Airtightness for floor plenums
BSRIA’s guide to the airtightness of floor plenums deals with the use of a raised access floor being used to distribute conditioned air to the spaces above. It is important that conditioned air flows into the occupied zone and does not leak into cavities, risers, stairwells, heating trenches or other occupied zones. Air leakage from a floor plenum can be a serious energy-efficiency issue and a source of discomfort to people.
Air supplied to a floor plenum should discharge through the floor-mounted diffusers or grilles rather than through joints in the raised access floor or between the raised access floor and the walls. A properly sealed floor plenum enables the diffusers and grilles to fulfil their primary role of delivering air at the correct flow rate.
The guide addresses these issues and recommends worst acceptable criteria for air leakage from floor plenums.