Dispersal chambers used for evaluation of cleanroom and surgical clothing systems - Examples of performed tests and results

Chalmers University of Technology in Sweden and Politecnico di Milano in Italy have developed and installed two experimental dispersal chambers (body-box) for the measurement of the rate of total and microbial airborne particle dispersion from persons (wearing technical clothing system) and from equipment in cleanrooms and in Operating Theaters (OT). This paper describes the two dispersal chambers and the adopted test procedures for person particle dispersion tests. The release rate of total airborne particles (in defined particle size ranges) emitted from a person and his gowning system while performing standard movements and the release rate of aerobic Colony Forming Unit (CFU) of the same person and gowning system, can be considered as the personnel source strength, a fundamental parameter both in design and in operation of a clean space. Moreover, the personnel source strength data could be used in order to compare technical clothing systems in terms of their particle shedding, and even more interestingly in terms of their ability to filter and to limit the personnel airborne particle release. The study presents data obtained in experimental campaigns made in the two labs. The results of the experimental tests carried out on different technical clothing systems are discussed and compared, highlighting the effect on emission rates of the garment type and of the number of undergone cycles of Washing, Drying and Sterilization (WDS). The source strength data presented in this paper can be used in the design phase of cleanrooms and of OT to size the total air flow required or contamination control and to forecast the concentrations of aerobic CFUs and total airborne particles.