2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
and the rest permeates through the PC without being absorbed. Therefore, the highest
temperature appears inside the PC itself. According to the calculation results, radiant heat flux
permeates to a depth of 0.26-0.29 mm for infrared, and to 0.21-0.24 mm for solar radiation in
the tested PCs (Figure 3). The permeation depth for long-wave radiation was found to be
deeper than that for solar radiation. The calculation results showed that radiation permeation
depth into the PC depends upon the difference in the wavelength of the radiation. It has been
indicated that the highest temperature appears in a depth of about 0.3 mm from the PC surface
in the case of the infrared, while about 0.2 mm in the case of the solar.
DISCUSSION
An analytical model has been developed and the calculated results agree well with
experimental observations. Radiant heat permeates into the protective clothing even through it
is tightly woven. The permeation depth can be calculated through this model. The depth for
the solar is found to be shorter than for the infrared radiation. The model explains why the
highest temperature arises not on the surface, but inside the protective clothing.
ACKNOWLEDGEMENTS
Funded by European Union GROWTH programme project “THERMPROTECT (contract
G6RD-CT-2002-00846), with participation by P. Broede (D), V. Candas (F), E. A. den
Hartog (NL), G. Havenith (UK), I. Holmér (S), H. Meinander (FIN), and M. Richards, (CH).
The first author T. Fukazawa acknowledges the financial support by the Japanese Society for
the Promotion of Science.
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Figure 3. Calculated permeation depth δsp of radiation into the PC.