2020 Volume 45 Issue 281 Pages 19-26
A fume hood is a type of local ventilation device that is designed to limit exposure to hazardous or toxic fumes, and it is sometimes called a draft chamber (especially, in Japan) or a fume closet. Its most important objective is to protect the user from inhaling toxic gases generated in the closet. The performance of a fume hood in terms of protection from hazardous gases generally determined in each country. The average surface wind speed at the apertural area with the sash is required to be 0.5m/s or more. However, this performance evaluation conditions, and criteria is carried out under ideal environmental conditions and there are few examples of precise measurement/prediction of inhalation exposure risk to users under actual environment conditions. In this study, we numerically investigate the protection performance of a fume hood under realistic environmental conditions. For this, the precise fume food model installed in the general laboratory environment is reproduced for computational fluid dynamics (CFD) analysis. A computer simulated person (CSP) has the details of the human body shape, and the respiratory tract is also adopted for investigating inhalation exposure risk quantitatively. Integrated CFD-CSP simulations are conducted considering the frontal opening area, e.g., the apertural area with sash; and indoor environmental laboratory conditions, e.g., operating conditions of heating, ventilating, and air conditioning system. It was confirmed that the presence of a user in front of a fume hood and the operation of a room ventilation system has a significant effect on the surface wind speed distributions.
