Biosafety Cabinet

Biosafety Cabinets: Principle and Application

Introduction to Biosafety Cabinets:

Biosafety Cabinets are one of the most interesting safety equipments in a scientific lab. Often a part of sci-fi movies, these Biosafety Cabinets are enclosed workplace which are ventilated and provide protection to the user while handling contaminated or potentially contaminated micro-organisms.

1NoDoes not cause any disease to human/animalNot required
2ModerateCauses diseaseAvailable
3HighCauses serious diseasesAvailable
4ExtremeCauses life threatening diseasesNot Available
ClassificationTypeBiosafety levelPurpose
BSC class I1For low to moderate risk
BSC class II A1, A2, B1, B22Moderate to high
BSC class III3 & 4High

BSC Class I –

It is the most basic design among the biological safety cabinets. BSC I provide protection to user and environment but not to sample. The plenum protects the user. When user is working on any biological agent in the BSC, the agent might be moving in the cabinet in the form of aerosol. While exiting from cabinet, these aerosols pass through HEPA filter. The filter traps the biological agent and decontaminated air is exhausted. BSC I does not protect the sample from the biological agents present in the air of room. Hence, in BSC I there is more possibility of contamination of sample.

BSC Class II –

It is advanced form of BSC I that provides protection to user, environment and Sample. The downward flow system of HEPA filter provides protection to experimental sample. The decontaminate airflow from HEPA filter on the working bench of cabinet protecting sample. BSC II protects environment by similar mechanism that is followed in BSC I by suing HEPA filtered exhaust. The further types of BSC II are based on the HEPA filtered exhaust air; in different following types the extent of recirculation of air varies.


  • BSC Class-I
  • Diagram for Class II A1 or A2 Cabinet Airflow
  • Diagram for Class II A1 or A2 Cabinet with Canopy Airflow
  • Diagram for Class II B1 Cabinet Airflow
  • Diagram Class II B2 Cabinet Airflow
  • Diagram for Class III Cabinet Airflow


This type of Biosafety cabinets are totally enclosed and associated with attached rubber gloves for user’s hands. This class is used for working on the biological agent, which are at biosafety risk level 3 and 4. This cabinet offers highest level of protection to person, environment, and experimental material.

Structural features of BSC –

  1. The sidewalls of the BSC working bench are made of stainless steel.
  2. The BSC has visible light of 800 lux.
  3. It also contains UV lamp for sterilization (User should not come in to direct contact of UV light).
  4. The unit has user-friendly microprocessor regulatory system that displays the required parameter digitally and allows the user to control it.
  5. The BSC are accompanied with sensors for external factors like heat, dust and moisture.
  6. High efficiency HEPA filter should be assembled with 0.2 to 0.3 μ.
  7. The BSC should not make much noise.
  8. It is should be easy to clean and decontaminate.

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