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Document ID (ISN)111722
CIS number 11-0436
ISSN - Serial title 1545-9624 - Journal of Occupational and Environmental Hygiene
Year 2009
Convention or series no.
Author(s) Bernard T.E., Ashley C.D.
Title Short-term heat stress exposure limits based on wet bulb globe temperature adjusted for clothing and metabolic rate
Bibliographic information Oct. 2009, Vol.6, p.632-638. Illus. 10 ref.
Abstract Most heat stress exposure assessments based on wet bulb globe temperature (WBGT) consider the environmental conditions, metabolic demands, and clothing requirements, and the exposure limit is for extended work periods (e.g., a typical workday). The U.S. Navy physiological heat exposure limit (PHEL) curves and rational models of heat stress also consider time as a job risk factor so that there is a limiting time for exposures above a conventional WBGT exposure limit. The PHEL charts have not been examined for different clothing and the rational models require personal computers. This study examined the role of clothing in short-term exposures and proposed a relationship between a Safe Exposure Time and WBGT adjusted for clothing and metabolic rate. Twelve participants worked at a metabolic rate of 380W in three clothing ensembles, namely work clothes, microporous coveralls and vapour-barrier coveralls at five levels of heat stress. The combinations of metabolic rate, clothing and environment were selected in anticipation that the participants would reach a physiological limit in less than 120 min. An equation was developed to recommend a safe exposure time for exposures up to 120 min.
Descriptors (primary) heat load; oxygen consumption monitoring; work clothing; WBGT index; short-term exposure
Descriptors (secondary) heat stress assessment; mathematical models; impermeable fabrics; description of technique
Document type D - Periodical articles
Subject(s) Occupational physiology
Broad subject area(s) Physiology, ergonomics
Browse category(ies) Protective clothing
Heat and cold