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Biosafety cabinets are classified based on their containment capabilities and performance attributes


While the degree of protection varies with each class, in general a laminar flow biological safety cabinet is designed to provide these three basic types of protection:

  • Personnel protection from harmful agents inside the cabinet.
  • Product protection to avoid contamination of the work, experiment, or process.
  • Environmental protection from contaminants contained within the cabinet.

How Biological Safety Cabinets Are Classified


Classification is an important consideration in the selection of any biological safety cabinet. Over the years, the scientific community has adopted commonly accepted classification criteria to differentiate containment capabilities and performance attributes. Biological safety cabinets are divided into three classifications. Baker designs and manufactures all of these types of biosafety containment cabinets.

NSF International (The National Sanitation Foundation) conducts tests on biological safety cabinets to ensure the products meet minimum standards for cabinet classifications devised by NSF.

  • NSF Standards are reviewed every five years.
  • Tests are conducted on cabinets submitted to NSF by the manufacturers.
  • Products which meet these standards are certified by NSF.
  • Tests on cabinets are repeated every five years.
Biosafety Cabinet ClassificationBiosafety LevelApplication
Class 1 Biosafety Cabinet1,2,3Low to moderate risk biological agents
Class 2 Biosafety Cabinet1,2,3Low to moderate risk biological agents
Class 3 Biosafety Cabinet4High risk biological agents

Class I Biosafety Cabinets – Personnel and Environmental Protection Only


The Class I biological safety cabinet is designed to provide personnel and environmental protection only.

  • A Class I cabinet does not protect the product from contamination because “dirty” room air constantly enters the cabinet front to flow across the work surface.
  • As a partial containment unit, the Class I cabinet is suitable for work involving low to moderate risk agents (biosafety levels 1,2 and 3) where there is a need for containment, but not for product protection.
  • Unlike conventional fume hoods, the HEPA filter in the Class I cabinet protects the environment by filtering air before it is exhausted.
  • Personnel protection is made possible by constant movement of air into the cabinet and away from the user.

Class II Biosafety Cabinets – Product, Personnel and Environmental Protection


A Class II cabinet must meet requirements for the protection of product, personnel and the environment. This type of cabinet is widely used in clinical, hospital, life science, research and pharmaceutical laboratories.

In general, cabinets are classified according to the method by which air volumes are recirculated or exhausted.

The Class II biological safety cabinet has three key features:

  • A front access opening with carefully maintained inward airflow.
  • HEPA-filtered, vertical, unidirectional airflow within the work area.
  • HEPA-filtered exhaust air to the room or exhaust to a facility exhaust system.

Vertical, unidirectional airflow and a front access opening are common to most Class II cabinets. But, because Class II designs permit different airflow patterns, velocities, HEPA air filter position, ventilation rates and exhaust methods, a sub-classification of Type is needed to differentiate Class II BSC designs. For more information on the types of Class II biosafety cabinets, download our Guide to Class II Biosafety Cabinets.

Class III Biosafety Cabinets – Total Containment Cabinets


Class III biological safety cabinets are gas-tight, designed for use with high risk biological agents. Class III cabinets provide the highest level of personnel, product and environmental protection. Because of the sensitive nature of most procedures performed within a Class III cabinet, Baker builds each BSC system to exact customer specifications.

Typical applications include:

  • Working with emerging diseases or diseases marked for near eradication.
  • Weighing and diluting chemical carcinogens.
  • Working with high concentrations of low to moderate risk agents.
  • Working with large amounts of low to moderate risk agents.
  • Use of equipment or instrumentation generating high aerosol volumes.
  • Maximum containment of highly infectious or hazardous experimental materials.
  • An extra level of safety not available in Class I or II cabinets.

Learn more about Class II Biosafety Cabinets

Review the protection levels and key features of Class II Biosafety Cabinets in this free guide that includes an easy-to-read chart explaining how the types of Class II cabinets differ and graphics illustrating the supply, exhaust and recirculation airflow patterns that classify Type A1, A2, B1 and B2 cabinets.

Download the free guide

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