What Level of Heat Index Is Safe for Outdoor Work?

Understanding Heat Index

Heat index is a measure of how hot it feels outside when temperature and humidity are combined. When the heat index reaches 91°F (33°C), workers are at risk of heat-related illnesses, such as heat exhaustion and heat stroke. Prolonged exposure to heat indexes above 95°F (35°C) can lead to severe symptoms and even death.

Preventing Heat-Related Illnesses

To prevent heat-related illnesses, employers should take steps to protect workers from heat stress. This includes providing regular breaks in shaded or air-conditioned areas, encouraging workers to drink plenty of water, and limiting the amount of physical activity during peak heat hours (usually between 11am and 3pm). Employers should also monitor the heat index and adjust work schedules accordingly.

First Aid for Heat-Related Illnesses

If a worker shows symptoms of heat-related illness, such as dizziness, nausea, or headaches, they should be removed from the heat immediately and provided with cool water and rest. In severe cases, call emergency services and provide first aid by moving the worker to a shaded or air-conditioned area, loosening tight clothing, and cooling the body with cool water or a fan. The American Red Cross recommends the “Cooling Measure” technique, which involves cooling the body at a rate of 1-2°F (0.5-1°C) per minute. This can be achieved by immersing the worker in a cool bath or using evaporative cooling methods, such as a wet cloth or a cooling towel.