Influence of high heat load on flow and containment of an inclined air-curtain (IAC) fume hood.

The inclined air-curtain (IAC) fume hood has been reported to have "almost null leakage"(1) at low suction flow rates when operated at regular temperatures. However, previous research has not investigated the performance or optimized operating parameters when a high heat load is used in the IAC fume hood. For the present work, the effects of a high heat load on the flow field and contaminant leakage characteristics of the IAC fume hood were examined. The heat load was supplied to an IAC hood according to the standard method of EN14175-7:2012. The laser-assisted smoke flow visualization technique was employed to identify the characteristic flow patterns. The standard tracer-gas concentration test method (EN14175-3:2003) was used to examine the leakage levels of the IAC fume hood under static conditions, sash movement, and simulated walk-by conditions. When the IAC fume hood was operated at a high heat load, the static test results showed negligibly small leakage levels at a face velocity greater than or equal to only 0.19 m/s (37.4 ft/min). The sash movement and simulated walk-by test results showed that to obtain negligibly small leakage levels at high heat load operation, the IAC fume hood required a face velocity greater than or equal to 0.32 m/s (63 ft/min). In addition, the IAC fume hood exhibited a superior hood containment performance with low energy consumption when compared with conventional fume hoods operated at a high heat load.