Heat Threat Calculator Worker Heat Safety Beta — under active development, not production-ready. Verify every result against the governing standard.

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Changelog

What changed in this calculator, when, and why. Corrections that moved a threshold in the less protective direction are called out explicitly in the entries below rather than folded into a general "updated thresholds" line.

Per-standard parameters, last updated

The date each registered standard’s numeric parameters last changed, from data/changelog.json. This is not the date the standard itself was published or amended — that is on each standard page with its sources.

StandardIDParameters last updated
AAFA Guide to Protecting Workers from Heat Stress 2026HGC-0062026-08-01
ACGIH TLV / Action LimitHGC-0022026-08-01
Ahmedabad Heat Action Plan 2019 Update (applied across Gujarat)HGC-0262026-08-01
Algeria Decret Executif 91-05 General DutyHGC-0912026-08-01
Argentina Resolución SRT 30/2023 — Especificaciones Técnicas de Carga Térmica (Heat Stress)HGC-1022026-08-01
Australia Thermal Work Limit (TWL)HGC-0552026-08-01
Austria "Hitzefrei" Construction Rule (BSchEG)HGC-0662026-08-01
Austria Hitzeschutzverordnung 2026HGC-0992026-08-01
Bahrain Midday Outdoor Work BanHGC-0162026-08-01
Bangladesh Labour Rules 2015 (Schedule-I)HGC-0242026-08-01
Belgium Code du bien-être au travail — WBGT Heat Stress ThresholdsHGC-0622026-08-01
Better Work / GLI Apparel Heat OverlayHGC-0502026-08-01
Brazil NR-15 Annex 3 (IBUTG)HGC-0222026-08-01
British Columbia WorkSafeBC Heat Exposure Standard (OHS Guideline G7.28)HGC-0602026-08-01
Brunei SHENA Heat Stress GuidanceHGC-0132026-08-01
Cal/OSHA Indoor Heat Illness Prevention (Title 8 §3396)HGC-0212026-08-01
Cal/OSHA Outdoor Heat Illness Prevention (Title 8 §3395)HGC-0712026-08-01
Cal/OSHA Protection from Wildfire Smoke (Title 8 §5141.1)HGC-0742026-08-01
Chile DS 594 Heat Stress Standard (TGBH/WBGT Limits)HGC-0612026-08-01
China GBZ 2.2-2007 Heat Stress LimitsHGC-0392026-08-01
Colombia Resolución 2400 de 1979 — Heat Stress ProvisionsHGC-0692026-08-01
Colorado Agricultural Labor Conditions Rules (7 CCR 1103-15 Rule 3)HGC-0722026-08-01
Costa Rica Thermal Stress Prevention Rule (Decreto No. 39147-S-TSS)HGC-0642026-08-01
CPWR / OSHA-CPWR Construction Heat OverlayHGC-0482026-08-01
Cyprus Code of Practice for Thermal StressHGC-0652026-08-01
Czech Government Regulation No. 361/2007 Coll. — Occupational Heat Load (Annex 1 Part A)HGC-1032026-08-01
Denmark Arbejdstilsynet Indoor-Climate Temperature GuidanceHGC-1062026-08-01
Ecuador Norma Técnica de Seguridad e Higiene del Trabajo — Art. 8 Heat (WBGT Ceilings)HGC-1012026-08-01
Egypt Ministerial Decree No. 211 of 2003HGC-0422026-08-01
El Salvador Decreto No. 89 (TGBH)HGC-0252026-08-01
EU Framework Directive 89/391/EECHGC-0362026-08-01
FIFA / Sports Hydration Break OverlayHGC-0512026-08-01
Finland Työsuojelu Kuumatyö (Hot Work) Indoor Break ScheduleHGC-0872026-08-01
France Decret n° 2025-482 Heat DutiesHGC-0332026-08-01
Germany ASR A3.5 Room Temperature RuleHGC-0292026-08-01
Greece Ministry Heatwave Emergency RuleHGC-0352026-08-01
Hong Kong Labour DepartmentHGC-0092026-08-01
India WBGT Work/Rest Bands (unverified)HGC-0072026-08-01
Indonesia Permenaker No. 5/2018 (ISBB)HGC-0462026-08-01
ISO 7243:2017 WBGT ScreeningHGC-0192026-08-01
ISO 7933 Predicted Heat Strain (PHS)HGC-0542026-08-01
Italy Regional Anti-Heat Ordinances (Lazio, Lombardy, Piedmont, Campania)HGC-0982026-08-01
Italy Worklimate / Regional Anti-Heat OverlayHGC-0342026-08-01
Japan MHLW WBGT Warning SystemHGC-0182026-08-01
Kenya OSH Act General DutyHGC-0372026-08-01
Kerala Seasonal Midday Outdoor-Work Rest Order (Minimum Wages Act, 1958, ss. 24-25)HGC-0862026-08-01
Kuwait Noon Work BanHGC-0172026-08-01
La Isla Network-informed RSH-s Default ProtocolHGC-0012026-08-01
Latvia Cabinet Regulation No. 359 — Workplace Microclimate LimitsHGC-0842026-08-01
Lithuania HN 69:2003 Indoor Temperature Ceilings + VDI Outdoor Heat-Break GuidanceHGC-0882026-08-01
Maharashtra State Heat Wave Action Plan 2024 (SDMA)HGC-1082026-08-01
Malaysia DOSH Heat Stress Guidelines 2016HGC-0202026-08-01
Malta OHSA Construction Heat-Stress Instrument (Admin Instrument No. 2 of 2025)HGC-0802026-08-01
Maryland OSHA Heat Stress Standard (COMAR 09.12.32)HGC-0582026-08-01
Mexico NOM-015-STPS-2001 (IBUTG)HGC-0412026-08-01
Minnesota OSHA Indoor Ventilation and Temperature Rule (5205.0110)HGC-0592026-08-01
MSHA Mining Heat Stress OverlayHGC-0492026-08-01
Nevada OSHA Heat Illness Prevention Regulation (R131-24)HGC-0732026-08-01
NFL / American Football Heat Practice OverlayHGC-0522026-08-01
Nicaragua Resolución Ministerial sobre Higiene Industrial — Heat Stress (Chapter XV)HGC-0682026-08-01
NIOSH 2016-106 Table 6-2HGC-0042026-08-01
NIOSH REL/RAL Logarithmic CurveHGC-0052026-08-01
Norway Arbeidstilsynet Workplace Temperature GuidanceHGC-1072026-08-01
NYC Executive Order No. 17 — Outdoor Worker Heat ProtectionHGC-0772026-08-01
Oil & Gas Heat Governance OverlayHGC-0532026-08-01
Oman Midday Work BanHGC-0152026-08-01
Ontario OHCOW Humidex Heat Response PlanHGC-0672026-08-01
Oregon OSHA Heat Illness Prevention Standard (AO 3-2022)HGC-0572026-08-01
Oregon OSHA Protection from Wildfire Smoke (OAR 437-002-1081)HGC-0752026-08-01
OSHA Federal Heat Rule NPRM (Proposed)HGC-0472026-08-01
OSHA Heat National Emphasis Program (CPL 03-00-024, April 2026)HGC-1052026-08-01
Philippines DOLE Labor Advisory No. 08-23HGC-0232026-08-01
Poland Maximum Workplace Temperature Rule (§30a, Dz.U. 2026 poz. 927)HGC-0952026-08-01
Poland Preventive Meals & Drinks Regulation (Dz.U. 1996 Nr 60 poz. 279)HGC-0832026-08-01
Qatar Ministerial Decision No. 17 of 2021HGC-0112026-08-01
Québec Regulation respecting occupational health and safety (RRQ S-2.1, r. 13) — Schedule V Heat StressHGC-1002026-08-01
Romania OUG nr. 99/2000 — Extreme Temperature Worker ProtectionHGC-0812026-08-01
Russia Rospotrebnadzor Heat-Work RecommendationsHGC-0962026-08-01
Safe Work Australia Heat GuideHGC-0302026-08-01
San Antonio Contractor Outdoor Heat OrdinanceHGC-0782026-08-01
Saudi MHRSD Heat Stress RuleHGC-0142026-08-01
Singapore MOM / WSH (WBGT ≥ 32°C)HGC-0102026-08-01
Slovakia Decree No. 99/2016 Coll. — Protection against Heat and Cold Load at WorkHGC-1042026-08-01
Slovenia Workplace Heat Rules (Pravilnik, Uradni list RS 53/2025)HGC-0792026-08-01
South Africa Physical Agents Regulations 2024HGC-0432026-08-01
South Korea KOSHA GUIDE W-12-2017 WBGT TableHGC-0452026-08-01
South Korea MoEL Heat-Work RuleHGC-0282026-08-01
Spain Outdoor Heat Amendment (RD 486/1997)HGC-0322026-08-01
Sweden AFS 2023:12 — Time-Weighted Heat Index (Work in Intense Heat)HGC-0822026-08-01
Taiwan Article 303-1 Heat-Index Control OverlayHGC-0442026-08-01
Taiwan High-Temperature Work/Rest StandardHGC-0272026-08-01
Tamil Nadu Heat Wave Action Plan (TNSDMA) + BOCW Outdoor-Work Timing RestrictionHGC-0852026-08-01
TB MED 507 Heat CategoriesHGC-0032026-08-01
Thailand Occupational Heat Standard 2006HGC-0402026-08-01
Turkey Law No. 6331 General DutyHGC-0382026-08-01
UAE Midday Break RuleHGC-0122026-08-01
UK HSE Temperature GuidanceHGC-0312026-08-01
Ukraine ДСН 3.3.6.042-99 — Sanitary Norms for Microclimate of Industrial PremisesHGC-0972026-08-01
US Navy / Marine Corps Ashore Flag ConditionsHGC-0632026-08-01
Vietnam QCVN 26:2016/BYTHGC-0082026-08-01
Washington L&I / DOSH Wildfire Smoke Rule (WAC 296-820)HGC-0762026-08-01
Washington State DOSH Outdoor Heat Standard (WAC 296-62-095)HGC-0562026-08-01

Release history

[Unreleased] - WBGT Estimator: Liljegren Globe Model, Reference Parity, And Published ACGIH Action Limits

Removed - 2026-07-27

Fixed - July 26, 2026

Added - July 26, 2026

Changed - July 26, 2026

Known gaps

[1.11.0] - 2026-07-01 - Tamil Nadu, Kerala, Finland, And Lithuania Heat Engines

Added - July 1, 2026

[1.10.1] - 2026-06-30 - API Layer Hardening: AQI Accuracy, Input Validation, Weather Timezone Fixes, And Country Filtering

Fixed - 2026-06-30

[1.10.0] - 2026-06-30 - EU Standards Wave, San Antonio Ordinance, And Interactive Jurisdiction Map

Added - June 30-July 1, 2026

Changed - June 30-July 1, 2026

Fixed - June 30-July 1, 2026

[1.9.0] - 2026-06-25 - NYC Heat Order, Source-Accuracy Audit, And Threshold Lanes Chart

Added - June 25, 2026

Fixed - June 25, 2026

[1.8.0] - 2026-06-23 - Standards Metadata Surfacing, Registry Hardening, And Data-Accuracy Fixes

Added - June 22-23, 2026

Changed - June 23, 2026

Fixed - June 22-23, 2026

[1.7.3] - 2026-06-11 - Washington Wildfire-Smoke Trigger-Message Fix

Fixed - June 11, 2026

[1.7.2] - 2026-06-11 - Calculation-Accuracy Audit

A standards-grounded audit of the calculation layer. Every numeric finding was verified against a primary source (NWS/WPC, ACGIH, NIOSH 2016-106, the cited TB MED 507 PDF, EPA 40 CFR Part 58 App. G, Liljegren et al. 2008, Dimiceli et al., WA L&I) before any change. Several flagged "issues" were verified to be CORRECT as written and left unchanged (see Verified-correct below).

Fixed - June 11, 2026

wet bulb (provider value or Stull 2011) directly as the natural wet bulb (Tnwb). Under solar load and low wind Tnwb runs ~0.8-2°C higher, so this under-estimated WBGT (unsafe direction) — enough to drop a heat category in calm, sunny conditions. Added FORMULAS.estimateNaturalWetBulbLiljegrenC, a faithful port of the Liljegren et al. 2008 energy-balance model (NWS operational standard; Argonne reference code), used for the 0.7 term whenever solar geometry allows, with a psychrometric fallback at night / when inputs are missing. Validated: night ≈ psychrometric, +2-3°C midday sun, +~5°C calm desert sun.

to the Rothfusz regression on the computed simple heat index (not raw temperature), and apply the NWS low-RH (RH<13%, 80-112°F) and high-RH (RH>85%, 80-87°F) adjustments, both previously omitted.

(WAC 296-62-085, mandatory at 555.5 µg/m³) to the permanent WAC 296-820: mandatory full respiratory protection program at 500.4 µg/m³, APF ≥ 25 at 555.0 µg/m³, with the 20.5 / 35.5 µg/m³ lower tiers. Workers in 500.4-555.4 µg/m³ were previously under-protected.

to the most-severe default band.

offset, not a clothing (CAF) factor; fixed the mislabeled note.

Verified correct (no change) - June 11, 2026

256000 = 4·40³ and 7,680,000 = 3·40⁴ are the exact Taylor linearization of t⁴ about 40°C, confirming the model is formulated in Celsius. A reported "Stefan-Boltzmann Kelvin bug" was a false positive; converting to Kelvin would have broken validated math.

4 work columns at 250/425/600/800 W, fluid caps 1.5 qt/hr & 12 qt/day, ±¼ qt sun/shade modifier). A subagent's "broken table" claim used an outdated 3-column reproduction.

metabolic categories, unit conversions, WBGT coefficients, and acclimatization handling (effectiveC = wbgtC + cafC, acclimatization applied once) all verified correct.

Notes

range is 2.5-3.5°C); the +1.5°C "partial" tier has no direct published basis. Left as disclosed approximations.

[1.7.1] - 2026-06-11 - Live Forecast Date And Shift-Time Accounting Fixes

Fixed - June 11, 2026

Notes

[1.7.0] - 2026-06-05 - State Rules Panel, AQI↔PM2.5 Conversion, Respirator Badge, Legend

Added - June 5, 2026

Changed - June 5, 2026

[1.6.0] - 2026-06-04 - U.S. State Heat And Wildfire-Smoke Guidance

Added - June 4, 2026

Notes

[1.5.0] - 2026-06-04 - Dynamic Chart Thresholds, Country-Aware Standards, And USARIEM HSDA

Added - June 4, 2026

Changed - June 4, 2026

Fixed - June 4, 2026

1.4.1 2026-05-22

Changed - pending registry plumbing

[1.4.0] - 2026-05-22 - WBGT Forecast Surface, Water Mode, And Operational Polish

Added - May 21, 2026

Changed - May 21-22, 2026

[1.3.0] - 2026-05-20 - Registry Hardening, Stable IDs, And Unit Localization

Added - May 20, 2026

Changed - May 11-20, 2026

[1.2.0] - 2026-05-07 - Symphony Workflow, Scenario UX, And Country Guidance Services

Added - May 4-7, 2026

Changed - May 7, 2026

[1.1.0] - 2026-05-03 - Outdoor Heat Standards Expansion

Added - May 3, 2026

Changed - May 3, 2026

[1.0.0] - 2026-05-01 - API, Weather, And Deployment Foundation

Added - April 29, 2026

Added - April 30-May 1, 2026

Changed - April 29-May 1, 2026

[0.4.0] - 2026-04-28 - Calculator Maturation And Standards Logic

Added - April 28, 2026

Changed - April 28, 2026

[0.2.0] - 2026-04-27 - Testable Prototype And Research Groundwork

Added - April 27, 2026

[0.1.0] - 2026-04-27 - Initial Import

Added - April 27, 2026