2007, Piran, Slovenia
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2007, Piran, Slovenia

2007, Piran, Slovenia 2007, Piran, Slovenia

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Environmental Ergonomics XII Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007 The liquid sweat transport (F) is another important thermophysiological textile property, particularly in situations with high sensible perspiration. The comparatively regular distribution of the standard deviations in Figure 3 indicates that the liquid sweat transport depends on both the textile construction, as well as the weft construction. DISCUSSION Outdoor clothing has to offer high wearer comfort in most situations with insensible or sensible perspiration, respectively. Various thermophysiological textile properties are influenced by different constructional parameters (fiber, yarn and textile construction as well as finishing). The Hohenstein Skin Model is able to simulate all these relevant wearer situations, and is for this reason not only applicable to obtain a complete thermophysiological characterization and evaluation of clothing textiles, but also to develop advanced textile products. ACKNOWLEDGEMENT We are grateful to the Forschungskuratorium Textil for the financial support of the research project (AiF No. 13806 BG), which was funded by the German Ministry of Economy and Technology via grants of the Arbeitsgemeinschaft industrieller Forschungsvereinigungen Otto von Guericke. REFERENCES [1] Outdoor clothing (foul weather protective clothing) with improved wear comfort by using spacer fabrics (in German). AiF research project Nr. 13806 BG. ITB Dresden and BPI Hohenstein, final report, 2006. 81 S. [2] ISO 11092. Textiles - Physiological effects - Measurements of the water vapour resistance under steady state conditions (sweating guarded-hotplate test). 1993. 136

Clothing TOTAL EVAPORATIVE RESISTANCE USING WEAR TRIALS FOR FIVE CLOTHING ENSEMBLES Victor Caravello 1 , Elizabeth A. McCullough 2 , Candi D. Ashley 1 , Thomas E. Bernard 1 1 University of South Florida, Tampa FL, USA and 2 Kansas State University, Manhattan KS USA Contact Person: tbernard@health.usf.edu INTRODUCTION A progressive heat stress protocol can be used to identify the critical conditions at which the maximum heat loss, due to evaporative cooling, is balanced by the net heat gain, due to internal sources and dry heat exchange. These relationships are illustrated by Equation 1. (Pa - Psk) / Re,T,r = Hnet + (Tdb - Tsk) / IT,r where Hnet = M - Wext - S + Cres - Eres (1) The resultant resistance to evaporative cooling (Re,T,r), and the total resultant insulation (IT,r), are recognized as the two primary coefficients for understanding the thermal characteristics of clothing. Recognizing that these were two unknowns, the Penn State group (Kenney and others) proposed a method based on simultaneous equations to solve for both coefficients using heat balance data from a physiological method, which provides an method to account for dry heat transfer through wet clothing and movement of the body. Their method provided a means to relate environmental and physiological measures at two critical conditions, and hence, the thermal characteristics could be determined. The USF group (Bernard and others) has taken the approach of estimating IT,r and using that value to estimate Re,T,r, believing that estimating evaporative resistance is robust to estimates of clothing insulation. In this paper, values for Re,T were determined from wear trials using the progressive heat stress protocol across five different ensembles. METHODS Twenty-nine adults participated. Prior to beginning the experimental trials to determine critical WBGT, they underwent a 5-day acclimatization to dry heat that involved walking on a treadmill at a metabolic rate of approximately 160 W m -2 at 50°C and 20% relative humidity (rh) for two hours. Participants wore a base ensemble of shorts, tee-shirt (or sports bra for women), socks and shoes. Five different clothing ensembles over the base ensemble were evaluated. The ensembles included work clothes (135 g m -2 cotton shirt and 270 g m -2 cotton pants), cotton coveralls (305 g m -2 ) and three limited-use protective clothing ensembles: particle-barrier ensembles (Tyvek® 1424 for half the participants and Tyvek® 1427 for the other half), water-barrier, vapour-permeable ensembles (NexGen® LS 417), and vapour-barrier ensembles (Tychem QC®, polyethylene-coated Tyvek® ). The limited-use coveralls had a zippered closure in the front and elastic cuffs at the arms and legs; and they did not include a hood. Each ensemble was worn by each participant at a moderate rate of work. Typically the dry bulb temperature (Tdb) was set at 34°C and relative humidity (rh) at 50%. Once the participant reached thermal equilibrium (no change in Tre and heart rate for at least 15 minutes.), Tdb was increased 0.8°C every 5 minutes. During trials, participants 137

Environmental Ergonomics XII<br />

Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana <strong>2007</strong><br />

The liquid sweat transport (F) is another important thermophysiological textile<br />

property, particularly in situations with high sensible perspiration. The comparatively<br />

regular distribution of the standard deviations in Figure 3 indicates that the liquid<br />

sweat transport depends on both the textile construction, as well as the weft<br />

construction.<br />

DISCUSSION<br />

Outdoor clothing has to offer high wearer comfort in most situations with insensible<br />

or sensible perspiration, respectively. Various thermophysiological textile properties<br />

are influenced by different constructional parameters (fiber, yarn and textile<br />

construction as well as finishing). The Hohenstein Skin Model is able to simulate all<br />

these relevant wearer situations, and is for this reason not only applicable to obtain a<br />

complete thermophysiological characterization and evaluation of clothing textiles, but<br />

also to develop advanced textile products.<br />

ACKNOWLEDGEMENT<br />

We are grateful to the Forschungskuratorium Textil for the financial support of the<br />

research project (AiF No. 13806 BG), which was funded by the German Ministry of<br />

Economy and Technology via grants of the Arbeitsgemeinschaft industrieller<br />

Forschungsvereinigungen Otto von Guericke.<br />

REFERENCES<br />

[1] Outdoor clothing (foul weather protective clothing) with improved wear comfort<br />

by using spacer fabrics (in German). AiF research project Nr. 13806 BG. ITB<br />

Dresden and BPI Hohenstein, final report, 2006. 81 S.<br />

[2] ISO 11092. Textiles - Physiological effects - Measurements of the water vapour<br />

resistance under steady state conditions (sweating guarded-hotplate test). 1993.<br />

136

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