Description
Heat Stress Index Workplace Safety Poster
Help employees understand how temperature and humidity can increase the risk of heat-related illness with the Heat Stress Index Workplace Safety Poster. This visual safety resource helps workers and supervisors recognize increasing heat conditions and reinforces precautions that can help reduce occupational heat stress.
The heat index combines air temperature and relative humidity to indicate how hot conditions feel. As heat and humidity increase, workers may require additional precautions such as more frequent rest breaks, hydration, cooling, reduced heat exposure, and closer monitoring for signs of heat illness.
What Is the Heat Index?
The heat index is a measure of how hot it feels when relative humidity is considered along with the actual air temperature. High humidity can make hot conditions more dangerous because it can reduce the body's ability to cool itself through the evaporation of sweat.
For outdoor workplaces, the heat index can be used as a screening tool to help employers and workers recognize when environmental conditions may increase the risk of heat-related illness.
How Can the Heat Index Be Used for Workplace Safety?
Monitoring the heat index can help employers and supervisors identify changing environmental conditions and determine when additional heat-safety precautions may be appropriate.
As workplace heat risk increases, precautions may include:
- Providing readily accessible cool drinking water
- Increasing rest and recovery periods
- Providing access to shade or cooler recovery areas
- Reducing the duration or intensity of strenuous work
- Scheduling demanding tasks during cooler portions of the day when practical
- Monitoring employees for signs and symptoms of heat-related illness
- Providing additional protection for new and unacclimatized workers
- Following established emergency procedures when heat illness is suspected
Is the Heat Index Enough to Measure Workplace Heat Risk?
No. The heat index can be a useful screening tool, but it should not be the only factor used to evaluate occupational heat exposure. Actual workplace heat stress can also be affected by physical workload, direct sunlight, radiant heat sources, air movement, clothing, personal protective equipment, and whether workers are acclimatized to hot conditions.
For a more comprehensive occupational heat assessment, Wet Bulb Globe Temperature (WBGT) can account for additional environmental factors and is commonly used by occupational safety and health professionals to evaluate workplace heat exposure.
Heat Index and Direct Sunlight
Workers exposed to direct sunlight may experience greater heat stress than the reported heat index suggests. Heat index values are based on shady, light-wind conditions, so employers should consider direct sun exposure and other workplace conditions when evaluating heat hazards.
Who Can Use a Heat Stress Index Poster?
A Heat Stress Index Workplace Safety Poster can be useful in indoor and outdoor workplaces where employees may be exposed to high temperatures or humidity, including:
- Construction sites
- Agricultural operations
- Landscaping and outdoor maintenance
- Warehouses and distribution centers
- Manufacturing facilities
- Commercial kitchens and bakeries
- Loading and shipping areas
- Industrial and maintenance operations
Heat Illness Prevention Requires More Than Temperature Monitoring
Employers should evaluate the complete working environment and implement appropriate measures to protect employees from hazardous heat exposure. Important heat illness prevention practices include hydration, rest, cooling, acclimatization, employee training, monitoring, and emergency response planning.
This poster is intended as a supplemental workplace safety and employee-awareness resource. It does not replace a workplace heat hazard assessment, employee training, heat illness prevention procedures, or applicable federal or state workplace safety requirements.
