Tracer techniques and data interpretation for infiltration measurements.

Describes a simple, inexpensive sampling technique for infiltration measurement using SF6 tracer gas. Uses pre-evacuated blood collecting test tubes with rubber stoppers for sampling. This is controlled by a micro-processor driven automatic sampler, which drives a hypodermic needle through the rubber stopper to fill the tube with an air sample. Analyzes samples using a gas chromatograph. Releases SF6 at ground level in a high-rise cold store and collects samples of air at different heights to see if stratification is present. Finds no evidence for this, but stresses the effect of internal partitioning which can lead to imperfect mixing and thereforeerror in calculating air change rates. Finds that the effect of tracer adsorption or absorption on infiltration calculations is greater when a modelis used than in an actual large-scale test.