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New OSHA Heat Regulations: Everything You Need to Know

osha heat rules

The Occupational Safety and Health Administration (OSHA) is proposing new heat regulations for the workplace, to address the growing work-related illnesses and fatalities due to heat exposure in the US. These proposed rules will affect different industries, with significant implications for air conditioning and HVAC systems. 

To help you understand the proposed rules, we created this comprehensive guide on what these regulations entail, and how they can impact your AC and ventilation systems.

What are the New OSHA Heat Regulations?

According to OSHA, heat is the number one cause of death among all weather-related phenomena in the US. And yet, there is no federal standard that regulates heat hazards in the workplace.

As such, OSHA published a Notice of Proposed Rulemaking (NPRM) for Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings last August 30, 2024. This proposal aims to create a federal heat standard to protect workers in all general industry, construction, maritime, and agriculture sectors where OSHA has jurisdiction.

Here are the key provisions:

Maximum Temperature Thresholds

osha heat regulations 2025

The regulations introduce specific temperature thresholds where intervention by the employer will be required to protect workers from heat stress.

  1. First, the working temperature should consistently be below 80°F.
  1. If the heat index goes over 80°F, workers must be provided 1 quart of drinking water per hour, as well as access to shade or an airconditioned break area.
  1. If the heat index surpasses 90 degrees, employers would need to provide 15-minute paid rest breaks every two hours. In addition, they must issue a “hazard alert” that notifies employees of the importance of staying hydrated and taking the mandatory rest breaks.

Acclimatization 

The proposed rules will introduce a period of acclimatization for new and returning workers.

For new employees: 

  1. Employers may implement a ramp-up system recommended by the National Institute for Occupational Safety and Health (NIOSH), wherein new workers work no more than 20% of their shift in the heat on day one, 40% on day two, and ramping up steadily, or:
  2. The employer could choose to provide fifteen-minute breaks every two hours, and provide the hazard alert information to new employees even when the temperature is below the high heat trigger of 90ºF.

For workers who have been absent for fourteen days or more:

  1. Employers could choose to implement the NIOSH system that recommends such workers spend no more than 50% working in the heat on day one, 60% on day two, etc., or;
  2. Apply the high-heat provisions for such returning workers even when the temperature is below 90ºF.

Heat Hazard Assessment

Employers must determine the heat hazards in their workplaces. This includes indoor and outdoor temperature, relative humidity, and indoor heat sources like machinery and HVAC systems.

Monitoring and Reporting

The workplace must implement monitoring systems that track temperature and humidity levels to ensure compliance with the regulations. Employers must identify areas where the heat index meets or exceeds 80°F and develop monitoring plans to measure heat levels accurately.

Emergency Action Plans

The rule will require the creation of comprehensive plans for heat-related emergencies, including access to medical care and procedures for evacuations.

New OSHA Heat Rules: Implications for HVAC Systems

OSHA’s new heat rules mean that HVAC systems are at the forefront of compliance. Heating and cooling equipment must now meet higher standards of performance, efficiency, and safety.

Air Conditioners

  • Enhanced Cooling Requirements

Workplaces will need air conditioners capable of maintaining indoor temperatures within OSHA’s acceptable range. In indoor environments, the AC should consistently maintain temperatures below 80°F to be exempt from certain requirements.

This means employers must invest in units with higher BTU capacities and advanced cooling technologies. 

  • Humidity Control

High humidity exacerbates heat stress. Employers may need HVAC systems with integrated dehumidification capabilities or standalone dehumidifiers to meet OSHA guidelines. The requirement for break areas for indoor work sites state that dehumidification would be required “if appropriate”.

  • Smart Monitoring

Smart thermostats and sensors are crucial for tracking real-time temperature and humidity levels, ensuring compliance.

Heaters

  • Balanced Heating for Colder Seasons

While heating equipment isn’t the primary focus, over-heated indoor spaces during winter can still pose a risk. Heaters with adjustable output and energy-efficient features will help employers strike the right balance.

  • Zoning Systems

HVAC zoning allows precise temperature control in different areas, preventing hotspots and ensuring compliance across the workplace.

Ventilation Systems

  • Improved Airflow

Proper ventilation is essential for heat mitigation. Systems that circulate fresh air and exhaust stale, warm air will become standard. The proposed regulations state that breakrooms for indoor work sites should be air-conditioned or have “increased air movement” from fans or natural ventilation.

  • Energy Recovery Ventilators (ERVs)

ERVs provide efficient ventilation by exchanging indoor and outdoor air while minimizing energy loss, ensuring a comfortable environment.

Upgrading Your HVAC System for Compliance

To meet OSHA’s heat regulations, employers should evaluate and potentially upgrade their HVAC systems. Here’s what to consider:

1. Capacity Assessment

Ensure your AC system has sufficient BTU capacity to meet OSHA-compliant temperatures, especially during peak heat periods.

2. Energy Efficiency Ratings

Look for ENERGY STAR-certified systems or units with high SEER (Seasonal Energy Efficiency Ratio) ratings to optimize cooling performance and reduce energy costs.

3. Integrated Smart Technology

Systems with IoT-enabled thermostats and sensors simplify compliance by providing real-time data and remote management. This also ties in with the heat monitoring clause proposed by the new rules.

4. New Refrigerants

The Environmental Protection Agency has started phasing out older refrigerants used by most air conditioning systems, like R32. If you will be replacing your AC units, it’s best to future-proof the investment by purchasing AC systems that use the new A2L refrigerants, which are less toxic, more efficient, and eco-friendly.

Health and Economic Impact of OSHA’s New Heat Rules

An initial economic impact analysis by OSHA estimates that compliance with the new regulations will cost businesses $3,085 per establishment per year. The industries with the highest number of affected employees are commercial kitchen operations, construction firms, and manufacturing companies.

According to the Bureau of Labor Statistics, nearly 500 workers in the US died from excessive heat from 2011-2022, or an average of 40 deaths per year caused by heat exposure. In addition, the bureau recorded almost 34,000 work-related heat injuries and illnesses that resulted in days away from work from 2011-2020, or an average of 3,389 per year. OSHA notes that these statistics are likely vast underestimates.

With the proposed heat hazard regulation, OSHA estimates it would prevent 531 heat-related fatalities and 16,027 heat-related injuries per year.

What Happens Next?

The Notice of Proposed Rulemaking was published in the Federal Register last August 30, 2024. After that, there was an initial 120-day public comment period that ended on Dec. 30, 2024.

However, OSHA extended the public comment period until Jan. 14, 2025 to provide stakeholders with more time to review the proposed rule and provide their feedback.

After this, there will be an informal public hearing on the proposed rule on June 16, 2025.

While the outcome of the proposed rule remains to be seen, it should be noted that OSHA continues heat-related inspections, under its National Emphasis Program – Outdoor and Indoor Heat-Related Hazards, which launched in 2022. 

Under this program, OSHA has conducted more than 5,000 federal heat-related inspections. So whether the proposed rules take effect or not, heat stress mitigation is crucial for commercial and industrial operations in the United States, especially in industries that fall under OSHA’s jurisdiction.

If you’re looking to upgrade your AC, ventilation, or dehumidification systems to comply with OSHA standards, don’t hesitate to contact us. HVAC systems are our specialty, and we can help you upgrade your setup for compliance and ensure a safe working environment for your employees.

Mickey Luongo

Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.

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