Guides
Guides for gas engineers
Written for people on the tools. No filler, and every figure traceable to where it came from.
Gas tightness test: what changes in IGEM/UP/1B Edition 4Edition 4 is mandatory from 1 October 2026. The permissible drop now comes from installation volume, not meter size.
How to gas rate a boiler, step by stepThe procedure, the formula, a worked example, and the four reasons a correct gas rate reads wrong.
Unsafe situations: ID, AR and NCS explainedWhat each classification requires you to do, what Edition 2 changed, and when RIDDOR actually applies.
Boiler pressure keeps rising: what to check, in orderOne question that halves the list, then filling loop, vessel pre-charge, sizing and plate heat exchanger.
Free calculators
The same four calculators that are in the app, free to use here with no sign-up.
Gas rate calculatorHeat input from a timed meter reading
CO/CO₂ ratio calculatorPass or fail against the 0.004 limit
Temperature rise (ΔT)Flow minus return across the appliance
Expansion vessel sizingMinimum vessel size and pre-charge
Tightness test (UP/1B Ed 4)Installation volume, permitted drop, timer
Flint is a reference tool for competent, Gas Safe registered engineers. Everything here informs your judgement and never replaces it. Always work to the manufacturer's instructions and the current standards, and check every figure against the appliance data badge and manual.