| CHAPTER 14 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| SECTION PC 1401 | |
| GENERAL | |
| 1401.1 Scope. | |
| The provisions of Chapter 14 shall govern the materials, design, construction and installation of sub- | |
| surface landscape irrigation systems connected to nonpotable water from on | |
| - | |
| site water reuse systems. | |
| 1401.2 Materials. | |
| Above | |
| - | |
| ground drain, waste and vent p | |
| iping for subsurface landscape irrigation systems shall con- | |
| form to one of the standards listed in Table 702.1. Subsurface landscape irrigation, underground building drainage | |
| and vent pipe shall conform to one of the standards listed in Table 702.2. | |
| 1401.3 | |
| Tests. | |
| Drain, waste and vent piping for subsurface landscape irrigation systems shall be tested in accordance | |
| with Section 312. | |
| 1401.4 Inspections. | |
| Subsurface landscape irrigation systems shall be inspected in accordance with Section 107. | |
| 1401.5 Disinfecti | |
| on. | |
| Disinfection shall not be required for on | |
| - | |
| site nonpotable water reuse for subsurface landscape | |
| irrigation systems. | |
| 1401.6 Coloring. | |
| On | |
| - | |
| site nonpotable water reuse for subsurface landscape irrigation systems shall not be required to | |
| be dyed. | |
| SECTION PC | |
| 1402 | |
| SYSTEM DESIGN AND SIZING | |
| 1402.1 Sizing. | |
| The system shall be sized in accordance with the sum of the output of all water sources connected to | |
| the subsurface irrigation system. Where gray water collection piping is connected to subsurface landscape irri | |
| gation | |
| systems, gray water output shall be calculated according to the gallons | |
| - | |
| per | |
| - | |
| day | |
| - | |
| per | |
| - | |
| occupant number based on the | |
| type of fixtures connected. The gray water discharge shall be calculated by the following equation: | |
| C = A | |
| × | |
| B | |
| (Equation | |
| 14 | |
| - | |
| 1) | |
| where: | |
| A | |
| = Number of occupants: | |
| Residential | |
| – | |
| Number of occupants shall be determined by the actual number of occupants, but not less than two | |
| occupants for one bedroom and one occupant for each additional bedroom. | |
| Commercial | |
| – | |
| Number of occupants s | |
| hall be determined by the | |
| New York City Building Code | |
| . | |
| B | |
| = Estimated flow demands for each occupant*: | |
| Residential | |
| – | |
| 25 gallons per day (94.6 lpd) per occupant for showers, bathtubs and lavatories and 15 gallons per day | |
| (56.7 lpd) per occupant for clothes w | |
| ashers or laundry trays. | |
| Commercial | |
| – | |
| Based on type of fixture or water use records minus the discharge of fixtures other than those discharg- | |
| ing gray water. | |
| *Alternative estimated flow demands for each occupant shall be permitted based on actual calculate | |
| d water usage for | |
| the building. | |
| C | |
| = Estimated gray water discharge based on the total number of occupants. | |
| 1402.2 Percolation tests. | |
| The permeability of the soil in the proposed absorption system shall be determined by | |
| percolation tests or | |
| permeability evaluation. | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1402.2.1 Percolation tests and procedures. | |
| At least three percolation tests in each system area shall be conducted. | |
| The holes shall be spaced uniformly in relation to the bottom depth of the proposed absorption system. More per- | |
| cola | |
| tion tests shall be made where necessary, depending on system design. | |
| 1402.2.1.1 Percolation test hole. | |
| The test hole shall be dug or bored. The test hole shall have vertical sides and | |
| a horizontal dimension of 4 inches to 8 inches (102 mm to 203 mm). The | |
| bottom and sides of the hole shall be | |
| scratched with a sharp | |
| - | |
| pointed instrument to expose the natural soil. All loose material shall be removed from | |
| the hole and the bottom shall be covered with 2 inches (51 mm) of gravel or coarse sand. | |
| 1402.2.1.2 Test pr | |
| ocedure, sandy soils. | |
| The hole shall be filled with clear water to a minimum of 12 inches | |
| (305 mm) above the bottom of the hole for tests in sandy soils. The time for this amount of water to seep away | |
| shall be determined, and this procedure shall be repeat | |
| ed if the water from the second filling of the hole seeps | |
| away in 10 minutes or less. The test shall proceed as follows: Water shall be added to a point not more than 6 | |
| inches (152 mm) above the gravel or coarse sand. Thereupon, from a fixed reference poin | |
| t, water levels shall be | |
| measured at 10 | |
| - | |
| minute intervals for a period of 1 hour. Where 6 inches (152 mm) of water seeps away in less | |
| than 10 minutes, a shorter interval between measurements shall be used, but in no case shall the water depth | |
| exceed 6 inche | |
| s (152 mm). Where 6 inches (152 mm) of water seeps away in less than 2 minutes, the test shall | |
| be stopped and a rate of less than 1 minute per inch (2.4 s/mm) shall be reported. The final water level drop shall | |
| be used to calculate the percolation rate. So | |
| ils not meeting the above requirements shall be tested in accordance | |
| with Section 1402.2.1.3. | |
| 1402.2.1.3 Test procedure, other soils. | |
| The hole shall be filled with clear water, and a minimum water depth | |
| of 12 inches (305 mm) shall be maintained above the b | |
| ottom of the hole for a 4 | |
| - | |
| hour period by refilling whenever | |
| necessary or by use of an automatic siphon. Water remaining in the hole after 4 hours shall not be removed. | |
| Thereafter, the soil shall be allowed to swell not less than 16 hours or more than 30 ho | |
| urs. Immediately after the | |
| soil swelling period, the measurements for determining the percolation rate shall be made as follows: any soil | |
| sloughed into the hole shall be removed and the water level shall be adjusted to 6 inches (152 mm) above the | |
| gravel or | |
| coarse sand. Thereupon, from a fixed reference point, the water level shall be measured at 30 | |
| - | |
| minute | |
| intervals for a period of 4 hours, unless two successive water level drops do not vary by more than | |
| 1 | |
| / | |
| 16 | |
| inch (1.59 | |
| mm). At least three water level drops | |
| shall be observed and recorded. The hole shall be filled with clear water | |
| to a point not more than 6 inches (152 mm) above the gravel or coarse sand whenever it becomes nearly empty. | |
| Adjustments of the water level shall not be made during the three measure | |
| ment periods except to the limits of | |
| the last measured water level drop. When the first 6 inches (152 mm) of water seeps away in less than 30 | |
| minutes, the time interval between measurements shall be 10 minutes and the test run for 1 hour. The water | |
| depth s | |
| hall not exceed 5 inches (127 mm) at any time during the measurement period. The drop that occurs | |
| during the final measurement period shall be used in calculating the percolation rate. | |
| 1402.2.1.4 Mechanical test equipment. | |
| Mechanical percolation test equip | |
| ment shall be of an approved | |
| type. | |
| 1402.2.2 Permeability evaluation. | |
| Soil shall be evaluated for estimated percolation based on structure and texture | |
| in accordance with accepted soil evaluation practices. Borings shall be made in accordance with | |
| Section 1402.2.1.1 | |
| for evaluating the soil. | |
| 1402.3 Subsurface landscape irrigation site location. | |
| The surface grade of all soil absorption systems shall be lo- | |
| cated at a point lower than the surface grade of any water well or reservoir on the same or adjoin | |
| ing lot. Where this is | |
| not possible, the site shall be located so surface water drainage from the site is not directed toward a well or reservoir. | |
| The soil absorption system shall be located with a minimum horizontal distance between various elements as in | |
| dicated | |
| in Table 1402.3. Private sewage disposal systems in compacted areas, such as parking lots and driveways, are prohib- | |
| ited. Surface water shall be diverted away from any soil absorption site on the same or neighboring lots. | |
| TABLE 1402.3 | |
| LOCATION OF S | |
| UBSURFACE IRRIGATION SYSTEM | |
| ELEMENT | |
| MINIMUM HORIZONTAL DISTANCE | |
| Storage tank (feet) | |
| Irrigation disposal field | |
| (feet) | |
| Buildings | |
| 5 | |
| 10 | |
| CHAPTER 14 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| SECTION PC 1401 | |
| GENERAL | |
| 1401.1 Scope. | |
| The provisions of Chapter 14 shall govern the materials, design, construction and installation of sub- | |
| surface landscape irrigation systems connected to nonpotable water from on | |
| - | |
| site water reuse systems. | |
| 1401.2 Materials. | |
| Above | |
| - | |
| ground drain, waste and vent p | |
| iping for subsurface landscape irrigation systems shall con- | |
| form to one of the standards listed in Table 702.1. Subsurface landscape irrigation, underground building drainage | |
| and vent pipe shall conform to one of the standards listed in Table 702.2. | |
| 1401.3 | |
| Tests. | |
| Drain, waste and vent piping for subsurface landscape irrigation systems shall be tested in accordance | |
| with Section 312. | |
| 1401.4 Inspections. | |
| Subsurface landscape irrigation systems shall be inspected in accordance with Section 107. | |
| 1401.5 Disinfecti | |
| on. | |
| Disinfection shall not be required for on | |
| - | |
| site nonpotable water reuse for subsurface landscape | |
| irrigation systems. | |
| 1401.6 Coloring. | |
| On | |
| - | |
| site nonpotable water reuse for subsurface landscape irrigation systems shall not be required to | |
| be dyed. | |
| SECTION PC | |
| 1402 | |
| SYSTEM DESIGN AND SIZING | |
| 1402.1 Sizing. | |
| The system shall be sized in accordance with the sum of the output of all water sources connected to | |
| the subsurface irrigation system. Where gray water collection piping is connected to subsurface landscape irri | |
| gation | |
| systems, gray water output shall be calculated according to the gallons | |
| - | |
| per | |
| - | |
| day | |
| - | |
| per | |
| - | |
| occupant number based on the | |
| type of fixtures connected. The gray water discharge shall be calculated by the following equation: | |
| C = A | |
| × | |
| B | |
| (Equation | |
| 14 | |
| - | |
| 1) | |
| where: | |
| A | |
| = Number of occupants: | |
| Residential | |
| – | |
| Number of occupants shall be determined by the actual number of occupants, but not less than two | |
| occupants for one bedroom and one occupant for each additional bedroom. | |
| Commercial | |
| – | |
| Number of occupants s | |
| hall be determined by the | |
| New York City Building Code | |
| . | |
| B | |
| = Estimated flow demands for each occupant*: | |
| Residential | |
| – | |
| 25 gallons per day (94.6 lpd) per occupant for showers, bathtubs and lavatories and 15 gallons per day | |
| (56.7 lpd) per occupant for clothes w | |
| ashers or laundry trays. | |
| Commercial | |
| – | |
| Based on type of fixture or water use records minus the discharge of fixtures other than those discharg- | |
| ing gray water. | |
| *Alternative estimated flow demands for each occupant shall be permitted based on actual calculate | |
| d water usage for | |
| the building. | |
| C | |
| = Estimated gray water discharge based on the total number of occupants. | |
| 1402.2 Percolation tests. | |
| The permeability of the soil in the proposed absorption system shall be determined by | |
| percolation tests or | |
| permeability evaluation. | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1402.2.1 Percolation tests and procedures. | |
| At least three percolation tests in each system area shall be conducted. | |
| The holes shall be spaced uniformly in relation to the bottom depth of the proposed absorption system. More per- | |
| cola | |
| tion tests shall be made where necessary, depending on system design. | |
| 1402.2.1.1 Percolation test hole. | |
| The test hole shall be dug or bored. The test hole shall have vertical sides and | |
| a horizontal dimension of 4 inches to 8 inches (102 mm to 203 mm). The | |
| bottom and sides of the hole shall be | |
| scratched with a sharp | |
| - | |
| pointed instrument to expose the natural soil. All loose material shall be removed from | |
| the hole and the bottom shall be covered with 2 inches (51 mm) of gravel or coarse sand. | |
| 1402.2.1.2 Test pr | |
| ocedure, sandy soils. | |
| The hole shall be filled with clear water to a minimum of 12 inches | |
| (305 mm) above the bottom of the hole for tests in sandy soils. The time for this amount of water to seep away | |
| shall be determined, and this procedure shall be repeat | |
| ed if the water from the second filling of the hole seeps | |
| away in 10 minutes or less. The test shall proceed as follows: Water shall be added to a point not more than 6 | |
| inches (152 mm) above the gravel or coarse sand. Thereupon, from a fixed reference poin | |
| t, water levels shall be | |
| measured at 10 | |
| - | |
| minute intervals for a period of 1 hour. Where 6 inches (152 mm) of water seeps away in less | |
| than 10 minutes, a shorter interval between measurements shall be used, but in no case shall the water depth | |
| exceed 6 inche | |
| s (152 mm). Where 6 inches (152 mm) of water seeps away in less than 2 minutes, the test shall | |
| be stopped and a rate of less than 1 minute per inch (2.4 s/mm) shall be reported. The final water level drop shall | |
| be used to calculate the percolation rate. So | |
| ils not meeting the above requirements shall be tested in accordance | |
| with Section 1402.2.1.3. | |
| 1402.2.1.3 Test procedure, other soils. | |
| The hole shall be filled with clear water, and a minimum water depth | |
| of 12 inches (305 mm) shall be maintained above the b | |
| ottom of the hole for a 4 | |
| - | |
| hour period by refilling whenever | |
| necessary or by use of an automatic siphon. Water remaining in the hole after 4 hours shall not be removed. | |
| Thereafter, the soil shall be allowed to swell not less than 16 hours or more than 30 ho | |
| urs. Immediately after the | |
| soil swelling period, the measurements for determining the percolation rate shall be made as follows: any soil | |
| sloughed into the hole shall be removed and the water level shall be adjusted to 6 inches (152 mm) above the | |
| gravel or | |
| coarse sand. Thereupon, from a fixed reference point, the water level shall be measured at 30 | |
| - | |
| minute | |
| intervals for a period of 4 hours, unless two successive water level drops do not vary by more than | |
| 1 | |
| / | |
| 16 | |
| inch (1.59 | |
| mm). At least three water level drops | |
| shall be observed and recorded. The hole shall be filled with clear water | |
| to a point not more than 6 inches (152 mm) above the gravel or coarse sand whenever it becomes nearly empty. | |
| Adjustments of the water level shall not be made during the three measure | |
| ment periods except to the limits of | |
| the last measured water level drop. When the first 6 inches (152 mm) of water seeps away in less than 30 | |
| minutes, the time interval between measurements shall be 10 minutes and the test run for 1 hour. The water | |
| depth s | |
| hall not exceed 5 inches (127 mm) at any time during the measurement period. The drop that occurs | |
| during the final measurement period shall be used in calculating the percolation rate. | |
| 1402.2.1.4 Mechanical test equipment. | |
| Mechanical percolation test equip | |
| ment shall be of an approved | |
| type. | |
| 1402.2.2 Permeability evaluation. | |
| Soil shall be evaluated for estimated percolation based on structure and texture | |
| in accordance with accepted soil evaluation practices. Borings shall be made in accordance with | |
| Section 1402.2.1.1 | |
| for evaluating the soil. | |
| 1402.3 Subsurface landscape irrigation site location. | |
| The surface grade of all soil absorption systems shall be lo- | |
| cated at a point lower than the surface grade of any water well or reservoir on the same or adjoin | |
| ing lot. Where this is | |
| not possible, the site shall be located so surface water drainage from the site is not directed toward a well or reservoir. | |
| The soil absorption system shall be located with a minimum horizontal distance between various elements as in | |
| dicated | |
| in Table 1402.3. Private sewage disposal systems in compacted areas, such as parking lots and driveways, are prohib- | |
| ited. Surface water shall be diverted away from any soil absorption site on the same or neighboring lots. | |
| TABLE 1402.3 | |
| LOCATION OF S | |
| UBSURFACE IRRIGATION SYSTEM | |
| ELEMENT | |
| MINIMUM HORIZONTAL DISTANCE | |
| Storage tank (feet) | |
| Irrigation disposal field | |
| (feet) | |
| Buildings | |
| 5 | |
| 10 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| Lot line adjoining | |
| private property | |
| 5 | |
| 5 | |
| Water wells | |
| 50 | |
| 100 | |
| Streams and lakes | |
| 50 | |
| 50 | |
| Seepage pits | |
| 5 | |
| 20 | |
| Septic | |
| tanks | |
| 0 | |
| 5 | |
| Water service | |
| 5 | |
| 5 | |
| Public water main | |
| 10 | |
| 10 | |
| For SI: 1 foot = 304.8 mm. | |
| SECTION PC 1403 | |
| INSTALLATION | |
| 1403.1 Installation. | |
| Absorption systems shall be installed in accordance with Sections 1403.1.1 through 1403.1.5 to | |
| provide landscape | |
| irrigation without surfacing of water. | |
| 1403.1.1 Absorption area. | |
| The total absorption area required shall be computed from the estimated daily gray | |
| water discharge and the design | |
| - | |
| loading rate based on the percolation rate for the site. The required absorpt | |
| ion area | |
| equals the estimated gray water discharge divided by the design | |
| - | |
| loading rate from Table 1403.1.1. | |
| TABLE 1403.1.1 | |
| DESIGN LOADING RATE | |
| PERCOLATION RATE | |
| (minutes per inch) | |
| DESIGN LOADING FACTOR | |
| (gallons per square foot per day) | |
| < 1 | |
| Not suitable | |
| 1 | |
| – | |
| 5 | |
| 1.20 | |
| 6 | |
| – | |
| 7 | |
| 1.00 | |
| 8 | |
| – | |
| 10 | |
| 0.90 | |
| 11 | |
| – | |
| 15 | |
| 0.80 | |
| 16 | |
| – | |
| 20 | |
| 0.70 | |
| 21 | |
| – | |
| 30 | |
| 0.60 | |
| 31 | |
| – | |
| 45 | |
| 0.50 | |
| 46 | |
| – | |
| 60 | |
| 0.45 | |
| 61 | |
| – | |
| 120 | |
| 0.20 | |
| > 120 | |
| Not Suitable | |
| For SI: 1 minute per inch = min/25.4 mm, | |
| 1 gallon per square foot = 40.7 L/m | |
| 2 | |
| . | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1403.1.2 Seepage trench excavations. | |
| Seepage trench excavations shall be not less than 1 foot (304 mm) in width | |
| and not greater than 5 feet (1524 mm) in width. Trench excavations shall be spaced not less than 2 feet (610 mm) | |
| apart. The soil absorption area | |
| of a seepage trench shall be computed by using the bottom of the trench area (width) | |
| multiplied by the length of pipe. Individual seepage trenches shall be not greater than 100 feet (30 480 mm) in | |
| developed length. | |
| 1403.1.3 Seepage bed excavations. | |
| Seepa | |
| ge bed excavations shall be not less than 5 feet (1524 mm) in width and | |
| have more than one distribution pipe. The absorption area of a seepage bed shall be computed by using the bottom | |
| of the trench area. Distribution piping in a seepage bed shall be unifo | |
| rmly spaced not greater than 5 feet (1524 mm) | |
| and not less than 3 feet (914 mm) apart, and greater than 3 feet (914 mm) and not less than 1 foot (305 mm) from | |
| the sidewall or headwall. | |
| 1403.1.4 Excavation and construction. | |
| The bottom of a trench or bed exc | |
| avation shall be level. Seepage trenches | |
| or beds shall not be excavated where the soil is so wet that such material rolled between the hands forms a soil | |
| wire. All smeared or compacted soil surfaces in the sidewalls or bottom of seepage trench or bed excav | |
| ations shall | |
| be scarified to the depth of smearing or compaction and the loose material removed. Where rain falls on an open | |
| excavation, the soil shall be left until sufficiently dry so a soil wire will not form when soil from the excavation | |
| bottom is roll | |
| ed between the hands. The bottom area shall then be scarified and loose material removed. | |
| 1403.1.5 Aggregate and backfill. | |
| Not less than 6 inches in depth of aggregate, ranging in size from | |
| 1 | |
| / | |
| 2 | |
| to 2 | |
| 1 | |
| / | |
| 2 | |
| inches (12.7 mm to 64 mm), shall be laid into the tren | |
| ch below the distribution piping elevation. The aggregate | |
| shall be evenly distributed not less than 2 inches (51 mm) in depth over the top of the distribution pipe. The aggre- | |
| gate shall be covered with approved synthetic materials or 9 inches (229 mm) of un | |
| compacted marsh hay or straw. | |
| Building paper shall not be used to cover the aggregate. Not less than 9 inches (229 mm) of soil backfill shall be | |
| provided above the covering. | |
| 1403.2 Distribution piping. | |
| Distribution piping shall be not less than 3 inches (7 | |
| 6 mm) in diameter. Materials shall | |
| comply with Table 1403.2. The top of the distribution pipe shall be not less than 4 inches (100 mm) or greater than 12 | |
| inches (300 mm) below the original surface. The slope of the distribution pipes shall be not less than | |
| 2 inches (51 mm) | |
| and not greater than 4 inches (102 mm) per 100 feet (30 480 mm). | |
| TABLE 1403.2 | |
| DISTRIBUTION PIPE | |
| MATERIAL | |
| STANDARD | |
| Polypropylene (PP) pipe | |
| ASTM F | |
| 2389 | |
| Polyethylene (PE) plastic pipe | |
| ASTM F | |
| 405 | |
| Polyvinyl chloride (PVC) plastic pipe | |
| a | |
| ASTM D | |
| 2729 | |
| Polyvinyl chloride (PVC) plastic pipe with a 3.5 | |
| - | |
| inch O.D. and solid cellular core or composite wall | |
| a | |
| ASTM F | |
| 1488 | |
| For SI: 1 inch = 25.4 mm. | |
| a. Limited to residential buildings five stories or less in | |
| height. | |
| 1403.2.1 Joints and fittings. | |
| Joints and fittings in distribution pipe shall be made in accordance with Table | |
| 1403.2.1. | |
| TABLE 1403.2.1 | |
| JOINTS AND FITTINGS | |
| MATERIAL | |
| STANDARD | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| Polyethylene (PE) plastic pipe | |
| ASTM F 405 | |
| Polypropylene (PP) pipe | |
| ASTM F 2389 | |
| Polyvinyl chloride (PVC) plastic in IPS | |
| diameters | |
| a | |
| ASTM D 2665; ASTM | |
| F 1866 | |
| Polyvinyl chloride (PVC) plastic pipe in | |
| sewer and drain diameters | |
| a | |
| ASTM D 3034 | |
| Polyvinyl chloride (PVC) plastic pipe | |
| with a 3.25 | |
| - | |
| inch O.D. | |
| a | |
| ASTM D 2949 | |
| For SI: 1 inch = 25.4 mm. | |
| a. Limited to residential buildings five stories or less in height. | |
| 1403.2.2 Diversion valves. | |
| Systems shall include a diversion valve to divert gray water | |
| to the building sanitary | |
| system when soils are saturated or frozen, there is a blockage or backup in the system, the maximum allowed | |
| gallons per day is reached, or when system maintenance is necessary. | |
| 1403.2.3 Overflow connection. | |
| Systems shall have a pi | |
| ped connection to the building drainage system to accom- | |
| modate tank overflow. | |
| CHAPTER 14 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| SECTION PC 1401 | |
| GENERAL | |
| 1401.1 Scope. | |
| The provisions of Chapter 14 shall govern the materials, design, construction and installation of sub- | |
| surface landscape irrigation systems connected to nonpotable water from on | |
| - | |
| site water reuse systems. | |
| 1401.2 Materials. | |
| Above | |
| - | |
| ground drain, waste and vent p | |
| iping for subsurface landscape irrigation systems shall con- | |
| form to one of the standards listed in Table 702.1. Subsurface landscape irrigation, underground building drainage | |
| and vent pipe shall conform to one of the standards listed in Table 702.2. | |
| 1401.3 | |
| Tests. | |
| Drain, waste and vent piping for subsurface landscape irrigation systems shall be tested in accordance | |
| with Section 312. | |
| 1401.4 Inspections. | |
| Subsurface landscape irrigation systems shall be inspected in accordance with Section 107. | |
| 1401.5 Disinfecti | |
| on. | |
| Disinfection shall not be required for on | |
| - | |
| site nonpotable water reuse for subsurface landscape | |
| irrigation systems. | |
| 1401.6 Coloring. | |
| On | |
| - | |
| site nonpotable water reuse for subsurface landscape irrigation systems shall not be required to | |
| be dyed. | |
| SECTION PC | |
| 1402 | |
| SYSTEM DESIGN AND SIZING | |
| 1402.1 Sizing. | |
| The system shall be sized in accordance with the sum of the output of all water sources connected to | |
| the subsurface irrigation system. Where gray water collection piping is connected to subsurface landscape irri | |
| gation | |
| systems, gray water output shall be calculated according to the gallons | |
| - | |
| per | |
| - | |
| day | |
| - | |
| per | |
| - | |
| occupant number based on the | |
| type of fixtures connected. The gray water discharge shall be calculated by the following equation: | |
| C = A | |
| × | |
| B | |
| (Equation | |
| 14 | |
| - | |
| 1) | |
| where: | |
| A | |
| = Number of occupants: | |
| Residential | |
| – | |
| Number of occupants shall be determined by the actual number of occupants, but not less than two | |
| occupants for one bedroom and one occupant for each additional bedroom. | |
| Commercial | |
| – | |
| Number of occupants s | |
| hall be determined by the | |
| New York City Building Code | |
| . | |
| B | |
| = Estimated flow demands for each occupant*: | |
| Residential | |
| – | |
| 25 gallons per day (94.6 lpd) per occupant for showers, bathtubs and lavatories and 15 gallons per day | |
| (56.7 lpd) per occupant for clothes w | |
| ashers or laundry trays. | |
| Commercial | |
| – | |
| Based on type of fixture or water use records minus the discharge of fixtures other than those discharg- | |
| ing gray water. | |
| *Alternative estimated flow demands for each occupant shall be permitted based on actual calculate | |
| d water usage for | |
| the building. | |
| C | |
| = Estimated gray water discharge based on the total number of occupants. | |
| 1402.2 Percolation tests. | |
| The permeability of the soil in the proposed absorption system shall be determined by | |
| percolation tests or | |
| permeability evaluation. | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1402.2.1 Percolation tests and procedures. | |
| At least three percolation tests in each system area shall be conducted. | |
| The holes shall be spaced uniformly in relation to the bottom depth of the proposed absorption system. More per- | |
| cola | |
| tion tests shall be made where necessary, depending on system design. | |
| 1402.2.1.1 Percolation test hole. | |
| The test hole shall be dug or bored. The test hole shall have vertical sides and | |
| a horizontal dimension of 4 inches to 8 inches (102 mm to 203 mm). The | |
| bottom and sides of the hole shall be | |
| scratched with a sharp | |
| - | |
| pointed instrument to expose the natural soil. All loose material shall be removed from | |
| the hole and the bottom shall be covered with 2 inches (51 mm) of gravel or coarse sand. | |
| 1402.2.1.2 Test pr | |
| ocedure, sandy soils. | |
| The hole shall be filled with clear water to a minimum of 12 inches | |
| (305 mm) above the bottom of the hole for tests in sandy soils. The time for this amount of water to seep away | |
| shall be determined, and this procedure shall be repeat | |
| ed if the water from the second filling of the hole seeps | |
| away in 10 minutes or less. The test shall proceed as follows: Water shall be added to a point not more than 6 | |
| inches (152 mm) above the gravel or coarse sand. Thereupon, from a fixed reference poin | |
| t, water levels shall be | |
| measured at 10 | |
| - | |
| minute intervals for a period of 1 hour. Where 6 inches (152 mm) of water seeps away in less | |
| than 10 minutes, a shorter interval between measurements shall be used, but in no case shall the water depth | |
| exceed 6 inche | |
| s (152 mm). Where 6 inches (152 mm) of water seeps away in less than 2 minutes, the test shall | |
| be stopped and a rate of less than 1 minute per inch (2.4 s/mm) shall be reported. The final water level drop shall | |
| be used to calculate the percolation rate. So | |
| ils not meeting the above requirements shall be tested in accordance | |
| with Section 1402.2.1.3. | |
| 1402.2.1.3 Test procedure, other soils. | |
| The hole shall be filled with clear water, and a minimum water depth | |
| of 12 inches (305 mm) shall be maintained above the b | |
| ottom of the hole for a 4 | |
| - | |
| hour period by refilling whenever | |
| necessary or by use of an automatic siphon. Water remaining in the hole after 4 hours shall not be removed. | |
| Thereafter, the soil shall be allowed to swell not less than 16 hours or more than 30 ho | |
| urs. Immediately after the | |
| soil swelling period, the measurements for determining the percolation rate shall be made as follows: any soil | |
| sloughed into the hole shall be removed and the water level shall be adjusted to 6 inches (152 mm) above the | |
| gravel or | |
| coarse sand. Thereupon, from a fixed reference point, the water level shall be measured at 30 | |
| - | |
| minute | |
| intervals for a period of 4 hours, unless two successive water level drops do not vary by more than | |
| 1 | |
| / | |
| 16 | |
| inch (1.59 | |
| mm). At least three water level drops | |
| shall be observed and recorded. The hole shall be filled with clear water | |
| to a point not more than 6 inches (152 mm) above the gravel or coarse sand whenever it becomes nearly empty. | |
| Adjustments of the water level shall not be made during the three measure | |
| ment periods except to the limits of | |
| the last measured water level drop. When the first 6 inches (152 mm) of water seeps away in less than 30 | |
| minutes, the time interval between measurements shall be 10 minutes and the test run for 1 hour. The water | |
| depth s | |
| hall not exceed 5 inches (127 mm) at any time during the measurement period. The drop that occurs | |
| during the final measurement period shall be used in calculating the percolation rate. | |
| 1402.2.1.4 Mechanical test equipment. | |
| Mechanical percolation test equip | |
| ment shall be of an approved | |
| type. | |
| 1402.2.2 Permeability evaluation. | |
| Soil shall be evaluated for estimated percolation based on structure and texture | |
| in accordance with accepted soil evaluation practices. Borings shall be made in accordance with | |
| Section 1402.2.1.1 | |
| for evaluating the soil. | |
| 1402.3 Subsurface landscape irrigation site location. | |
| The surface grade of all soil absorption systems shall be lo- | |
| cated at a point lower than the surface grade of any water well or reservoir on the same or adjoin | |
| ing lot. Where this is | |
| not possible, the site shall be located so surface water drainage from the site is not directed toward a well or reservoir. | |
| The soil absorption system shall be located with a minimum horizontal distance between various elements as in | |
| dicated | |
| in Table 1402.3. Private sewage disposal systems in compacted areas, such as parking lots and driveways, are prohib- | |
| ited. Surface water shall be diverted away from any soil absorption site on the same or neighboring lots. | |
| TABLE 1402.3 | |
| LOCATION OF S | |
| UBSURFACE IRRIGATION SYSTEM | |
| ELEMENT | |
| MINIMUM HORIZONTAL DISTANCE | |
| Storage tank (feet) | |
| Irrigation disposal field | |
| (feet) | |
| Buildings | |
| 5 | |
| 10 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| Lot line adjoining | |
| private property | |
| 5 | |
| 5 | |
| Water wells | |
| 50 | |
| 100 | |
| Streams and lakes | |
| 50 | |
| 50 | |
| Seepage pits | |
| 5 | |
| 20 | |
| Septic | |
| tanks | |
| 0 | |
| 5 | |
| Water service | |
| 5 | |
| 5 | |
| Public water main | |
| 10 | |
| 10 | |
| For SI: 1 foot = 304.8 mm. | |
| SECTION PC 1403 | |
| INSTALLATION | |
| 1403.1 Installation. | |
| Absorption systems shall be installed in accordance with Sections 1403.1.1 through 1403.1.5 to | |
| provide landscape | |
| irrigation without surfacing of water. | |
| 1403.1.1 Absorption area. | |
| The total absorption area required shall be computed from the estimated daily gray | |
| water discharge and the design | |
| - | |
| loading rate based on the percolation rate for the site. The required absorpt | |
| ion area | |
| equals the estimated gray water discharge divided by the design | |
| - | |
| loading rate from Table 1403.1.1. | |
| TABLE 1403.1.1 | |
| DESIGN LOADING RATE | |
| PERCOLATION RATE | |
| (minutes per inch) | |
| DESIGN LOADING FACTOR | |
| (gallons per square foot per day) | |
| < 1 | |
| Not suitable | |
| 1 | |
| – | |
| 5 | |
| 1.20 | |
| 6 | |
| – | |
| 7 | |
| 1.00 | |
| 8 | |
| – | |
| 10 | |
| 0.90 | |
| 11 | |
| – | |
| 15 | |
| 0.80 | |
| 16 | |
| – | |
| 20 | |
| 0.70 | |
| 21 | |
| – | |
| 30 | |
| 0.60 | |
| 31 | |
| – | |
| 45 | |
| 0.50 | |
| 46 | |
| – | |
| 60 | |
| 0.45 | |
| 61 | |
| – | |
| 120 | |
| 0.20 | |
| > 120 | |
| Not Suitable | |
| For SI: 1 minute per inch = min/25.4 mm, | |
| 1 gallon per square foot = 40.7 L/m | |
| 2 | |
| . | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1403.1.2 Seepage trench excavations. | |
| Seepage trench excavations shall be not less than 1 foot (304 mm) in width | |
| and not greater than 5 feet (1524 mm) in width. Trench excavations shall be spaced not less than 2 feet (610 mm) | |
| apart. The soil absorption area | |
| of a seepage trench shall be computed by using the bottom of the trench area (width) | |
| multiplied by the length of pipe. Individual seepage trenches shall be not greater than 100 feet (30 480 mm) in | |
| developed length. | |
| 1403.1.3 Seepage bed excavations. | |
| Seepa | |
| ge bed excavations shall be not less than 5 feet (1524 mm) in width and | |
| have more than one distribution pipe. The absorption area of a seepage bed shall be computed by using the bottom | |
| of the trench area. Distribution piping in a seepage bed shall be unifo | |
| rmly spaced not greater than 5 feet (1524 mm) | |
| and not less than 3 feet (914 mm) apart, and greater than 3 feet (914 mm) and not less than 1 foot (305 mm) from | |
| the sidewall or headwall. | |
| 1403.1.4 Excavation and construction. | |
| The bottom of a trench or bed exc | |
| avation shall be level. Seepage trenches | |
| or beds shall not be excavated where the soil is so wet that such material rolled between the hands forms a soil | |
| wire. All smeared or compacted soil surfaces in the sidewalls or bottom of seepage trench or bed excav | |
| ations shall | |
| be scarified to the depth of smearing or compaction and the loose material removed. Where rain falls on an open | |
| excavation, the soil shall be left until sufficiently dry so a soil wire will not form when soil from the excavation | |
| bottom is roll | |
| ed between the hands. The bottom area shall then be scarified and loose material removed. | |
| 1403.1.5 Aggregate and backfill. | |
| Not less than 6 inches in depth of aggregate, ranging in size from | |
| 1 | |
| / | |
| 2 | |
| to 2 | |
| 1 | |
| / | |
| 2 | |
| inches (12.7 mm to 64 mm), shall be laid into the tren | |
| ch below the distribution piping elevation. The aggregate | |
| shall be evenly distributed not less than 2 inches (51 mm) in depth over the top of the distribution pipe. The aggre- | |
| gate shall be covered with approved synthetic materials or 9 inches (229 mm) of un | |
| compacted marsh hay or straw. | |
| Building paper shall not be used to cover the aggregate. Not less than 9 inches (229 mm) of soil backfill shall be | |
| provided above the covering. | |
| 1403.2 Distribution piping. | |
| Distribution piping shall be not less than 3 inches (7 | |
| 6 mm) in diameter. Materials shall | |
| comply with Table 1403.2. The top of the distribution pipe shall be not less than 4 inches (100 mm) or greater than 12 | |
| inches (300 mm) below the original surface. The slope of the distribution pipes shall be not less than | |
| 2 inches (51 mm) | |
| and not greater than 4 inches (102 mm) per 100 feet (30 480 mm). | |
| TABLE 1403.2 | |
| DISTRIBUTION PIPE | |
| MATERIAL | |
| STANDARD | |
| Polypropylene (PP) pipe | |
| ASTM F | |
| 2389 | |
| Polyethylene (PE) plastic pipe | |
| ASTM F | |
| 405 | |
| Polyvinyl chloride (PVC) plastic pipe | |
| a | |
| ASTM D | |
| 2729 | |
| Polyvinyl chloride (PVC) plastic pipe with a 3.5 | |
| - | |
| inch O.D. and solid cellular core or composite wall | |
| a | |
| ASTM F | |
| 1488 | |
| For SI: 1 inch = 25.4 mm. | |
| a. Limited to residential buildings five stories or less in | |
| height. | |
| 1403.2.1 Joints and fittings. | |
| Joints and fittings in distribution pipe shall be made in accordance with Table | |
| 1403.2.1. | |
| TABLE 1403.2.1 | |
| JOINTS AND FITTINGS | |
| MATERIAL | |
| STANDARD | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| Polyethylene (PE) plastic pipe | |
| ASTM F 405 | |
| Polypropylene (PP) pipe | |
| ASTM F 2389 | |
| Polyvinyl chloride (PVC) plastic in IPS | |
| diameters | |
| a | |
| ASTM D 2665; ASTM | |
| F 1866 | |
| Polyvinyl chloride (PVC) plastic pipe in | |
| sewer and drain diameters | |
| a | |
| ASTM D 3034 | |
| Polyvinyl chloride (PVC) plastic pipe | |
| with a 3.25 | |
| - | |
| inch O.D. | |
| a | |
| ASTM D 2949 | |
| For SI: 1 inch = 25.4 mm. | |
| a. Limited to residential buildings five stories or less in height. | |
| 1403.2.2 Diversion valves. | |
| Systems shall include a diversion valve to divert gray water | |
| to the building sanitary | |
| system when soils are saturated or frozen, there is a blockage or backup in the system, the maximum allowed | |
| gallons per day is reached, or when system maintenance is necessary. | |
| 1403.2.3 Overflow connection. | |
| Systems shall have a pi | |
| ped connection to the building drainage system to accom- | |
| modate tank overflow. | |
| CHAPTER 14 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| SECTION PC 1401 | |
| GENERAL | |
| 1401.1 Scope. | |
| The provisions of Chapter 14 shall govern the materials, design, construction and installation of sub- | |
| surface landscape irrigation systems connected to nonpotable water from on | |
| - | |
| site water reuse systems. | |
| 1401.2 Materials. | |
| Above | |
| - | |
| ground drain, waste and vent p | |
| iping for subsurface landscape irrigation systems shall con- | |
| form to one of the standards listed in Table 702.1. Subsurface landscape irrigation, underground building drainage | |
| and vent pipe shall conform to one of the standards listed in Table 702.2. | |
| 1401.3 | |
| Tests. | |
| Drain, waste and vent piping for subsurface landscape irrigation systems shall be tested in accordance | |
| with Section 312. | |
| 1401.4 Inspections. | |
| Subsurface landscape irrigation systems shall be inspected in accordance with Section 107. | |
| 1401.5 Disinfecti | |
| on. | |
| Disinfection shall not be required for on | |
| - | |
| site nonpotable water reuse for subsurface landscape | |
| irrigation systems. | |
| 1401.6 Coloring. | |
| On | |
| - | |
| site nonpotable water reuse for subsurface landscape irrigation systems shall not be required to | |
| be dyed. | |
| SECTION PC | |
| 1402 | |
| SYSTEM DESIGN AND SIZING | |
| 1402.1 Sizing. | |
| The system shall be sized in accordance with the sum of the output of all water sources connected to | |
| the subsurface irrigation system. Where gray water collection piping is connected to subsurface landscape irri | |
| gation | |
| systems, gray water output shall be calculated according to the gallons | |
| - | |
| per | |
| - | |
| day | |
| - | |
| per | |
| - | |
| occupant number based on the | |
| type of fixtures connected. The gray water discharge shall be calculated by the following equation: | |
| C = A | |
| × | |
| B | |
| (Equation | |
| 14 | |
| - | |
| 1) | |
| where: | |
| A | |
| = Number of occupants: | |
| Residential | |
| – | |
| Number of occupants shall be determined by the actual number of occupants, but not less than two | |
| occupants for one bedroom and one occupant for each additional bedroom. | |
| Commercial | |
| – | |
| Number of occupants s | |
| hall be determined by the | |
| New York City Building Code | |
| . | |
| B | |
| = Estimated flow demands for each occupant*: | |
| Residential | |
| – | |
| 25 gallons per day (94.6 lpd) per occupant for showers, bathtubs and lavatories and 15 gallons per day | |
| (56.7 lpd) per occupant for clothes w | |
| ashers or laundry trays. | |
| Commercial | |
| – | |
| Based on type of fixture or water use records minus the discharge of fixtures other than those discharg- | |
| ing gray water. | |
| *Alternative estimated flow demands for each occupant shall be permitted based on actual calculate | |
| d water usage for | |
| the building. | |
| C | |
| = Estimated gray water discharge based on the total number of occupants. | |
| 1402.2 Percolation tests. | |
| The permeability of the soil in the proposed absorption system shall be determined by | |
| percolation tests or | |
| permeability evaluation. | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1402.2.1 Percolation tests and procedures. | |
| At least three percolation tests in each system area shall be conducted. | |
| The holes shall be spaced uniformly in relation to the bottom depth of the proposed absorption system. More per- | |
| cola | |
| tion tests shall be made where necessary, depending on system design. | |
| 1402.2.1.1 Percolation test hole. | |
| The test hole shall be dug or bored. The test hole shall have vertical sides and | |
| a horizontal dimension of 4 inches to 8 inches (102 mm to 203 mm). The | |
| bottom and sides of the hole shall be | |
| scratched with a sharp | |
| - | |
| pointed instrument to expose the natural soil. All loose material shall be removed from | |
| the hole and the bottom shall be covered with 2 inches (51 mm) of gravel or coarse sand. | |
| 1402.2.1.2 Test pr | |
| ocedure, sandy soils. | |
| The hole shall be filled with clear water to a minimum of 12 inches | |
| (305 mm) above the bottom of the hole for tests in sandy soils. The time for this amount of water to seep away | |
| shall be determined, and this procedure shall be repeat | |
| ed if the water from the second filling of the hole seeps | |
| away in 10 minutes or less. The test shall proceed as follows: Water shall be added to a point not more than 6 | |
| inches (152 mm) above the gravel or coarse sand. Thereupon, from a fixed reference poin | |
| t, water levels shall be | |
| measured at 10 | |
| - | |
| minute intervals for a period of 1 hour. Where 6 inches (152 mm) of water seeps away in less | |
| than 10 minutes, a shorter interval between measurements shall be used, but in no case shall the water depth | |
| exceed 6 inche | |
| s (152 mm). Where 6 inches (152 mm) of water seeps away in less than 2 minutes, the test shall | |
| be stopped and a rate of less than 1 minute per inch (2.4 s/mm) shall be reported. The final water level drop shall | |
| be used to calculate the percolation rate. So | |
| ils not meeting the above requirements shall be tested in accordance | |
| with Section 1402.2.1.3. | |
| 1402.2.1.3 Test procedure, other soils. | |
| The hole shall be filled with clear water, and a minimum water depth | |
| of 12 inches (305 mm) shall be maintained above the b | |
| ottom of the hole for a 4 | |
| - | |
| hour period by refilling whenever | |
| necessary or by use of an automatic siphon. Water remaining in the hole after 4 hours shall not be removed. | |
| Thereafter, the soil shall be allowed to swell not less than 16 hours or more than 30 ho | |
| urs. Immediately after the | |
| soil swelling period, the measurements for determining the percolation rate shall be made as follows: any soil | |
| sloughed into the hole shall be removed and the water level shall be adjusted to 6 inches (152 mm) above the | |
| gravel or | |
| coarse sand. Thereupon, from a fixed reference point, the water level shall be measured at 30 | |
| - | |
| minute | |
| intervals for a period of 4 hours, unless two successive water level drops do not vary by more than | |
| 1 | |
| / | |
| 16 | |
| inch (1.59 | |
| mm). At least three water level drops | |
| shall be observed and recorded. The hole shall be filled with clear water | |
| to a point not more than 6 inches (152 mm) above the gravel or coarse sand whenever it becomes nearly empty. | |
| Adjustments of the water level shall not be made during the three measure | |
| ment periods except to the limits of | |
| the last measured water level drop. When the first 6 inches (152 mm) of water seeps away in less than 30 | |
| minutes, the time interval between measurements shall be 10 minutes and the test run for 1 hour. The water | |
| depth s | |
| hall not exceed 5 inches (127 mm) at any time during the measurement period. The drop that occurs | |
| during the final measurement period shall be used in calculating the percolation rate. | |
| 1402.2.1.4 Mechanical test equipment. | |
| Mechanical percolation test equip | |
| ment shall be of an approved | |
| type. | |
| 1402.2.2 Permeability evaluation. | |
| Soil shall be evaluated for estimated percolation based on structure and texture | |
| in accordance with accepted soil evaluation practices. Borings shall be made in accordance with | |
| Section 1402.2.1.1 | |
| for evaluating the soil. | |
| 1402.3 Subsurface landscape irrigation site location. | |
| The surface grade of all soil absorption systems shall be lo- | |
| cated at a point lower than the surface grade of any water well or reservoir on the same or adjoin | |
| ing lot. Where this is | |
| not possible, the site shall be located so surface water drainage from the site is not directed toward a well or reservoir. | |
| The soil absorption system shall be located with a minimum horizontal distance between various elements as in | |
| dicated | |
| in Table 1402.3. Private sewage disposal systems in compacted areas, such as parking lots and driveways, are prohib- | |
| ited. Surface water shall be diverted away from any soil absorption site on the same or neighboring lots. | |
| TABLE 1402.3 | |
| LOCATION OF S | |
| UBSURFACE IRRIGATION SYSTEM | |
| ELEMENT | |
| MINIMUM HORIZONTAL DISTANCE | |
| Storage tank (feet) | |
| Irrigation disposal field | |
| (feet) | |
| Buildings | |
| 5 | |
| 10 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| Lot line adjoining | |
| private property | |
| 5 | |
| 5 | |
| Water wells | |
| 50 | |
| 100 | |
| Streams and lakes | |
| 50 | |
| 50 | |
| Seepage pits | |
| 5 | |
| 20 | |
| Septic | |
| tanks | |
| 0 | |
| 5 | |
| Water service | |
| 5 | |
| 5 | |
| Public water main | |
| 10 | |
| 10 | |
| For SI: 1 foot = 304.8 mm. | |
| SECTION PC 1403 | |
| INSTALLATION | |
| 1403.1 Installation. | |
| Absorption systems shall be installed in accordance with Sections 1403.1.1 through 1403.1.5 to | |
| provide landscape | |
| irrigation without surfacing of water. | |
| 1403.1.1 Absorption area. | |
| The total absorption area required shall be computed from the estimated daily gray | |
| water discharge and the design | |
| - | |
| loading rate based on the percolation rate for the site. The required absorpt | |
| ion area | |
| equals the estimated gray water discharge divided by the design | |
| - | |
| loading rate from Table 1403.1.1. | |
| TABLE 1403.1.1 | |
| DESIGN LOADING RATE | |
| PERCOLATION RATE | |
| (minutes per inch) | |
| DESIGN LOADING FACTOR | |
| (gallons per square foot per day) | |
| < 1 | |
| Not suitable | |
| 1 | |
| – | |
| 5 | |
| 1.20 | |
| 6 | |
| – | |
| 7 | |
| 1.00 | |
| 8 | |
| – | |
| 10 | |
| 0.90 | |
| 11 | |
| – | |
| 15 | |
| 0.80 | |
| 16 | |
| – | |
| 20 | |
| 0.70 | |
| 21 | |
| – | |
| 30 | |
| 0.60 | |
| 31 | |
| – | |
| 45 | |
| 0.50 | |
| 46 | |
| – | |
| 60 | |
| 0.45 | |
| 61 | |
| – | |
| 120 | |
| 0.20 | |
| > 120 | |
| Not Suitable | |
| For SI: 1 minute per inch = min/25.4 mm, | |
| 1 gallon per square foot = 40.7 L/m | |
| 2 | |
| . | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1403.1.2 Seepage trench excavations. | |
| Seepage trench excavations shall be not less than 1 foot (304 mm) in width | |
| and not greater than 5 feet (1524 mm) in width. Trench excavations shall be spaced not less than 2 feet (610 mm) | |
| apart. The soil absorption area | |
| of a seepage trench shall be computed by using the bottom of the trench area (width) | |
| multiplied by the length of pipe. Individual seepage trenches shall be not greater than 100 feet (30 480 mm) in | |
| developed length. | |
| 1403.1.3 Seepage bed excavations. | |
| Seepa | |
| ge bed excavations shall be not less than 5 feet (1524 mm) in width and | |
| have more than one distribution pipe. The absorption area of a seepage bed shall be computed by using the bottom | |
| of the trench area. Distribution piping in a seepage bed shall be unifo | |
| rmly spaced not greater than 5 feet (1524 mm) | |
| and not less than 3 feet (914 mm) apart, and greater than 3 feet (914 mm) and not less than 1 foot (305 mm) from | |
| the sidewall or headwall. | |
| 1403.1.4 Excavation and construction. | |
| The bottom of a trench or bed exc | |
| avation shall be level. Seepage trenches | |
| or beds shall not be excavated where the soil is so wet that such material rolled between the hands forms a soil | |
| wire. All smeared or compacted soil surfaces in the sidewalls or bottom of seepage trench or bed excav | |
| ations shall | |
| be scarified to the depth of smearing or compaction and the loose material removed. Where rain falls on an open | |
| excavation, the soil shall be left until sufficiently dry so a soil wire will not form when soil from the excavation | |
| bottom is roll | |
| ed between the hands. The bottom area shall then be scarified and loose material removed. | |
| 1403.1.5 Aggregate and backfill. | |
| Not less than 6 inches in depth of aggregate, ranging in size from | |
| 1 | |
| / | |
| 2 | |
| to 2 | |
| 1 | |
| / | |
| 2 | |
| inches (12.7 mm to 64 mm), shall be laid into the tren | |
| ch below the distribution piping elevation. The aggregate | |
| shall be evenly distributed not less than 2 inches (51 mm) in depth over the top of the distribution pipe. The aggre- | |
| gate shall be covered with approved synthetic materials or 9 inches (229 mm) of un | |
| compacted marsh hay or straw. | |
| Building paper shall not be used to cover the aggregate. Not less than 9 inches (229 mm) of soil backfill shall be | |
| provided above the covering. | |
| 1403.2 Distribution piping. | |
| Distribution piping shall be not less than 3 inches (7 | |
| 6 mm) in diameter. Materials shall | |
| comply with Table 1403.2. The top of the distribution pipe shall be not less than 4 inches (100 mm) or greater than 12 | |
| inches (300 mm) below the original surface. The slope of the distribution pipes shall be not less than | |
| 2 inches (51 mm) | |
| and not greater than 4 inches (102 mm) per 100 feet (30 480 mm). | |
| TABLE 1403.2 | |
| DISTRIBUTION PIPE | |
| MATERIAL | |
| STANDARD | |
| Polypropylene (PP) pipe | |
| ASTM F | |
| 2389 | |
| Polyethylene (PE) plastic pipe | |
| ASTM F | |
| 405 | |
| Polyvinyl chloride (PVC) plastic pipe | |
| a | |
| ASTM D | |
| 2729 | |
| Polyvinyl chloride (PVC) plastic pipe with a 3.5 | |
| - | |
| inch O.D. and solid cellular core or composite wall | |
| a | |
| ASTM F | |
| 1488 | |
| For SI: 1 inch = 25.4 mm. | |
| a. Limited to residential buildings five stories or less in | |
| height. | |
| 1403.2.1 Joints and fittings. | |
| Joints and fittings in distribution pipe shall be made in accordance with Table | |
| 1403.2.1. | |
| TABLE 1403.2.1 | |
| JOINTS AND FITTINGS | |
| MATERIAL | |
| STANDARD | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| Polyethylene (PE) plastic pipe | |
| ASTM F 405 | |
| Polypropylene (PP) pipe | |
| ASTM F 2389 | |
| Polyvinyl chloride (PVC) plastic in IPS | |
| diameters | |
| a | |
| ASTM D 2665; ASTM | |
| F 1866 | |
| Polyvinyl chloride (PVC) plastic pipe in | |
| sewer and drain diameters | |
| a | |
| ASTM D 3034 | |
| Polyvinyl chloride (PVC) plastic pipe | |
| with a 3.25 | |
| - | |
| inch O.D. | |
| a | |
| ASTM D 2949 | |
| For SI: 1 inch = 25.4 mm. | |
| a. Limited to residential buildings five stories or less in height. | |
| 1403.2.2 Diversion valves. | |
| Systems shall include a diversion valve to divert gray water | |
| to the building sanitary | |
| system when soils are saturated or frozen, there is a blockage or backup in the system, the maximum allowed | |
| gallons per day is reached, or when system maintenance is necessary. | |
| 1403.2.3 Overflow connection. | |
| Systems shall have a pi | |
| ped connection to the building drainage system to accom- | |
| modate tank overflow. | |
| CHAPTER 14 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| SECTION PC 1401 | |
| GENERAL | |
| 1401.1 Scope. | |
| The provisions of Chapter 14 shall govern the materials, design, construction and installation of sub- | |
| surface landscape irrigation systems connected to nonpotable water from on | |
| - | |
| site water reuse systems. | |
| 1401.2 Materials. | |
| Above | |
| - | |
| ground drain, waste and vent p | |
| iping for subsurface landscape irrigation systems shall con- | |
| form to one of the standards listed in Table 702.1. Subsurface landscape irrigation, underground building drainage | |
| and vent pipe shall conform to one of the standards listed in Table 702.2. | |
| 1401.3 | |
| Tests. | |
| Drain, waste and vent piping for subsurface landscape irrigation systems shall be tested in accordance | |
| with Section 312. | |
| 1401.4 Inspections. | |
| Subsurface landscape irrigation systems shall be inspected in accordance with Section 107. | |
| 1401.5 Disinfecti | |
| on. | |
| Disinfection shall not be required for on | |
| - | |
| site nonpotable water reuse for subsurface landscape | |
| irrigation systems. | |
| 1401.6 Coloring. | |
| On | |
| - | |
| site nonpotable water reuse for subsurface landscape irrigation systems shall not be required to | |
| be dyed. | |
| SECTION PC | |
| 1402 | |
| SYSTEM DESIGN AND SIZING | |
| 1402.1 Sizing. | |
| The system shall be sized in accordance with the sum of the output of all water sources connected to | |
| the subsurface irrigation system. Where gray water collection piping is connected to subsurface landscape irri | |
| gation | |
| systems, gray water output shall be calculated according to the gallons | |
| - | |
| per | |
| - | |
| day | |
| - | |
| per | |
| - | |
| occupant number based on the | |
| type of fixtures connected. The gray water discharge shall be calculated by the following equation: | |
| C = A | |
| × | |
| B | |
| (Equation | |
| 14 | |
| - | |
| 1) | |
| where: | |
| A | |
| = Number of occupants: | |
| Residential | |
| – | |
| Number of occupants shall be determined by the actual number of occupants, but not less than two | |
| occupants for one bedroom and one occupant for each additional bedroom. | |
| Commercial | |
| – | |
| Number of occupants s | |
| hall be determined by the | |
| New York City Building Code | |
| . | |
| B | |
| = Estimated flow demands for each occupant*: | |
| Residential | |
| – | |
| 25 gallons per day (94.6 lpd) per occupant for showers, bathtubs and lavatories and 15 gallons per day | |
| (56.7 lpd) per occupant for clothes w | |
| ashers or laundry trays. | |
| Commercial | |
| – | |
| Based on type of fixture or water use records minus the discharge of fixtures other than those discharg- | |
| ing gray water. | |
| *Alternative estimated flow demands for each occupant shall be permitted based on actual calculate | |
| d water usage for | |
| the building. | |
| C | |
| = Estimated gray water discharge based on the total number of occupants. | |
| 1402.2 Percolation tests. | |
| The permeability of the soil in the proposed absorption system shall be determined by | |
| percolation tests or | |
| permeability evaluation. | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1402.2.1 Percolation tests and procedures. | |
| At least three percolation tests in each system area shall be conducted. | |
| The holes shall be spaced uniformly in relation to the bottom depth of the proposed absorption system. More per- | |
| cola | |
| tion tests shall be made where necessary, depending on system design. | |
| 1402.2.1.1 Percolation test hole. | |
| The test hole shall be dug or bored. The test hole shall have vertical sides and | |
| a horizontal dimension of 4 inches to 8 inches (102 mm to 203 mm). The | |
| bottom and sides of the hole shall be | |
| scratched with a sharp | |
| - | |
| pointed instrument to expose the natural soil. All loose material shall be removed from | |
| the hole and the bottom shall be covered with 2 inches (51 mm) of gravel or coarse sand. | |
| 1402.2.1.2 Test pr | |
| ocedure, sandy soils. | |
| The hole shall be filled with clear water to a minimum of 12 inches | |
| (305 mm) above the bottom of the hole for tests in sandy soils. The time for this amount of water to seep away | |
| shall be determined, and this procedure shall be repeat | |
| ed if the water from the second filling of the hole seeps | |
| away in 10 minutes or less. The test shall proceed as follows: Water shall be added to a point not more than 6 | |
| inches (152 mm) above the gravel or coarse sand. Thereupon, from a fixed reference poin | |
| t, water levels shall be | |
| measured at 10 | |
| - | |
| minute intervals for a period of 1 hour. Where 6 inches (152 mm) of water seeps away in less | |
| than 10 minutes, a shorter interval between measurements shall be used, but in no case shall the water depth | |
| exceed 6 inche | |
| s (152 mm). Where 6 inches (152 mm) of water seeps away in less than 2 minutes, the test shall | |
| be stopped and a rate of less than 1 minute per inch (2.4 s/mm) shall be reported. The final water level drop shall | |
| be used to calculate the percolation rate. So | |
| ils not meeting the above requirements shall be tested in accordance | |
| with Section 1402.2.1.3. | |
| 1402.2.1.3 Test procedure, other soils. | |
| The hole shall be filled with clear water, and a minimum water depth | |
| of 12 inches (305 mm) shall be maintained above the b | |
| ottom of the hole for a 4 | |
| - | |
| hour period by refilling whenever | |
| necessary or by use of an automatic siphon. Water remaining in the hole after 4 hours shall not be removed. | |
| Thereafter, the soil shall be allowed to swell not less than 16 hours or more than 30 ho | |
| urs. Immediately after the | |
| soil swelling period, the measurements for determining the percolation rate shall be made as follows: any soil | |
| sloughed into the hole shall be removed and the water level shall be adjusted to 6 inches (152 mm) above the | |
| gravel or | |
| coarse sand. Thereupon, from a fixed reference point, the water level shall be measured at 30 | |
| - | |
| minute | |
| intervals for a period of 4 hours, unless two successive water level drops do not vary by more than | |
| 1 | |
| / | |
| 16 | |
| inch (1.59 | |
| mm). At least three water level drops | |
| shall be observed and recorded. The hole shall be filled with clear water | |
| to a point not more than 6 inches (152 mm) above the gravel or coarse sand whenever it becomes nearly empty. | |
| Adjustments of the water level shall not be made during the three measure | |
| ment periods except to the limits of | |
| the last measured water level drop. When the first 6 inches (152 mm) of water seeps away in less than 30 | |
| minutes, the time interval between measurements shall be 10 minutes and the test run for 1 hour. The water | |
| depth s | |
| hall not exceed 5 inches (127 mm) at any time during the measurement period. The drop that occurs | |
| during the final measurement period shall be used in calculating the percolation rate. | |
| 1402.2.1.4 Mechanical test equipment. | |
| Mechanical percolation test equip | |
| ment shall be of an approved | |
| type. | |
| 1402.2.2 Permeability evaluation. | |
| Soil shall be evaluated for estimated percolation based on structure and texture | |
| in accordance with accepted soil evaluation practices. Borings shall be made in accordance with | |
| Section 1402.2.1.1 | |
| for evaluating the soil. | |
| 1402.3 Subsurface landscape irrigation site location. | |
| The surface grade of all soil absorption systems shall be lo- | |
| cated at a point lower than the surface grade of any water well or reservoir on the same or adjoin | |
| ing lot. Where this is | |
| not possible, the site shall be located so surface water drainage from the site is not directed toward a well or reservoir. | |
| The soil absorption system shall be located with a minimum horizontal distance between various elements as in | |
| dicated | |
| in Table 1402.3. Private sewage disposal systems in compacted areas, such as parking lots and driveways, are prohib- | |
| ited. Surface water shall be diverted away from any soil absorption site on the same or neighboring lots. | |
| TABLE 1402.3 | |
| LOCATION OF S | |
| UBSURFACE IRRIGATION SYSTEM | |
| ELEMENT | |
| MINIMUM HORIZONTAL DISTANCE | |
| Storage tank (feet) | |
| Irrigation disposal field | |
| (feet) | |
| Buildings | |
| 5 | |
| 10 | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| Lot line adjoining | |
| private property | |
| 5 | |
| 5 | |
| Water wells | |
| 50 | |
| 100 | |
| Streams and lakes | |
| 50 | |
| 50 | |
| Seepage pits | |
| 5 | |
| 20 | |
| Septic | |
| tanks | |
| 0 | |
| 5 | |
| Water service | |
| 5 | |
| 5 | |
| Public water main | |
| 10 | |
| 10 | |
| For SI: 1 foot = 304.8 mm. | |
| SECTION PC 1403 | |
| INSTALLATION | |
| 1403.1 Installation. | |
| Absorption systems shall be installed in accordance with Sections 1403.1.1 through 1403.1.5 to | |
| provide landscape | |
| irrigation without surfacing of water. | |
| 1403.1.1 Absorption area. | |
| The total absorption area required shall be computed from the estimated daily gray | |
| water discharge and the design | |
| - | |
| loading rate based on the percolation rate for the site. The required absorpt | |
| ion area | |
| equals the estimated gray water discharge divided by the design | |
| - | |
| loading rate from Table 1403.1.1. | |
| TABLE 1403.1.1 | |
| DESIGN LOADING RATE | |
| PERCOLATION RATE | |
| (minutes per inch) | |
| DESIGN LOADING FACTOR | |
| (gallons per square foot per day) | |
| < 1 | |
| Not suitable | |
| 1 | |
| – | |
| 5 | |
| 1.20 | |
| 6 | |
| – | |
| 7 | |
| 1.00 | |
| 8 | |
| – | |
| 10 | |
| 0.90 | |
| 11 | |
| – | |
| 15 | |
| 0.80 | |
| 16 | |
| – | |
| 20 | |
| 0.70 | |
| 21 | |
| – | |
| 30 | |
| 0.60 | |
| 31 | |
| – | |
| 45 | |
| 0.50 | |
| 46 | |
| – | |
| 60 | |
| 0.45 | |
| 61 | |
| – | |
| 120 | |
| 0.20 | |
| > 120 | |
| Not Suitable | |
| For SI: 1 minute per inch = min/25.4 mm, | |
| 1 gallon per square foot = 40.7 L/m | |
| 2 | |
| . | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| 1403.1.2 Seepage trench excavations. | |
| Seepage trench excavations shall be not less than 1 foot (304 mm) in width | |
| and not greater than 5 feet (1524 mm) in width. Trench excavations shall be spaced not less than 2 feet (610 mm) | |
| apart. The soil absorption area | |
| of a seepage trench shall be computed by using the bottom of the trench area (width) | |
| multiplied by the length of pipe. Individual seepage trenches shall be not greater than 100 feet (30 480 mm) in | |
| developed length. | |
| 1403.1.3 Seepage bed excavations. | |
| Seepa | |
| ge bed excavations shall be not less than 5 feet (1524 mm) in width and | |
| have more than one distribution pipe. The absorption area of a seepage bed shall be computed by using the bottom | |
| of the trench area. Distribution piping in a seepage bed shall be unifo | |
| rmly spaced not greater than 5 feet (1524 mm) | |
| and not less than 3 feet (914 mm) apart, and greater than 3 feet (914 mm) and not less than 1 foot (305 mm) from | |
| the sidewall or headwall. | |
| 1403.1.4 Excavation and construction. | |
| The bottom of a trench or bed exc | |
| avation shall be level. Seepage trenches | |
| or beds shall not be excavated where the soil is so wet that such material rolled between the hands forms a soil | |
| wire. All smeared or compacted soil surfaces in the sidewalls or bottom of seepage trench or bed excav | |
| ations shall | |
| be scarified to the depth of smearing or compaction and the loose material removed. Where rain falls on an open | |
| excavation, the soil shall be left until sufficiently dry so a soil wire will not form when soil from the excavation | |
| bottom is roll | |
| ed between the hands. The bottom area shall then be scarified and loose material removed. | |
| 1403.1.5 Aggregate and backfill. | |
| Not less than 6 inches in depth of aggregate, ranging in size from | |
| 1 | |
| / | |
| 2 | |
| to 2 | |
| 1 | |
| / | |
| 2 | |
| inches (12.7 mm to 64 mm), shall be laid into the tren | |
| ch below the distribution piping elevation. The aggregate | |
| shall be evenly distributed not less than 2 inches (51 mm) in depth over the top of the distribution pipe. The aggre- | |
| gate shall be covered with approved synthetic materials or 9 inches (229 mm) of un | |
| compacted marsh hay or straw. | |
| Building paper shall not be used to cover the aggregate. Not less than 9 inches (229 mm) of soil backfill shall be | |
| provided above the covering. | |
| 1403.2 Distribution piping. | |
| Distribution piping shall be not less than 3 inches (7 | |
| 6 mm) in diameter. Materials shall | |
| comply with Table 1403.2. The top of the distribution pipe shall be not less than 4 inches (100 mm) or greater than 12 | |
| inches (300 mm) below the original surface. The slope of the distribution pipes shall be not less than | |
| 2 inches (51 mm) | |
| and not greater than 4 inches (102 mm) per 100 feet (30 480 mm). | |
| TABLE 1403.2 | |
| DISTRIBUTION PIPE | |
| MATERIAL | |
| STANDARD | |
| Polypropylene (PP) pipe | |
| ASTM F | |
| 2389 | |
| Polyethylene (PE) plastic pipe | |
| ASTM F | |
| 405 | |
| Polyvinyl chloride (PVC) plastic pipe | |
| a | |
| ASTM D | |
| 2729 | |
| Polyvinyl chloride (PVC) plastic pipe with a 3.5 | |
| - | |
| inch O.D. and solid cellular core or composite wall | |
| a | |
| ASTM F | |
| 1488 | |
| For SI: 1 inch = 25.4 mm. | |
| a. Limited to residential buildings five stories or less in | |
| height. | |
| 1403.2.1 Joints and fittings. | |
| Joints and fittings in distribution pipe shall be made in accordance with Table | |
| 1403.2.1. | |
| TABLE 1403.2.1 | |
| JOINTS AND FITTINGS | |
| MATERIAL | |
| STANDARD | |
| SUBSURFACE LANDSCAPE IRRIGATION SYSTEMS | |
| Polyethylene (PE) plastic pipe | |
| ASTM F 405 | |
| Polypropylene (PP) pipe | |
| ASTM F 2389 | |
| Polyvinyl chloride (PVC) plastic in IPS | |
| diameters | |
| a | |
| ASTM D 2665; ASTM | |
| F 1866 | |
| Polyvinyl chloride (PVC) plastic pipe in | |
| sewer and drain diameters | |
| a | |
| ASTM D 3034 | |
| Polyvinyl chloride (PVC) plastic pipe | |
| with a 3.25 | |
| - | |
| inch O.D. | |
| a | |
| ASTM D 2949 | |
| For SI: 1 inch = 25.4 mm. | |
| a. Limited to residential buildings five stories or less in height. | |
| 1403.2.2 Diversion valves. | |
| Systems shall include a diversion valve to divert gray water | |
| to the building sanitary | |
| system when soils are saturated or frozen, there is a blockage or backup in the system, the maximum allowed | |
| gallons per day is reached, or when system maintenance is necessary. | |
| 1403.2.3 Overflow connection. | |
| Systems shall have a pi | |
| ped connection to the building drainage system to accom- | |
| modate tank overflow. |