Occupational heat stress risk depends on the environment (WBGT), how hard the body is working (metabolic rate), clothing, and acclimatization status. This calculator evaluates dozens of government, technical, and industry standards side by side and reports the single most protective applicable result — standards are never averaged.
Workload categories map to a metabolic rate in Watts (OSHA/ACGIH), the input every schedule-producing engine here uses:
| Workload | Metabolic rate |
|---|---|
| Light | 180 W |
| Moderate | 300 W |
| Heavy | 415 W |
| Very heavy | 520 W |
For a given WBGT, workload, and acclimatization state, each applicable standard's engine returns its own result. The "most protective" composite applies a stop-work override if any applicable standard requires it, otherwise the minimum work minutes and maximum rest minutes across schedule-producing standards. Wildfire-smoke overlays are a separate hazard axis and are never folded into this composite — see wildfire smoke guidance.