Update README.md

README.md

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+# ASME Section VIII — Preliminary Pressure Vessel Calculator (Streamlit)
+
+**Version:** 0.1.0
+
+**Disclaimer:** This tool is for preliminary design and educational purposes only. Final design, verification, and construction decisions must be made and stamped by a licensed professional engineer and verified against the latest ASME code editions.
+
 ---
-title: Shell Head Calculator
-emoji: 🦀
-colorFrom: red
-colorTo: green
-sdk: streamlit
-sdk_version: 1.49.1
-app_file: app.py
-pinned: false
+
+## What this app does
+
+This Streamlit app performs preliminary pressure-vessel calculations referenced to ASME Section VIII style rules:
+
+- UG-27 shell thickness (circumferential & longitudinal checks)
+- UG-32 head thickness (ellipsoidal, torispherical, hemispherical)
+- Simplified UG-37-style nozzle reinforcement area check (conservative approximation)
+- PWHT recommendation (simplified, UCS-56 guidance)
+- Impact test / MDMT comparison (approximate UCS-66-style check)
+- MAWP from thickness (inverse calculation)
+- Exports: Summary CSV and optional PDF (requires `reportlab`)
+
+**Important:** The app contains approximations and conservative assumptions. Use it for preliminary sizing, documentation, and educational purposes only.
+
 ---
 
-Check out the configuration reference at https://huggingface.co/docs/hub/spaces-config-reference
+## Installation
+
+1. Clone or download the repository.
+2. Create a Python 3.10+ virtual environment (recommended).
+3. Install dependencies:
+
+```bash
+python -m pip install -r requirements.txt