| Abstract: | Microbiological Safety Cabinets are designed to provide protection to an operator from aerosol hazards that may be generated when handling infectious material. In addition, some types of cabinet can provide protection to the work being handled. Several national standards have been published in recent years which define the construction and performance of these devices; the three types of safety cabinet designated Classes I, II, and III are defined and described in this paper. A measured degree of operator protection is required at the front aperture of Class I and II cabinets, and a new method for assessing operator protection factor based upon a challenge aerosol of potassium iodide is described. Cabinet performance is discussed in relation to containment test results using this system. Working procedures and unsuitable environments can prejudice the containment performance of open-fronted cabinets by several orders of magnitude, and various aspects of this problem are discussed and illustrated. The importance of on-site commissioning tests to ensure adequate operator protection is emphasised. The application of safety cabinet testing techniques has been extended to assess the performance of fume cupboards (hoods), complete laboratories, and special “hybrid” installations such as may be used for handling carcinogenic or radiopharmaceutical material. |
