Is there a federal OSHA heat rule I have to follow?

Not a final one. The proposed standard has not been finalized as of this page's review date. OSHA enforces heat hazards under the General Duty Clause and the Heat National Emphasis Program renewed in April 2026.

How cold does a cool-down area have to be?

California's rule says less than 82°F unless the employer demonstrates that is infeasible. Other states say shaded or climate-controlled. An air-conditioned room held in the low 70s is the common target.

Can a break room count as the cool-down area?

If it is cooled, shielded, seated, and close enough to the work that people actually use it during a rest period. A break room across the plant usually fails the 'close to the work' test.

What do you need to quote a cool-down room?

How many people rest at once, where on the floor it goes, the clear ceiling height there, and whether power is nearby. We quote the room, the cooling unit, seating, and a water hookup as line items.

Compliance · Modular Offices

Indoor heat illness prevention: which rules apply and what a cool-down area has to be

Reviewed September 25, 2026. Official sources are linked where they exist.

Short answer

There is no final federal OSHA heat standard as of this review: the proposed rule was published August 30, 2024 and the post-hearing comment period closed October 30, 2025, with no final date posted. OSHA still enforces heat hazards under the General Duty Clause and renewed its heat National Emphasis Program in April 2026 for five years, covering indoor work. Several states already have indoor rules. California's is the most specific: at 82°F indoors the employer must provide a cool-down area that is shielded from radiant heat, ventilated or cooled, kept below 82°F unless infeasible, seated, and close to the work. An air-conditioned modular room on the floor is the direct way to meet that.

Federal: enforcement without a final rule

OSHA's proposed heat injury and illness prevention standard would cover indoor and outdoor work. It was published in August 2024, the informal hearing ran from June 16 to July 2, 2025, and post-hearing comments closed October 30, 2025. The rulemaking page shows no final rule as of this page's review date.

Enforcement did not wait. The updated Heat National Emphasis Program, CPL 03-00-024, was issued April 10, 2026 for five years and covers outdoor and indoor heat hazards, with inspections triggered on National Weather Service heat advisory days. A plant with no plan and no place to cool down is exposed under the General Duty Clause today.

State rules that already apply indoors

Five states have indoor requirements on the books. The triggers and what they ask for differ, which is why a heat plan should be written to the state the plant is in.

State indoor heat rules
California, §3396	Applies at 82°F indoors; full provisions at 87°F. Cool-down area shielded from radiant heat, ventilated or cooled, under 82°F unless infeasible, seating for those resting, close to work areas.
Oregon, OAR 437-002-0156	Indoor and outdoor at heat index 80°F; exempt where mechanical ventilation holds the heat index below 80°F. Shaded or climate-controlled rest areas immediately available; written rest schedule at 90°F.
Minnesota, Rule 5205.0110	Indoor two-hour time-weighted WBGT limits: 77°F heavy work, 80°F moderate, 86°F light.
Nevada, R131-24AP	Adopted November 20, 2024. Employers with more than 10 employees complete a one-time job hazard analysis; program must include water, rest breaks, and a means of cooling.
Colorado, HB26-1272	Signed June 4, 2026, effective August 12, 2026; data collection by January 15, 2027 and a model prevention plan by July 1, 2028.

What a cool-down room needs

Taking California's text as the most specific standard: the area must be blocked from direct sunlight and shielded from other high radiant heat sources, open to the air or provided with ventilation or cooling, kept below 82°F unless the employer demonstrates that is infeasible, large enough that resting employees can sit in a normal posture without touching each other, and located as close as practicable to the work areas.

A modular cool-down room satisfies each item by construction: insulated panels shield radiant heat, a through-wall or mini-split unit provides the cooling, bench seating is sized to the rest rotation, and the room sits on the floor near the hot work. Size it to the number of people on break at once, not the headcount.

10' x 12' for a rest rotation of six to eight; larger rooms for bigger crews
Air conditioning sized to the room and the ambient, with a visible temperature display
Bench seating and a water station hookup
Placed near the hot work, with a self-closing door
HVLS fans and hydration stations complete the plan where a room alone is not enough

Questions buyers ask

Is there a federal OSHA heat rule I have to follow?: Not a final one. The proposed standard has not been finalized as of this page's review date. OSHA enforces heat hazards under the General Duty Clause and the Heat National Emphasis Program renewed in April 2026.
How cold does a cool-down area have to be?: California's rule says less than 82°F unless the employer demonstrates that is infeasible. Other states say shaded or climate-controlled. An air-conditioned room held in the low 70s is the common target.
Can a break room count as the cool-down area?: If it is cooled, shielded, seated, and close enough to the work that people actually use it during a rest period. A break room across the plant usually fails the 'close to the work' test.
What do you need to quote a cool-down room?: How many people rest at once, where on the floor it goes, the clear ceiling height there, and whether power is nearby. We quote the room, the cooling unit, seating, and a water hookup as line items.

Do your own research

Official sources first. We link the rule, not a summary of the rule, wherever one exists.

Heat Injury and Illness Prevention rulemaking
OSHA
Status of the federal proposed rule and hearing record.
California Code of Regulations, Title 8, §3396 Heat Illness Prevention in Indoor Places of Employment
Cal/OSHA
The 82°F trigger and the cool-down area requirements, verbatim.
Oregon OAR 437-002-0156 Heat Illness Prevention
Oregon OSHA via Cornell LII
Heat index triggers and rest area requirements.
Minnesota Rule 5205.0110 Indoor Ventilation and Temperature
Minnesota Legislature
Indoor WBGT limits by work load.
Nevada OSHA Heat Illness Regulation Approved
Nevada Department of Business and Industry
R131-24AP adoption and requirements.
Colorado HB26-1272
Colorado General Assembly
Bill text, effective dates, and deadlines.
OSHA updates and extends its heat program five more years
Littler
Summary of the April 2026 Heat National Emphasis Program renewal.

What we quote for this

Modular Offices

Cool-Down Room, Modular, Air-Conditioned

A pre-sized, air-conditioned rest room on the plant floor for heat-illness prevention plans, with seating and water.

Size: 10' x 12' standard (6 to 8 people); 12' x 16' and 12' x 20' for larger crews
Wall height: 8'
Wall system: Insulated pre-finished panels

MO-COOLView & quote

Dock Equipment

HVLS Fan Package for Docks and Plant Floors

High-volume, low-speed ceiling fans that move air across a dock or a bay for heat plans and air mixing.

Diameter: 8' to 24' (verify by model)
Mounting: Beam or joist mount with drop tube; structural review included
Control: Wall controller or building integration

DK-HVLSView & quote