CI-2657 -- An Appraisal of the Sulphur Hexafluoride Decay Technique for Measuring Air Infiltration Rates in Buildings PDF

Sulfur hexafluoride is useful as a tracer gas for air-infiltration studies because sensitive detectors measuring in the parts per billion range are readily available. In addition, the gas is non-toxic and can readily be separated from other detectable gases chromatographically.

Sulfur hexafluoride is, however, a heavy gas and potentially difficult to mix with air. This study compares the air change rates measured with SF6 and C02 using the tracer gas decay technique and the fan extraction method over a wide variety of test chamber sizes and mixing systems. Three important aims are :

1) To provide direct experimental evidence that conventional air handling systems or an
arrangement of floor fans comes close enough to achieving the perfect mixing required in
principle.
2) To establish limits of accuracy and reproducibility for SF6 decay results.
3) To refine our SF6 tracer decay experimental procedure for.further infiltration studies.