Table 1: Screening criteria for heat stress exposure based on ACGIH standard (WBGT values in °C).

Work and rest cycle Acclimatized Unacclimatized
Light Moderate Heavy Very heavy Light Moderate Heavy Very heavy
100% work 29.5 27.5 26 - 27.5 25 22.5 -
75% work-25% rest 30.5 28.5 27.5 - 29 26.5 24.5 -
50% work-50% rest 31.5 29.5 28.5 27.5 30 28 26.5 25
25% work-75% rest 32.5 31 30 29.5 31 29 28 26.5

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