The Occupational Safety and Health Administration (OSHA) regulates working conditions to protect worker health and safety. Although OSHA does not establish specific maximum temperatures, its technical manual sets forth guidelines to prevent heat stress.
Threshold Limit Values
One guideline OSHA employs is the threshold limit value equation, set by the American Conference of Governmental Industrial Hygienists (ACGIH). TLVs determine how safe it is to work at given temperatures. For example, workers can perform light duties continuously in temperatures up to 86 degrees Fahrenheit, while employees can only perform heavy duties up to 77 degrees Fahrenheit. At 87 and 78 degrees Fahrenheit, respectively, workers must spend 25 percent of each hour at rest. As temperatures continue to increase, work time continues to decrease.
The OSHA manual also outlines precautions to reduce heat stress. Employers must have air-conditioned rest areas and plenty of cool water easily accessible. They must schedule work during the coolest parts of the day whenever possible, and provide first aid equipment and trained personnel on site.
Private sector employers must comply with all federal and state OSHA standards or face severe fines and penalties. Some states administer their own OSHA plans to cover government employees.