Arc Flash Protection
OSHA regulation 1910.269 requires that “employees shall wear clothing resistant to flash flame wherever there is possible exposure to an electric arc flash.” The National Fire Protection Association (NFPA) has issued NFPA 70E advising that apparel made of polyester, nylon, acetate, or rayon be prohibited from the workplace where a risk of arc flash exists. The American Society for Testing of Materials (ASTM) has issued specification ASTM 1506, “Standard Performance Specification for Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards.”
Cleanrooms present a unique situation for electrical arc protection because of the additional prohibition on self-linting materials. Few materials exist in filament forms that satisfy both OSHA requirements for safety and cleanroom requirements for non-linting. Composed of 100% filament Nomex(r) and meeting the requirements of ASTM F1506, ChemStat 919, ChemStat 487, and ChemStat 541 are not only inherently flame resistant and static dissipative; compatible with most cleanroom protocols. They exhibit Arc Thermal Performance ATPv ratings of 6.3, 5.0, and 12.0 cal/cm2, respectively, in accordance with ASTM F1959-99.
The rating of the fabric in itself is not an indicator of protection; ultimately the protective garment must be rated for total arc flash protection. Moreover, the use of flame resistant Nomex(r) clothing does not necessarily preclude the possibility of burn injury; the thickness of a fabric layer or the number of layers must increase with increased hazard levels.
ChemStat 919, ChemStat 487, and ChemStat 541 may be used as the outer layer of a protective garment. ChemStat 16 SG is a lightweight Nomex(r) fabric without static protection that can be used as part of multi-layer garment system to provide additional layering and protection.
ChemStat 919, ChemStat 487, ChemStat 541, and ChemStat 16 SG exhibit high resistance to beta and gamma radiation.
Designed for outer garments, ChemStat 919, ChemStat 487, and ChemStat 541 employ a patented grid of conductive carbon-polyester yarn (US Patent 4,606,968). The grid rises slightly above the plane of the fabric, acting as a wick to draw static electricity out of the fabric and then to dissipate it innocuously into the surrounding humidified air.