Heat Stress Index (HSI)

Heat Stress Index (HSI)

HS-03
ASPCSPAdvanced

Formula
HSI = (Ereq ÷ Emax) × 100
When to Use

Quantify heat strain as a percentage. HSI = 100 represents maximum tolerance. Used to assess heat risk and recovery needs.

Symbol Legend
SymbolMeaningUnitNote
HSIHeat Stress Index%HSI 100 = maximum; HSI>100 = body temperature rises
EreqRequired evaporative heat loss to maintain heat balancekcal/hr or BTU/hr
EmaxMaximum evaporative cooling capacity of the environmentkcal/hr or BTU/hr

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