Heat Illness Prevention Plan

Heat stress is the overall effect of excessive heat on the human body and can lead to heat-related illnesses if proper measures aren’t taken. When the body’s temperature control system is overworked, people can suffer from minor conditions such as heat cramps, heat syncope, and heat exhaustion, as well as a more severe condition known as heat stroke. Most heat illnesses occur when you are exposed to the heat for a long period of time. Normally, the body is able to cool itself by sweating but during hot weather, and especially during humid conditions, sweating is just not enough. Instead, the body temperature can rise to dangerous levels.

 

The heat index, otherwise known as “apparent temperature”, is what the human body temperature feels like when relative humidity and air temperature are accounted for. When the relative humidity is high, the body feels warmer. When the relative humidity decreases, the body feels cooler. The direct correlation between air temperature and relative humidity and the heat index is shown in the chart below provided by the National Weather Service (NWS) agency of the National Oceanic and Atmospheric Administration (NOAA).

In order to determine the heat index using the chart above, you must know the air temperature and relative humidity. If the temperature outside is 100°F and the relative humidity is 55%, the heat index will be 124°F. As the air temperature and relative humidity increases, so does the heat index and vice versa

To determine the heat index for a specific location, you can use the Full Heat Index Chart that specifies a wide range of temperatures and relative humidity values or by using the Weather Calculator found on the NOAA website. 

Comparison of Indoor and Outdoor Heat Illness Prevention Standards

By U.S. Department of Labor (DOL), Occupational Safety and Health Administration (OSHA) and the Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH)

                   

When you're working in the heat, safety comes first. With the OSHA-NIOSH Heat Safety Tool, you have vital safety information available whenever and wherever you need it - right on your mobile phone.

The App allows workers and supervisors to calculate the heat index for their worksite, and, based on the heat index, displays a risk level to outdoor workers. Then, with a simple "click," you can get reminders about the protective measures that should be taken at that risk level to protect workers from heat-related illness-reminders about drinking enough fluids, scheduling rest breaks, planning for and knowing what to do in an emergency, adjusting work operations, gradually building up the workload for new workers, training on heat illness signs and symptoms, and monitoring each other for signs and symptoms of heat-related illness.

Working in full sunlight can increase heat index values by 15 degrees Fahrenheit. Keep this in mind and plan additional precautions for working in these conditions.

The OSHA-NIOSH Heat Tool is available in English and Spanish for Android and iPhone devices. To access the Spanish version, set the phone language to Spanish.

Stay informed and safe in the heat, check your risk level.

For more information about safety while working in the heat, see OSHA's heat illness webpage, including online guidance about using the heat index to protect workers.

• Cal/OSHA Heat Illness Prevention
• CDC Heat Illness
• Heat Illness Prevention Program Template
• NIOSH Heat Stress
• NOAA
• OSHA Heat-Related Illnesses
• Safety Alert 24-02 Heat Illness Prevention for Student Athletes