Introduction to Class III Biological Safety Cabinets

The Class III Biological Safety Cabinet, also referred to as a Class III BSC, is designed to provide the highest level of containment when working with hazardous materials. These gas-tight enclosures protect the operator, the environment as well as the work in progress. Class III units are also referred to as gloveboxes, as work is conducted by utilizing arm-length gloves. Samples contained within the enclosure are visible via a completely sealed viewing panel.

Class III Biosafety Cabinets must be fabricated from materials that are highly durable and resistant to decontamination processes. The interior of the unit should incorporate smooth finishes with coved, radiused corners to allow for ease of cleaning and effective decontamination. Ergonomic engineering and design is critical for Class III Biological Safety Cabinets to ensure user safety and prevent operator fatigue. For example, glove ports must be configured at the optimal angle, which helps to enhance user dexterity and range of motion.

Class III Filtration Systems

Supply air entering the Class III BSC is HEPA-filtered. Exhaust air passes through two HEPA filters in series before it is discharged outside of the facility. According to Biosafety in Microbiological and Biomedical Laboratories (BMBL) 5th Edition, “Class III cabinets are not exhausted through the general laboratory exhaust system. Airflow is maintained by an exhaust system exterior to the cabinet, which keeps the cabinet under negative pressure (minimum of 0.5 inches of water gauge).” For certain applications additional types of filtration may be integrated. For example, Class III Biosafety Cabinets can incorporate a HEPA/Carbon Filtration System that utilizes redundant HEPA and carbon filters. Additionally, enclosures that are equipped with special Nuclear, Biological, and Chemical (NBC) Filter Systems allow first responders to contain materials having an unknown risk level.

Integration of Equipment in the Class III Biological Safety Cabinet

The seamless integration of equipment and analytical instruments is imperative to provide an efficient workflow that does not break containment. Equipment controls are often positioned outside of the containment zone. The proper ingress and egress of materials into the Class III enclosure is critical. Entry for materials into the Class III Biological Safety Cabinet can be handled via a variety of methods that may include: dunk tanks, integral autoclaves, rapid transfer ports and other pass-through chambers. Proper procedures are developed to maintain containment. Methods for the safe removal of materials are incorporated. These include reversing the ingress process as well as the availability of fumigation/decontamination methods.

Class III Biosafety Cabinets Provide Containmentfor Many Applications

The Class III BSC can be installed into a diverse range of research environments. For work involving highly infectious microbiological agents, the Class III BSC is a critical lab component. Class III Biological Safety Cabinets provide the primary containment for manipulation of dangerous pathogens in BSL-4 Cabinet Laboratories. Additionally, when installed in BSL-3 labs, these enclosures offer an added level of containment for higher risk work. Class III units are also utilized for handling materials with an unknown risk level in security applications.

Class III systems must be engineered to meet the specific requirements and provide the most effective design for the application. Multiple Class III Cabinets can be engineered as a ‘line’. These units are joined together to add capacity for large-scale operations or to provide the required workflow for more complex processes. Class III Biosafety Cabinets are often custom engineered and equipped to the exact specifications required for specialized and demanding applications.

Specialized Applications

Aerobiology labs utilize Class III Biological Safety Cabinets that are built around aerosol generators for work in aerobiological studies. Transfer carts that are equipped with Rapid Transfer Ports and a Class III BSC insure personnel and environmental safety, improve research productivity, as well as provide for animal welfare. Aerobiology processes can be designed to handle multiple species. Specialized aerosol exposure systems are fully integrated into the cabinet, and precisely control the challenge concentration ensuring uniform exposures to achieve consistent research results. Vapor phase generators or other systems provide for ease of decontamination.

Class III Biological Safety Cabinets also play an essential role in All Hazard Receipt Facilities (AHRF). These units are installed to provide containment for laboratories that are designated to receive high-risk samples or materials having an unknown risk factor, particularly agents that could pose a serious chemical or biological risk. National security/military, public health agencies, as well as police and fire departments typically operate these labs. The Class III Biosafety Cabinet must be designed to meet the triage requirements of Laboratory Response Networks (LRN) and Public Health Labs (PHL). The enclosures utilize special HEPA and ASZM-TEDA carbon filtration systems to provide the highest level of protection against chemical and biological hazards.

Standard enclosures are available to be readily installed into a laboratory. Class III Biosafety Cabinets are available with a wide range of added features and options to meet the user demands. Many applications call for completely customized Class III cabinets that integrate advanced systems and components for highly specialized research applications. Transportable units provide added flexibility in research facilities. Additionally, Class III technological developments allow for the use of mobile and portable units to offer containment for first responders and field deployment.

For additional information, please visit our Class III Biological Safety Cabinets section.

For other types of Biological Safety Cabinets please visit these sections:
Class II Biological Safety Cabinets – Please visit this page for further information.
Class I Biological Safety Cabinets – Please visit this page for further information.
Pharmacy Compounding Equipment: Glovebox/Isolators used for sterile compounding and handling hazardous drugs, please see our Compounding Aseptic Isolators in our Pharmacy Equipment section.