Heat categories guide to heat safety

To ensure the safety of Airmen working in extreme weather conditions, the 39th Medical Operations Squadron’s Bioenvironmental Engineering Flight monitors the Wet Bulb Globe Temperature by testing ambient air, humidity and radiant heat to establish the heat category. (U.S. Air Force photo by Tech. Sgt. Michael B. Keller/Released)

To ensure the safety of Airmen working in extreme weather conditions, the 39th Medical Operations Squadron’s Bioenvironmental Engineering Flight monitors the Wet Bulb Globe Temperature by testing ambient air, humidity and radiant heat to establish the heat category. (U.S. Air Force photo by Tech. Sgt. Michael B. Keller/Released)

INCIRLIK AIR BASE, Turkey -- Throughout the summer at Incirlik AB, you may notice several e-mails pop up throughout the course of a day that read "Heat Category " followed by a number, but you may not realize why you keep getting them, or why they are important.

The command post sends out these periodic heat category updates based on inputs from bioenvironmental engineering.

"Because of the high temperatures at Incirlik through the summer, heat-related injuries are a real concern," said Senior Airman Tyler Stoltz, 39th Medical Operations Squadron bioenvironmental engineering technician. "Fatigue and dehydration can be common, and are a real workplace hazard for all shops that don't work in a temperature controlled environment."

The body's exact response to environmental conditions depends on physiological factors such as weight, physical fitness, age, alcohol consumption and acclimatization to the weather.

These factors determine reactions to working in hot conditions, and it can be useful to learn other precautions to stay healthy and fit to fight, said Maj. Steven Tang, 39th MDOS aerospace medicine flight commander.

The Wet Bulb Globe Temperature is a calculation that takes into account ambient temperature, humidity, and radiant heat from direct sunlight.

The Air Force developed five heat categories based on the WBGT which can be combined with levels of work performed to determine adequate work-rest cycles and hydration recommendations, Tang added.

The heat categories are as follows:

Heat Category 1 (78 to 81.9) - Normal activity for people accustomed to climate; extremely intense physical exertion may cause heat stroke for people who aren't. No limits on light and moderate work; heavy work 40 minutes, rest 20 minutes.

Heat Category 2 (82 to 84.9) - Normal activity for those accustomed to the climate; people who aren't should use discretion in planning intense physical activity. No limit on light work; moderate work 50 minutes, rest 10; heavy work 30 minutes, rest 30.

Heat Category 3 (85 to 87.9) - People accustomed to the climate should use caution in planning intense physical activity; those who aren't should curtail strenuous activities. No limit on light work; moderate work 40 minutes, rest 20; heavy work 30 minutes, rest 30.

Heat Category 4 (88 to 89.9) - Those accustomed to the climate should curtail strenuous exercise and limit conditioning for periods not exceeding six hours; people who aren't should terminate all physical conditioning. No limit on light work; moderate work 30 minutes, rest 30; heavy work 20 minutes, rest 50.

Heat Category 5 (90 and above) - Light work 50 minutes, rest 10; moderate work 20 minutes, rest 40; heavy work 10 minutes, rest 50.

Bioenvironmental emphasizes that people conducting outdoor activities on particularly hot days should obtain information concerning heat stress conditions and follow preventive measures as follows:

-- Drink plenty of water 12 hours prior to the activities and small amounts frequently throughout the day
-- Wear loose-fitting clothes
-- Avoid alcohol and caffeinated beverages if engaged in strenuous activities
-- Be aware of heat injury symptoms and first aid for heat injuries
-- Slowly acclimate yourself to Turkey's heat [up to 10 days]
-- Modify activity schedules to perform the heaviest work at the coolest time of day
-- Supervisors must monitor the heat categories to ensure all personnel are compliant with preventive work-rest cycles