Military Personnel Children

Civilian Personnel


 

  

Heat Cat. WBGT Index, F° Easy Work Moderate Work Hard Work
Work / Rest
Water Intake (Qt/H)
Work / Rest
Water Intake (Qt/H)
Work / Rest
Water Intake (Qt/H)
1 78°F - 81.9°F NL 1/2 NL 3/4 40/20 min 3/4
2 82°F - 84.9°F NL 1/2 50/10 min 3/4 30/30 min 1
3 85°F - 87.9°F NL 3/4 40/20 min 3/4 30/30 min 1
4 88°F - 89.9°F NL 3/4 30/30 min 3/4 20/40 min 1
5 >90°F 50/10 min 1 20/40 min 1 10/50 min 1
** CAUTION: Hourly fluid intake should not exceed 1.5 quarts. Daily fluid intake should not exceed 12 quarts.
  Soldier Heat Stress Guidance Table:
Easy Work Moderate Work Hard Work
  • Weapon Maintenance
  • Walking Hard Surface at 2.5 miles per hour, less than 30 pounds load
  • Marksmanship Training
  • Drill and Ceremony
  • Walking Loose Sand at 2.5 miles per hour, no load
  • Walking Hard Surface at 3.5 miles per hour, less than 40 pounds load
  • Calisthenics
  • Patrolling
  • Individual Movement Techniques, i.e. Low Crawl, High Crawl, etc.
  • Walking Hard Surface at 3.5 miles per hour, equal to or greater than 40 pounds load
  • Walking Loose Sand at 2.5 miles per hour with load
  • Field Assaults
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  • The work-rest times and fluid replacement volumes will sustain performance and hydration for at least 4 hours of work in the specified heat category. Fluid needs can vary based on individual differences. (plus or minus .25 quart per hour) and exposure to full sun or full shade (plus or minus .25 quart per hour).
  • NL = No limit to work time per hour.
  • Rest means minimal physical activity (sitting or standing), accomplished in shade if possible.
  • Caution: Hourly fluid intake should not exceed 1.5 quarts.
  • If wearing body armor add 5°F to WBGT in humid climates.
  • If wearing NBC clothing (MOPP 4) add 10°F to WBGT.

 

  School-Aged Children Heat Stress Guidance Table: Heat affects children at different WBGT levels than for adults!
Heat Injury Risk Level WBGT (F°) Restraints on Activities
Low <75 All activities allowed, but be alert for symptoms of heat-related illness in prolonged events.
Medium 75.0-78.9 Longer rest periods in the shade; enforce drinking every 15 minutes.
High 79-84 Stop activity of unacclimatized persons and other persons with high risk; limit activities of all others (disallow long-distance races, cut down further duration of other activities).
Extremely High >84 Cancel all athletic activities.
From the American Academy of Pediatrics, Committee on Sports Medicine and Fitness. (American Academy of Pediatrics, Committee on Sports Medicine and Fitness. Sports Medicine: Health Care for Young Athletes. 2nd ed. Elk Grove Village, IL: American Academy of Pediatrics; 1991;98)
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Heat Stress Risk Color Scale:
Color coding assumes adults
involved in heavy work.
  Civilian Heat Stress Guidance Table:
Permissible Heat Exposure Threshold Limit Values for Adults
Heat Risk Category Work/Rest Regimen Light Moderate Heavy
Low Continuous Work. <87 <82 <78
Medium 15 minute rest per hour. 87-88.9 82-84.9 78-81.9
High 30 minute rest per hour. 89-89.9 85-87.9 82-85.9
Extremely High 45 minute rest per hour. >=90 >=88 >=86
This table is from the Occupational Safety and Health Administration (OSHA) Technical Manual, Section III: Chapter 4
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*** These values are based on the assumption that workers are physically fit, acclimatized individuals wearing light summer clothing, and that they have adequate water and salt intake. They are also based on the assumption that the WBGT of the resting place is the same or very close to that of the workplace. If heavier clothing that impedes sweat or has a higher insulation value is required, the permissible WBGT Cutoff must be reduced by the corrections in the table below:
Clothing Type WBGT Corrections (F°)
Summer lightweight working clothing 0
Cotton Overalls -3.6
Winter work clothing -7.2
Water barrier, permeable -10.8
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  Examples of Activities within Work Demand Categories:
Resting Light Work Moderate Work Heavy Work
  • Sitting quietly.
  • Sitting with moderate arm and leg movement.
  • Standing with light work at machine or bench while using mostly arms.
  • Using a table saw.
  • Standing with light or moderate work at machine or bench and some walking about.
  • An easy walk.
  • Scrubbing in a standing position or mopping.
  • Walking about with moderate lifting or pushing.
  • Walking on level ground at 3.5 miles/hour while carrying a 6.5 lb. load.
  • Softball, Golf.
  • Gardening.
  • Carpenter sawing by hand.
  • Shoveling sand.
  • Heavy assembly work on a non-continuous basis.
  • Intermittent heavy lifting with pushing or pulling (e.g., pick & shovel work).
  • Running, Soccer, Tennis.
Source: ACGIH, 2000 TLVs® and BEIs® Booklet. [Back to Top]