ارزیابی عملکرد هودهای بیولوژِیکی ایمن در یک مرکز تحقیقاتی

The use of biological safety cabinets (BSCs) in laboratories has greatly increased over the last few decades. BSCs are used in laboratories to protect both the scientists and the experiments from contamination by biological hazards during tissue culture procedures. The function of BSCs depends upon the HEPA filtration, the fan performance and the airflow patterns in the cabinet. To ensure BSCs proper functioning, regular performance evaluation tests are necessary. Failure to observe this may lead to direct and indirect losses. The objective of this study which was conducted at a biological research center was to evaluate the performance of seven present BSCs used in different laboratories. Based on BS 5726 (1992), two sets of measurements were performed: a) Determination bioaerosol concentration in the cabinet and b) inflow and downflow velocity measurements at the cabinet. The results revealed that the lowest and the highest bioaerosol concentrations were 0.2 cfu/m3 and 1.33 cfu/m3, respectively. The lowest inflow mean velocity was found to be 0.33 m/s which was far less than the recommended value in BS 5726 (0.7 m/s). The highest inflow velocity was 1.1 m/s. The lowest downflow velocity equaled to 0.09 m/s which was below the recommended value (0.25- 0.5 m/s). The highest downflow measured was 0.55 m/s. As a conclusion, in general, none of the BSCs evaluated in this study provided sterile atmosphere at the cabinets. In no case, airflow patterns met the recommended values proposed in BS 5726.