Page 222 - Industrial Ventilation Design Guidebook

5.1 THERMAL COMFORT 1 83

FIGURE 5.5 Clothing insulation necessary for neutral thermal sensation of sedentary persons (I
9
met) in a thermally uniform still-air environment with 50% relative humidity. For higher activity levels
the temperature at a clo level can be reduced about 1.4 °C per met increase. 10

long-term comfort and because the hands are usually uncovered, the minimum
practical temperature is about 20 °C. n
Clo values are usually measured on heated manikins in specialized labo-
ratories. The skin temperature of the manikin is controlled to about 33 °C
and the power input is measured (Fig. 5.6). Clo can also be similarly mea-
sured on humans with instruments to measure T^, metabolism, and rate of
weight loss.
A very useful way to estimate clo is by summing the clo values of the indi-
vidual items worn:

FIGURE 5.6 Clo value measured on heated manikins in a controlled environment.