STP1133: Physiological and Biophysical Properties of a Semipermeable Attached Hood to a Chemical Protective Garment

    Gonzalez, RR
    ChiefResearch Physical Scientists, U.S. Army Research Institute of Environmental Medicine, Natick, MA

    Santee, WR
    ChiefResearch Physical Scientists, U.S. Army Research Institute of Environmental Medicine, Natick, MA

    Endrusick, TL
    ChiefResearch Physical Scientists, U.S. Army Research Institute of Environmental Medicine, Natick, MA

    Pages: 26    Published: Jan 1992


    Abstract

    An evaluation was done on a prototype 70-mil permeable hood integrated to a standard 90-mil chemical protective overgarment to verify its potential in reducing heat strain during continuous exercise. Each of 14 subjects (in two groups of seven) did treadmill exercise (heat production, M = 473 W) in six environments: at ambient air temperature (Ta) = 32°C/80 %rh/ V=l m·s-1 and 5m·s-1; T2 = 35°C / 50 %rh / V=1 m·s-1 and 5 m·s-1; and Ta = 43°C / 20 %rh / V=1 m·s-1 and 5 m·s-1. Rectal (Tre), heart rate, 3-site skin temperatures, and head temperature and dewpoint in the skin-air space underneath each hood were recorded continuously. Subjects exercised until Tre reached 39°C and/or heart rates were = 180 beats/min for 5 min. These end-points signified the endurance time limit for each subject. The 70-mil semipermeable hood integrated to a BDO gave no significant advantages compared to the standard BDO + butyl hood in reduction of heat strain, improvement in vapor permeation to a given thermal insulation, and overall extension of endurance times. Present use of a butyl hood with an appropriate respiratory mask is a preferable option because of the reduced thickness of the hood which offers augmented heat transfer at high wind speeds.

    Keywords:

    automatic dew point hygrometry, exercise, chemical protection, respiratory masks, heat stress, evaporation, heat transfer


    Paper ID: STP19187S

    Committee/Subcommittee: F23.96

    DOI: 10.1520/STP19187S


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