2007, Piran, Slovenia

Clothing
PHYSIOLOGICAL RESPONSES AT 10 AND 25 °C IN WET AND
DRY UNDERWEAR IN PERMEABLE AND IMPERMEABLE
COVERALLS
Kalev Kuklane 1 , Chuansi Gao 1 , Ingvar Holmér 1 , Peter Bröde 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 THERMPROTECT project (Havenith et al., 2006) several studies were carried
out on manikins (Gao and Holmer, 2006; Candas et al., 2006; Richards et al., 2006;
etc.) and on subjects (Dorman et al., 2006; Meinander et al., 2006; etc.). One main
objective of the work package 2 (WP2) Moisture was to answer the question: What is
the effect of evaporation/ condensation within protective clothing on the heat transfer
to the environment? This paper describes the subject tests that were intended to study
this question. For that purpose 3 conditions at the same work load were combined:
wet and dry underwear, high and low ambient temperature, and permeable and
impermeable outer layer. We had following expectations: 1) less evaporates from
impermeable coverall; 2) more condensation at low temperatures; 3) wet underwear
has more cooling effect in permeable coverall.
METHODS
Eight healthy male subjects (age 30±6 yrs, height 1.78±0.04 m, weight 74.8±9.7 kg)
participated in the study. The subjects walked on the treadmill at 4.5 km/h for 60
minutes. The variables were permeability of coverall (permeable and impermeable),
wetness of underwear (dry and wet) and ambient temperature (10 °C and 25 °C).
Two-way factorial design (2x2x2) was employed in the experiments. Each subject
started the test at the same time of the day each time. The humidity was kept at 1 kPa
water vapour pressure for both ambient temperatures. The air velocity was 0.40±0.12
m/s for all conditions. The two layer clothes used in the study were permeable
(PERM, polypropylene layer with inner PTFE membrane) and impermeable (IMP,
polyamide with PVC coating) coverall and cotton underwear (dry and wet). The
underwear (cotton shirt, ~320 g and trousers ~290 g) was pre-wetted in the washing
machine for wet tests. The total water content in the underwear was 968±42 g. Prior to
the test the wet underwear was placed inside a plastic bag and into drying cupboard
where it was pre-warmed. Other clothes worn by the subjects were briefs, socks and
sport shoes. Skin (8 sites) and body core temperature (rectal temperature (Trec) at 10
cm depth), and heart rate were recorded continuously for 60 minutes with 15 second
intervals. The mean skin temperature (Tsk) was calculated according to Gagge and
Nishi (1977). In some conditions mean skin temperature stayed under 32 °C and in
some it stayed above that. Therefore, a floating calculation was used for mean body
temperature (Tb): if Tsk>33.5 °C then Tb=0.2Tsk +0.8Trec was used, if Tsk