The professional tool for gas engineers. Step-by-step IGEM/UP/1B procedures, displays fuel specific test pressures, and documented results — all in your pocket.
One-time purchase · £8.99 early adopter price · normally £14.99 · No subscription
Enter the fuel type and the app instantly displays the test pressure.
Never miss a step. The app guides you through each phase of the tightness test and purging procedure in the correct sequence, from isolation to purge completion.
Clear, unambiguous results at every stage. The app tells you whether readings are satisfactory, require further investigation, or indicate a suspected escape.
Works anywhere — no signal required. All calculations run on-device so you're never left waiting on a job. When you're back online, results and settings sync automatically so nothing is ever lost.
Generate a clear summary of your test results to attach to your gas safety record or keep for your own records. Perfect for commercial compliance jobs.
Covers domestic and small commercial installations, different pipe volumes, and varying working pressures — all handled automatically based on your inputs.
Eight guided steps take you from setup to a signed PDF record — nothing missed, nothing guessed.
Saves me double-checking every time. I used to have the standard bookmarked on my phone — now I just open this and it walks me through the whole thing. No mistakes, no stress.
Worth every penny. The Edition 4 changes caught me out when they first dropped — this app has everything updated. I use it on every domestic job now. The exported result is a nice touch.
As a trainer I've been recommending this to everyone on my ACS courses. Brilliant for learners and experienced engineers alike. Exactly what the industry needed.
Finally an app that takes the guesswork out of tightness testing. Clean, straightforward and totally reliable. I've given every team member a license for this app — it's a no-brainer at this price.
IGEM/UP/1B Edition 4 was published in March 2026 and supersedes Edition 3. It's the current standard for tightness testing and purging of domestic and small commercial gas installations in the UK, and all Gas Safe engineers are expected to work to it.
If you're still using Edition 3 figures or memory from your initial training, there's a good chance something has changed. UP/1B Calculator implements Edition 4 in full — so you don't have to track it yourself.
Clarifications to Stage 1 and Stage 2 permissible pressure drop thresholds and how let-by is assessed against installation volume.
Updated working pressure references and test pressure calculations for LPG and LPG-Air installations.
Refined guidance on purge volumes for different installation sizes and appliance types, covering direct and indirect purging sequences.
Strengthened requirements for recording and retaining test results — reinforcing the need for a documented audit trail on every job.
Every calculation, permissible pressure drop, stabilisation period, and purging sequence inside UP/1B Calculator is based on the current IGEM/UP/1B Edition 4 standard — the authoritative procedure for tightness testing and purging of domestic and small commercial gas installations in the UK.
UP/1B Calculator wasn't built by software developers guessing at gas procedures. It was developed in close collaboration with industry-leading gas engineering experts with decades of hands-on experience in the field.
Our technical team includes professionals who spent over two decades as senior Gas Safe / CORGI inspectors — working directly on the standards, procedures, and compliance frameworks that govern the industry. The same knowledge that shaped IGEM/UP/1B is built into every step of this app.
No other software company in this space has access to this level of gas industry expertise. That's not a claim — it's a fact. UP/1B Calculator is in a class of its own.
Technical queries, procedure questions, or bulk purchase enquiries — just get in touch.
Stop double-checking your workings. Get the right answer, first time, every time — fully in line with IGEM/UP/1B Edition 4.
Intellectual Property Notice: The design, user interface, visual style, layout, and workflow of UP/1B Calculator are the exclusive intellectual property of Gas Installers Workmate Ltd and are protected under UK and international copyright law. This includes the structure, navigation, screen design, and the unique way in which the IGEM/UP/1B procedure has been implemented and presented within the application. Unauthorised reproduction, imitation, or distribution of any part of this application's design or workflow — in whole or in part — is strictly prohibited and will be pursued vigorously through civil and, where applicable, criminal legal proceedings. All rights reserved. © 2026 Gas Installers Workmate Ltd.