GasTest Pro

GasTest Pro is the professional on-site calculation tool for gas engineers carrying out domestic tightness testing and purging to IGEM/UP/1B Edition 4. Designed for qualified, registered engineers working in homes, flats and small domestic installations, it replaces error-prone manual calculations and printed tables with a fast, accurate, standards-based reference you can rely on at the meter and on the job. Whether you're commissioning a new domestic installation, carrying out a routine tightness test after fitting or replacing a boiler, or purging a section after work has been carried out, GasTest Pro guides you through the volumes that matter. Enter the pipework you've surveyed, the valves and fittings in the section, and the meter details, and the app instantly calculates the total installation volume, the permissible pressure drop for your tightness test, and the required purge volume — all in one clean, mobile-first screen built for on-site use. How it works GasTest Pro breaks the calculation into three core components that make up an installation volume: 1. Pipe volume — Survey the whole section and enter only the pipe sizes actually used. The app references standard pipe internal volumes to IGEM/UP/1 Edition 4 (Appendix 7), so you don't need to look up diameters or carry printed tables. Leave any sizes you haven't used blank and they're excluded from the total. 2. Valves and fittings volume — Enter the actual component volume first, taken from manufacturer data where available. Where a calculated volume can't be determined, the app applies the 10% fallback as permitted by the standard, so you're always working within the accepted method. 3. Meter volume — Select the meter from the standard meter table or enter a manufacturer figure for non-standard installations. The app confirms your selection before including it, so there's no ambiguity about what's been counted. From these inputs, GasTest Pro calculates the total installation volume (IV), determines the permissible pressure drop for the tightness test based on gas type and volume, and calculates the purge volume at 1.5 × IV — the volume of gas that must be passed through the section to complete a safe purge. Typical use * Commissioning a new domestic gas installation * Tightness testing after a boiler change or meter swap * Purging a section after pipework alterations * Routine tightness testing on existing installations * Calculating volumes for a gas safety record Key features * Pipe, fittings and meter volume calculation to IGEM/UP/1 Edition 4 * Automatic permissible pressure drop for the tightness test * Purge volume at 1.5 × installation volume * Natural gas and LPG support * Mobile-first interface designed for one-handed use on site * Pull-to-reset to clear all inputs * Copy-to-clipboard results summary for your records * Secure account login and account deletion from within the app Who it's for GasTest Pro is designed for qualified, registered gas engineers who carry out domestic tightness testing and purging as part of their day-to-day work. It is a calculation aid only and does not replace the current standard, formal training, manufacturer instructions, or your own professional judgement. Always verify values on site and confirm the section is within IGEM/UP/1B scope before relying on any result. A note on standards All calculations are based on IGEM/UP/1B Edition 4 (Appendix 7). Standards are updated periodically and this app is a guide only — always refer to the current edition of the standard for the authoritative requirements. GasTest Pro is not affiliated with IGEM and the Institution of Gas Engineers & Managers does not endorse this product.