Many researchers have investigated the effect of the ventilation rate on the indoor air quality of a laboratory in the case of chemical spill.Klein et al.experimentally investigated the transient variation of contaminant concentration at different ventilation rates under a controlled release of organic solvents as small spills.Their results suggested that a ventilation rate above 12 ACH was unnecessary.while a rate below 8 ACH warrented careful consideration.An optimal design for an air supply and exhaust system could potentially allow a lower ventilation rate.Memarzadeh et al.applied Computational Fluid Dynamics to assess the contaminant concentration in a laboratory with bench top chemical spills when the ventilation rate was reduced from 12 to 6 ACH