Structural firefighters can receive second-degree burns while working in thermal exposures considerably lower than flashover conditions. These exposures are usually several minutes in duration, and the exposure levels are generally not sufficient to degrade the turnout shell fabric. There is considerable interest in the role played by moisture, absorbed by clothing materials exposed to perspiration from a sweating firefighter, in burn injuries received in these conditions. Recent studies have shown that moisture, present in firefighter turnout systems, has a complex influence on heat transmission and potential for skin burn injuries [1,2]. At the same time, there is significant current interest in developing laboratory thermal protective performance testing protocols that incorporate reliable and realistic moisture preconditioning procedures. This paper describes an analysis of the effects of moisture on the thermal protective performance of turnout systems exposed to a low-level heat source.
Sweat Absorption in Firefighter TurnoutsDuring fire fighting, firefighters 1 can sweat profusely causing moisture to accumulate in their turnout garments. This accumulated moisture can affect the ability of the turnout clothing materials to protect against prolonged exposure to heat in a structural fire within a room that has not reached flashover condition. This research was conducted to study the effects of moisture on the thermal protective performance of firefighter turnout materials in this type of radiant heat environment.Abstract This paper describes research on the effects of absorbed moisture on the thermal protective performance of the fire fighter turnout materials exposed to thermal assaults lower than flashover conditions. A thermal testing platform and sensor are used to measure thermal protective performance of turnout systems exposed to a sub flashover heat flux range 6.3 kw/m 2 (0.15 cal/ cm 2 s). The effects of moisture level on predicted second-degree burn injury for turnout systems having different moisture vapor permeability and total heat loss are discussed. Heat transfer analysis and experimental results show that, for selected test conditions, moisture negatively impacts protective performance most severely when the amount of added moisture is at a comparatively low level (15-20% of turnout system weight).
This paper traces the evolution of objective measurement of textile hand and comfort from Pierce through modern methodology and approaches. Special emphasis is given to discuss the contribution of the Kawabata Evaluation System (KES) towards advancing the state of objective measurement. Laboratory case studies are used to show how data generated by the KES and other instruments can be integrated into a comprehensive approach that attempts to explain human comfort response to garment wear in terms of fabric mechanical, surface and heat and moisture transfer properties.
This research developes a numerical model to predict skin burn injury resulting from heat transfer through a protective garment worn by an instrumented manikin exposed to laboratory-controlled flash fire exposures. This model incorporates characteristics of the simulated flash fire generated in the chamber and the heat-induced changes in fabric thermophysical properties. The model also accounts for clothing air layers between the garment and the manikin. The model is validated using an instrumented manikin fire test system. Results from the numerical model help contribute to a better understanding of the heat transfer process in protective garments exposed to intense flash fires, and to establishing systematic methods for engineering materials and garments to produce optimum thermal protective performance.
A test method that measures microclimate drying time is used to compare the ability of different knit materials to dissipate moisture vapor from a saturated clothing environment to the ambient atmosphere. The performance assessment provided by this novel method is compared with those from common test methods. The latter include measures of the moisture vapor transmission rate provided by the upright cup and the evaporative thermal resistance provided by the sweating guarded hot plate procedure. Upright cup and sweating hot plate measurements are shown to be predominately influenced by fabric thickness, but microclimate drying time, or the time-dependent dissipation of accumulated moisture vapor, assessed by the new method is most influenced by the pore characteristics of the fabric. Moisture vapor transmission through fabrics is assumed to be controlled mostly by fiber, yarn, and fabric variables that determine fabric thickness and porosity. Therefore, constructional variables that lead to thin knit structures, with unobstructed interyarn pores, are shown to be important considerations for designing fabrics with optimum moisture vapor dissipation properties.
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