Pipe figures include the 10% allowance for fittings.
Result
Installation volume
0 m³
Max permitted drop
–
Purge volume (1.5 × IV)
0 m³
Test
1:00
If you can smell gas, trace and repair the escape whatever the gauge shows.
IGEM/UP/1B Edition 4 (mandatory from 1 October 2026). Small installations up to 0.035 m³.
Heat input entered as
Label the points along the pipework, starting at the meter (A). Add one section for each pipe between two points, and put each appliance on the section that ends at it. Flows through each section add up automatically.
Result
Natural gas, BS 6891 Tables A.1 (copper) and A.2 (steel). Maximum 1 mbar loss from the meter outlet to each appliance. Gas rate = gross kW ÷ 10.8 (net kW × 1.1 = gross). Flow is rounded up to the next table row.
Ventilation
Coming soon. This needs the BS 5440-2 ventilation rules (free area per kW for each appliance type) so the figures are accurate.