This calculator evaluates 102 occupational heat-stress and wildfire-smoke standards against one set of conditions and reports the single most protective applicable result. Standards are never averaged; where two conflict, the more protective limit is taken and both are shown. This page is the outline — the full methodology lives on the about page, and each section below links straight into it.
Every threshold in the registry traces to a primary source — a published regulation, a standards-body document, or a peer-reviewed paper — recorded as a source id in data/sources.json and surfaced on each standard page. Rules whose sourcing could not be verified are labelled as such and are barred from setting the composite verdict.
Wet Bulb Globe Temperature, the natural-wet-bulb versus psychrometric-wet-bulb distinction, the indoor and outdoor weightings, and how WBGT is estimated from a weather forecast when no instrument is on site — including the per-hour uncertainty band published with each estimate.
Parity against the Argonne reference implementation, validation against observed hours across six climates, the bias-direction tests, and an explicit statement of what the uncertainty band does and does not cover.
The formulas themselves: the WBGT weightings, the workload-to-metabolic-rate mapping, the per-standard threshold tables, and how the most-protective composite is selected across standards without averaging them.
Screening-level guidance. This tool provides screening-level heat guidance for planning. It is a decision-support instrument, not a sole compliance authority or a medical prescription. Verify against the governing standard for your jurisdiction and consult a qualified professional for individual medical decisions.