Physiological Responses to Wearing a Prototype Firefighter Ensemble Compared with a Standard Ensemble

Abstract

This study investigated the physiological responses to wearing a standard firefighter ensemble (SE) and a prototype ensemble (PE) modified from the SE that contained additional features, such as magnetic ring enclosures at the glove-sleeve interface, integrated boot-pant interface, integrated hood-SCBA facepiece interface, and a novel hose arrangement that rerouted self-contained breathing apparatus (SCBA) exhaust gases back into the upper portion of the jacket. Although the features of the PE increased the level of encapsulation of the wearer that could lead to increased physiological stress compared with the SE, it was hypothesized that the rerouted exhaust gases provided by the PE hose assembly would (1) provide convective cooling to the upper torso, (2) reduce the thermal stress experienced by the wearer, and (3) reduce the overall physiological stress imposed by the PE such that it would be either less or not significantly different from the SE. Ten subjects (seven male, three female) performed treadmill exercise in an environmental chamber (22°C, 50% RH) at 50% [image omitted]O(2max) while wearing either the SE with an SCBA or the PE with an SCBA either with or without the hose attached (designated PEWH and PENH, respectively). Heart rate (HR), rectal and intestinal temperatures (T(re), T(in)), sweat loss, and endurance time were measured. All subjects completed at least 20 min of treadmill exercise during the testing. At the end of exercise, there was no difference in T(re) (p = 0.45) or T(in) (p = 0.42), HR, or total sweat loss between the SE and either PEWH or PENH (p = 0.59). However, T(sk) was greater in PEWH and PENH compared with SE (p < 0.05). Total endurance time in SE was greater than in either PEWH or PENH (p < 0.05). Thus, it was concluded that the rerouting of exhaust gases to the jacket did not provide significant convective cooling or reduce thermal stress compared with the SE under the mild conditions selected, and the data did not support the hypotheses of the present study.

Mitigation and Prevention of Exertional Heat Stress in Firefighters: A Review of Cooling Strategies for Structural Firefighting and Hazardous Materials Responders

“…This enhanced gear did not provide a convective cooling advantage; instead, it decreased work performance in relation to standard thermal protective clothing. 35 To determine whether air or liquid cooling is better at alleviating physiologic strain during work in chemical protective clothing, the effectiveness of both modalities applied to the torso during heat strain for up to three hours of treadmill exercise in the heat (40 • C, 30% RH) were compared while subjects were wearing chemical protective clothing. There were no differences between liquid or air cooling on core temperature, skin temperature, HR, sweat rate, or heat storage, as the two methods provided similar relief compared with no cooling while subjects were wearing chemical protective clothing.…”

Subjective perceptions and ergonomics evaluation of a liquid cooled garment worn under protective ensemble during an intermittent treadmill exercise

“…While the main features of this ensemble are the same as a standard firefighting ensemble, consisting of helmet, coat, pants, gloves and boots, the study PFE included several innovations in its design aimed at providing wearer-integrated protection from hazardous materials such as nuclear, biological and chemical materials (Williams et al 2011). Total carriage load imposed on the wearer by the ensemble and SCBA was 20.2 + 0.2 kg.…”

Physiological impact of flame resistant clothing: managing heat stress

“…The increase in T core causes increased skin blood fl ow resulting in an increase in skin temperature ( T sk ) . The increase in T sk in persons wearing the FR-PPE refl ects a physiological adjustment in an attempt to conduct an elevated T core to the periphery for heat dissipation (as long as a thermal gradient exists between T core and T sk ) (Williams et al ., 2011 ). As such, T sk is greatly infl uenced by trapped heat and reduced heat dissipation created by the PPE microclimate.…”

“…Nevertheless, several cooling strategies and technologies have been explored including hydration status and relative aerobic fi tness McLellan, 1998a , 1998b;McLellan and Cheung, 2000 ), comparisons of air and liquid cooling garments (Bishop et al ., 1991 ;Vallarand et al ., 1991;Chen et al ., 1997 ;Nishihara et al ., 2002 ), dry-ice vs water spray cooling systems (Cadarette et al ., 2002 ;Heled et al ., 2004 ), and cooling of various selective areas of the body including feet (Livingstone et al ., 1995 ), whole-body vs upper torso (Sleivert et al ., 2001 ;Kim et al ., 2011aKim et al ., , 2011b, cooling of the facial area (Armada- de-Silva et al ., 2004 ), and incorporation of a passive cooling system into a prototype FR-PPE (Williams, et al ., 2011 ). All of these strategies involve technological hurdles to accomplish a practical means to mitigate heat stress in FR-PPEs.…”

“…The garment utilized by the military is full NBC protection clothing, and is required to be worn for an exceptionally long period of time. These strategies and cooling systems have been aimed primarily at the use of an encapsulating NBC garment worn by the military and only a moderate number of studies have examined the physiological responses to fi refi ghter ensembles (Stull and Duffy, 2000 ;Selkirk and McLellan, 2004 ;Williams et al ., 2011 ). Thus, while the military experience with cooling technologies can be used as a valuable reference, it is still necessary to complete similar measurements on fi refi ghter turnout gear because of its dissimilarity to the military gear and mission.…”