The professional tool for gas engineers. Step-by-step IGEM/UP/1B procedures, live pressure calculations, and documented results — all in your pocket.
One-time purchase · £7.99 · No subscription · Free updates forever
Enter your readings and the app instantly calculates test pressures, permissible pressure drops, and stabilisation times — all in line with IGEM/UP/1B Edition 4.
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 clean summary of your test results to attach to your gas safety certificate or keep for your own records. Perfect for commercial compliance jobs.
Covers domestic and commercial installations, different pipe volumes, and varying working pressures — all handled automatically based on your inputs.
Select whether you're carrying out a tightness test, a purging operation, or both. The app loads the correct IGEM/UP/1B sequence automatically.
Enter working pressure, pipe volume, and live gauge readings as prompted. The app calculates permissible drop values and test durations in real time.
Receive a clear pass/fail assessment compliant with Edition 4. Export a summary to attach to your certificate or share directly with your customer.
Eight guided steps take you from setup to a signed PDF certificate — 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.
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.
Edition 4 extends scope to include caravans and LAVs for the first time, with dedicated test procedures and pressure limits.
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 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.
When the app tells you a result is satisfactory, you can be confident it's because someone who helped write the rules says so.
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.
We're a small team and we reply to every message. 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.