Safety Cabinets

Safety Cabinets

	Safety Cabinets They are essentially isolation chambers that provide a safe environment for the manipulation of pathogenic microbes. They are characterised by having considerable negative pressure air flow that provides protection from infectious bio-aerosols generated within the cabinets. They are of three classes.
Class I Exhaust protection cabinets They protect the operator by maintaining a rapidly moving stream of air, which entrains infectious particles and deposits them on a high efficiency filter. The air is then discharged outside the building (Fig. 13.2) Class II Laminar flow cabinets These are open-fronted and are designed to protect the material that is being handled from extraneous contamination. It is suitable for most work with moderate pathogens. They do not protect the operator, though they can be modified to do so (Fig. 13.3).
Class III cabinets These are used for the handling of very dangerous materials and are completely enclosed. Materials are handled through gastight glove ports and air enters through a non-return valve and is extracted through a high efficiency filter (Fig. 13.4).