Validation and application of the personnel factor for the garment used in cleanrooms

Abstract

The cleanroom environment has many potential sources of contamination, including: operators, equipment, structures, and any surface that can create particles via friction, heat, exhaust, outgassing, and static electricity charge. Operatives working in the cleanroom are the major source of particles. While cleanroom operators work, they emit millions of particles from every activity. Particles migrate up the cleanroom garment to the head and drop to the legs during cleanroom movements. Specialized textile fabrics have been used in cleanroom garments for many years. The need for this type of fabric has increased mainly due to the need to protect critical operations in cleanrooms as well as creating comfort for operators and other personnel. This study covers the general static wind-driven method, the Helmke Drum method and the dispersal chamber to measure particle penetration, shedding, and generation, in regards to the filtration efficiency of cleanroom fabrics and garments. Firstly, particle penetration is shown to increase with increasing face velocity and decreasing particle size below 1 μm. Secondly, that a recommended upper particle-size limit should be 5 µm. Using the Helmke drum test, the size distribution of particles released from the garment is shown to follow a power law distribution, with a slope of less than 1. Furthermore, the study introduces dynamic body box for testing fabrics as well as cleanroom garments. It is more practical and sensitive when compared to traditional methods and is based on a more concise technical approach. The life-time cycle performance of a typical cleanroom garment coverall is examined, particularly looking at the implications of pre-use steralization.