Moisture Effects in Heat Transfer Through Clothing Systems for Wildland Firefighters

Abstract

Wildland firefighters work in unfavourable environments involving both heat and moisture. Moisture in clothing systems worn by wildland firefighters may increase or decrease heat transfer, depending on its source and location in the clothing system, location on the body, timing of application and degree of sorption. In this experiment, 4 outerwear/underwear combinations were exposed to 1 of 5 different conditions varying on amount and location of moisture. The fabric systems were then exposed to either a high-heat-flux flame exposure (83 kW/m(2)) or a low-heat-flux radiant exposure (10 kW/m(2)). Under high-heat-flux flame exposures, external moisture tended to decrease heat transfer through the fabric systems, while internal moisture tended to increase heat transfer. Under low-heat-flux radiant exposures, internal moisture decreased heat transfer through the fabric systems. The nature and extent of such differences was fabric dependent. Implications for test protocol development are discussed.

Recent trends and future scope in the protection and comfort of fire-fighters’ personal protective clothing

“…The amount of moisture and its distribution; the material used for the clothing system and the clothing design; and the thermal intensity affects the level of thermal protection of the FFPPC (Mell and Lawson 2000;Lawson et al 2004;Barker et al 2006). Accumulated moisture on the skin and in the fabric ensembles can alter the level of protection.…”

“…The effect of moisture (both internal and external) on heat transfer from convective and radiant sources through single-layered Barker 1986, Song 2007), twolayered (Lawson et al 2004), three-layered and fourlayered protective clothing systems has been studied. It has been established that moisture can affect both positively and negatively on the thermal protection performance of the clothing systems.…”

“…Hence, for effective design of the FFPPC, it is essential to understand the effect and mechanism of moisture transfer through the clothing system at high temperature. Some of the researchers have focused to establish a relationship between the presence of moisture and transfer properties of clothing at high temperature by evaluating properties such as heat transfer index (HTI), thermal protective performance (TPP) and radiative protective performance (RPP) (Lee and Barker 1986;Veghte 1987;Havenith et al 1990;Rossi and Zimmerli 1996;Torvi and Dale 1998;Lawson et al 2004).…”

Protection From Steam at High Pressures: Development of a Test Device and Protocol

“…The effect on heat transfer of moisture in fabrics, garments and garment assemblies exposed to high heat fluxes has been reviewed and reported elsewhere [8,9,10,11]. In general, moisture has been found to decrease thermal insulation, and as the fabric is saturated, the thermal conductivity of water influences heat transfer more than that of the material.…”

Analysis of Moisture Evaporation from Underwear Designed for Fire-Fighters

“…Thus, a research was started to study the effect of moisture on the thermal protective performance of fire-fighter clothing in lowlevel radiant heat environment, the most common conditions in which the fire-fighters work. Understanding mechanisms by which moisture in textiles affects heat transfer through clothing systems could lead to improvements in the design of thermal protective clothing [15].…”