Types of Biosafety Cabinets

Written by ATSC230@545404 on . Posted in WordPress

Whether it be in education or chemical manufacturing, biosafety cabinets are crucial to any workspace dealing with the study and handling of chemicals. Used primarily to protect from noxious or radioactive materials, biosafety cabinets serve as a safe space that both shelters a substance and promotes the observation of it. Standard biosafety cabinet classification contains the three main types of cabinet classes. These variations in biological safety technology contain similar designs (centered around a clean room HEPA filter) but vary among three general specifications: risk, inlet velocity, and protection capabilities.

Class I

The first standard class of biosafety cabinets is considered largely outdated and is not commonly seen as a result thereof. This is due to its failure to protect the substance being observed. While all biosafety cabinets are expected to protect both the personnel and environment from the substance at hand, actual protection of the substance should not be overlooked. The main design flaw in Class I cabinets is the open intake of unfiltered air into the interior chamber, allowing potentially contaminated air from affecting the chemical within. Overall, this class has low to moderate risk and an inlet velocity of 75.

Class II (A & B)

The second class improves upon the first by having a dual HEPA filter system in which air both taken in and pumped out of the inner chamber is free of contamination. This ensures all three protection factors: personal, chemical, and environmental. This class is most commonly used, but it does split into two subcategories. The main difference between Class IIA and IIB is that the exhaust of IIB is ducted to the exterior of the facilities rather than being recirculated into the building like in IIA. This brings an additional level of protection from chemicals producing especially harsh fumes. This class has low to moderate risk and an inlet velocity of 75.

Class III

This class is reserved for the harshest materials, differing from Class II by completely enclosing the interior chamber from air exposure. Instead, personnel only have access to the materials through glove ports sealed to the wall of the cabinet. Other than that, this class has the same dual HEPA filter system found in Class II. However, because of the harsh materials at hand, this class has a high risk and a 100-inlet velocity.

Below is a compiled comparison of factors that differentiate the three main classes of biosafety cabinets.

Class I

  • Low to moderate risk
  • Protects personnel and environment
  • 75 inlet velocity

Class II

  • Low to moderate risk
  • Protects personnel, substance, and environment
  • 75 inlet velocity

Class III

  • High risk
  • Protects personnel, substance, and environment
  • 75 inlet velocity