ROOM. A room meeting prescribed safety requirements and in which refrigeration systems or com- ponents thereof are located (see Sections 1105 and 1106 of this code, and Section 1006.2.2.2 of the New York City Building Code ). MECHANICAL DRAFT SYSTEM. A venting system designed to remove flue or vent gases by mechanical means that consists of an in duced - draft portion under nonpositive static pressure or a forced - draft portion under positive static pressure. Forced - draft venting system. A portion of a venting system using a fan or other mechanical means to cause the removal of flue or vent gases unde r positive static pressure. Induced - draft venting system. A portion of a venting system using a fan or other mechanical means to cause the removal of flue or vent gases under nonpositive static vent pressure. Power venting system. A portion of a venting sy stem using a fan or other mechanical means to cause the removal of flue or vent gases under positive static vent pressure. MECHANICAL EQUIPMENT/APPLIANCE ROOM. A room or space in which nonfuel - fired mechanical equip- ment and appliances are located. MECHANIC AL EXHAUST SYSTEM. A system for removing air from a room or space by mechanical means. MECHANICAL SYSTEM. A system specifically addressed and regulated in this code and composed of components, devices, appliances and equipment that become part of the build ing . MEDIUM - DUTY COOKING APPLIANCE. Medium - duty cooking appliances include electric discrete element ranges (with or without oven), electric and gas hot - top ranges, electric and gas griddles, electric and gas double - sided griddles, electric and gas fryers (including open deep fat fryers, donut fryers, kettle fryers and pressure fryers), electric and gas conveyor pizza ovens, electric and gas tilting skillets (braising pans) and electric and gas rotisseries. MODULAR BOILER. A steam or hot - wat er - heating assembly consisting of a group of individual boilers called modules intended to be installed as a unit without intervening stop valves. Modules are under one jacket or are indi- vidually jacketed . The individual modules shall be limited to a maxim um input rating of 400,000 Btu/h (117 228 W) gas, 3 gallons per hour (gph) (11.4 L/h) oil, or 115 kW (electric). DEFINITIONS NATURAL DRAFT SYSTEM. A venting system designed to remove flue or vent gases under nonpositive static vent pressure entirely by natural draft. NATURAL VENTILATION. The movement of air into and out of a space through intentionally provided openings, such as windows and doors, or through nonpowered ventilators. NET OCCUPIABLE FLOOR AREA. The floor area of an occupiable space defined by the inside surfaces of its walls but excluding shafts, column enclosures and other permanently enclosed, inaccessible and unoccupiable areas. Obstructions in the space such as furnishings, display or storag e racks and other obstructions, whether temporary or permanent, shall not be deducted from the space area. NONABRASIVE/ABRASIVE MATERIALS. Nonabrasive particulate in high concentrations, moderately abrasive particulate in low and moderate concentrations, a nd highly abrasive particulate in low concentrations, such as alfalfa, asphalt, plaster , gypsum and salt. NONCOMBUSTIBLE MATERIALS. Materials that, when tested in accordance with ASTM E 136, have at least three of four specimens tested meeting all of the f ollowing criteria: 1. The recorded temperature of the surface and interior thermocouples shall not at any time during the test rise more than 54°F (12.2°C ) above the furnace temperature at the beginning of the test. 2. There shall not be flaming from the s pecimen after the first 30 seconds. 3. If the weight loss of the specimen during testing exceeds 50 percent, the recorded temperature of the surface and interior thermocouples shall not at any time during the test rise above the furnace air temperature at the begin - ning of the test, and there shall not be flaming of the specimen . ‡‡‡ OCCUPATIONAL EXPOSURE LIMIT (OEL). The timeweighted average (TWA) concentration for a normal 8 - hour workday and a 40 - hour workweek to which nearly all workers can be repeatedl y exposed without adverse effect, based on the OSHA PEL, ACGIH TLV - TWA, AIHA WEEL, or consistent value. OCCUPIABLE SPACE. An enclosed space intended for human activities, excluding those spaces intended primarily for other purposes, such as storage rooms a nd equipment rooms, that are only intended to be occupied occasionally and for short periods of time. OFFSET (VENT). A combination of approved bends that make two changes in direction bringing one section of the vent out of line but into a line parallel wi th the other section. OUTDOOR AIR. Air taken from the outdoors, and therefore not previously circulated through the system. OUTDOOR OPENING. A door, window, louver or skylight openable to the outdoor atmosphere. OUTLET, GAS. A threaded connection or bolted flange in a piping system to which a gas - burning appliance is attached. PANEL HEATING. A method of radiant space heating in which heat is supplied by large heated areas of room surfaces. The heating element usually consists of warm water piping, warm air ducts, or electrical resistance elements embedded in or located behind ceiling, wall or floor surfaces. PELLET FUEL - BURNING APPLIANCE. A closed - combustion , vented appliance equipped with a fuel - feed mechanism for burning processed pellets of solid fuel of a specified size and composition. PIPING. Where used in this code, “piping” refers to either pipe or tubing, or both. Pipe. A rigid conduit of iron, steel, copper, brass or plastic. Tubing. Semirigid conduit of copper, aluminum, plastic or steel. PLASTIC, THERMOPLASTIC. A plastic that is capable of being repeatedly softened by increase of temperature and hardened by decrease of temperature. PLASTIC, THERMOSETTING. A plastic that is capable of being changed into a substantially infusible or insoluble product when cured under application of heat or chemical means. DEFINITIONS PLENUM. A compartment or chamber located in one story only to which one or more air ducts are connected a nd that forms part of the air supply or return system and may be part of the building construction, such as the concealed space above a ceiling. PORTABLE FUEL CELL APPLIANCE. A fuel cell generator of electricity, which is not fixed in place. A portable fue l cell appliance utilizes a cord and plug connection to a grid - isolated load and has an integral fuel supply. POWER BOILER. See “Boiler.” PREMISES. Land, improvements thereon, or any part thereof. PRESSURE, FIELD TEST. A test performed in the field to prov e system tightness. PRESSURE - LIMITING DEVICE. A pressure - responsive mechanism designed to stop automatically the operation of the pressure - imposing element at a predetermined pressure. PRESSURE RELIEF DEVICE. A pressure - actuated valve or rupture member des igned to relieve excessive pressure automatically. PRESSURE RELIEF VALVE. A pressure - actuated valve held closed by a spring or other means and designed to relieve pressure automatically in excess of the device’s setting. PRESSURE VESSELS. Closed containers , tanks or vessels that are designed to contain liquids or gases, or both, under pressure. PRESSURE VESSELS — REFRIGERANT. Any refrigerant - containing receptacle in a refrigerating system. This does not include evaporators where each separate section does not exceed 0.5 cubic foot (0.014 m 3 ) of refrigerant - containing volume , regardless of the maximum inside dimensions, evaporator coils, controls, headers, pumps and piping. PROTECTIVE ASSEMBLY (REDUCED CLEARANCE). Any noncombustible assembly that is labeled or con- structed in accordance with Table 308.4.2 and is placed between combustible materials or assemblies and mechanical appliances , devices or equipment, for the purpose of reducing required airspace clearances. Protective assemblies attached directly to a combustible assembly shall not be considered as part of that combustible assembly. PURGE. To clear of air, water or other foreign substances. PUSH - FIT JOINTS. A type of mechanical joint consisting of elastomeric seals and corrosion - resistant tube gripper s. The joint is made by pushing the pipe into the joint and allowing the grippers to secure the connection. QUICK - OPENING VALVE. A valve that opens completely by fast action, either manually or automatically con- trolled. A valve requiring one - quarter round turn or less is considered to be quick opening. RADIANT HEATER. A heater designed to transfer heat primarily by direct radiation. READY ACCESS (TO). That which enables a device, fixture, appliance or equipment to be directly reached, without requiring the removal or movement of any panel, door or similar obstruction ( see “Access (to )”). RECEIVER, LIQUID. A vessel permanently connected to a refrigeration system by inlet and outlet pipes for storage of liquid refrigerant. RECIRCULATED AIR. Air removed from a conditioned space and intended for reuse as supply air. RECLAIMED REFRIGERANTS. Refrigerants reproces sed to the same specifications as for new refrigerants by means including distillation. Such refrigerants have been chemically analyzed to verify that the specifications have been met. Reclaiming usually implies the use of processes or procedures that are available only at a reprocessing or manufacturing facility. RECOVERED REFRIGERANTS. Refrigerants removed from a system in any condition without necessarily testing or processing them. RECYCLED REFRIGERANTS. Refrigerants from which contaminants have been re duced by oil separation, re- moval of noncondensable gases, and single or multiple passes through devices that reduce moisture, acidity and DEFINITIONS particulate matter, such as replaceable core filter dryers . These procedures usually are performed at the field job si te or in a local service shop. REFRIGERANT. A substance used for heat transfer in a refrigerating system; the refrigerant absorbs heat and transfers it at a higher temperature and higher pressure, usually with a change of state. REFRIGERANT SAFETY CLASSIF ICATIONS. Groupings that indicate the toxicity and flammability classes in accordance with ASHRAE 34. REFRIGERATED ROOM OR SPACE. A room or space in which an evaporator or brine coil is located for the purpose of reducing or controlling the temperature wit hin the room or space to below 68ºF (20ºC). REFRIGERATING SYSTEM. A combination of interconnected refrigerant - containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat. REFRIGERATIO N MACHINERY ROOM. See “Machinery room.” REFRIGERATION SYSTEM, ABSORPTION. A heat - operated , closed - refrigeration cycle in which a secondary fluid (the absorbent) absorbs a primary fluid (the refrigerant) that has been vaporized in the evaporator. Direct sys tem. A system in which the evaporator is in direct contact with the material or space refrigerated, or is located in air - circulating passages communicating with such spaces. Indirect system. A system in which a brine coil cooled by the refrigerant is circu lated to the material or space refrigerated , or is utilized to cool the air so circulated. Indirect systems are distinguished by the type or method of application. REFRIGERATION SYSTEM CLASSIFICATION. Refrigeration systems are classified according to the d egree of probability that leaked refrigerant from a failed connection, seal or component will enter an occupied area. The distinction is based on the basic design or location of the components. REFRIGERATION SYSTEM, MECHANICAL. A combi - nation of interconne cted refrigeration - containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat and in which a compressor is used for compressing the refrigerant vapor. REFRIGERATION SYSTEM, SELF - CONT AINED. A complete factory - assembled and tested system that is shipped in one or more sections and that does not have refrigerant - containing parts that are joined in the field by other than companion or block valves. RETURN AIR SYSTEM. An assembly of connec ted ducts, plenums, fittings, registers and grilles through which return air from the space or spaces to be heated or cooled is conducted back to the supply unit or relieved to the outdoors (see also “Supply air system”). ROOM HEATER, VENTED. A free - standi ng heating unit burning solid or liquid fuel for direct heating of the space in and adjacent to that in which the unit is located. SAFETY VALVE. A valve that relieves pressure in a steam boiler by opening fully at the rated discharge pressure. The valve is of the spring - pop type. SELF - CONTAINED EQUIPMENT. Complete, factory - assembled and tested, heating, air - conditioning or refriger- ation equipment installed as a single unit, and having all working parts, complete with motive power, in an enclosed unit of sai d machinery. SHAFT. An enclosed space extending through one or more stories of a building, connecting vertical openings in successive floors, or floors and the roof. SHAFT ENCLOSURE. The walls or construction forming the boundaries of a shaft. SLEEPING UNIT. A dwelling unit, which may contain either toilet or kitchen facilities but not both. Any sleeping unit housing more than one family shall also be classified as a congregate living unit. The creation of or conversion to sleeping units shall b e limited by Section 27 - 2077 of the New York City Housing Maintenance Code . DEFINITIONS SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to resist the passage of air and smoke. The device is installed to operate automatically, contro lled by a smoke detection system, and where re- quired, is capable of being positioned from a fire command center. SMOKE - DEVELOPED INDEX. A comparative measure, expressed as a dimensionless number, derived from meas- urements of smoke obscuration versus time for a material tested in accordance with ASTM E 84. SOLID FUEL (COOKING APPLICATIONS). Applicable to commercial food service operations only, solid fuel is any bulk material such as hardwood, mesquite, charcoal or briquettes that is combusted to produ ce heat for cooking operations. SOURCE CAPTURE SYSTEM. A mechanical exhaust system designed and constructed to capture air contaminants at their source and to exhaust such contaminants to the outdoor atmosphere. STATIONARY FUEL CELL POWER PLANT. A self - con tained package or factory - matched package that consti- tute an automatically operated assembly of integrated systems for generating useful electrical energy and recoverable thermal energy that is permanently connected and fixed in place. STOP VALVE. A shutof f valve for controlling the flow of liquid or gases. STORY. That portion of a building included between the upper surface of a floor and the upper surface of the floor next above, except that the topmost story shall be that portion of a building included b etween the upper surface of the topmost floor and the ceiling or roof above. STRENGTH, ULTIMATE. The highest stress level that the component will tolerate without rupture. SUPPLY AIR. That air delivered to each or any space supplied by the air distribution system or the total air delivered to all spaces supplied by the air distribution system, which is provided for ventilating, heating, cooling, humidification, dehumidification and other similar purposes. SUPPLY AIR SYSTEM. An assembly of connected ducts, p lenums, fittings, registers and grilles through which air, heated or cooled, is conducted from the supply unit to the space or spaces to be heated or cooled (see also “Return air system”). THEORETICAL AIR. The exact amount of air required to supply oxygen for complete combustion of a given quan- tity of a specific fuel. THERMAL RESISTANCE (R). A measure of the ability to retard the flow of heat. The R - value is the reciprocal of thermal conductance. THIRD - PARTY CERTIFICATION AGENCY. An approved agency operatin g a product or material certification system that incorporates initial product testing, assessment and surveillance of a manufacturer’s quality control sys- tem. THIRD - PARTY CERTIFIED. Certification obtained by the manufacturer indicating that the function a nd perfor- mance characteristics of a product or material have been determined by testing and ongoing surveillance by an ap- proved third - party certification agency. Assertion of certification is in the form of identification in accordance with the requirement s of the third - party certification agency. THIRD - PARTY TESTED. Procedure by which an approved testing laboratory provides documentation that a prod- uct, material or system conforms to specified requirements. THRESHOLD LIMIT VALUE - TIME WEIGHTED AVERAGE (TLV - TWA). The time - weighted average con- centration of a refrigerant or other chemical in air for a normal 8 - hour workday and a 40 - hour workweek, to which nearly all workers are repeatedly exposed, day after day, without adverse effects, as adopted by the Americ an Confer- ence of Government Industrial Hygienists (ACGIH). TOILET ROOM. A room containing a water closet and, frequently , a lavatory, but not a bathtub, shower, spa or similar bathing fixture. TOXICITY CLASSIFICATION. Refrigerants shall be classified for t oxicity in one of two classes in accordance with ASHRAE 34. ‡‡‡ Chapter 2 was amended by Local Law 77 of 2023 . This law has an effective date of June 10, 2023. CHAPTER 2 DEFINITIONS SECTION MC 201 GENERAL 201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter. 201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular. 201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the New York City Building Code , the New York City Electrical Code , the New York City Fire Code , the New York City Fuel Gas Code , the New York City Plumbing Code , or the New York City Energy Conse rvation Code, such terms shall have meanings ascribed to them as in those codes. ‡‡‡ 201.3.1 Terms defined in the general administrative provisions. The following terms are defined in Section 28 - 101.5 of the Administrative Code : 1968 BUILDING CODE. 1968 OR PRIOR CODE BUILDINGS OR STRUCTURES (PRIOR CODE BUILDINGS). ACCEPTANCE OR ACCEPTED. ADDITION. ADMINISTRATIVE CODE. ALTERATION. APPROVAL OR APPROVED. APPROVED AGENCY. APPROVED FABRICATOR. APPROVED INSPECTION AGENCY. APPROVED TESTING AGENCY. ARCHITECT. BUILDING. CHARTER. CERTIFICATE OF COMPLIANCE. CITY. COMMISSIONER. CONSTRUCTION DOCUMENTS. DEFINITIONS DAY. DEFERRED SUBMITTAL. DEMOLITION. DEMOLITION, FULL. DEMOLITION, PARTIAL. DEPARTMENT. ENGINEER. ENLARGEMENT. ENVIRONMENTAL CONTROL BOARD or ECB. EXISTING BUILDING OR STRUCTURE. FABRICATED ITEM. FIRE PROTECTION PLAN. HEREAFTER. HERETOFORE. INSPECTION CERTIFICATE. INTERIM CERTIFICATE OF OCCUPANCY. LA BEL. LABELED. LAND SURVEYOR. LANDSCAPE ARCHITECT. LETTER OF COMPLETION. LIMITED ALTERATION APPLICATION. LIMITED PLUMBING ALTERATIONS. LIMITED SPRINKLER ALTERATIONS. LIMITED STANDPIPE ALTERATIONS. LISTED. MAIN USE OR DOMINANT OCCUPANCY (OF A BUILDING). MANUFACTURER’S DESIGNATION. MARK. MATERIALS. OCCUPANCY. OWNER. PARTY WALL. PERMIT. DEFINITIONS PERSON. PREMISES. PRIOR CODE BUILDING. PROFESSIONAL CERTIFICATION. PROGRESS INSPECTION. PROJECT. REGISTERED DESIGN PROFESSIONAL. REGISTERED DESIGN PROFESSIONAL OF RECORD. REQUIRED. RETAINING WALL. SERVICE EQUIPMENT. SIGN - OFF. SINGLE ROOM OCCUPANCY MULTIPLE DWELLING. SPECIAL INSPECTION. SPECIAL INSPECTION AGENCY. SPECIAL INSPEC TOR. STRUCTURE. SUBMITTAL DOCUMENTS. SUPERINTENDENT OF CONSTRUCTION (CONSTRUCTION SUPERINTENDENT). USE (USED). UTILITY COMPANY OR PUBLIC UTILITY COMPANY. UTILITY CORPORATION OR PUBLIC UTILITY CORPORATION. WORK NOT CONSTITUTIN G MINOR ALTERATIONS OR ORDINARY REPAIRS. WRITING (WRITTEN). WRITTEN NOTICE. ZONING RESOLUTION. 201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. ‡‡‡ SECTION MC 202 GENERAL DEFINITIONS DEFINITIONS ABRASIVE MATERIALS. Moderately abrasive particulate in high concentrations, and highly abrasive particulate in moderate and high concentrations, such as alumina, bauxite, iron sili cate, sand and slag. ABSORPTION SYSTEM. A refrigerating system in which refrigerant is pressurized by pumping a chemical solution of refrigerant in absorbent, and then separated by the addition of heat in a generator, condensed (to reject heat), ex- panded, evaporated (to provide refrigeration), and reabsorbed in an absorber to repeat the cycle; the system may be single or multiple effect, the latter using multiple stages or internally cascaded use of heat to improve efficiency. ACCESS (TO). That which enable s a device, fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction ( see also “Ready access (t o)”). AIR. All air supplied to mechanical equipment and ap pliances for combustion, ventilation, cooling and similar pur- poses. Standard air is air at standard temperature and pressure, namely, 70°F (21.1°C ) and 29.92 inches of mercury (101.3 kPa). AIR CONDITIONING. The treatment of air so as to control simultaneou sly the temperature, humidity, cleanness and distribution of the air to meet the requirements of a conditioned space. AIR - CONDITIONING SYSTEM. A system that consists of heat exchangers, blowers, filters, supply, exhaust and return ducts, and shall include any apparatus installed in connection therewith. AIR DISPERSION SYSTEM. Any diffuser system designed to both convey air within a room, space or area and diffuse air into that space while operating under positive pressure. Systems are commonly constructed o f, but not limited to, fabric or plastic film. AIR DISTRIBUTION SYSTEM. Any system of ducts, plenums and air - handling equipment that circulates air within a space or spaces and includes systems made up of one or more air - handling units. AIR, EXHAUST. Air b eing removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. AIR, INTAKE. Air supplied from the outdoors to any space, appliance or piece of equipment. AIR - HANDLING UNIT. A blower or fan used for the purpose of distributing supply air to a room, space or area. AIR, MAKEUP. Any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. AIR, RELIEF. Air removed from any space, appliance or piece of equipment that serves to balance building pres- surization due to introduction of outdoor air. Exhaust air shall not be considered relief air. AIR, RETURN. Air removed from a conditioned space or location and recirculated or relieved to the outdoors. AIR, TRANSFER. Air moved from one indoor space to another. AIR TRANSFER OPENING. An ope ning designed to allow the movement of environmental air between two con- tiguous spaces. APPLIANCE. A device or apparatus that is manufactured and designed to utilize energy and for which this code provides specific requirements. APPLIANCE, EXISTING. Any ap pliance regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install has been issued. APPLIANCE, FUEL - FIRED. An appliance that burns solid, liquid and/or gaseous fuel, including but not limite d to wood stoves, household cooking ranges, furnaces, boilers, water heaters, clothes dryers and gas - fired refrigerators. APPLIANCE, GAS (EQUIPMENT). Any apparatus or equipment that uses gas as a fuel or raw material to produce light, heat, power, refriger ation or air conditioning. APPLIANCE TYPE. DEFINITIONS High - heat appliance. Any appliance in which the products of combustion at the point of entrance to the flue under nor - mal operating conditions have a temperature greater than 2, 000°F (1093.3°C ). Low - heat appliance (residential appliance). Any appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1, 000°F (537.8°C ) or less. Medium - heat appliance. Any appliance in which the prod - ucts of combustion at the point of entrance to the flue under normal operating conditions have a temperature of more than 1, 000°F (537.8°C ), but not greater than 2, 000°F (1093.3°C). APPLIANCE, VENTED. An appliance designed and installed in such a manner that all of the products of combustion are conveyed directly from the appliance to the outdoor atmosphere through an approved chimney or vent system. AUTOMATIC BOILER. Any class of boiler that is equipped with the co ntrols and limit devices specified in Chapter 10. BATHROOM. A room containing a bathtub, shower, spa or similar bathing fixture. BOILER, HIGH - PRESSURE. An appliance for supplying steam or hot water that, for a steam boiler, operates at a pressure of more than 15 psig (103.4 kPa gauge), and for a hot water boiler, operates at a pressure exceeding 160 psig (1103.2 kPa gauge) or at a temperature exceeding 250°F (121.1°C). BOILER, LOW - PRESSURE. A self - contained appliance for supplying steam or hot water as fol lows: Hot water heating boiler. A boiler in which no steam is generated, from which hot water is circulated for heating purposes and then returned to the boiler, and that operates at water pressures not exceeding 160 pounds per square inch gauge (psig) (11 03.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet. Hot water supply boiler. A boiler, completely filled with water, which furnishes hot water to be used externally to itself, and that operates at water pre ssures not exceeding 160 psig (1103.2 kPa gauge) and at water temperatures not exceeding 250°F (121.1°C) at or near the boiler outlet . Steam heating boiler. A boiler in which steam is generated and that operates at a steam pressure not exceeding 15 psig (1 03.4 kPa gauge). BOILER ROOM. A room primarily utilized for the installation of a boiler. BRAZED JOINT. A gas - tight joint obtained by the joining of metal parts with metallic mixtures or alloys that melt at a temperature above 1, 000°F (537.8°C ), but lower than the melting temperature of the parts to be joined. BRAZING. A metal - joining process wherein coalescence is produced by the use of a nonferrous filler metal having a melting point above 1, 000°F (537.8°C ), but lower than that of the base metal being joi ned. The filler material is distributed between the closely fitted surfaces of the joint by capillary attraction. BREATHING ZONE. The region within an occupied space between planes 3 and 72 inches (76.2 and 1828.8 mm) above the floor and more than 2 feet ( 609.6 mm) from the walls of the space or from fixed air - conditioning equipment. BTU. Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (453.6 g) of water 1°F ( - 17.22°C ) (1 Btu = 1055 J). CEILING RADIATION DAMPER. A listed device installed in a ceiling membrane of a fire - resistance - rated floor/ceiling or roof/ceiling assembly to limit automatically the radiative heat transfer through an air inlet/outlet open- ing. CHIMNEY. A primarily vertic al structure containing one or more flues used to remove products of combustion from fuel - burning appliances, refuse incineration, or industrial processes. Factory - built chimney. A listed and labeled chimney com - posed of factory - made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. Masonry chimney. A field - constructed chimney composed of solid masonry units, bricks, stones or concrete. Metal chimney. A field - constructed chimney composed of metal. DEFINITIONS CHIMNEY CONNECTOR. A pipe that connects a fuel - burning appliance to a chimney. CLEARANCE. The minimum distance through air measured between the heat - producing surface of the mechanical appliance, device or equipment and the surface of the combustibl e material or assembly. CLOSED COMBUSTION SOLID FUEL - BURNING APPLIANCE. A heat - producing appliance that employs a combustion chamber that does not have openings other than the flue collar, fuel charging door and adjustable openings provided to control the amount of combustion air that enters the combustion chamber. CLOTHES DRYER. An appliance used to dry wet laundry by means of heat. COMBINATION FIRE/SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, be controlled by a smoke detection system, and where required, is capable of being positioned from a fire command center. COMBUSTIBLE AS SEMBLY. Wall, floor, ceiling or other assembly constructed of one or more component mate- rials that are not defined as noncombustible. COMBUSTIBLE LIQUID. For the purposes of transportation, a combustible liquid as defined in the regulations of the United S tates Department of Transportation, as set forth in 49 CFR 173.120. For all other purposes, a liquid, other than a compressed gas or cryogenic fluid, having a closed cup flash point at or above 100°F (37.8°C) classified as follows: Class II. Liquids having a closed cup flash point at or above 100°F (37.8°C) and below 140°F (60°C). Class IIIA. Liquids having a closed cup flash point at or above 140°F (60°C) and below 200°F (93.3°C). Class IIIB. Liquids having a closed cup flash point at or above 200°F (93. 3°C ). COMBUSTIBLE MATERIAL. Any material not defined as noncombustible. COMBUSTION. In the context of this code, refers to the rapid oxidation of fuel accompanied by the production of heat or heat and light. COMBUSTION AIR. Air necessary for complete combustion of a fuel, including theoretical air and excess air. COMBUSTION CHAMBER. The portion of an appliance within which combustion occurs. COMBUSTION PRODUCTS. Constituents resulting from the combustion of a fuel with the oxygen of the air, in- cluding the inert gases, but excluding excess air. COMMERCIAL COOKING APPLIANCES. Appliances used in a commercial food service establishment for heat- ing or cooking food and which produce grease vapors, steam, fumes, smoke or odors that are required to be removed through a local exhaust ventilation system. Such appliances include deep fat fryers; upright broilers; griddles; broilers; steam - jacketed kettles; hot - top ranges; under - fired broilers (charbroilers); ovens; barbeques ; rotisseries; and similar appliances. For the purpose of this definition, a food service establishment shall include any building or a portion thereof used for the preparation and serving of food. COMMERCIAL COOKING RECIRCULATING SYSTEM. Self - contained system consisting of the exhaust hood, the cooking equipment, the filters and the fire suppression system . The system is designed to capture cooking vapors and res - idues generated from commercial cooking equipment. The system removes contaminants from the exhaust air and recirculates the air to the space from which it was withdrawn. COMMERCIAL KITCHEN EXHAUST HOODS. Backshelf hood. A backshelf hood is also referred to as a low - proximity hood, or as a sidewall hood where wall mounted. Its front lower lip is low over the appliance(s) and is “set back” from the front of the appliance(s). It is always closed to the rear of the appliances by a panel where free - standing, or by a panel or wall where wall mounted, and its height above the cooking surface varies. (This style of hood can be constructed with partial end panels to increase its effectiveness in capturing the effluent generated by the cooking operation). Double island canopy hood. A double island canopy hood is placed over back to back appl iances or appliance lines. It is open on all sides and overhangs both fronts and the sides of the appliance(s). It could have a wall panel between the backs of the appliances. (The fact that exhaust air is drawn from both sides of the double canopy to DEFINITIONS meet in the center causes each side of this hood to emulate a wall canopy hood, and thus it functions much the same with or without an actual wall panel between the backs of the appliances). Eyebrow hood. An eyebrow hood is mounted directly to the face of an a ppliance, such as an oven and dishwasher, above the opening(s) or door(s) from which effluent is emitted , extending past the sides and overhanging the front of the opening to capture the effluent. Pass - over hood. A pass - over hood is a free - standing form of a backshelf hood constructed low enough to pass food over the top. Single island canopy hood. A single island canopy hood is placed over a single appliance or appliance line. It is open on all sides and overhangs the front, rear and sides of the appliance (s). A single island canopy is more sus- ceptible to cross drafts and requires a greater exhaust air flow than an equivalent sized wall - mounted canopy to capture and contain effluent generated by the cooking operation(s). Wall canopy hood. A wall canopy hood is mounted against a wall above a single appliance or line of appliance(s), or it could be free - standing with a back panel from the rear of the appliances to the hood. It overhangs the front and sides of the appliance(s) on all open sides. The wall acts a s a back panel, forcing the makeup air to be drawn across the front of the cooking equipment, thus increasing the effectiveness of the hood to capture and contain effluent generated by the cooking operation(s). COMPENSATING HOODS. Compensating hoods are th ose having integral (built - in) makeup air supply. The makeup air supply for such hoods is generally supplied from: short - circuit flow from inside the hood, air curtain flow from the bottom of the front face, and front face discharge from the outside front wall of the hood. The compensating makeup airflow can also be supplied from the rear or side of the hood, or the rear, front or sides of the cooking equipment. The makeup air flow can be one or a combination of methods. COMPRESSOR. A specific machine, with or without accessories, for compressing a gas. COMPRESSOR, POSITIVE DISPLACEMENT. A compressor in which increase in pressure is attained by chang- ing the internal volume of the compression chamber. COMPRESSOR UNIT. A compressor with its prime mover and acc essories. CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finished surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed. CONDENSAT E. The liquid that condenses from a gas (including flue gas) caused by a reduction in temperature or increase in pressure . CONDENSER. A heat exchanger designed to liquefy refrigerant vapor by removal of heat. CONDENSING UNIT. A specific refrigerating machi ne combination for a given refrigerant, consisting of one or more power - driven compressors, condensers and, where required, liquid receivers, and the regularly furnished acces- sories. CONDITIONED SPACE. An area or room within a building that is within the t hermal envelope of a building that is directly or indirectly heated or cooled using fossil fuel or electricity as the energy source. Spaces that are indirectly heated or cooled where they communicate through openings with conditioned spaces, where they are separated from conditioned spaces by uninsulated walls, floors or ceilings, or where they contain uninsulated ducts, piping or other sources of heating or cooling using fossil fuel or electricity. CONFINED SPACES. A space having a volume less than 50 cubi c feet per 1,000 British thermal units per hour (Btu/h) (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. CONTROL. A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system. CONVERSION BURNER. A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. COOKING APPLIANCE. See “Commercial cooking appliances.” DEFINITIONS DAMPER. A manua lly or automatically controlled device to regulate draft or the rate of flow of air or combustion gases. Volume damper. A device that will restrict, retard or direct the flow of air in a duct, or the products of combustion in a heat - producing appliance, its vent connector, vent or chimney therefrom. DECORATIVE SHROUD. A listed, partial, noncombustible enclosure for aesthetic purposes that is installed at the termination of a venting system that surrounds or conceals a factory - built chimney system or vent ca p. DESIGN FLOOD ELEVATION. Refer to Section G201.2 of Appendix G of the New York City Building Code . DESIGN WORKING PRESSURE. The maximum allowable working pressure for which a specific part of a system is designed. DIRECT REFRIGERATION SYSTEM. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated. DIRECT - VENT APPLIANCES. Appliances that are constructed and installed so that all air for combustion is de- rived directly from the outdoor atmosphere and all flue gases are discharged directly to the outdoor atmosphere. DISCRETE PRODUCT. Products that are non - con tinuous, individual, distinct pieces such as, but not limited to, electrical, plumbing and mechanical products and duct straps, duct fittings, duct registers and pipe hangers. DRAFT. The pressure difference existing between the appliance or any component part and the atmosphere, that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmos- phere. Induced draft. The pressure difference created by the action of a fan, blower or ejector, that is located b etween the appliance and the chimney or vent termination. Natural draft. The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere. DRIP. The container placed at a l ow point in a system of piping to collect condensate and from which the condensate is removable. DRY CLEANING SYSTEMS. Dry cleaning plants or systems are classified as follows: Type I. Those systems using Class I flammable liquid solvents having a flash po int below 100°F (37.8°C). Type II. Those systems using Class II combustible liquid solvents having a flash point at or above 100°F (37.8°C ) and below 140°F (60°C). Type III. Those systems using Class III combustible liquid solvents having a flash point at or above 140°F (60°C ). Types IV and V. Those systems using Class IV nonflammable liquid solvents. DUCT. A tube or conduit utilized for conveying air. The air passages of sel f- contained systems are not to be construed as air ducts. DUCT FURNACE. A warm - air furnace or heater normally installed in an air distribution duct to supply warm air for heating. This definition shall apply only to a warm - air heating appliance that, for a ir circulation, depends on a blower not furnished as part of the furnace. DUCT SYSTEM. A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans and accessory air - handling equipment and a ppliances. DUCTLESS MINI - SPLIT SYSTEM. A heating and cooling system that is comprised of one or multiple indoor evaporator/air - handling units and an outdoor condensing unit that is connected by refrigerant piping and electrical wiring. A ductless mini - spli t system is capable of cooling or heating one or more rooms without the use of a traditional ductwork system. DWELLING. A building or structure that is occupied in whole or in part as the home, residence or sleeping place of one or more families. DEFINITIONS DWELLING UNIT . A single unit consisting of one or more habitable rooms and occupied or arranged to be occu- pied as a unit separate from all other units within a dwelling. ELECTRIC HEATING APPLIANCE. An appliance that produces heat energy to create a warm environment by the application of electric power to resistance elements, refrigerant compressors or dissimilar material junctions. ENERGY RECOVERY VENTILATION SYSTEM. Systems that employ air - to - air heat exchangers to recover energy from or reject energy to exhaust ai r for the purpose of preheating, precooling , humidifying or dehumidifying outdoor ventilation air prior to supplying such air to a space, either directly or as part of an HVAC system. ENGINEERED SMOKE CONTROL SYSTEM. Refer to Smoke Control System in Sectio n 909 of the New York City Building Code . ENVIRONMENTAL AIR. Air that is conveyed to or from occupied areas through ducts that are not part of the heating or air - conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bath room exhaust, and domestic clothes dryer exhaust. EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for bu ildings. This definition shall also include other systems specifically regulated in this code. EQUIPMENT, EXISTING. Any equipment regulated by this code that was legally installed prior to the effective date of this code, or for which a permit to install h as been issued. EVAPORATIVE COOLER. A device used for reducing the sensible heat of air for cooling by the process of evap- oration of water into an airstream. EVAPORATIVE COOLING SYSTEM. The equipment and appliances intended or installed for the purpose of environmental cooling by an evaporative cooler from which the conditioned air is distributed through ducts or plenums to the conditioned area. EVAPORATOR. That part of the system in which liquid refrigerant is vaporized to produce refrigeration. EXCESS AIR. The amount of air provided in addition to theoretical air to achieve complete combustion of a fuel, thereby preventing the formation of dangerous produc ts of combustion . EXFILTRATION. Uncontrolled outward air leakage from conditioned spaces through unintentional openings in ceilings, floors and walls to unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stack effect create d by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. EXHAUST SYSTEM. An assembly of connected ducts, plenums , fittings, registers, grilles and hoods through which air is conducted from a space or spaces and exhausted to the outdoor atmosphere. EXTRA - HEAVY - DUTY COOKING APPLIANCE. Extra - heavy - duty cooking appliances are those utilizing open flame combustion of solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or pa rt of the heat source for cooking at any time. FIELD ERECTED BOILER. A boiler where the pressure vessel is constructed partially or totally in the field. Field erected boilers do not include cast iron sectional boilers that are considered factory built sin ce each section is a separate pressure vessel. FIRE DAMPER. A listed device installed in ducts and air transfer openings designed to close automatically upon detection of heat and to restrict the passage of flame. Fire dampers are classified for use in eit her static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. FIREPLACE. An assembly con sisting of a hearth and fire chamber of noncombustible material and provided with a chimney, for use with solid fuels. A fireplace shall be considered an appliance. Factory - built fireplace. A listed and labeled fireplace and chimney system composed of fact ory - made compo- nents, and assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing. DEFINITIONS Masonry fireplace. A hearth and fire chamber of solid masonry units such as bricks, stones, listed masonry units or reinforced concrete, provided with a suitable chimney. FIREPLACE STOVE. A free - standing chimney - connected solid - fuel - burning heater, designed to be operated with the fire chamber doors in either the open or closed position. FLAME SAFEGUARD. A device that will automa tically shut off the fuel supply to a main burner or group of burners when the means of ignition of such burners becomes inoperative, and when flame failure occurs on the burner or group of burners. FLAME SPREAD INDEX. A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84 or UL 723. FLAMMABILITY CLASSIFICATION. Refrigerants shall be assigned to one of the three classes — 1, 2 or 3 — in ac cordance with ASHRAE 34. FLAMMABLE LIQUIDS. Any liquid that has a closed cup flash point below 100°F (37.8°C) , and has a vapor pressure not exceeding 40 psi (275.8 kPa) at 100°F (37.8°C ). Flammable liquids shall be known as Class I liquids and shall be div ided into the following classifications: Class IA. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point below 100°F (37.8°C). Class IB. Liquids having a closed cup flash point below 73°F (22.8°C ) and a boiling point at or above 100°F (37.8°C). Class IC. Liquids having a closed cup flash point at or above 73°F (22.8°C ) and below 100°F (37.8°C ). FLAMMABLE VAPOR OR FUMES. Mixtures of gases in air at concentrations equal to or greater than the LFL an d less than or equal to the upper flammability limit (UFL). FLASH POINT. The minimum temperature at which the application of a test flame causes the vapors of a portion of the sample to ignite under the conditions specified by the test procedures and appar atus . The flash point of a liquid shall be determined in accordance with ASTM D 56, ASTM D 93 or ASTM D 3278. FLEXIBLE AIR CONNECTOR. A conduit for transferring air between an air duct or plenum and an air terminal unit or between an air duct or plenum and an air inlet or air outlet. Such conduit is limited in its use, length and location. FLOOR AREA, NET. The actual occupied area, not including unoccupied accessory areas or thicknesses of walls. FLOOR FURNACE. A completely self - contained furnace suspended from the floor of the space being heated, taking air for combustion from outside such space and with means for observing flames and lighting the appliance from such space. Fan type. A floor furnace equipped with a fan that provides the primary means for ci rculating air. Gravity type. A floor furnace depending primarily on circulation of air by gravity. This classification shall also include floor furnaces equipped with booster - type fans that do not materially restrict free circulation of air by gravity flow when such fans are not in operation. FLUE. A passageway within a chimney or vent through which gaseous combustion products pass. FLUE CONNECTION (BREECHING). A passage for con - ducting the products of combustion from a fuel - fired appliance to the vent or c himney (see also “Chimney connector” and “Vent connector”). FLUE GASES. Products of combustion plus excess air in fireplace and appliance flues, or heat exchangers. FLUE LINER (LINING). A system or material used to form the inside surface of a flue in a ch imney or vent, for the purpose of protecting the surrounding structure from the effects of combustion products and conveying combustion products without leakage to the atmosphere. FUEL GAS. A natural gas, manufactured gas, liquefied petroleum gas or a mixt ure of these gases. FUEL OIL. Kerosene or any hydrocarbon oil having a flash point not less than 100°F (37.8°C). DEFINITIONS FUEL - OIL PIPING SYSTEM. A closed piping system that connects a combustible liquid from a source of supply to a fuel - oil - burning appliance. FURNACE. A completely self - contained heating unit that is designed to supply heated air to spaces remote from or adjacent to the appliance location. FURNACE ROOM. A room primarily utilized for the installation of fuel - burning, s pace - heating and water - heating appliances other than boilers (see also “Boiler room”). FUSIBLE PLUG. A device arranged to relieve pressure by operation of a fusible member at a predetermined tem- perature. GROUND SOURCE HEAT PUMP LOOP SYSTEM. Piping buried i n horizontal or vertical excavations or placed in a body of water for the purpose of transporting heat transfer liquid to and from a heat pump. Included in this definition are closed loop systems in which the liquid is recirculated and open loop systems in which the liquid is drawn from a well or other source. HAZARDOUS LOCATION. Any location considered to be a fire hazar d for flammable vapors, dust, combustible fibers or other highly combustible substances. The location is not necessarily categorized in the New York City Build- ing Code as a high - hazard use group classification. HEAT EXCHANGER. A device that transfers heat from one medium to another. HEAT PUMP. A refrigeration system that extracts heat from one substance and transfers it to another portion of the same substance or to a second substance at a higher temperature for a beneficial purpose. HEAT TRANSFER LIQUID. T he operating or thermal storage liquid in a mechanical system, including water or other liquid base, and additives at the concentration present under operating conditions used to move heat from one location to another. Refrigerants are not included as heat transfer liquids. HEAVY - DUTY COOKING APPLIANCE. Heavy - duty cooking appliances include electric under - fired broilers, electric chain (conveyor) broilers, gas under - fired broilers, gas chain (conveyor) broilers, gas open - burner ranges (with or without oven) , electric and gas wok ranges, smokers, smoker ovens, and electric and gas over - fired (upright) broil- ers and salamanders. HIGH - PROBABILITY SYSTEMS. A refrigeration system in which the basic design or the location of components is such that a leakage of ref rigerant from a failed connection, seal or component will enter an occupancy classified area, other than the machinery room. HIGH - SIDE PRESSURE. The parts of a refrigerating system subject to condenser pressure. HOOD. An air - intake device used to capture b y entrapment, impingement, adhesion or similar means, grease, mois- ture, heat and similar contaminants before they enter a duct system. Type I. A kitchen hood for collecting and removing grease vapors and smoke. Such hoods are equipped with a fire suppressi on system. Type II. A general kitchen hood for collecting and removing steam, vapor, heat, odors and products of combustion. HOOD, FUME. A hood used for hazardous exhaust systems. HYDROGEN GENERATING APPLIANCE. A self - contained package or factory - matched p ackages of integrated systems for generating gaseous hydrogen. Hydrogen generating appliances utilize electrolysis, reformation, chemical, or other processes to generate hydrogen. IGNITION SOURCE. A flame, spark or hot surface capable of igniting flammable vapors or fumes. Such sources include appliance burners, burner ignitors and electrical switching devices. IMMEDIATELY DANGEROUS TO LIFE OR HEALTH (IDLH). The concentration of airborne contaminants that poses a threat of death, immediate or delayed perman ent adverse health effects, or effects that could prevent escape from such an environment. This contaminant concentration level is established by the National Institute of Occupational Safety and Health (NIOSH) based on both toxicity and flammability. It i s generally expressed in parts per million by volume (ppm v/v) or milligrams per cubic meter (mg/m 3 ). DEFINITIONS INDIRECT REFRIGERATION SYSTEM. A system in which a secondary coolant cooled or heated by the refrig- erating system is circulated to the air or other substa nce to be cooled or heated. Indirect systems are distinguished by the following methods of application: Closed system. A system in which a secondary fluid is either cooled or heated by the refrigerating system and then circulated within a closed circuit in indirect contact with the air or other substance to be cooled or heated. Double - indirect open - spray system. A system in which the secondary substance for an indirect open - spray system is heated or cooled by an intermediate coolant circulated from a second enclosure. Open - spray system. A system in which a secondary coolant is cooled or heated by the refrigerating system and then circulated in direct contact with the air or other substance to be cooled or heated. Vented closed system. A system in which a secondary coolant is cooled or heated by the refrigerating system and then passed through a closed circuit in the air or other substance to be cooled or heated, except that the evaporator or con - denser is placed in an open or appropriately vented tank. ‡‡‡ INFILTRATION. Uncontrolled inward air leakage to conditioned spaces through unintentional openings in ceil- ings, floors and walls from unconditioned spaces or the outdoors caused by pressure differences across these openings resulting from wind, the stac k effect created by temperature differences between indoors and outdoors, and imbalances between supply, return and exhaust airflow rates. INTEGRAL VENT APPLIANCES. Appliances designed for outdoor installation that have built - in natural or me- chanical venti ng means and are constructed and installed so that all air for combustion is derived from the outdoor atmosphere and all flue gases are discharged to the outdoor atmosphere through an integral vent termination. INTERLOCK. A device actuated by another devic e with which it is directly associated, to govern succeeding oper- ations of the same or allied devices. A circuit in which a given action cannot occur until after one or more other actions have taken place. JOINT, FLANGED. A joint made by bolting together a pair of flanged ends. JOINT, FLARED. A metal - to - metal compression joint in which a conical spread is made on the end of a tube that is compressed by a flare nut against a mating flare. JOINT, MECHANICAL. A connection between pipes, fittings, or pipes and fittings, which is neither screwed, caulked, threaded, soldered, solvent cemented, brazed nor welded. Also, a joint in which compression is applied along the centerline of the pieces being joined. Some joi nts are part of a coupling, fitting or adapter. These joints include both the press - type and push - fit joining systems. JOINT, PLASTIC ADHESIVE. A joint made in thermoset plastic piping by the use of an adhesive substance that forms a continuous bond betwee n the mating surfaces without dissolving either one of them. JOINT, PLASTIC HEAT FUSION. A joint made in thermo - plastic piping by heating the parts sufficiently to permit fusion of the materials when the parts are pressed together. JOINT, PLASTIC SOLVENT C EMENT. A joint made in thermoplastic piping by the use of a solvent or solvent cement that forms a continuous bond between the mating surfaces. JOINT, SOLDERED. A gas - tight joint obtained by the joining of metal parts with metallic mixtures of alloys that melt at temperatures between 400°F (204.4°C ) and 1, 000°F (537.8°C ). JOINT, WELDED. A gas - tight joint obtained by the joining of metal parts in molten state. LIGHT - DUTY COOKING APPLIANCE. Light - duty cooking appliances include gas and electric ovens (includi ng standard , bake, roasting, revolving, retherm, convection, combination convection/steamer, countertop conveyorized baking/finishing, deck and pastry), electric and gas steam - jacketed kettles, electric and gas pasta cookers, electric and gas compartment steamers (both pressure and atmospheric ) and electric and gas cheesemelters. LIMIT CONTROL. A device responsive to changes in pressure , temperature or level for turning on, shutting off or throttling the gas supply to an appliance. DEFINITIONS LIMITED CHARGE SYSTEM. A system in which, with the compressor idle, the design pressure will not be ex- ceeded when the refrigerant charge has completely evaporated. LIMITED COMBUSTIBLE MATERIAL. A building construction material not complying with the definition of noncombustible material, which, in the form in which it is used, has a potential heat value not exceeding 3,500 Btu/lb (8141 kj/kg) and complies with the following: Materials, in the form and thickness used, having neit her a flame spread index/rating greater than 25 nor evidence of continued combustion, and of such composition that surfaces that would be exposed by cutting through the material on any place would have neither a flame spread index/rating greater than 25 no r evidence of continued progressive combustion. Materials subject to increase in combustibility or flame spread index/rating beyond the limits herein established through the effects of age, moisture, or other atmospheric condition shall be considered combu stible. LIVING SPACE. Space within a dwelling unit utilized for living , sleeping, eating, cooking, bathing, washing and sanitation purposes. LOWER EXPLOSIVE LIMIT (LEL). See “LFL.” LOWER FLAMMABLE LIMIT (REFRIGERANT) (LFL). The minimum concentration of re frigerant that is ca- pable of propagating a flame through a homogeneous mixture of refrigerant and air. LOWER FLAMMABLE LIMIT (LFL). The minimum concentration of vapor in air at which propagation of flame will occur in the presence of an ignition source. Th e LFL is sometimes referred to as LEL or lower explosive limit. LOW - PROBABILITY SYSTEMS. A refrigeration system in which the basic design or the location of components is such that a leakage of refrigerant from a failed connection, seal or component will n ot enter an occupancy - classified area, other than the machinery room. LOW - SIDE PRESSURE. The parts of a refrigerating system subject to evaporator pressure. MACHINERY ROOM. A room meeting prescribed safety requirements and in which refrigeration systems or com- ponents thereof are located (see Sections 1105 and 1106 of this code, and Section 1006.2.2.2 of the New York City Building Code ). MECHANICAL DRAFT SYSTEM. A venting system designed to remove flue or vent gases by mechanical means that consists of an in duced - draft portion under nonpositive static pressure or a forced - draft portion under positive static pressure. Forced - draft venting system. A portion of a venting system using a fan or other mechanical means to cause the removal of flue or vent gases unde r positive static pressure. Induced - draft venting system. A portion of a venting system using a fan or other mechanical means to cause the removal of flue or vent gases under nonpositive static vent pressure. Power venting system. A portion of a venting sy stem using a fan or other mechanical means to cause the removal of flue or vent gases under positive static vent pressure. MECHANICAL EQUIPMENT/APPLIANCE ROOM. A room or space in which nonfuel - fired mechanical equip- ment and appliances are located. MECHANIC AL EXHAUST SYSTEM. A system for removing air from a room or space by mechanical means. MECHANICAL SYSTEM. A system specifically addressed and regulated in this code and composed of components, devices, appliances and equipment that become part of the build ing . MEDIUM - DUTY COOKING APPLIANCE. Medium - duty cooking appliances include electric discrete element ranges (with or without oven), electric and gas hot - top ranges, electric and gas griddles, electric and gas double - sided griddles, electric and gas fryers (including open deep fat fryers, donut fryers, kettle fryers and pressure fryers), electric and gas conveyor pizza ovens, electric and gas tilting skillets (braising pans) and electric and gas rotisseries. MODULAR BOILER. A steam or hot - wat er - heating assembly consisting of a group of individual boilers called modules intended to be installed as a unit without intervening stop valves. Modules are under one jacket or are indi- vidually jacketed . The individual modules shall be limited to a maxim um input rating of 400,000 Btu/h (117 228 W) gas, 3 gallons per hour (gph) (11.4 L/h) oil, or 115 kW (electric). DEFINITIONS NATURAL DRAFT SYSTEM. A venting system designed to remove flue or vent gases under nonpositive static vent pressure entirely by natural draft. NATURAL VENTILATION. The movement of air into and out of a space through intentionally provided openings, such as windows and doors, or through nonpowered ventilators. NET OCCUPIABLE FLOOR AREA. The floor area of an occupiable space defined by the inside surfaces of its walls but excluding shafts, column enclosures and other permanently enclosed, inaccessible and unoccupiable areas. Obstructions in the space such as furnishings, display or storag e racks and other obstructions, whether temporary or permanent, shall not be deducted from the space area. NONABRASIVE/ABRASIVE MATERIALS. Nonabrasive particulate in high concentrations, moderately abrasive particulate in low and moderate concentrations, a nd highly abrasive particulate in low concentrations, such as alfalfa, asphalt, plaster , gypsum and salt. NONCOMBUSTIBLE MATERIALS. Materials that, when tested in accordance with ASTM E 136, have at least three of four specimens tested meeting all of the f ollowing criteria: 1. The recorded temperature of the surface and interior thermocouples shall not at any time during the test rise more than 54°F (12.2°C ) above the furnace temperature at the beginning of the test. 2. There shall not be flaming from the s pecimen after the first 30 seconds. 3. If the weight loss of the specimen during testing exceeds 50 percent, the recorded temperature of the surface and interior thermocouples shall not at any time during the test rise above the furnace air temperature at the begin - ning of the test, and there shall not be flaming of the specimen . ‡‡‡ OCCUPATIONAL EXPOSURE LIMIT (OEL). The timeweighted average (TWA) concentration for a normal 8 - hour workday and a 40 - hour workweek to which nearly all workers can be repeatedl y exposed without adverse effect, based on the OSHA PEL, ACGIH TLV - TWA, AIHA WEEL, or consistent value. OCCUPIABLE SPACE. An enclosed space intended for human activities, excluding those spaces intended primarily for other purposes, such as storage rooms a nd equipment rooms, that are only intended to be occupied occasionally and for short periods of time. OFFSET (VENT). A combination of approved bends that make two changes in direction bringing one section of the vent out of line but into a line parallel wi th the other section. OUTDOOR AIR. Air taken from the outdoors, and therefore not previously circulated through the system. OUTDOOR OPENING. A door, window, louver or skylight openable to the outdoor atmosphere. OUTLET, GAS. A threaded connection or bolted flange in a piping system to which a gas - burning appliance is attached. PANEL HEATING. A method of radiant space heating in which heat is supplied by large heated areas of room surfaces. The heating element usually consists of warm water piping, warm air ducts, or electrical resistance elements embedded in or located behind ceiling, wall or floor surfaces. PELLET FUEL - BURNING APPLIANCE. A closed - combustion , vented appliance equipped with a fuel - feed mechanism for burning processed pellets of solid fuel of a specified size and composition. PIPING. Where used in this code, “piping” refers to either pipe or tubing, or both. Pipe. A rigid conduit of iron, steel, copper, brass or plastic. Tubing. Semirigid conduit of copper, aluminum, plastic or steel. PLASTIC, THERMOPLASTIC. A plastic that is capable of being repeatedly softened by increase of temperature and hardened by decrease of temperature. PLASTIC, THERMOSETTING. A plastic that is capable of being changed into a substantially infusible or insoluble product when cured under application of heat or chemical means. DEFINITIONS PLENUM. A compartment or chamber located in one story only to which one or more air ducts are connected a nd that forms part of the air supply or return system and may be part of the building construction, such as the concealed space above a ceiling. PORTABLE FUEL CELL APPLIANCE. A fuel cell generator of electricity, which is not fixed in place. A portable fue l cell appliance utilizes a cord and plug connection to a grid - isolated load and has an integral fuel supply. POWER BOILER. See “Boiler.” PREMISES. Land, improvements thereon, or any part thereof. PRESSURE, FIELD TEST. A test performed in the field to prov e system tightness. PRESSURE - LIMITING DEVICE. A pressure - responsive mechanism designed to stop automatically the operation of the pressure - imposing element at a predetermined pressure. PRESSURE RELIEF DEVICE. A pressure - actuated valve or rupture member des igned to relieve excessive pressure automatically. PRESSURE RELIEF VALVE. A pressure - actuated valve held closed by a spring or other means and designed to relieve pressure automatically in excess of the device’s setting. PRESSURE VESSELS. Closed containers , tanks or vessels that are designed to contain liquids or gases, or both, under pressure. PRESSURE VESSELS — REFRIGERANT. Any refrigerant - containing receptacle in a refrigerating system. This does not include evaporators where each separate section does not exceed 0.5 cubic foot (0.014 m 3 ) of refrigerant - containing volume , regardless of the maximum inside dimensions, evaporator coils, controls, headers, pumps and piping. PROTECTIVE ASSEMBLY (REDUCED CLEARANCE). Any noncombustible assembly that is labeled or con- structed in accordance with Table 308.4.2 and is placed between combustible materials or assemblies and mechanical appliances , devices or equipment, for the purpose of reducing required airspace clearances. Protective assemblies attached directly to a combustible assembly shall not be considered as part of that combustible assembly. PURGE. To clear of air, water or other foreign substances. PUSH - FIT JOINTS. A type of mechanical joint consisting of elastomeric seals and corrosion - resistant tube gripper s. The joint is made by pushing the pipe into the joint and allowing the grippers to secure the connection. QUICK - OPENING VALVE. A valve that opens completely by fast action, either manually or automatically con- trolled. A valve requiring one - quarter round turn or less is considered to be quick opening. RADIANT HEATER. A heater designed to transfer heat primarily by direct radiation. READY ACCESS (TO). That which enables a device, fixture, appliance or equipment to be directly reached, without requiring the removal or movement of any panel, door or similar obstruction ( see “Access (to )”). RECEIVER, LIQUID. A vessel permanently connected to a refrigeration system by inlet and outlet pipes for storage of liquid refrigerant. RECIRCULATED AIR. Air removed from a conditioned space and intended for reuse as supply air. RECLAIMED REFRIGERANTS. Refrigerants reproces sed to the same specifications as for new refrigerants by means including distillation. Such refrigerants have been chemically analyzed to verify that the specifications have been met. Reclaiming usually implies the use of processes or procedures that are available only at a reprocessing or manufacturing facility. RECOVERED REFRIGERANTS. Refrigerants removed from a system in any condition without necessarily testing or processing them. RECYCLED REFRIGERANTS. Refrigerants from which contaminants have been re duced by oil separation, re- moval of noncondensable gases, and single or multiple passes through devices that reduce moisture, acidity and DEFINITIONS particulate matter, such as replaceable core filter dryers . These procedures usually are performed at the field job si te or in a local service shop. REFRIGERANT. A substance used for heat transfer in a refrigerating system; the refrigerant absorbs heat and transfers it at a higher temperature and higher pressure, usually with a change of state. REFRIGERANT SAFETY CLASSIF ICATIONS. Groupings that indicate the toxicity and flammability classes in accordance with ASHRAE 34. REFRIGERATED ROOM OR SPACE. A room or space in which an evaporator or brine coil is located for the purpose of reducing or controlling the temperature wit hin the room or space to below 68ºF (20ºC). REFRIGERATING SYSTEM. A combination of interconnected refrigerant - containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat. REFRIGERATIO N MACHINERY ROOM. See “Machinery room.” REFRIGERATION SYSTEM, ABSORPTION. A heat - operated , closed - refrigeration cycle in which a secondary fluid (the absorbent) absorbs a primary fluid (the refrigerant) that has been vaporized in the evaporator. Direct sys tem. A system in which the evaporator is in direct contact with the material or space refrigerated, or is located in air - circulating passages communicating with such spaces. Indirect system. A system in which a brine coil cooled by the refrigerant is circu lated to the material or space refrigerated , or is utilized to cool the air so circulated. Indirect systems are distinguished by the type or method of application. REFRIGERATION SYSTEM CLASSIFICATION. Refrigeration systems are classified according to the d egree of probability that leaked refrigerant from a failed connection, seal or component will enter an occupied area. The distinction is based on the basic design or location of the components. REFRIGERATION SYSTEM, MECHANICAL. A combi - nation of interconne cted refrigeration - containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat and in which a compressor is used for compressing the refrigerant vapor. REFRIGERATION SYSTEM, SELF - CONT AINED. A complete factory - assembled and tested system that is shipped in one or more sections and that does not have refrigerant - containing parts that are joined in the field by other than companion or block valves. RETURN AIR SYSTEM. An assembly of connec ted ducts, plenums, fittings, registers and grilles through which return air from the space or spaces to be heated or cooled is conducted back to the supply unit or relieved to the outdoors (see also “Supply air system”). ROOM HEATER, VENTED. A free - standi ng heating unit burning solid or liquid fuel for direct heating of the space in and adjacent to that in which the unit is located. SAFETY VALVE. A valve that relieves pressure in a steam boiler by opening fully at the rated discharge pressure. The valve is of the spring - pop type. SELF - CONTAINED EQUIPMENT. Complete, factory - assembled and tested, heating, air - conditioning or refriger- ation equipment installed as a single unit, and having all working parts, complete with motive power, in an enclosed unit of sai d machinery. SHAFT. An enclosed space extending through one or more stories of a building, connecting vertical openings in successive floors, or floors and the roof. SHAFT ENCLOSURE. The walls or construction forming the boundaries of a shaft. SLEEPING UNIT. A dwelling unit, which may contain either toilet or kitchen facilities but not both. Any sleeping unit housing more than one family shall also be classified as a congregate living unit. The creation of or conversion to sleeping units shall b e limited by Section 27 - 2077 of the New York City Housing Maintenance Code . DEFINITIONS SMOKE DAMPER. A listed device installed in ducts and air transfer openings designed to resist the passage of air and smoke. The device is installed to operate automatically, contro lled by a smoke detection system, and where re- quired, is capable of being positioned from a fire command center. SMOKE - DEVELOPED INDEX. A comparative measure, expressed as a dimensionless number, derived from meas- urements of smoke obscuration versus time for a material tested in accordance with ASTM E 84. SOLID FUEL (COOKING APPLICATIONS). Applicable to commercial food service operations only, solid fuel is any bulk material such as hardwood, mesquite, charcoal or briquettes that is combusted to produ ce heat for cooking operations. SOURCE CAPTURE SYSTEM. A mechanical exhaust system designed and constructed to capture air contaminants at their source and to exhaust such contaminants to the outdoor atmosphere. STATIONARY FUEL CELL POWER PLANT. A self - con tained package or factory - matched package that consti- tute an automatically operated assembly of integrated systems for generating useful electrical energy and recoverable thermal energy that is permanently connected and fixed in place. STOP VALVE. A shutof f valve for controlling the flow of liquid or gases. STORY. That portion of a building included between the upper surface of a floor and the upper surface of the floor next above, except that the topmost story shall be that portion of a building included b etween the upper surface of the topmost floor and the ceiling or roof above. STRENGTH, ULTIMATE. The highest stress level that the component will tolerate without rupture. SUPPLY AIR. That air delivered to each or any space supplied by the air distribution system or the total air delivered to all spaces supplied by the air distribution system, which is provided for ventilating, heating, cooling, humidification, dehumidification and other similar purposes. SUPPLY AIR SYSTEM. An assembly of connected ducts, p lenums, fittings, registers and grilles through which air, heated or cooled, is conducted from the supply unit to the space or spaces to be heated or cooled (see also “Return air system”). THEORETICAL AIR. The exact amount of air required to supply oxygen for complete combustion of a given quan- tity of a specific fuel. THERMAL RESISTANCE (R). A measure of the ability to retard the flow of heat. The R - value is the reciprocal of thermal conductance. THIRD - PARTY CERTIFICATION AGENCY. An approved agency operatin g a product or material certification system that incorporates initial product testing, assessment and surveillance of a manufacturer’s quality control sys- tem. THIRD - PARTY CERTIFIED. Certification obtained by the manufacturer indicating that the function a nd perfor- mance characteristics of a product or material have been determined by testing and ongoing surveillance by an ap- proved third - party certification agency. Assertion of certification is in the form of identification in accordance with the requirement s of the third - party certification agency. THIRD - PARTY TESTED. Procedure by which an approved testing laboratory provides documentation that a prod- uct, material or system conforms to specified requirements. THRESHOLD LIMIT VALUE - TIME WEIGHTED AVERAGE (TLV - TWA). The time - weighted average con- centration of a refrigerant or other chemical in air for a normal 8 - hour workday and a 40 - hour workweek, to which nearly all workers are repeatedly exposed, day after day, without adverse effects, as adopted by the Americ an Confer- ence of Government Industrial Hygienists (ACGIH). TOILET ROOM. A room containing a water closet and, frequently , a lavatory, but not a bathtub, shower, spa or similar bathing fixture. TOXICITY CLASSIFICATION. Refrigerants shall be classified for t oxicity in one of two classes in accordance with ASHRAE 34. DEFINITIONS TRANSITION FITTINGS, PLASTIC TO STEEL. An adapter for joining plastic pipe to steel pipe. The purpose of this fitting is to provide a permanent, pressure - tight connection between two materials tha t cannot be joined directly one to another. ‡‡‡ UNCONFINED SPACE. A space having a volume not less than 50 cubic feet per 1,000 Btu/h (4.8 m 3 /kW) of the aggregate input rating of all appliances installed in that space. Rooms communicating directly with the space in which the appliances are installed, through openings not furnished with doors, are considered a part of the unconfined space. UNIT HEATER. A self - contained appliance of the fan type, designed for the delivery of warm air directly into the spac e in which the appliance is located. UNUSUALLY TIGHT CONSTRUCTION. Construction meeting all of the following requirements: 1. Walls exposed to the outside atmosphere having a continuous water vapor retarder with a rating of 1 perm (57 ng/s·m 2 ·Pa) or less w ith openings gasketed or sealed; and 2. Openable windows and doors meeting the air leakage requirements of the New York City Energy Conservation Code , Section 502.4.1; and 3. Caulking or sealants are applied to areas, such as joints around window and door frames, between sole plates and floors, between wall - ceiling joints, between wall panels, at penetrations for plumbing, electrical and gas lines, and at other openings. VENT. A pipe or other conduit composed of factory - made components, containing a passage way for conveying com- bustion products and air to the atmosphere, listed and labeled for use with a specific type or class of appliance. Pellet vent. A vent listed and labeled for use with listed pellet - fuel - burning appliances. Type L vent. A vent listed and labeled for use with the following: Oil - burning appliances that are listed for use with Type L vents. VENT CONNECTOR. The pipe that connects an approved fuel - fired appliance to a vent. VENT DAMPER DEVICE, AUTOMATIC. A device intended for install ation in the venting system, in the outlet of an individual automatically operated fuel - burning appliance that is designed to open the venting system automati- cally when the appliance is in operation and to close off the venting system automatically when th e appliance is in a standby or shutdown condition. VENTED ROOM HEATER. A vented self - contained, free - standing , nonrecessed appliance for furnishing warm air to the space in which it is installed, directly from the heater without duct connections. VENTILATI ON. The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, any space. VENTILATION AIR. That portion of supply air that comes from the outside (outdoors), plus any recirculated air that has been treated to maintain the desired quality of air within a designated space. VENTING SYSTEM. A continuous open passageway from the flue collar of an appliance to the outside atmosphere for the purpose of removing flue or vent gases. A venting system is usuall y composed of a vent or a chimney and vent connector, if used, assembled to form the open passageway. WATER HEATER. Any heating appliance or equipment that heats potable water and supplies such water to the potable hot water distribution system. ZONE. One occupiable space or several occupiable spaces with similar occupancy classification (see Table 403.3.1.1), occupant density, zone air distribution effectiveness and zone primary airflow rate per unit area.