Safety primary decontamination

Exhaust air from primary containment devices (fume hoods, safety cabinets or other) shall be appropriately treated by filtration using a high efficiency particulate air filter (HEPA), or by adsorption, absorption, reaction, incineration, or dilution used individually or in an appropriate combination. If HEPA or charcoal filters are used, these must be installed and operated to permit decontamination, maintenance, and replacement without exposing personnel or causing contamination of the environment. 

A dunk tank or attached decontamination air lock system may be used to introduce or remove material from the Class III system. Figure 8. All primary containment devices shall be certified to meet performance criteria on initial installation, following any move or maintenance, and at least annually. Other safety features of facility design include nonporous surfaces on floors, walls, and ceiling self-closing doors that must remain closed to maintain air balance and directional airflows. If floor drains are present, their traps should be filled with water weekly. 

Examples of some devices which meet only the first criterion are the safety blender (Figure 10.1), centrifuge safety tubes (Figure 10.2), and flexible film containers (Figure 10.3). These devices do limit the amount of material used and contained, but they do not allow easy transfer or decontamination. Therefore, they are not true primary barriers however, they do provide the best possible containment available for mixing and centrifuging operations. The most familiar primary barrier device that meets all three criteria is the biolog-... 

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