Proposed US federal heat rule for outdoor and indoor work settings (29 CFR 1910.148 NPRM). Not final — rulemaking paused by Trump administration regulatory freeze (Jan 2025). OSHA's NEP (updated Apr 2026) is the current federal enforcement vehicle.
Open OSHA Federal Heat Rule NPRM (Proposed) in the interactive Guidance Wiki →
No standalone formula is published for this standard; see programmable logic and parameters below.
Governing metric: Heat index or WBGT
Programmable logic: Initial trigger at 80°F heat index or NIOSH RAL; high trigger at 90°F heat index or NIOSH REL.
This standard does not take WBGT as a required input, and publishes no standalone numeric parameter table here; see the governing metric and programmable logic above, and the primary source below.
Required inputs: none
Optional inputs: heatIndexF, wbgtC, metabolicRateW, acclimatization, workerStatus
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