Performance enhancement of biological safety cabinet Type 2 class A2 using numerical modelling

Abstract

Biological safety cabinets are devices that are widely used in microbiology labs, where operators handle biological materials which sometime pose a threat to their health. The safety of the operators using these devices is not always achieved due to the sensitivity of these devices to the air movement inside and outside of the cabinet. To enhance the performance of the biological safety cabinet class II type A2 in providing safety to the personnel using such devices a 3D numerical study was performed studying a baseline BSC and a modified BSC. The baseline BSC was a simplified design of a 4-foot local manufactured biological safety cabinet where it’s dimensions, supply air velocity, exhaust air velocity, HEPA filter pressure drop was used in the 3D model. The baseline BSC was modified by adding a fan module installed at the operator’s interface with the device. The fan module had two functions, the first was to isolate the outside of the BSC from the inside by supplying a high velocity air curtain of 1.68 m/s in front of the BSC sash opening while the second function was to draw the air from the breathing zone of the operator making the operator’s face a slightly negative pressurized zone. 1x10 ^5 Particles were discharged from the supply HEPA filter of each model; these particles were traced at the breathing zone of the operator. The modified BSC had 16.32 % less particles at the operator’s breathing zone than the baseline model.