A New Method for Quantitative, In-Use Testing of Laboratory Fume Hoods

Abstract

A new method has been developed for testing fume hood performance in a controlled, ventilation laboratory setting or in the field during normal use conditions. It involves a steady release of a tracer material, such as sulfur hexafluoride, inside a hood through a hollow rectangular diffuser that surrounds the work and then measurement of concentrations outside the hood. Hood tests in the ventilation laboratory using an immobile manikin as a fixed reference point, showed the effects of changing face velocity, sash height, and percentage of auxiliary air on the fraction of tracer escaping from the work area inside the hood. When used to determine hood leakage under a variety of common laboratory activities (e.g., pipetting, centrifuging), the results helped to identify other causes of hood leakage. Field studies demonstrated the case and usefulness of this method to determine hood performance and the magnitude of personnel exposures under diverse operating conditions. The value of this test method as an edu...