Moisture Transport and Absorption in Multilayer Protective Clothing Fabrics

Abstract

The distribution of moisture in state-of-the-art firefighter protective clothing was analyzed on a sweating torso. After one hour of sweating, only 35 % of moisture evaporated from the layers, but after another hour of drying out, only about 10 % of the supplied moisture remained in the clothing. Over 75 % of this moisture accumulated in the innermost three layers of the clothing system consisting of five and six layers, respectively. The interaction of the moisture transport properties of the different layers proved to be very important for the distribution of moisture. In particular, the neighboring layer of the underwear turned out to be dominant for the moisture distribution. Depending on its hygroscopic properties, it could even act as a water barrier.

Analysis of Steam Formation and Migration in Firefighters’ Protective Clothing Using X-Ray Radiography

“…These amounts corresponded to typical moisture accumulations measured in similar layers during a previous study [1] where we analysed the mass transport in firefighters' ensembles with a sweat release corresponding to 1 L/h for a human body. The different humidity conditions were denominated accordingly (e.g., UW 0.6 or TB 1.0).…”

“…Firefighters usually work in a hot and very moist environment, which leads to a large moisture accumulation in the protective clothing [1,2,3,4]. Moisture trapped in the clothing system strongly affects the heat transfer properties of the clothing.…”

Opportunities and constraints of presently used thermal manikins for thermo-physiological simulation of the human body

“…Presently, manikins are usually operated at uniform steady-state surface temperatures and homogenous sweat rates in comparative measurements, for example according to standards, such as ASTM (Gao et al 2012;Keiser et al 2008), or non-uniform surface temperatures over the body, such as cooler hands and feet (McCullough 2002;McCullough et al 1985), or uniform surface temperature change over time (Tanabe et al 1994). These attempts indicate the growing interest in using manikins to adequately simulate the effect of clothing and environmental exposures on human thermal responses such as body core temperature and skin temperature distribution, onset of vasomotor reactions, sweating and shivering.…”

Evaporative cooling: effective latent heat of evaporation in relation to evaporation distance from the skin

“…Each of the phase changes mentioned will cause heat to be released or absorbed (24) at the location where it occurs. Once moisture is present as liquid, layer-to-layer wicking may occur (23).…”