# Commercial Gas Calculator > Calculates purge time for non-domestic natural gas installations per IGE/UP/1A. (iPhone/iPad app by Oliver Shingler.) - Source: https://appshunter.io/ios/app/commercial-gas-calculator/id997737518 (this page in markdown: same URL + `.md`) - Developer: [Oliver Shingler](https://appshunter.io/developer/886565740) - Category: Utilities, Reference - Price: $1.99 with in-app purchases - Age rating: 4+ - Requires: iOS 15.0 · 2 MB - Languages: American English - Released: 2015-06-06 - Data updated: 2026-09-04 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/commercial-gas-calculator/id997737518/reviews.md ## What is Commercial Gas Calculator? This quick and simple-to-use app will assist gas engineers in calculating the maximum time required to purge air from a non-domestic natural gas installation, allowing the appliances to fire correctly. Suitable for natural gas (NG) installations only, with an installation volume not exceeding 1m³, and a maximum operating pressure (MOP) not exceeding 40mbar at the outlet of the primary meter regulator. Calculations are performed in accordance with IGE/UP/1A and are intended to help you double-check your own calculations. If you also require the tightness testing duration (TTD) for the system, the option to calculate this is available to purchase in-app. For the busy multi-client gas professional, there's an option to purchase a Save Installations add-on allowing you to save and retrieve installation layouts for future reference. ## Key features - Calculate maximum purge time - Supports non-domestic natural gas - Adheres to IGE/UP/1A standards - In-app purchase for tightness testing - Optional save installations add-on ## Pricing and in-app purchases Base price: $1.99. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Tightness Testing Duration | $0.99 | one-time | | Save Installations | $0.99 | one-time | ## Recent user reviews (10 of 17) All indexed reviews: https://appshunter.io/ios/app/commercial-gas-calculator/id997737518/reviews.md ### 1/5 — Absolute rubbish *2025-07-24* Doesn’t do anything lets you put measurements in then wont add to system tried on iPhone and ipad same results zero **Developer response:** I have just tested on an iPhone 14 Pro, 16 Pro and an 11-inch iPad Pro (M4), all running iOS 18.5. I can't find any issues with adding pipe lengths to the system, it all appears to be working fine. Could you please let me know your device and iOS version so as I can try and replicate your issue please? You can contact me via my web site here: https://www.speaktothegeek.co.uk/support-and-contact-info ### 3/5 — Could be better *2023-01-12* Would be a lot better and more useful if it was made useable for UP1 as well ### 2/5 — Hose size on the purge makes no difference *2021-01-07* Very disappointed to see that the purge time remains the same for a 15mm purge point as it does a 50mm Something very wrong here hey ### 2/5 — Seriously lacking *2020-09-27* This is fine for domestic and medium-sized commercial installations, but where it falls short is on calculations involving larger internal volumes. I find that once you get up to about 1.8 cubic meters or above, it simply errors and does not give purge and test times at all. Furthermore the steel pipe sizes (a) are given in mm when steel is always measured imperially - in inches and fractions (b) only goes up to 150mm - six inches - when eight inch, twelve and above are common. Disappointing app that really could be indispensable with these small changes. ### 1/5 — Could be so much better *2020-03-15* Yes the calculator gives TTD but the calculations above do no indicate IVmeter so does not give IV to total I expected the calculator to allow for maximum permissible leak rates, but sadly it just works out the purge volume and TTD although given i had to manually work out to see if it was correct NO TTP nor let by period Unfortunately the app is sadly lacking however it does work out the pipe volume correctly ! ### 1/5 — Not Great. *2020-03-09* Does not offer standard UK sizes for pipework or even press systems. No 35mm, 54mm, 66.7mm etc etc Update, I was referring to press systems, Mapress, Xpress, M-Press etc etc What about Stainless or Carbon Press? Copper and barrel are old hat these days **Developer response:** This app is specifically targeted at the UK with UK specific sizes listed for pipework, including copper pipes with a diameter of 35mm, 54mm and 67mm. ### 1/5 — Dangerously inaccurate *2019-12-19* Bought this in the hope that all the other reviews were wrong and somehow it would be ok for me, tested it on a tightness test that I had already calculated, true system volume was 0.95xxxm3, the app came out with 0.85xxxm3 and said the test time would be..... 2 minutes!!!! **Developer response:** Hi, could you please contact me at support@speaktothegeek.co.uk with your worked example so as I can reproduce the problem. Your assistance in resolving this will be greatly appreciated as current test scenarios are not showing any errors. ### 1/5 — RIP OFF!! *2019-12-18* Load of rubbish!!!! Will be asking for my money back!!! Not paying every time I want a calculation! Much rather pay £50.00 for one that works every time and not charge for the results each time! Do not buy!! It’s a scam! They don’t tell you that you need to pay for each result!! **Developer response:** This is not true, you do not have to pay for each calculation. Included with the purchase of the app is unlimited calculations of purge times. If you would like the tightness testing duration then this can be unlocked in-app for unlimited calculations as a one-time purchase. ### 2/5 — Wrong calculations *2019-11-14* Was a good app when I bought it until I realised the calculations were somehow wrong. I worked one out today using the book (did it three times) & came out as 191 second purge time where as this app said 94 seconds ! Be using the trusted book next time ! **Developer response:** Hi, could you please contact me at support@speaktothegeek.co.uk with your worked example so as I can reproduce the problem. Your assistance in resolving this will be greatly appreciated as current test scenarios are not showing any errors. ### 1/5 — Very carefully not good apps *2018-08-26* Dear buyers be careful from this apps because not good at all. I Used this apps for couple weeks suddenly I realised the calculation is in correct. From now I am using my book. ## Frequently asked questions about Commercial Gas Calculator ### What is the Commercial Gas Calculator used for? The Commercial Gas Calculator is used by gas engineers to determine the maximum time required to purge air from non-domestic natural gas installations, ensuring appliances fire correctly. It follows IGE/UP/1A guidelines for installations up to 1m³ and 40mbar. ### Does the Commercial Gas Calculator support all types of gas installations? No, the Commercial Gas Calculator is suitable for natural gas (NG) installations only. It is designed for installations with a volume not exceeding 1m³ and a maximum operating pressure (MOP) not exceeding 40mbar. ### Can I calculate tightness testing duration with the Commercial Gas Calculator? Yes, the option to calculate the tightness testing duration (TTD) for the system is available to purchase as an in-app feature. This allows for a more comprehensive calculation. ### How can I save my installation calculations? For busy professionals, a 'Save Installations' add-on is available for purchase within the app. This feature allows you to save and retrieve installation layouts for future reference, streamlining your workflow. ### What is the price of the Commercial Gas Calculator? The base Commercial Gas Calculator is priced at $1.99. Additional features like tightness testing duration and saving installations are available as separate in-app purchases. ### On which devices can I use the Commercial Gas Calculator? The Commercial Gas Calculator is available for iPhone, iPad, and iPod. It is designed to run on Apple's iOS operating system. ### How often is the Commercial Gas Calculator updated? The Commercial Gas Calculator was last updated on December 16, 2025, with version 1.3.3. Updates typically address bug fixes and feature enhancements to improve user experience and accuracy. ### Does the Commercial Gas Calculator have ads? No, the Commercial Gas Calculator does not contain advertisements. The app is free to download with optional in-app purchases for advanced features. ## Version history (last 5 releases) ### 1.3.3 — 2025-12-16 Updated for new age rating compliance only ### 1.3.2 — 2025-10-17 Updated for iOS 26 ### 1.3.1 — 2024-02-08 Updated for iOS 17 ### 1.3.0 — 2021-11-30 Fix for issues around saving installations. Improved error alert when exceeding maximum system volume size for the IGE/UP/1A Edition 2 standard. ### 1.2.9 — 2021-11-21 Fix for issues around saving installations. ## Apps similar to Commercial Gas Calculator | App | Rating | Price | Category | | --- | --- | --- | --- | | [KANE DTHA2](https://appshunter.io/ios/app/kane-dtha2/id1566778991) | — | Free | Utilities | | [TracPipe UK Sizing & Reference](https://appshunter.io/ios/app/tracpipe-uk-sizing-and-reference/id1075847160) | — | Free | Utilities | | [Gas Checker](https://appshunter.io/ios/app/gas-checker/id523576969) | 5.0 (1) | Free | Utilities | | [aicON for professionals](https://appshunter.io/ios/app/aicon-for-professionals/id1475883803) | — | Free | Utilities | | [NovoCheck](https://appshunter.io/ios/app/novocheck/id1215614772) | — | Free | Utilities | | [AlphaOne.](https://appshunter.io/ios/app/alphaone/id979169302) | — | Free | Utilities | ## More apps by Oliver Shingler - [Vital Values](https://appshunter.io/ios/app/vital-values/id460023541) - [Watercolour Reference](https://appshunter.io/ios/app/watercolour-reference/id467961113) - [Ken's Pub Quiz](https://appshunter.io/ios/app/kens-pub-quiz/id557878888) - [Kenbats](https://appshunter.io/ios/app/kenbats/id834892439) - [Config Reference](https://appshunter.io/ios/app/config-reference/id920356771) - [Sailing Reference](https://appshunter.io/ios/app/sailing-reference/id978062677) All apps by Oliver Shingler: https://appshunter.io/developer/886565740 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-04.*