Abstract
Using a previously developed test for hood performance, the effect of room air supply system on laboratory fume hood performance was investigated. The test measures the concentration of tracer gas in the breathing zone of the worker (mannikin) when the tracer, mixed with air, is released at known rates at various positions within the hood. The terminal velocity of supply air jets is at least as important as the hood face velocity in its effect on hood performance. Terminal velocity of jets should be no more than 1/2 to 2/3 the face velocity. Data for wall grilles, ceiling diffusers, and perforated ceiling panels are presented.