Biosafety Cabinet Principle & Application

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.

Table Of Contents

  1. Introduction to Biosafety Cabinets
  2. BSC Class I
  3. BSC Class II
  4. BSC Class III
  5. Structural features of BioSafety Cabinets

Introduction to Biosafety Cabinets

“Safety” is a very well-known word; it is defined as, a condition of being protected from danger, risk, accident or injury. Biosafety means safety from biological agents like pathogenic microorganism or toxins. Biosafety includes rules, protocols, technologies, and practices. It is mandatory for all the laboratories to follow the Biosafety norms.

Biosafety Cabinet
UV Sterilisation (Orla Keogh / CC BY (

Based on the risk caused by biological agents, WHO classified biosafety into 4 levels and called as Biosafety Levels (BSL)-

1NoDoes not cause any disease to human/animalNot required
2ModerateCauses diseaseAvailable
3HighCauses serious diseasesAvailable
4ExtremeCauses life threatening diseasesNot Available

Based on the Biosafety level, working cabinets have been designed into 3 categories to fulfill the need of mentioned risk level and they are called as Biosafety cabinets. The biosafety cabinets are complemented with HEPA filters for directional flow of sterile air. The biosafety cabinets provide protection from harmful biological agent to the user. The Cabinets also reduced the probability of contamination. The Biosafety Cabinet (BSC) classification is as follows-

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 –

BSC Class-I
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 –

Diagram for Class II A1 or A2 Cabinet Airflow
BSC Class-II (A1) (

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.



Diagram for Class II B1 Cabinet Airflow
BSC Class-II (B1) (

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 BioSafety Cabinets –

  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.

Need more help? Click here to read more.

Dr. Sangha Bijekar has 9 years of Teaching Experience at University level. She loves to get engage in teaching and learning process. She is into blogging from last two years. She intends to provide student friendly reading material. She is avid Dog Lover and animal rescuer. She is learned Bharatnatyam and Katthak Dancer. She is into biking and She also loves to cook.

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.