SRS HEAT STRESS INDEX CARD (OSR 4-703, dated 2-23-17)

** Scroll table to see more information **

I. 77-83 0.5 qt/hr 100% Enforce water/fluid intake
II. 83-84 0.5 qt/hr 75% Enforce water intake; Use buddy system
III. 84-86 1 qt/hr 50% Enforce water intake; Use buddy system; No strenuous work
IV. 86-88 1.5 qt/hr 25% Enforce water intake; Use buddy system; Light work only
V. 88 or above Heat stress guidelines exceeded. IH consultation and additional controls required for work under these conditions.

* Add the WBGT Clothing Adjustment Factor from the appropriate clothing ensemble listed below to the observed or predicted WBGT. Then compare the resulting adjusted WBGT to the index ranges.

  • Woven PC or Work Clothes 0
  • Woven PC with hood +2
  • 2 layer woven PC (no hood) +5.5
  • Woven PC plus tyvek (no hood) +5.5
  • 2 layer woven PC with hood +7
  • Woven PC plus tyvek with hood +7
  • Vapor barrier suit with hood +20
  • Woven PC plus vapor barrier suit with hood +21.5

** Workers should not be required to consume these specific quantities, but they should be available to the workers. Extended shift workers should hydrate as needed, at any time.


  • Drink water every 15-20 minutes, even if you don't feel thirsty. You can lose as much as 1.6 quarts of fluid in an hour by sweating.
  • Caution: Fluid intake should not exceed 1.5 quarts per hour or 12 quarts per day; otherwise, an electrolyte imbalance could occur and cause an advese health effect.
  • Allow time to acclimatize, especially if you are returning from vacation or switching jobs.
  • Perform hot work as early in the day as possible, and take breaks frequently in a shaded or air-conditioned environment.
  • Be aware of early symptoms of heat illness, such as headaches, dizziness, and nausea.
  • Employ a buddy system to keep a close watch on each other for signs of heat-related illnesses.
  • Be aware that illness affects the body's tolerance of heat stress. Inform your supervisor of any illness and/or medications you are taking.

COMMON HEAT RELATED ILLNESSES (from 4Q, Proc. 502 dated 2-23-17)

Heat Stroke Hot dry skin (red or blue), irritability, confusion, shivering, convulsions, collapse. MEDICAL EMERGENCY. Aggressively cool victim. Use ice bath or pour ice and water on victim, if available. Call medical immediately.
Heat Syncope Gray-out or black out, Fainting in heat. (no signs or symptoms of heat stroke) Promptly move to cooler area. Give water or electrolyte drink if conscious.
Heat Exhaustion Fatigue, nausea, headache, giddiness, clammy, moist skin, pale complexion. Promptly move to cooler area. If victim is conscious give water or electrolyte drink.
Heat Cramps Painful spasms of muscles used during work (arms, legs or abdominal). Rest in a cool area. Give electrolyte drink if available.
Heat Rash Many tiny blisterlike lesions on affected area. Wash area; then thoroughly dry. Wear loose clothing.
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