Impact of heat generation and use of experimental instruments in a fume hood on pollutant capture efficiency

A fume hood is a local ventilation system that is typically installed in a laboratory space to ensure the safety of workers from chemical exposure. A fume hood is designed to capture hazardous gas-phase pollutants generated inside a box-like enclosure, and the pollutant capture efficiency is regulated by the average opening surface air velocity. However, few cases exist in which the pollutant capture efficiency inside the fume hood is precisely analyzed and quantitatively visualized. In this study, the capture performance of a fume hood under actual use conditions was evaluated using computational fluid dynamics (CFD). The factors that could affect the performance, that is, the exhaust airflow rate, experimental instruments inside, worker in front, and heat source within the fume hood, were parametrically considered. The numerical analyses revealed that experimental instruments near the opening surface significantly affected the airflow into the fume hood and decreased its capture performance. Under the inadequate condition of a low exhaust airflow rate, pollutant leakage inside the chamber was observed due to the presence of a worker in front of the fume hood and the heat source inside. Furthermore, the pollutant capture performance was slightly improved by changing the layout/position of the experimental instrument.