2007, Piran, Slovenia
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2007, Piran, Slovenia

2007, Piran, Slovenia 2007, Piran, Slovenia

lboro.ac.uk
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Environmental Ergonomics XII Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007 434 MEASURING CLOTHING INSULATION: ANALYSIS OF HUMAN DATA BASED ON MANIKIN TESTS. Kalev Kuklane 1 , Chuansi Gao 1 , Ingvar Holmér 1 , Peter Broede 2 , Victor Candas 2 , Emiel den Hartog 2 , Harriet Meinander 2 , Wolfgang Nocker 2 , Mark Richards 2 , George Havenith 2 1 EAT, Dept. of Design Sciences, Lund University, Sweden 2 Thermprotect study group Contact person: kalev.kuklane@design.lth.se INTRODUCTION Within the THERMPROTECT project (Havenith et al., 2006) work package 2 Moisture (WP2), a series of human tests was carried out (Kuklane et al., 2007). One main objective of the WP2 was to study the question: What is the effect of evaporation/condensation within protective clothing on the heat transfer to the environment? This paper compares some methods of estimating clothing insulation, analyses human data based on manikin tests and discusses the sources for differences. METHODS In human tests, three variables at the same work load were combined: permeable (PERM, Rct=0.025 m 2 °C/W, Ret=5.6 m 2 Pa/W) and impermeable (IMP, Rct=0.007 m 2 °C/W, Ret=∞) outer layer, high (25°C) and low (10°C) ambient temperature, and wet (W) and dry (D) cotton underwear. Based on mean skin and body temperature, metabolic rate (Kuklane et al., 2007) and heat balance analysis, the total resultant clothing insulation (Itr) was calculated for all conditions. Data from standing manikin measurements (va=0.2 m/s) with dry underwear were used to compare the different calculation methods with data from the subjects. Heat losses from the whole manikin (covered and uncovered areas) were used to calculate the total clothing insulation (Itot) according to parallel method (equation 3 in EN/ISO 15831, 2004, here Eq. 1; Ts and Ta – manikin surface alt. ambient air temperature; A – manikin surface area; Hc – dry heat losses), and then corrected for wind and walking by equation 32 of ISO/FDIS 9920 (2007, here Eq. 2; var – air velocity; vw – walking velocity ) that was intended for the ensembles within the particular insulation range. Data from wet manikin tests (Havenith et al., 2006) at 10 and 34°C (both with 1 kPa ambient water vapour pressure) were used for further analysis and discussion of the differences. The conditions included dry and sweating tests. tot ( Ts − Ta ) A H c I = × (Eq. 1) I tr = e 2 2 [ −0. 281× ( v −0. 15) + 0. 044× ( v −0. 15) −0. 492v + 0. 176v ] ar ar w w × I tot (Eq. 2) RESULTS AND DISCUSSION The measured metabolic rate was 168 ±19 W/m 2 . In the wet tests, the metabolic rate averaged 8 W/m 2 higher than the dry tests. Figure 1 shows the heat balance components. Evaporation was assumed to take place at the skin surface. For condition PERM25W, in particular, this produced unrealistic dry heat loss values. The most reasonable insulation values (Figure 2) from the subjects came from dry test at 10°C, where the evaporation component was minimal and body heat storage relatively small (Figure 1). These values did fit best with the insulation correction of the manikin measurements according to ISO/FDIS 9920 (Figure 2). Figure 2 also shows for reference the original insulation value from a standing manikin, at an air velocity of 0.2 m/s (Itot(

Heat balance components 100% 80% 60% 40% 20% 0% -20% E K+C+R RES S IMP10D IMP10W IMP25D IMP25W PERM10D PERM10W PERM25D PERM25W Manikins Figure 1. Ratio of heat balance components: evaporation (E), conduction , convection and radiation (K+C+R), respiration (RES) and heat storage (S). Physical work (W) was taken equal to zero. Evaporative component was based on the mass loss. Insulation (m 2 °C/W) 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Impermeable Permeable Itr,10D Itr,10W Itr,25D Itr,25W Itot(

Heat balance components<br />

100%<br />

80%<br />

60%<br />

40%<br />

20%<br />

0%<br />

-20%<br />

E K+C+R RES S<br />

IMP10D IMP10W IMP25D IMP25W PERM10D PERM10W PERM25D PERM25W<br />

Manikins<br />

Figure 1. Ratio of heat balance components: evaporation (E), conduction , convection and<br />

radiation (K+C+R), respiration (RES) and heat storage (S). Physical work (W) was taken<br />

equal to zero. Evaporative component was based on the mass loss.<br />

Insulation (m 2 °C/W)<br />

0.30<br />

0.25<br />

0.20<br />

0.15<br />

0.10<br />

0.05<br />

0.00<br />

Impermeable Permeable<br />

Itr,10D Itr,10W Itr,25D Itr,25W Itot(

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