Ahhhhhh summer, it’s finally upon us. The sun, the surf and the sand, and that high humidity that our Canadian summers can bring! Love it or hate it, it’s our climate. With those hot, hazy summer days, comes a workplace hazard that often goes overlooked: heat stress.
Employers have a duty to ensure that reasonable precautions are taken to protect the health and safety of workers. Hot workplaces such as foundries, canneries, chemicals plants, automotive manufacturing, commercial kitchens, bakeries, deep mines, and outdoor workers, are typical environments where heat is a byproduct from the work process. Very hot environments have the potential to overwhelm the body’s coping mechanisms and lead to potentially serious and fatal conditions.
“Heat stress is the net heat load to which a worker may be exposed from the combined contributions of metabolic heat, environmental factors (i.e. air temperature, humidity, air movement, and radiant heat), and clothing requirements. Metabolic heat is the heat produced by the body through chemical processes, exercise, hormone activity, digestion etc.”
The body is continuously trying to maintain a core temperature of approximately 37 degrees Celsius. Sweat is your bodies cooling mechanism, as it evaporates from the skin, it helps to cool the body. It is much harder for sweat to evaporate when the humidity is high, when clothing or equipment is tight and covers most of your skin, and when you are dehydrated (producing less sweat) or are taking certain medications, such as antihistamines or blood pressure medication.
Heat stress is a less serious condition than heat stroke. Symptoms of heat stress include clammy pale skin, heavily sweating, rapid pulse, headache, dizziness, nausea, muscle cramps, fatigue, shallow breathing, and dark urine.
Heat stroke is a serious, potentially fatal condition in which the body does not have the ability to cool itself. The body’s core temperature rises to a point where it can no longer produce sweat. Early symptoms of heat stroke include lack of sweat, hot dry skin, rapid pulse, and difficulty breathing. If body temperature is not reduced, symptoms may progress to confusion and disorientation, seizure, loss of consciousness, coma or death.
Preventing heat stress and heat stroke in the workplace needs to be done through proper heat stress management. There are a few keys to implementing a successful heat stress prevention program. Before managing heat stress, the following needs to be determined;
- Measurement and monitoring methods – Humidex, temperature reading instrumentation
- Sampling strategy – At what temperature to start monitoring, how often, location
- Response strategy – Rest breaks, job rotation, air conditioning, shutdown
- Training – When, content, how often
- Water – Ensuring there is a sufficient supply of potable water
- Reporting – First aid, critical injury, emergencies
Once the above has been completed, we can determine control measures. Controls can be broken down into general, specific and personal controls.
General controls start with implementation and training. The plan must be implemented and workers trained to recognize the signs and symptoms of heat stress and how to avoid them. On hot humid days with a sufficient work load, a cup of water should be consumed every 20 to 30 minutes. Workers must be given time to acclimatize to the heat. This could take up to two weeks. Humidex levels should be measured and work/rest cycles adjusted accordingly.
Specific controls can include shielding workers from radiant heat or providing fans when the temperature is below 35 degrees and less than 70 percent humidity. Fan use when temperature is above 35 degrees and 70 percent humidity will increase worker’s temperature. Additional controls include reducing manual material handling using carts, dollies and equipment, starting earlier or finishing later, ensuring that shade is available when working outdoors and rotating workers in and out of hot areas.
Finally, when it comes to the individual, avoid caffeinated beverages as these make the body lose water and increase the risk of heat stress, use sunscreen and wear light clothing that allows sweat to evaporate, make healthy lifestyle choices and try to get enough rest.
Stay safe, stay alert, stay hydrated, and heed your body’s warning signs. Have a healthy and safe summer everyone.
Written by Jeff Thorne | Manager of Training and Consulting
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