Experimental study of ventilation performance in laboratories with chemical spills

Chemical spills occur frequently in laboratories. The current ventilation code for laboratories recommends a ventilation rate of 12 ACH for maintaining a safe laboratory environment. On the other hand, the energy saving potential encourages a reduction of the ventilation rate. But the effect of reducing the ventilation rate on the indoor air quality in a laboratory with chemical spills has not been well studied. This experimental study investigated the ventilation performance under different ventilation rates in a chemistry laboratory mockup. The impact of wall exhaust locations and chemical spill positions was examined related to the contaminant concentration distribution in the laboratory. This investigation also studied the ventilation performance with and without the use of bench hood exhausts. The results showed that the contaminant concentration was not linearly proportional to the ventilation rate. If the chemical spill position was close to an exhaust, the contaminant concentration in the laboratory could be rather low. The bench hood exhaust had the potential to effectively reduce the contaminant concentration. The results indicated that the ventilation rate in a chemistry laboratory may be reduced without increasing the safety risk if the ventilation system is properly designed.

► The ventilation performance in a laboratory with chemical spills is studied.
► Contaminant concentration will not be linearly reduced with increasing ventilation rate.
► The use of bench hood exhausts should be combined with normal exhausts.
► It is better to increase the ventilation effectiveness rather than the ventilation rate.