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Microbiological Safety Cabinets

Microbiological safety cabinets are used to contain aerosols from hazardous biological material and ensure that the adjacent environment and operator is protected. There are three main classifications for MSCs;

• Class 1, Safety cabinet with a front aperture through which the operator can carry out manipulations inside the cabinet and which is constructed so that the worker is protected and the escape of airborne particulate contamination generated within the cabinet is controlled by means of an inward airflow through the working front aperture and filtration of the exhaust air.
• Class 2, Safety cabinet with a front aperture through which the operator can carry out manipulations inside the cabinet and which is constructed so that the worker is protected, the risk of product and cross contamination is low and the escape of airborne particulate contamination generated within the cabinet is controlled by means of an appropriate filtered internal airflow and filtration of the exhaust air. Note: A typical way of achieving this is by means of a uni-directional downward (laminar) airflow inside the cabinet and an air-curtain at the front aperture.
• Class 3 Safety cabinet in which the working area is totally enclosed and the operator is separated from the work by a physical barrier (i.e. gloves mechanically attached to the cabinet). Filtered air is continuously supplied to the cabinet and the exhaust air is treated to prevent release of microorganisms.

All types are covered by EN12469 Biotechnology - Performance criteria for microbiological safety cabinets 2000 (which replaces the old BS 5726 Microbiological Safety Cabinets 1992, Parts 1 & 3)

Risk assessments should be carried out for the specific operating requirements to establish the class of MSC that is needed for any particular application.

Class 2 MSCs are the most commonly used, and are the first choice for most applications, providing both product and operator protection, whilst enabling good access via an open front aperture. Two distinct airflow functions are incorporated; a HEPA filtered Unidirectional downflow, that ensures that first-pass filtered air cascades down onto the working area, and an inflow across the front aperture to ensure that any airborne particulate or aerosol generated by the product is drawn away from the operator, underneath the workzone, and up to the HEPA filter mounted above. The majority of the air (70%) recirculates within the cabinet. However, air needs to be exhausted from the unit to balance the air drawn into the cabinet via the aperture inflow. This exhausted air is terminally filtered (by single or dual HEPA filter) to ensure that any particulate is arrested by the filter rather than exhausted. When aerosols are expected, the exhaust air is either ducted away from the laboratory, or is passed through an activated carbon filter to suit the type of aerosols being generated.

Please view our range of microbiological safety cabinets or, alternatively contact us to discuss your requirements in more detail.

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