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Effect of Accelerated Ultraviolet (UV) Weathering on Firefighter Protective Clothing Outer Shell Fabrics

出版	National Institute of Standards and Technology, 2010
URL	http://books.google.com.hk/books?id=TroBaAEACAAJ&hl=&source=gbs_api

註釋The outer shell of the jacket and pants of a firefighter's protective clothing is constructed of a fabric that is commonly a blend of polyaramid, polybenzimidazole, and/or poly(melamine-formaldehyde) fibers. The outer shell contributes to the thermal and moisture protection of the garment, but its primary purpose is to provide protection from other physical hazards, such as sharp objects and abrasive surfaces. The research discussed in this manuscript indicates that the mechanical performance, which is critical to the outer shell providing protection against these physical hazards, of polyaramid and polybenzimidazole based outer shell fabrics will rapidly deteriorate when exposed to simulated ultraviolet sunlight at 50 °C and 50% relative humidity. For example, these fabrics lost as high as 80% of their tear and tensile strength after only 13 days of exposure to these conditions. In addition, a water repellant coating on these fabrics was significantly degraded as a result of these conditions. Even though these exposure conditions caused catastrophic mechanical failure, the amount of ultraviolet light transmitted through these fabrics was quite low. More specifically, after 13 days exposure these fabrics blocked more than 94% of the ultraviolet light (Ultraviolet Protection Factor of 18). Using a conversion factor (defined in the manuscript), these outer shell fabrics will lose a high as 80% of its mechanical performance, but still block at least 94 % of the sunlight after being in service for 6.3 years.