2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
166
THE CHARACTERISTICS OF THERMAL INSULATION OF
SOCKS TOWARDS PREVENTION OF GLOBAL WARMING
Mikie Kusunoki
Yasuda Women’s University, Hiroshima, Japan
Contact person: kusunoki@yasuda-u.ac.jp
INTRODUCTION
Global warming advances faster than we predict, and effective measures should be
taken by each nation. In our daily life, world-wide saving energy is demanded. The
use of heating in the winter creates comfortable life spaces, but uses a great deal of
energy. Therefore, it is necessary for individuals to refrain from using heating, and to
rely more on clothing for thermal insulation. In other words, the switch from heating
to thermal insulation is demanded. The purpose of this study is to clarify the responses
of foot skin temperature to cold stimuli, and the characteristics of thermal insulation
by socks.
METHODS
Twelve healthy female students participated in Experiment 1 (20 y, 156.77 ±4.87 cm,
49.76 ±6.18 kg, 20.29 ±2.28 body mass index) to obtain substantial skin temperature
data. Each subject sat in a chair for 30 min in pre-test room (20 o C), then entered the
climatic chamber. The chamber was controlled at 22 o C, relative humidity of 55% RH,
and still air. The surface skin temperature was measured using an infrared
thermography.
In Experiment 2, two subjects who showed the similar surface skin temperature in
Experiment 1 were chosen to consider the characteristics of thermal insulation of
socks (A: 20 y, 151 cm, 46 kg, 20.2 body mass index, 1.389 m 2 surface area; B: 20 y,
163 cm, 52 kg, 19.6 body mass index, 1.547 m 2 surface area). Each subject sat down
on a chair for 30 min in pre-test room (20 o C), then entered the chamber controlled at
10 o C or 15 o C (50% RH). Surface skin temperature (thermography) and blood pressure
(before and after) were measured. Two different types of socks were studied (normal
box and five-toe types). These were made of the same fibers. Every wearing time was
15 min, so that surface skin temperatures became constant. Experiments were
performed in the two situations: rest and movement. The movement situation was 100
time of standstill for one minute according to rhythm of a metronome. There two
experimental sequences: A (no socks → thermography → normal socks →
thermography → finger socks → thermography); B (no socks → thermography →
finger socks → thermography → normal socks → thermography). The results from
both sequences were averaged.
RESULTS and DISCUSSION
Experiment 1: The results of surface skin temperature of 12 subjects are shown in
Table 1. The domain from the knee to the toe in thermograph was measured as a
surface skin temperature of foot. Minimal foot temperature was 24.9 ±1.46oC (right
foot) and 24.8 ±1.48oC (left). The maximal temperature was 34.9 ±1.07oC (right)
34.8 ±1.08oC (left), with mean temperatures of 32.0 ±1.35oC (right) and 31.9
±1.24oC (left), and this difference was significant (P