2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
SERIAL AND PARALLEL METHOD IN CALCULATING THERMAL
INSULATION OF SINGLE GARMENTS WITH A THERMAL
MANIKIN
Joo Young Lee**, Eun Sook Ko*, Hyo Hyun Lee*, Jae Young Kim*, Jeong Wha Choi*
*Seoul National University, Seoul, Korea
**University of Minnesota, Minneapolis, USA
Joo Young Lee: leex3140@umn.edu
INTRODUCTION
Since one segment copper manikin made for the US Army was reported in 1945 (Holmer,
2004), thermal manikins have continuously progressed with the features of walking, sweating
and breathing. As thermal manikins evolved from one segment model to models with more
than 30 individually heated segments, one issue in calculating the thermal insulation of
clothing came up: a serial and a parallel method. Anttonen et al. (2004) reported differences
in thermal insulation calculated by a parallel and a serial method with identical clothing
ensembles, as well as the reproducibility of thermal insulation using manikins located in eight
different European laboratories. The coefficient of variation of the thermal insulation among 8
laboratories was lower than 8%, but parallel values were about 20% lower than serial ones.
This seemed to depend on what body regions were covered (Anttonen et al., 2004;
Meinander, 2004). In addition, the difference was influenced by the number of independently
heated body zones as well. Serial value on 35 body segments was higher than on 15 segments
(Redortier, 1997). If the manikin is covered with exactly the same insulation over all sections,
the results from two methods would be the same (Nilsson, 1997). However, our typical
clothing does not cover evenly the whole body. The variations of thermal insulation by the
two models may increase more when measuring the thermal insulation of single garments,
than for clothing ensembles. The present study selected comprehensive single garments and
examined 1) variations between the thermal insulations of single garments calculated by a
serial and a parallel method, and 2) the clothing factors affecting the extent of the difference.
METHODS
Selection of single garments and their physical characteristics: Single garments were
selected within clothes worn by adult women. For this, we surveyed the daily/work clothing
by questionnaire and interviews (825 women) (Choi et al., 2006). Based on the survey, a total
of 150 single garments were evenly selected for winter, spring/fall and summer ware (13
underwear, 16 T-shirts, 7 blouses, 6 vests, 7 cardigans, 18 Jackets/coats, 23 pants/overalls, 2
coveralls, 14 skirts/dresses; 15 headwear; 4 mufflers/scarves; 10 gloves; 15 panty
hoses/footwear). Surface area covered by clothing (covering area, CA, % BSA) was estimated
based on a photographic method and regional body surface area (Lee, 2005). Every garment
was weighed three times on an electronic balance (Sartorius Company, Germany, Sensitivity
1g).
Measurement of dry thermal insulation with a thermal manikin: Thermal insulation values
of single garments were determined using a thermal manikin with 20 independently heated
thermal zones (Newton, Measurement Technology NORTHWEST, USA, 1.7m 2 of BSA). All
zones were fit with heaters to simulate heat output so as to maintain a mean skin temperature
of 33.3±0.5 . Air temperature and air humidity in the chamber was set at 21.5±0.5 and
50±5%RH, respectively. Air speed was limited to 0.1ms -1 . The measurements were conducted
two times for every garment and the average was regarded as the total clo-value. The total
insulation (IT) of a garment including the insulation of air layer (Ia) around the clothed body
was calculated as follows:
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