Table 6.6 Components of the total clothing insulation of a person, in clo units (a do equals 0.155 m2.K/W). For instance, someone wearing only underpants, T-shirt and shorts would have insulation/ equal to 0.1 8 clo (i.e. 0.04+0.08+0.06); total insulation of 0.6 clo is reckoned as standard
Thick long socks 0.06
Long-sleeve thin shirt 0.25
Long-sleeve flannel shirt 0.34
Thick trousers 0.24
Thin skirt 0.14
Thick skirt 0.23
Thin short-sleeve dress 0.29
Thick long-sleeve dress 0.47
Thin long-sleeve sweater 0.25
Thick long-sleeve sweater 0.36
Thin single-breasted jacket 0.36
Thick double-breasted jacket 0.48
words, ET* takes only temperature and humidity into account (Figure 6.11). The effect of humidity is trivial when ET* is below 23.6°C, but it becomes important at high temperatures. A drop of relative humidity by 10 per cent at 40°C improves conditions by lowering ET* by about 2 K.
An instance of humidity affecting human comfort is the annual 'Build-up' in Australia's Top End (i.e. northern part), in October and November, just prior to the onset of the monsoonal Wet in December to March (Chapter 12). Daily maxima remain about 33°C, but there is a gradual increase of afternoon dewpoint during the Build-up from about 19°C to 27°C, so the RH increases from 38 per cent to 69 per cent, and ET* rises from 32°C to an uncomfortable 35°C (Figure 6.11).
An indoor environment can be made more comfortable in climates as hot and dry as those of inland Australia by means of an evaporative cooler, discussed in Note 6.H. These are much cheaper than air conditioners, but need water.
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