Containment testing of installled laboratory fume hoods.

54 fume hoods in three laboratory buildings in Norway were tested for containment using two tracer methods based on European and American standards, in addition to face velocity measurements. In the first method, an abridged version of Nordtest VVS 095, tracer gas was measured at one point in the sash opening, in front of a mannequin placed at the fume hood with a sash height of 30 cm. In the second method, based on ASHRAE 110-1995, tracer was measured in the breathing zone of the mannequin for a 67 cm sash height. The results demonstrated that fume hoods with low face velocities (< 0.3 m/s) have a high probability of exhibiting poor containment of tracer gas, while those with high face velocities (≥ 0.5 m/s) generally exhibit good containment. Fume hoods with face velocities in the range 0.3 - 0.49 m/s yielded a roughly even mixture of good and poor containment values. In this velocity range, which included more than half of the fume hoods tested, face velocity cannot be used as an indicator of containment performance, as measured by the tracer tests.