Effect of Clothing Layers on Mass Transfer of Methyl Salicylate Vapor Through CBRN Materials in a Cylinder Test

Abstract

Abstract The testing of protective clothing materials against chemical and biological (CB) hazards is usually done at either a swatch of fabric or at the systems level. In this paper, a cylinder test method was developed in combination with a MethylSalicylate (MeS) Simulant test (variant to the MIST test) to study the effect of air-permeable and membrane clothing systems and specifically the effects of layering on protection. Three fabrics, material A air permeable absorptive, material B air impermeable, non-absorptive (membrane) and material C air permeable non-absorptive were tested on the cylinder alone and in combinations at 1 m/s and 10 m/s wind speeds. At high wind speeds, the MeS vapor penetrated all three materials and protection factors (PF) were lower than 10. At the lower wind speed much higher protection was found, PF(material A) = 36, PF(material B) = 29, PF(material C) = 2, and material B showed a significant decrease in protection with a leakage added (PF = 2), which did not occur with material A (PF = 29). When materials A and C were combined the combination of any layer to material A increased protection, especially with material A close to the cylinder: PF = 983 with material A twice, and PF = 765 with material C outside and material A inside. With material C on both layers, essentially no protection was obtained (PF = 2) and with material A outside and material C inside PF was 55, slightly higher than material A alone. In conclusion, the cylinder method provided very useful information in the development of protective clothing systems, especially at the lower wind speed of 1 m/s, and may provide a reliable quick and efficient way to obtain information on protection of air permeable absorptive fabrics. The method provides much more realistic data than current standard swatch tests on such materials and is cheaper and faster than a whole system MIST test.