First used by the Marines for training in muggy South Carolina, the WBGT indicates how much the summer heat could stress Airmen’s bodies while they work in the sun and recommends water intake and rest periods to help prevent heat injury.
Instead of measuring ambient temperature alone, the WBGT accounts for humidity through the wet-bulb temperature and wind, cloud cover and the angle of the sun through the globe thermometer temperature, all factors that can make the air feel hotter or prevent the body from releasing heat through sweat evaporation.
Military jobs and protocols often ramp up the heat even higher. According to Air Force Instruction 48-151, wearing a second layer of clothing like chemical protective gear over ABUs or civilian clothes adds 10°F to the WBGT during easy work and 20°F during moderate or hard work. Body armor increases the WBGT by 5°F.
Airmen at Wright-Patterson must comply with Air Force guidelines for water intake and rest in order to effectively and safely carry out their missions in the sun this season.
Work guidelines
• Rest: Taking a break from the current outdoor activity to stand or sit in the shade if possible.
• Easy Work: Walking on hard surfaces at 2.5 mph with a less than 30-pound load. Guard duty and drill and ceremony are example.
• Moderate Work: Walking on hard surfaces at 3.5 mph with a less than 40-pound load. Activities such as light maintenance work and construction equipment operation are moderate.
• Hard Work: Walking on hard surfaces at 3.5 mph with a more than 40-pound weight. Loading and unloading pallets and dragging hoses or lines are considered hard work.
For more information, see Air Force Instruction 48-151: https://static.e-publishing.af.mil/production/1/af_sg/publication/afi48-151/afi48-151.pdf
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