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Heat strain imposed by personal protective ensembles
Quantitative analysis using a thermoregulation model The objective of this paper is to study the effects of personal protective equipment (PPE) and specific PPE layers, defined as thermal/evaporative resistances and the mass, on heat strain during physical activity. A stepwise thermal manikin testing and modeling approach was used to analyze a PPE ensemble with four layers: uniform, ballistic protection, chemical protective clothing, and mask and gloves. The PPE was tested on a thermal manikin, starting with the uniform, then adding an additional layer in each step. Wearing PPE increases the metabolic...
Real-time core body temperature estimation from heart rate for first responders wearing different levels of personal protective equipment
First responders often wear personal protective equipment (PPE) for protection from on-the-job hazards. While PPE ensembles offer individuals protection, they limit one's ability to thermoregulate, and can place the wearer in danger of heat exhaustion and higher cardiac stress. Automatically monitoring thermal-work strain is one means to manage these risks, but measuring core body temperature (Tc) has proved problematic. An algorithm that estimates Tc from sequential measures of heart rate (HR) was compared to the observed Tc from 27 US soldiers participating in three different chemical/biological...
The influence of arc-flash and fire resistant clothing on thermoregulation during exercise in the heat
PURPOSE: We evaluated the effect of arc-flash and fire resistant (AFR) clothing ensembles (CE) on whole-body heat dissipation during work in the heat. METHODS: On 10 occasions, seven males performed four 15-min cycling bouts at a fixed rate of metabolic heat production (400W) in the heat (35°C), each separated by 15-min of recovery. Whole-body heat loss and metabolic heat production were measured by direct and indirect calorimetry, respectively. Body heat storage was calculated as the temporal summation of heat production and heat loss. Responses were compared in a semi-nude state and while...
Reducing heat stress under thermal insulation in protective clothing
Microclimate cooling by a 'physiological' method Heat stress caused by protective clothing limits work time. Performance improvement of a microclimate cooling method that enhances evaporative and to a minor extent convective heat loss was tested. Ten male volunteers in protective overalls completed a work-rest schedule (130 min; treadmill: 3 x 30 min, 3 km/h, 5% incline) with or without an additional air-diffusing garment (climatic chamber: 25 °C, 50 % RH, 0.2 m/s wind). Heat loss was supported by ventilating the garment with dry air (600 l/min, «5% RH, 25 °C). Ventilation...
The European, Japanese and US protective helmet, gloves and boots for firefighters
Thermoregulatory and psychological évaluations The purpose of this study was to investigate the physiological and subjective responses of the European, Japanese (JPN) and US firefighters' helmet, gloves and boots for international standardisation. Three experimental conditions were evaluated (clothing mass: 9.4, 8.2 and 10.1 kg for the three conditions, respectively) at the air temperature of 32°C and 60% relative humidity. The results showed that there was no significant difference among the three conditions in oxygen consumption, heart rate, total sweat rate, rectal temperature...
Review of standards for thermal protection PPE in the explosives industry
The suitability of PPE for use against different thermal challenges is often described by way of compliance with British, European or Internationally agreed standards. The review compared the range of test standards currently used for flame protective PPE for both general industrial use and specialist PPE for motor racing and fire fighting tasks with the thermal challenge expected from a range of explosive events. Disparity has been found between the levels of challenge required to pass the test standards and the level displayed by the burning explosive materials – these practical challenges...
The Effect of Air Permeability Characteristics of Protective Garments on the Induced Physiological Strain under Exercise-Heat Stress
Objectives : The high values of thermal resistance (Rct) and/or vapor resistance (Ret) of chemical protective clothing (CPC) induce a considerable thermal stress. The present study compared the physiological strain induced by CPCs and evaluates the relative importance of the fabrics' Rct, Ret, and air permeability in determining heat strain. Methods : Twelve young (20–30 years) healthy, heat-acclimated male subjects were exposed fully encapsulated for 3h daily to an exercise-heat stress (35°C and 30% relative humidity, walking on a motor-driven treadmill at a pace of 5 km h1 and a...
Technologie de réfrigération «intelligente» pour les vêtements de protection
Sur les gilets pare-balles, le kevlar ne laisse pas passer les balles – mais pas non plus la vapeur d’eau. Les forces de sécurité qui doivent porter un tel gilet sous leur uniforme ne transpirent ainsi pas même par les grandes chaleurs ce qui peut devenir dangereux lors d’une intervention. L’Empa a développé avec un partenaire industriel un gilet de protection «intelligent» à système de réfrigération intégré basé sur la technologie Coolpad développée initialement...
Les combinaisons étanches : que mesurer lorsque les indices d'astreinte normalisés ne peuvent être utilisés
Cet article rappelle succinctement dans une première partie les principes de l'adaptation de l'Homme à la chaleur et les risques qui découlent de ces expositions en insistant sur les aspects relatifs au port de combinaisons étanches. Dans un second temps, sont rapportées deux études ayant comparé des combinaisons étanches ventilées et non ventilées en situation réelle de travail et en laboratoire. Des métrologies simples, telles que le recueil de la fréquence cardiaque (FC) en continu et des évaluations...
Methods for calculating thermal insulation of clothing measured with a thermal manikin
There are three methods for calculating thermal insulation of clothing measured with a thermal manikin, i.e. the global method, the serial method, and the parallel method. Under the condition of homogeneous clothing insulation, these three methods yield the same insulation values. If the local heat flux is uniform over the manikin body, the global and serial methods provide the same insulation value. In most cases, the serial method gives a higher insulation value than the global method. There is a possibility that the insulation value from the serial method is lower than the value from the global...
Intolerance to the thermal effects of PFMs leads to decreased use and concomitant decreased protection for the user
A computerized literature search was undertaken for the period 1950–2010, references selected for inclusion in the review were those that included information relating to heat, comfort, and tolerance associated with the use of PFMs. The use of protective facemasks (PFMs) negatively impacts respiratory and dermal mechanisms of human thermoregulation through impairment of convection, evaporation, and radiation processes. The relatively minor reported increases in core temperature directly attributable to the wearing of PFMs suggest that associated perceptions of increased body temperature may...

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