Heat strain models applicable for protective clothing systems: comparison of core temperature response

Abstract

Core temperature (Tc) output comparisons were analyzed from thermal models applicable to persons wearing protective clothing. The two models evaluated were the United States (US) Army Research Institute of Environmental Medicine (USARIEM) heat strain experimental model and the United Kingdom (UK) Loughborough (LUT25) model. Data were derived from collaborative heat-acclimation studies conducted by three organizations and included an intermittent-work protocol (Canada) and a continuous-exercise/heat stress protocol (UK and US). Volunteers from the US and the UK were exposed to a standard exercise/heat stress protocol (ambient temperature 35 degrees C/50% relative humidity, wind speed 1 m/s, level treadmill speed 1.34 m/s). Canadian Forces volunteers did an intermittent-work protocol (15 min moderate work/15 min rest at ambient temperature of 40 degrees C/30% relative humidity, wind speed approximately 0.4 m/s). Each model reliably predicted Tc responses (within the margin of error determined by 1 root mean square deviation) during work in the heat with protective clothing. Models that are analytically similar to the classic Stolwijk-Hardy model serve as robust operational tools for prediction of physiological heat strain when modified to incorporate clothing heat-exchange factors.

The Management of Heat Stress for the Firefighter: A Review of Work Conducted on Behalf of the Toronto Fire Service

“…In addition, the validation of the heat strain model with our laboratory findings was consistent 19) . with previous validation studies using military protective ensembles 32) . Thus, the internal validity of the prediction model from the current and past 32) work generated an increased confidence in applying the model to other environmental conditions that were not specifically examined in the current project.…”

Heat and mass transfer in air-fed pressurised suits

“…Because there is no need to take compressibility effects into account, the density can be assumed constant. Compressibility may be neglected in the flow of gases if M a 2 1. For a considered case the maximal (local) velocity is estimated to be 5.5 m s −1 , which corresponds to M a ≈ 0.016.…”

“…The turbulence intensity defined as τ t := 1 U 2 3 k was taken to be 1% and the viscosity ratio µ t µ = 1, that is a low turbulent intensity. Equations for eddy viscosity enable the inlet k to be determined in the form k = 3 2Ū 2 τ t , with the dissipation rate given by the equation ε = C µ ρ k 2 µ . (ii) Outlet -there are four outlets: two above the head (where the outlet temperatures T out have been measured) and two at the lower part of the back.…”

“…Normal body temperature T b0 is about 310 K and this is achieved when there is thermal balance between the amount of heat produced by the body and losses due to a number of different causes. The heat storage q S may be expressed as (Henane et al [4]; Gonzalez et al [2]; Havenith [3])…”

Progress in Development of a Miniature Environmental Heat Stress Monitor (HSM)

“…The environmental heat stress monitor (HSM) is a pocket-sized electronic device that uses microprocessor technology to integrate the USARIEM heat strain prediction model (3,5) software with a comprehensive suite of environmental sensors. It can provide real-time tailored guidance to reduce heat injury risk across the spectrum of heat stress environments including chemical protective clothing encapsulation.…”