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A method of assessing the heat load on workers moving about in a complex thermal environment.
Humphreys CM; Dukes-Dubos F
Int J Biometeorol 1966 Nov; 10(2):187-196
Methods for determining the total heat load of workers moving about in a hot working environment were described. The methods were based on heat stress studies conducted in a glass making facility, a chemical factory, and an aluminum reduction facility near the Gulf of Mexico. The studies were performed during the summer and winter seasons such that work rates and environmental conditions varied widely among different work sites. Environmental conditions were assessed by continuous recordings of dry bulb, wet bulb, and globe temperatures and air velocity as well as direct readings of the same variables at the same sites several times per day. Differences between the observed and recorded temperatures were determined to be relatively constant during the day. Continuous observation of worker job, task duration, and location within the facility by a time and motion study was used for estimation of the 8 hour shift metabolic heat production. The 8 hour metabolic heat production was related to the evaporation rate according to equations based on the relative strain index of Lee and Henschel. The validity of the calculated values for evaporation rate during an 8 hour work shift were evaluated in comparison to the actual sweat loss from workers determined from nude body weights at the beginning and end of the shift. A good correlation was found between sweat loss and calculated amount of evaporation required for maintenance of heat balance. The relationship was dependent on work environment vapor pressure.
NIOSH-Author; Industrial-environment; Analytical-methods; Chemical-manufacturing-industry; Thermal-effects; Metal-industry; Industrial-hygiene; Occupational-hazards; Worker-health; Temperature-regulation; Glass-manufacturing-industry
Issue of Publication
International Journal of Biometeorology
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division