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The Influence of the Humidity of the Air on Capacity for Work at High Temperatures

Published online by Cambridge University Press:  15 May 2009

H. M. Vernon  and
C. G. Warner
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The physiological reactions of two subjects were investigated in air at a temperature of 70–100° F., and of 40–96 per cent. relative humidity. The experiments lasted 3 hours, and one of the subjects performed mechanical work (step climbing) at the rate of 14,000 kg. m. per hour.

The pulse rate was about 10 beats greater in dry air than in moist air of the same wet-bulb temperature. The winter observations agreed well with the effective temperature scale, but did not agree with the wet bulb, the dry-bulb or the kata-thermometer scales.

Acclimatisation effects showed themselves in experiments made at a dry-bulb temperature of 87° F. or more, but only very slightly in those made at 81° or less. Acclimatisation was fairly well marked in the summer, the pulse rate being 5 to 10 beats less than in the winter, and no longer agreeing with the effective temperature scale.

The body temperature corresponded with the pulse rate, for it was 0·3–0·6° F. higher in dry air than in moist air of the same wet-bulb temperature, and was 0·15° lower in summer than in winter. The winter observations agreed well with the effective temperature scale.

The skin temperature of the face was found to depend on the dry-bulb temperature of the air, but that of the trunk showed no agreement with any of the scales. In moist air it was 1° F. lower than that of the face, and in dry air, 6° lower, owing to the cooling effect of increased sweating.

The gross mechanical efficiency fell off slightly at temperatures above 70 or 75° F. It was affected by the dry-bulb temperature of the air as well as the wet bulb, but not to the extent indicated by the effective temperature scale.

The weight of moisture lost by sweating corresponded well with the effective temperature scale. It increased gradually in consecutive experiments made in dry air, and diminished in those made in moist air.

The degree of fatigue experienced in dry air was considerably greater than in moist air of the same wet-bulb temperature, and it corresponded with the effective temperature scale.

Acknowledgments. We wish, to express our indebtedness to the authorities at the London School of Hygiene and Tropical Medicine, and especially to Dr G. P. Crowden, for the facilities offered to us in our work.

Type
Research Article
Information
Journal of Hygiene , Volume 32 , Issue 3 , July 1932 , pp. 431 - 462
Copyright
Copyright © Cambridge University Press 1932

References

Bedford, T. and Warner, C. G. (1931). Observations on the working capacity of coal miners in relation to atmospheric conditions. J. Industr. Hyg. 13, 252.Google Scholar
Bedford, T. and Warner, C. G. (1931). The reduction of mine air temperatures. J. Industr. Hyg. 13, 135.Google Scholar
Benedict, F. G. (1925). Die Temperatur der menschlichen Haut. Ergebn. d. Physiol. 24, 594.CrossRefGoogle Scholar
Benedict, F. G. and Cathcart, E. P. (1913). Muscular work: a metabolic study with special reference to the efficiency of the human body as a machine. Carnegie Inst. of Washington Publ. No. 187.CrossRefGoogle Scholar
Campbell, J. A. and Angus, T. C. (1928). Physiologic reactions of resting subjects to cooling power and effective temperature. J. Industr. Hyg. 10, 331.Google Scholar
Davies, E. (1921). The air-cooling plant at the Morro Velho mine. Trans. Inst. Min. Engin. p. 326, 1922, p. 424.Google Scholar
Dill, D. B., Edwards, H. T., Bauer, P. S. and Levenson, E. J. (1931). Physical performance in relation to external temperature. Arbeitsphysiol. 4, 508.Google Scholar
Egan, A. L. (1931). Methods of improving the kata conditions of atmospheric air in deep-level mines. Engineering, 09Google Scholar
Haldane, J. S. (1904). Report to Secretary of State on health of Cornish miners, p. 93.Google Scholar
Haldane, J. S. (1905). The influence of high air temperatures. J. Hyg. 5, 494.Google Scholar
Haldane, J. S. (1929). Atmospheric conditions in Indian coal mines. Trans. Inst. Mining Engin. 76, 340.Google Scholar
Haldane, J. S. (1930). Brit. Association Report for 1929, p. 376.Google Scholar
Hill, L. and Campbell, J. A. (1922). Cooling power of the atmosphere and comfort during work. J. Industr. Hyg. 4, 246.Google Scholar
Hill, L., Vernon, H. M. and Hargood-Ash, D. (1922). The kata-thermometer as a measure of ventilation. Proc. Roy. Soc. B, 93, 198.Google Scholar
Houghten, F. C., Teague, W. W. and Miller, W. E. (1926). Effective temperature of persons lightly clothed and working in still air. J. Amer. Soc. Heating and Vent. Eng. 32, 473.Google Scholar
Jones, J. S. (1924). Hygrometry in deep mines. Bull. Inst. Min. and Metall. No. 240.Google Scholar
Liese, W. (1930). Hauttemperaturmessungen am ruhenden und arbeitenden Menschen unter dem Einfluss schwacher Luftströme. Arch. f. Hyg. 104, 24.Google Scholar
Moss, K. N. (1923). Some effects of high air temperatures and muscular exertion upon colliers. Proc. Roy. Soc. B, 95, 181.Google Scholar
Moss, K. N. (1924). Some effects of high air temperatures upon the miner. Trans. Inst. Mining Engin. 66, 284.Google Scholar
Moss, K. N. (1925). The mechanical efficiency of the human body during work at high air temperatures. Trans. Inst. Mining Engin. 68, 377.Google Scholar
Vernon, H. M. (1928). The measurement of radiant heat. Report No. 46 of Indust. Fatigue Res. Board.Google Scholar
Vernon, H. M. (1930). The measurement of radiant heat in relation to human comfort. J. Physiol. Proc. 70, xv: also (1932), J. Industr. Hyg. 14, 95.Google Scholar
Vernon, H. M., Bedford, T. and Warner, C. G. (1926). The influence of cooling power and variability of air currents on sensations of air movement. Med. Research Council, Report No. 100, p. 31.Google Scholar