2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
improve the prediction except during standing after TN preconditioning, when nose
temperature and heat flux from forehead improved the model significantly.
Table 1 Pearson correlation coefficients (r) at different exposures to exercise and wind. S = standing,
L = light work, M = moderate work. Preconditioning: TN = thermoneutral, C = cool. Hforehead = heat
flux from the forehead.
Exer-
cise
354
Precond.
Tcheek Tforehead Tnose Hforehead Cooling
rate of
cheek
Cooling
rate of
forehead
Cooling
rate of
nose
S TN 0.694** 0.597** 0.195 0.132 -0.024 -0.132 0.108
S C 0.657** 0.474** 0.091 -0.172 -0.152 -0.189 0.040
L TN 0.510** 0.559** 0.137 -0.270** 0.048 -0.010 0.105
M TN 0.587** 0.469** 0.155 0.071 -0.067 -0.100 -0.025
In the beginning of the wind exposure, all face skin temperatures decreased rapidly. Most of
the cooling took place during the first 10 min of the exposure, and later cooling rate was slow,
as cheek temperature shows in the Table 2. After initial sharp increase, average heat flux of
the body stabilized to the level of 130-200 W·m -2 . Heat flux from the forehead stabilized to
230-430 W·m -2 , depending on wind velocity and exercise.
Table 2 Cooling rate at different combinations of exercise, wind and preconditioning (TN =
thermoneutral, C = cool), mean ± SD, n = 8 in each cell. S = standing, L = light work, M = moderate
work.
Cooling rate (°C/10 min)
Exer- Pre- Wind
cise cond. (m·s -1 0-10 11-20 21-30 31-40 41-50 51-60
) min min min min min min
S TN 0.2 9.0±1.2 2.2±0.4 1.1±0.6
S TN 1.0 11.2±2.1 2.7±0.8 1.8±0.8
S TN 5.0 19.9±3.3 1.3±1.1 0.9±1.0
S C 0.2 3.0±0.7 0.7±0.4 0.7±0.5
S C 1.0 5.5±1.4 0.9±0.6 1.2±0.8
S C 5.0 10.4±0.8 0.9±1.4 0.5±0.9
L TN 0.2 10.6±2.6 1.8±1.4 -0.5±2.1 1.9±2.1 0.1±0.4 0.1±1.9
L TN 1.0 10.5±1.6 2.4±0.5 1.0±1.3 0.1±1.4 0.5±0.3 0.4±0.5
L TN 5.0 17.3±1.4 1.8±1.3 0.5±2.0 -0.1±2.1 0.6±0.9 0.4±1.1
M TN 0.2 9.7±1.5 1.8±0.4 0.7±0.5 0.6±0.7 0.3±0.3 0.4±0.6
M TN 1.0 12.0±1.5 2.2±0.5 0.1±1.2 0.8±1.4 0.6±0.3 0.1±0.4
M TN 5.0 17.5±1.8 2.0±0.8 -1.4±1.9 1.8±1.8 0.4±0.7 -0.1±0.5
During exposure to wind, thermal sensations of the face reached by 10 min, the typical
thermal sensation and remained at that level: in standing measurements -1 to -2 (slightly cool
to cool) at 0.2-1.0 m·s -1 wind and about -3 (cold) at 5.0 m·s -1 wind. During light exercise, the
sensations stabilized to the level of -1 (slightly cool) at 0.2-1.0 m·s -1 wind and -2 (cool) at 5.0
m·s -1 .
At each exposure, there was a wide individual variation both in thermal sensations and in
facial skin temperatures. Table 3 shows the average cheek skin temperatures during the
exposures, associated with each thermal sensation. Wind velocity had a clear effect on the
association between thermal sensation and cheek skin temperature: with increasing wind
velocity, clearly lower skin temperatures were associated with a given thermal sensation.
Likewise, also exercise decreased the skin temperature producing each thermal sensation.
Table 3 Cheek skin temperatures associated with different thermal sensations (ISO 10551). Values are
mean ± SD (n). S = standing, L = light work, M = moderate work. Preconditioning (PC): TN =
thermoneutral, C = cool.