The calculation from weather records of the requirement for clothing insulation
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Standard meteorological measurements of dry bulb temperature, wind speed, sunshine, cloud cover and rainfall are used to calculate the clothing insulation required by man for thermal comfort under given weather conditions. The calculation is based on earlier work on the effect of weather on sensible (non-evaporative) heat loss from sheep, which used the relation between heat flow, thermal insulation and the difference between body and environmental temperatures.
Clothing insulation for man is estimated in two ways: as clothing (Ic) that is impervious to the effects of wind and rain; and as the equivalent depth of sheep fleece (fm), which is not impervious. This allows the assessment of wind chill for a range of clothing of varied penetration by wind instead of for only one type of garment.
Results are given as daily means calculated from hourly measurements throughout 1973 for Plymouth (on the south coast of Britain) and Aberdeen (on the far northeast coast of Britain). Wind chill is estimated both by its effect on fm requirement and by the fall in air temperature that would be needed to produce under still-air conditions the same demand for fm that occurs in the actual environment. The monthly mean fm requirement is reduced by about 40% when the effect of wind is removed. When wind chill is estimated as an equivalent fall in air temperature it approximates to 1 K per knot wind speed measured at the standard meteorological height of 10 m.
KeywordsWind Speed Cloud Cover Thermal Insulation Thermal Comfort Actual Environment
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- BLAXTER, K. L. (1977): Environmental factors and their influence on the nutrition of farm livestock. In: W. Haresign, H. Swan and D. Lewis (Editors), Nutrition and the Climatic Environment. Butterworths, London; pp. 1–16.Google Scholar
- BURTON, A. C. and EDHOLM, O. G. (1955): Man in a Cold Environment. Edward Arnold, London; reprinted 1969, Hafner, New York and London.Google Scholar
- CAMPBELL, G. S., McARTHUR, A. J. and MONTEITH, J. L. (1980): Windspeed dependence of heat and mass transfer through coats and clothing. Boundary-Layer Meteorol.18: 485–493.Google Scholar
- DAUNCEY, M. J. (1980): Metabolic effects of altering the 24h energy intake in man, using direct and indirect calorimetry. Br. J. Nutr.43: 257–269.Google Scholar
- DAUNCEY, M. J. (1981): Influence of mild cold on 24h energy expenditure, resting metabolism and diet-induced thermogenesis. Br. J. Nutr.45: 257–267.Google Scholar
- JOKL, M. V. (1982): Standard layers — a new criterion of the thermal insulating properties of clothing, Int. J. Biometeor.26: 37–48.Google Scholar
- McARTHUR, A. J. and MONTEITH, J. L. (1980): Air movement and heat loss from sheep. II. Thermal insulation of fleece in wind. Proc. R. Soc. London. Ser. B.,209: 209–217.Google Scholar
- MOUNT, L. E. (1979): Adaptation to Thermal Environment: Man and his Productive Animals. Edward Arnold, London: 333 pp.Google Scholar
- MOUNT, L. E. (1984): Meteorological measurement and mammalian heat loss. Weather39(4): 104–111.Google Scholar
- MOUNT, L. E. and BROWN, D. (1982): The use of meteorological records in estimating the effects of weather on sensible heat loss from sheep. Agric. Meteor.27: 241–255.Google Scholar
- MOUNT, L. E. and BROWN, D. (1983): Wind chill in sheep: its estimation from meteorological records. Agric. Meteor.29: 259–268.Google Scholar
- MUMFORD, A. M. (1979): Problems of estimating lowland wind chill. Weather34: 424–429.Google Scholar
- SMITHSON, P. A. and BALDWIN, H. (1978): Wind chill in lowland Britain. Weather33: 463–474.Google Scholar
- STEADMAN, R. G. (1971): Indices of wind chill of clothed persons. J. appl. Meteorol.10: 674–683.Google Scholar