Airflow control modes of ⅡB2 biosafety cabinets in high-level biosafety laboratory

Analyses the airflow control modes of 79 biosafety cabinets in 22 high-level biosafety laboratory projects. Presents the control modes of variable air supply and constant air exhaust, constant air supply and variable air exhaust, and variable air supply (bistable state) and variable air exhaust and the possible problems, and puts forward some solutions. Discusses and empirically studies the control mode of constant air supply and variable air exhaust for the system, meanwhile the air discharge switching equivalently between the biosafety cabinet and the room. The comparative analysis result indicates that this control mode is less invested, with good applicability and stability.