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Heat stress in protective clothing: validation of a computer model and the heat-humidity index (HHI).
Aviat Space Environ Med. 1992 Dec; 63(12):1087-92.AS

Abstract

Ability to work while wearing protective clothing is often limited by rising body temperature. Peterson analyzed the combined effects of heat, humidity and workload using the Texas Model of Thermoregulation and suggested that environmental heat load imposed on a person wearing heavy, semipermeable clothing could be predicted using the Heat-Humidity Index (HHI = 0.5 Tdb + 0.5 Twb), where Tdb = dry bulb temperature and Twb = wet bulb temperature. Our study was designed to: 1) test the validity of this computer model; and 2) evaluate the applicability of the HHI to heavily clothed subjects working in a variety of thermal environments. Nine men wearing chemical defense clothing were each studied under eight conditions over the range Tdb = 20 - 40 degrees C, Tbg = Tdb + 5 degrees C, relative humidity = 9-75%, and oxygen uptake = 14-27 ml.kg-1 x min-1. Variables analyzed included tolerance time (TT), rectal temperature (Tre), skin temperature, heart rate (HR), weight loss, sweat rate, evaporation rate, and evaporative efficiency. Experiments were designed to last 30-180 min, and continued until Tre = 39 degrees C except when subjective tolerance limits occurred first (12 of 72 experiments). The observed time to reach Tre = 39 degrees C bracketed the predicted time in the more severe conditions, but the model seriously underestimated heat storage in the milder conditions.(

ABSTRACT

TRUNCATED AT 250 WORDS)

Authors+Show Affiliations

Armstrong Laboratory, San Antonio, TX 78235.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

1456921

Citation

Antuñano, M J., and S A. Nunneley. "Heat Stress in Protective Clothing: Validation of a Computer Model and the Heat-humidity Index (HHI)." Aviation, Space, and Environmental Medicine, vol. 63, no. 12, 1992, pp. 1087-92.
Antuñano MJ, Nunneley SA. Heat stress in protective clothing: validation of a computer model and the heat-humidity index (HHI). Aviat Space Environ Med. 1992;63(12):1087-92.
Antuñano, M. J., & Nunneley, S. A. (1992). Heat stress in protective clothing: validation of a computer model and the heat-humidity index (HHI). Aviation, Space, and Environmental Medicine, 63(12), 1087-92.
Antuñano MJ, Nunneley SA. Heat Stress in Protective Clothing: Validation of a Computer Model and the Heat-humidity Index (HHI). Aviat Space Environ Med. 1992;63(12):1087-92. PubMed PMID: 1456921.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Heat stress in protective clothing: validation of a computer model and the heat-humidity index (HHI). AU - Antuñano,M J, AU - Nunneley,S A, PY - 1992/12/1/pubmed PY - 1992/12/1/medline PY - 1992/12/1/entrez SP - 1087 EP - 92 JF - Aviation, space, and environmental medicine JO - Aviat Space Environ Med VL - 63 IS - 12 N2 - Ability to work while wearing protective clothing is often limited by rising body temperature. Peterson analyzed the combined effects of heat, humidity and workload using the Texas Model of Thermoregulation and suggested that environmental heat load imposed on a person wearing heavy, semipermeable clothing could be predicted using the Heat-Humidity Index (HHI = 0.5 Tdb + 0.5 Twb), where Tdb = dry bulb temperature and Twb = wet bulb temperature. Our study was designed to: 1) test the validity of this computer model; and 2) evaluate the applicability of the HHI to heavily clothed subjects working in a variety of thermal environments. Nine men wearing chemical defense clothing were each studied under eight conditions over the range Tdb = 20 - 40 degrees C, Tbg = Tdb + 5 degrees C, relative humidity = 9-75%, and oxygen uptake = 14-27 ml.kg-1 x min-1. Variables analyzed included tolerance time (TT), rectal temperature (Tre), skin temperature, heart rate (HR), weight loss, sweat rate, evaporation rate, and evaporative efficiency. Experiments were designed to last 30-180 min, and continued until Tre = 39 degrees C except when subjective tolerance limits occurred first (12 of 72 experiments). The observed time to reach Tre = 39 degrees C bracketed the predicted time in the more severe conditions, but the model seriously underestimated heat storage in the milder conditions.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0095-6562 UR - https://www.unboundmedicine.com/medline/citation/1456921/Heat_stress_in_protective_clothing:_validation_of_a_computer_model_and_the_heat_humidity_index__HHI__ DB - PRIME DP - Unbound Medicine ER -