How to Prevent Heat Stress

Welcome to this Chemscape presentation on heat stress. With summers getting hotter and heat waves lasting longer, heat stress is a growing hazard for many outdoor workers. Heat stress can occur indoors, outdoors, and in any season if the conditions are right. Millions of workers are exposed to heat in their workplaces. Illness from exposure to heat is preventable. However, thousands become sick from occupational heat exposure, and some cases are fatal every year. Most fatalities related to heat occur in the first week of working in warm or hot environments because the body needs to acclimatize, that is build a tolerance to the heat gradually over time. 

Industries Impacted by Occupational Heat Stress

Industries and workplaces where heat stress may occur include agriculture, construction, landscaping and gardening, mail and package delivery, road building and maintenance, and oil and gas well operations.

Factors Influencing Heat Stress

Climate and environmental conditions increase the potential for heat-related disorders. This includes hot temperatures and humidity, low air movement, and the radiant heat of surrounding surfaces. The intensity of work influences heat stress. This includes work grade, level of physical effort, and activity duration strains the body's temperature regulation system. 

Clothing influences heat stress. Clothing thickness, permeability, weight, fit, and ventilation also affect the body's ability to regulate internal temperature. Personal Protective Equipment, PPE, increases the risk of heat-related disorders. Layering personal protective equipment on clothing or the worker may also increase the risk of heat-related disorders. Your personal health can elevate your risk of heat-related illness, including older age, being overweight, history of heat stress, medical conditions, for example, diabetes, cardiovascular disorders, chronic pulmonary disease, and thyroid disorders, certain medications, poor level of fitness, and being a new employee with no acclimatization to the work environment. 

Risks of Heat Stress

Working with heat stress symptoms increases the risk for more severe heat-related conditions, such as heat exhaustion and heatstroke, and increases the risk of accidents due to lower mental alertness and physical performance. Working outdoors exposed to UV radiation is a specific hazard related to heat stress.  

Implementing Safe Outdoor Work Practices

Remember sun safety. One, cover up with a long-sleeved shirt. Two, use sunscreen SPF30 or greater. Three, wear sunglasses and a broad-brimmed hat. Four, seek shade whenever possible. Usually, under hot environmental conditions, the body cools itself by sweating, but under some conditions, sweating is not enough. The chart shows the progression of heat exposure. Heat exposure gradually compromises mental alertness. Be aware of yourself and your co-workers' health in the heat. Work in the buddy system, and report symptoms to a supervisor. The symptoms between heat exhaustion and heatstroke look very similar, but there is a big difference between heat exhaustion and heatstroke. 

Recognizing and Responding to Heat-Related Illnesses

When sweating stops, the skin is dry and hot, and the person becomes confused or loses consciousness, and it's a medical emergency. Heat exhaustion, the person needs to be moved to a cooler place, drink water if able, and take a cold shower, or apply cold compresses to the skin. Heatstroke is life-threatening and needs immediate medical attention. Heat exhaustion can progress into heatstroke if not treated. Preventing heat stress requires daily assessment of the work environment, worksite, and individual factors. 

Engineering Controls for Preventing Heat Stress in the Workplace

The best engineering controls to prevent heat-related illness is to make the work environment cooler and use machines to replace manual labor. Air conditioning, such as air-conditioned crane or construction equipment caps, air conditioning in break rooms, increased general ventilation, cooling fans, local exhaust ventilation at points of high heat production or moisture, such as exhaust hoods and laundry rooms, reflective shields to redirect radiant heat, insulation of hot surfaces, such as furnace walls, elimination of steam leaks, cooled seats or benches for rest breaks, use of mechanical equipment to reduce manual work, such as conveyors and forklifts, misting fans that produce a spray of fine water droplets. 

Essential Safety Tips for Outdoor Workers

1. Build a Tolerance to Heat

Build a tolerance to heat gradually by increasing your intensity by 20% a day. Acclimatization may diminish after four days away from working in the heat and may be completely lost in three to four weeks. According to the ACGIH TLV booklet, good work practices may help reduce excessive heat exposure. Examples include rescheduling outdoor work to cooler periods of the day, scheduling work near hot equipment during shutdowns or when it is off or cooler, schedule according to the weather forecast, rotating workers between indoor and outdoor tasks to lessen each employee's total heat exposure, implementing a rotation schedule every hour or sooner, pace your work so you can take frequent water breaks, drink cool water continuously and as required, drink before you are thirsty, avoid alcohol, soda, and caffeine. 

2. Rest and Take Breaks

Rest is important when working in hot weather. You should rest long enough in the shade or air-conditioned room to cool down. Rest breaks are determined by the intensity of your job. A 15-minute break every 2 hours of working in the heat is recommended as a general guideline. There are products on the market that can be used to reduce the risk of heat stress and UV exposure. Wide-brimmed hats, lightweight, light-colored, and loose-fitting clothing, ice vests can be used for body cooling. 

Work in a Buddy System

Implement a buddy system when working in the heat as a group. Have co-workers monitor the condition of others. Self-monitor for symptoms such as headache, or nausea, weakness, or dizziness, heavy sweating, or hot dry skin, elevated body temperature, thirst, and decreased urine output. Report any signs to the supervisor so that immediate action can be taken to prevent heat stress.  

Conclusion

This concludes our presentation. Please consult your company health and safety resource for more information on heat stress as it applies to your job.