Domestic gas pipework located in voids which may need ventilation.
Big thanks to Mike Baldwin for spotting my rounding up fauxpas.
Width of duct in cm
Depth of duct in cm
Requirement of ventilation openings (in cm2)
This calculator is based on BS6891 (Domestic pipework), regulation 8.11.1, the regulations additionally state that ventilation should not be required in areas under 0.1m3 in volume.
