Microbial garment-penetration tested
By Tammy Wright
A new test method that measures microbial penetration in new and laundered cleanroom garments was presented by the Research Triangle Institute (Research Triangle Park, NC) during the recent CleanRooms East `98 conference and exhibition.
RTI`s study expands the industry`s research capabilities beyond existing tests for particle shedding and particle penetration properties of cleanroom garments. According to Karin Foarde, manager of RTI`s Environmental Microbiology Laboratory, the importance of the new test is that it “is part of a comprehensive evaluation of fabric and garments for particles and mircroorganisms.”
Lab experiments conducted by RTI were able to make a comparison of the penetrations of different fabrics using the pathogen Staphylococcus epidermidis as a test organism. Three garment types, two woven and one nonwoven, were tested. The garments referred to as new and laundered Woven A were made of woven, calendared fabric containing a carbon filament; those called new and laundered Woven B were herringbone coveralls made of woven fabric with no carbon; and those called nonwoven material C were made of spunbonded polyolefin.
Generating the test bacteria as a liquid challenge aerosol with a GBI Collison nebulizer, a total of 50 fabric samples were evaluated in a 142 mm stainless steel filter holder in a Class II biological safety cabinet. Twenty-five samples were run dry and 25 were wetted with artificial sweat formulated as described in ASTM D2322-69.
To effectively compare the results obtained from the different fabrics, RTI ran the tests