Heat index work rest chart

A heat index work/rest chart pairs a heat index reading with a suggested split of work time and rest time. Hotter readings mean longer or more frequent breaks. Many charts also factor in the workload.

OSHA notes the NIOSH/OSHA Heat App gives only the heat index, not WBGT, though it also gives workload guidance. OSHA says workers should generally take hourly breaks when heat stress passes its limits. Break length depends on heat, workload and a cool place to rest. A chart is a starting point. Sun, gear and acclimatization change the real risk. See our work/rest chart guide, and the terms heat index and work/rest schedule.