Personnel Safety Performance Enhancement of a Numerically Modeled Biological Safety Cabinet Class II Type A2 By Adding an Air Curtain

Biological safety cabinets (BSC) are devices that are widely used by microbiologists and pharmacists when handling biohazardous materials. A safe working environment shall be achieved while using such devices. However, the safety of the BSC operators is compromised as these devices are very sensitive to the air pattern surrounding them. Isolating the interior area of the BSC from the surroundings using an air curtain at the front of the BSC was simulated using a 3D numerical model. The air used as an air curtain was drawn from the breathing zone of the operator to decrease the probability of any contaminant escape from the inside of the device towards the face of the operator. This numerical study was done simulating the dimensions, air velocities, air pressures of an actual 4-foot BSC class II type A2. The air curtain modification was added to the numerical model to compare the safety performance enhancement before and after adding the air curtain. To calculate the performance enhancement in the numerical study 1x10^5 particles were discharged from the supply HEPA filter and were traced at the breathing zone of the operator where the BSC after modification showed 16.32 % decrease in the number of the traced particles