Reducing heat stress under thermal insulation in protective clothing: microclimate cooling by a ‘physiological’ method

—The purpose of the present study was to determine the separate and combined effects of aerobic fitness, short-term heat acclimation, and hypohydration on tolerance during light exercise while wearing nuclear, biological, and chemical protective clothing in the heat (40°C, 30% relative humidity). Men who were moderately fit [(MF); <50 ml ⋅ kg−1 ⋅ min−1maximal O2 consumption; n = 7] and highly fit [(HF); >55 ml ⋅ kg−1 ⋅ min−1maximal O2 consumption; n = 8] were tested while they were euhydrated or hypohydrated by ∼2.5% of body mass through exercise and fluid restriction the day preceding the trials. Tests were conducted before and after 2 wk of daily heat acclimation (1-h treadmill exercise at 40°C, 30% relative humidity, while wearing the nuclear, biological, and chemical protective clothing). Heat acclimation increased sweat rate and decreased skin temperature and rectal temperature (Tre) in HF subjects but had no effect on tolerance time (TT). MF subjects increased sweat rate but did not alter heart rate, Tre, or TT. In both MF and HF groups, hypohydration significantly increased Tre and heart rate and decreased the respiratory exchange ratio and the TT regardless of acclimation state. Overall, the rate of rise of skin temperature was less, while ΔTre, the rate of rise of Tre, and the TT were greater in HF than in MF subjects. It was concluded that exercise-heat tolerance in this uncompensable heat-stress environment is not influenced by short-term heat acclimation but is significantly improved by long-term aerobic fitness.

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Development of high-insulating materials with aerogel for protective clothing applications – an overview

International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde) ◽

10.1515/ijmr-2020-8042 ◽

2021 ◽

Vol 112 (2) ◽

pp. 164-172

Author(s):

Agnieszka Greszta ◽

Sylwia Krzemińska ◽

Grażyna Bartkowiak ◽

Anna Dąbrowska

Keyword(s):

Thermal Conductivity ◽

Thermal Insulation ◽

Protective Clothing ◽

State Of The Art ◽

Knitted Fabrics ◽

Insulating Materials ◽

Textile Materials ◽

Wide Range ◽

Properties Of Materials ◽

Hot Environments

Abstract Aerogels are ultra-light solids with extremely low thermal conductivity (even lower than air), thanks to which they have a huge potential in a wide range of applications. The purpose of this publication is to present the state-of-the art knowledge of the possibility of using aerogels to increase the thermal insulation properties of clothing materials intended for use in both cold and hot environments. Various methods of aerogels application to textile materials (non-woven, woven and knitted fabrics) are discussed, indicating their advantages and limitations. Numerous research studies confirm that aerogels significantly improve the thermal insulation properties of materials, but due to their delicate and brittle structure and their tendency to dusting, their application still poses considerable problems.

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Modeling heat stress and heat strain in protective clothing

Protective Clothing ◽

10.1533/9781782420408.3.416 ◽

2014 ◽

pp. 416-434 ◽

Cited By ~ 1

Author(s):

P. Bishop ◽

K. Crew ◽

J. Wingo ◽

A. Nawaiseh

Keyword(s):

Heat Stress ◽

Protective Clothing ◽

Heat Strain

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Thermal insulation property of graphene/polymer coated textile based multi-layer fabric heating element with aramid fabric

Scientific Reports ◽

10.1038/s41598-020-74339-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Hyelim Kim ◽

Han Seong Kim ◽

Sunhee Lee

Keyword(s):

Surface Temperature ◽

Thermal Insulation ◽

Temperature Difference ◽

Protective Clothing ◽

Woven Fabrics ◽

Heating Element ◽

Electrical Heating ◽

High Porosity ◽

Insulation Property ◽

Thermal Insulation Property

Abstract This study investigated the thermal insulation properties based on electrical heating test of graphene-based multi-layer fabric heating elements to confirm the possibility of application for fabric heating element for protective clothing. Four layers were designed as layers of outer, filler, electrical heating textile, and lining. The outer fabrics used two different densities of aramid woven fabrics (LD_ARW and HD_ARW), an aramid knit (AR_KT), and nonwoven (AR_NW). Fabricated graphene/polymer coated electrical heating textile (GR) exhibits a surface temperature of about 85 °C, a current of 0.12 A, and a power of 3 W when 30 V is applied. As composed with 4-layer, the surface temperature of LD_ARW and HD_ARW used as the outer for sample indicated less than 50 °C, due to their excellent heat resistance property; whereas, when AR_KT and AR_NW were used, the temperature was about 50 °C. This is because their fine fibers form high porosity that can entrap air. As a result of the thermal insulation properties, the temperature difference of each layer was in the order ΔT(GR-N3) < ΔT(GR-Lining) < ΔT(GR-Outer). In particular, when AR_NW was used as the outer fabric, ΔT(GR-Outer) was decreased by about 10 °C, compared with that of the other outer fabric. By the effect of relative humidity under dry 25% RH and comfortable 55% RH, the temperature difference was decreased under 55% RH; thus, the thermal insulation property was improved under comfortable humidity condition. Therefore, the best thermal insulation performance was exhibited when AR_NW was used as outer under 55% RH, and it is expected to expand its application to fabric heating element for protective clothing.

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Infrared thermometry in the measurement of heat stress in firefighters wearing protective clothing

Applied Ergonomics ◽

10.1016/0003-6870(91)90127-4 ◽

1991 ◽

Vol 22 (6) ◽

pp. 422-423

Author(s):

T.C. Hower ◽

K.D. Blehm

Keyword(s):

Heat Stress ◽

Protective Clothing ◽

Infrared Thermometry

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Characteristics of Specialised Firefighter Clothing Used in Poland – the Thermal Parameters

Fibres and Textiles in Eastern Europe ◽

10.5604/01.3001.0013.5860 ◽

2020 ◽

Vol 28 (1(139)) ◽

pp. 65-70

Author(s):

Magdalena Młynarczyk

Keyword(s):

Thermal Insulation ◽

Protective Clothing ◽

Thermal Parameters ◽

Thermal Manikin ◽

Test Results ◽

Evaporative Resistance ◽

Different Types ◽

Local Thermal Insulation ◽

Materials Used ◽

The Impact

This paper describes the characteristic thermal parameters of firefighters’ personal protective clothing (FFPPC) used in Poland. The total thermal insulation and evaporative resistance of three different types of FFPPC were measured and used on a thermal manikin. Next, the results were compared. Based on the analyses and calculations of the test results, it was shown that FFPPC provides a barrier to the heat exchange between the user and the surrounding environment. Differences in the local thermal insulation can be triggered not only by the material used but they can also be attributable to clothes fitted on the manikin. The biggest differences can be noted on the segments forming part of the manikin’s trunk. No difference was found in the evaporative resistance between the clothes tested. In order to examine further the impact of the materials used on thermal parameters of protective clothing, it is necessary to carry out an analysis of the impact of individual layers.

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Thermal Properties of Special New Generation Personal Protective Clothing for Firefighters-Rescuers

Zeszyty Naukowe SGSP ◽

10.5604/01.3001.0015.6479 ◽

2021 ◽

Vol 1 (80) ◽

pp. 45-67

Author(s):

Marzena Rachwał ◽

Małgorzata Majder-Łopatka ◽

Tomasz Węsierski ◽

Artur Ankowski ◽

Magdalena Młynarczyk ◽

...

Keyword(s):

Thermal Properties ◽

Thermal Insulation ◽

Protective Clothing ◽

Body Shape ◽

Thermal Protection ◽

Thermal Manikin ◽

Protective Equipment ◽

Everyday Work ◽

New Generation ◽

Full Body

Every day, firefighters put their health and life at risk by saving people and their property not only during fires, but by being always ready during all kinds of unfortunate events. Therefore, they need special personal protective equipment, including protective clothing. The purpose of the study was to compare thermal properties of new (PROTON and SYRIUSZ) and old (US-03) personal protective clothing for firefighters. Measurements of thermal insulation (total, effective and local) were carried out using a full body shape thermal manikin Newton consisting of 34 segments, in which temperature and heat flux were controlled independently. Results of the total thermal insulation of the entire clothing reveal differences between all three models. The lowest values were noticed for the model PROTON with light and shorter jacket and the highest values of thermal insulation for the new model SYRIUSZ, indicating that this model protect the user against heat most effectively. New models of personal protective clothing for firefighters should be recommended for use in everyday work, because they are characterized by better parameters than the previous type of protective clothing, both in terms of thermal protection and mobility.

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