Heat index calculator for outdoor work
Enter the air temperature and relative humidity. The calculator works out the heat index with the National Weather Service formula and shows the risk level OSHA and NIOSH use to plan work in the heat.
What the result means
- Below 91°F: lower risk. Provide water, rest and shade, and watch new workers closely.
- 91°F to 103°F: moderate risk. Remind the crew to drink water often, set up shade and rest breaks, and use a buddy system.
- 103°F to 115°F: high risk. Schedule frequent rest breaks in shade, move heavy work to cooler times, and check on workers often.
- Above 115°F: very high to extreme. Reschedule heavy work if you can, and use strict work and rest schedules with close monitoring.
- Direct sun can add up to 15°F to the heat index. Heavy work and protective clothing raise the risk further.
Tell the crew
Run the heat stress toolbox talk and get it signed on the phone.
Sources
More help
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