222
Humans and their Environment
humidify the air with the cost of keeping the room a few degrees warmer.
Figure 13.6 also shows that a relatively small change in activity results in
a fairly large change in comfortable temperature. This is also confirmed
by common experience.
Many other aspects of comfort could be investigated using the energy
budget equation. For example, one sometimes feels cold or hot in a room
even when the thermometer indicates an air temperature of 22" C. This is
particularly true in rooms with large windows. If we were to measure the
window temperatures (and possibly wall or ceiling temperature) we would
likely find that they are significantly above or below air temperature. The
radiation from these cold or hot areas therefore produces an operative
temperature that is quite different from air temperature. Thus we see
that our radiant energy environment is very important to comfort, even
indoors.
References
Darwin, Charles (1832) Journal of Researches into the Natural History
and Geology of the Countries Visited During the Voyage of H.M.S.
Beagle Round the World. London: John Murray.
Dubois, D. and E. F. Dubois (1915) The measurement of the surface area
of Man. Arch. Intern. Med. 15:868-881.
Gagge, A. P. (1981) Rational temperature indices of thermal comfort.
p.79-98 in K. Cena and J. A. Clark (eds.), Bioengineering, Thermal
Physiology and Comfort. Amsterdam: Elsevier.
Kerslake, D. McK. (1972) The Stress of Hot Environments. London:
Cambridge University Press.
Landsberg, H. E. (1969) Weather and Health, an Introduction to
Biometeorology. Garden City, NY Doubleday.
Newburgh, L. H. (ed.) (1968) Physiology of Heat Regulation and The
Science of Clothing. New York: Hafner.
Problems
13.1. Find your body surface area using the DuBois formula (Eq. (1 3.1))
and compare the result to the area predicted by Eq. (13.2).
13.2. Find the standard operative temperature for a windy, overcast day
(u = 10 mls, T, = 0" C). If you were intending to walk outdoors
on such a day, what clothing conductance would be needed?
13.3. What is the hottest humid operative temperature you could work at
with u = 3 m/s and light clothing (gHc = 1 mol m-2 s-I)?
13.4. What is the humid operative temperature for the sunbather in Problem 12.4? Assume e, = 2 kPa. What rate of water consumption
would be required to maintain water balance?
Humans and their Environment
humidify the air with the cost of keeping the room a few degrees warmer.
Figure 13.6 also shows that a relatively small change in activity results in
a fairly large change in comfortable temperature. This is also confirmed
by common experience.
Many other aspects of comfort could be investigated using the energy
budget equation. For example, one sometimes feels cold or hot in a room
even when the thermometer indicates an air temperature of 22" C. This is
particularly true in rooms with large windows. If we were to measure the
window temperatures (and possibly wall or ceiling temperature) we would
likely find that they are significantly above or below air temperature. The
radiation from these cold or hot areas therefore produces an operative
temperature that is quite different from air temperature. Thus we see
that our radiant energy environment is very important to comfort, even
indoors.
References
Darwin, Charles (1832) Journal of Researches into the Natural History
and Geology of the Countries Visited During the Voyage of H.M.S.
Beagle Round the World. London: John Murray.
Dubois, D. and E. F. Dubois (1915) The measurement of the surface area
of Man. Arch. Intern. Med. 15:868-881.
Gagge, A. P. (1981) Rational temperature indices of thermal comfort.
p.79-98 in K. Cena and J. A. Clark (eds.), Bioengineering, Thermal
Physiology and Comfort. Amsterdam: Elsevier.
Kerslake, D. McK. (1972) The Stress of Hot Environments. London:
Cambridge University Press.
Landsberg, H. E. (1969) Weather and Health, an Introduction to
Biometeorology. Garden City, NY Doubleday.
Newburgh, L. H. (ed.) (1968) Physiology of Heat Regulation and The
Science of Clothing. New York: Hafner.
Problems
13.1. Find your body surface area using the DuBois formula (Eq. (1 3.1))
and compare the result to the area predicted by Eq. (13.2).
13.2. Find the standard operative temperature for a windy, overcast day
(u = 10 mls, T, = 0" C). If you were intending to walk outdoors
on such a day, what clothing conductance would be needed?
13.3. What is the hottest humid operative temperature you could work at
with u = 3 m/s and light clothing (gHc = 1 mol m-2 s-I)?
13.4. What is the humid operative temperature for the sunbather in Problem 12.4? Assume e, = 2 kPa. What rate of water consumption
would be required to maintain water balance?