Outdoor Heat Exposure

Updated July 12, 2023

University units with personnel who work outdoors are required to implement safety measures to help prevent heat-related illness, including providing initial and annual training, and implementing a written Outdoor Heat Safety Plan.

Guidance for indoor heat and thermal comfort issues can be found on the Indoor Air Quality page.

Requirements

Washington state outdoor heat exposure rules apply to University units and departments with personnel performing work outdoors for more than 15 minutes in any 60-minute period when personnel are exposed to outdoor heat at or above the temperature and conditions listed in Table 1 below.

Table 1: Outdoor temperature action levels

TYPE OF CLOTHING WORN	ACTION REQUIRED AT OR ABOVE THIS TEMPERATURE
Non-breathable clothes, including vapor barrier clothing or PPE such as chemical resistant suits	52 degrees F
All other clothing	80 degrees F

The action temperatures apply only if personnel are required to perform a work activity outdoors for more than 15 minutes in any 60-minute period. The rules apply to every hour during the work shift.

Responsibilities

To ensure personnel safety and compliance with the Washington state rules (WAC 296-62-095 Outdoor Heat Exposure), units are required to:

Ensure personnel who work outdoors and their supervisors complete the EH&S Outdoor Heat Safety training course initially and annually.
Develop and implement an Outdoor Heat Safety Plan by completing the EH&S template, which includes requirements for providing drinking water, shade, cool-down and rest periods, heat stress monitoring, and response procedures if personnel show signs or symptoms of heat-related illness.
Review the Outdoor Heat Safety Plan with your personnel initially (upon hire or prior to starting work outdoors) and annually.

Complete the EH&S Outdoor Heat Safety training course initially (upon hire or prior to starting work outdoors) and annually.
Follow the University and unit requirements for preventing heat-related illness.
Drink adequate amounts of suitably cool water (up to one quart/hour).
Request breaks when needed.
When temperatures are at or above 90° Fahrenheit (F) take preventive cool-down rest breaks of at least 10 minutes every 2 hours.
When temperatures are at or above 100°F take preventive cool-down rest breaks of at least 15 minutes every hour.
Recognize and monitor yourself for symptoms of heat-related illness and know your personal risk factors for heat-related illness, which may include obesity, diabetes, heart disease among others.

Develop and oversee the personnel safety and compliance requirements.
Provide Outdoor Heat Safety training and update as needed.
Provide a template Heat Safety Plan and update as needed.
Provide technical assistance to units and departments.
Incident response, tracking, and prevention
Serve as the University representative and liaison to Washington State Department of Labor & Industries (L&I) for all campus locations.

Training

Prior to outdoor work in temperatures exceeding those listed in Table 1 (above) and annually thereafter, personnel and supervisors are required to complete the online EH&S Outdoor Heat Safety Training course.

Services available

Contact EH&S at airquality@uw.edu or (206) 543-7388 for consultation and assistance.

More information

Definitions

Working conditions that increase susceptibility for heat-related illness such as air temperature, relative humidity, radiant heat from the sun and other sources, conductive heat sources such as the ground, air movement, workload (i.e., light, moderate or heavy) and duration, and personal protective equipment worn by employees; measurement of environmental factors is not required by WAC 296-62-095.

Frequently asked questions

Excessive exposure to heat can cause a range of heat-related illnesses, from less serious heat rash and heat cramps to more serious heat exhaustion and heat stroke. Heat stroke requires immediate medical attention because it can result in serious health effects or death, so take precautions while working in the summer heat.

Certain factors, including personal health conditions, activities being conducted, and weather can increase the risk of a heat-related illness.

Heat exhaustion can also make workers more susceptible to falls, equipment-related injuries, and other on-the-job safety hazards.

Supervisors and workers should become familiar with signs and symptoms of heat-related illnesses, including heat stroke, heat exhaustion, heat cramps, heat syncope, heat rash and rhabdomyolysis (muscle breakdown).

When any of these are present, promptly provide first aid. Do not try to diagnose which illness is occurring. These conditions can worsen quickly and result in fatalities. When in doubt, cool the worker and call 9-1-1.