Temperatures, humidity, direct sunlight and hard physical labor all affect the body’s ability to handle the heat. Since the human body must maintain a core temperature of 98.6 degrees Fahrenheit to function properly, exposure to extreme heat will trigger a natural response to reduce the physical strain: sweat. Danger enters in when the body’s attempts to cool itself are no longer effective or when the loss of fluid exceeds the amount of water being consumed. Understanding the risk factors and taking steps to reduce worker exposure prior to facing extreme heat are critical in avoiding heat-related injuries and illnesses on the job. Developing strategies to handle the challenges high temperatures and humidity will bring to the workplace can help the company and its workers survive the heat.
Strategy #1: Use Engineering Controls
Implementing engineering controls is the best way to prevent heat-related illnesses because they can make the work environment cooler. Creating a cool environment can be accomplished in a variety of ways.
- Controlling the air condition. Usually, heat will transfer from a higher temperature object to a cooler one. To enhance the transfer of heat away from your workers, change the air temperature and air movement through ventilation, air conditioning or spot-cooling equipment such as fans or blowers. Also, eliminate sources of water vapor, which can increase humidity, by sealing steam leaks and making sure that floors are kept dry.
- Controlling exposure to direct heat. Shield employees from direct sunlight or high temperatures from manufacturing equipment. This can be accomplished through outside canopies or other temporary structures that are open to air movement. Also, the use of body cooling garments, heat protective clothing and insulation of hot surfaces can be effective.
Strategy #2: Train on Ways to Prevent, Recognize and Treat Heat-Related Illnesses
Communicating the hazards and methods used to prevent heat-related illness can provide the knowledge necessary to make good decisions. Workers and supervisors should be trained to recognize the hazards that can lead to heat illness, along with the personal and environmental risk factors that can affect the body’s response to heat. They should also understand the controls in place to prevent exposure, the common signs and symptoms of heat illness, and the procedures to follow in a medical emergency.
Strategy #3: Monitor Weather Reports
Paying close attention to heat advisories or warnings that have been issued can help in planning work for the day. The National Weather Service issues several types of heat-related updates depending on the heat index to alert people to extremely hot conditions. Monitoring weather reports daily and rescheduling jobs with high heat exposure to cooler times of the day is important, especially during heat waves. When possible, schedule routine maintenance and repair projects for cooler times of the year.
Strategy #4: Implement a Heat Acclimatization Program
Acclimatizing workers to heat exposure can decrease the risk of heat-related illnesses if the program is properly designed and implemented. It is a program that involves exposing workers to heat for progressively longer time periods. According to OSHA, workers should be allowed to get used to hot environments by gradually increasing their exposure over a 5-day work period. Begin with 50 percent of the normal workload and time spent in the hot environment and then gradually build up to 100 percent by the fifth day. New workers and those returning from an absence of two weeks or more should have a 5-day adjustment period as well.
Strategy #5: Provide for and Encourage Proper Hydration
Providing workers with plenty of cool drinking water (a water temperature of 50 to 60 degrees Fahrenheit, if possible) in visible locations close to the work area can encourage hydration. Remind workers to frequently drink small amounts of water before they become thirsty to maintain good hydration. During moderate activity, in moderately hot conditions, at least one pint of water per hour is needed. Workers should drink about six ounces or a medium-sized glass-full every 15 minutes.
Strategy #6: Establish Work/Rest Schedules
Distributing the workload evenly over the day and scheduling frequent rest periods with water breaks in shaded or air-conditioned recovery areas also can be effective in reducing heat stress. Work/rest schedules are often based on 1-hour cycles and might call for a rest period of 15 minutes every hour during hot weather, or 45 minutes per hour when temperature and humidity are extreme. Individual requirements may vary greatly, so an industrial hygienist may need to be consulted.
Strategy #7: Evaluate Work Practices
Assessing the work-load and work practices that are in place may reveal areas of improvement. Under conditions of high temperature and heavy workload, OSHA compliance officers are advised to determine the work-load category of each job. They do this by determining averaging metabolic rates for the tasks and then ranking them:
- Light work – up to 200 kcal/hour;
- Medium work – 200-350 kcal/hour; and
- Heavy work – 350-500 kcal/hour.
If workers are at an increased risk of heat stress due to the job activities being performed or from use of personal protective equipment, the consideration of other administrative controls may be necessary. These include:
- Reducing the physical demands of work, e.g., excessive lifting or digging with heavy objects;
- Using shifts;
- Using relief workers;
- Pacing the work; and
- Assigning extra workers and limiting worker occupancy, or the number of workers present, especially in confined or enclosed spaces.
Heat-related injuries and illnesses are preventable. Understanding the risk factors and taking steps to reduce worker exposure prior to facing extreme heat are two critical components. Developing strategies to handle the challenges high temperatures and humidity will bring to the workplace can help the company and its workers survive the heat.
About the Author
Stefanie Williams is an editor for J. J. Keller & Associates Inc.