1. Heat Stress UW-Eau Claire Facilities Management By: Chaizong Lor, FM Safety Coordinator

2. Heat Stress Training Objectives: –Background Factors –Heat Stress Hazards –Heat Stress Control Measures –Prevention of Heat Stress

3. Heat Stress What is Heat Stress? –The combination of environmental and physical work factors that constitute the total heat load imposed on your body’s cooling system.

4. Heat Stress Body’s Cooling System –Blood is pumped close to skin for cooling reducing blood going to the brain and rest of your body. –As temperatures rise, surface blood vessels get bigger and pulse rate goes up. –As temperatures rise your body gains heat instead of losing it.

5. Heat Stress Body’s Cooling System Cont. –Most people lose about a quart of sweat/hr. in extreme heat. –This adds a strain to your circulatory system which now has to lower the amount of blood in your body.

6. Heat Stress

7. –Mechanisms for heat loss/transfer Evaporation –The body transfers water vapor to the skin through pores and sweat glands Background – Heat Exchange

8. Heat Stress Background – Heat Exchange Cont. –Mechanisms for heat loss/transfer Conduction –The direct transfer of heat from skin to the surrounding air as the ambient temp rises Convection –Air blowing over the skin e.g. use fan Radiation –The transfer of heat to or from surrounding objects that are not in direct contact with the body

9. Least Severe Most Severe 5432154321 Heat Stress Types of Heat Stress:

10. Heat Stress Heat Stress Hazards Cont. –Heat Rash Cause –Hot humid environment –Skin is constantly wet from sweat –Sweat gland ducts become plugged Signs & Symptoms –Painful or itchy skin –Blister-like rash Treatment –Keep skin clean and dry –Stay cool with air conditioning –Fans and cool showers –Wear lightweight & loose-fitting clothing Prevention –Shower after working in hot environment –Keep skin clean and dry

11. Heat Stress Heat Stress Hazards Cont. –Heat Fatigue Cause –Lack of acclimatization –Depletion of water and salt due to sweating Signs & Symptoms –Discomfort –Feeling of weakness and tiredness –Impaired performance of skilled tasks in heat –Inability to concentrate Treatment –No treatment necessary unless other signs of heat illness are present Prevention –Acclimatization of workers for work in the heat

12. Heat Stress Heat Stress Hazards –Heat Cramps Cause –Heavy sweating during hot work, drinking large amount of water without replacing salt loss Signs & Symptoms –Painful muscle spasms of arms, legs and stomach –Usually occur after heavy sweating and may begin towards the end of the workday Treatment –Drink water, move to a cool shaded area –Spray the person with water and massage the cramp –Adequate salt intake at meals, try eating more fruits Prevention –Adequate salt intake with meals, and adequate water intake –Drink fluids regularly

13. Heat Stress Heat Stress Hazards Cont. –Heat Exhaustion Cause –Dehydration causes blood volume to decrease –Inadequate salt and water intake causes a person’s body’s cooling system to break down Signs & Symptoms –Fatigue, weakness, dizziness, faintness –Nausea, headache, heavy sweating –Low to normal blood pressure Treatment –Move person to a cool shaded area –Provide cool water to drink –Fan and spray with cool water Prevention –Acclimatize worker using a work rest –Drink plenty of water

14. Heat Stress Heat Stress Hazards Cont. –Heat Stroke Cause –Partial or complete failure of sweating mechanism –Body cannot get rid of excess heat Sign & Symptoms –Hot dry skin, elevated body core temperature, confusion, loss of consciousness »Fatal if treatment is delayed Treatment –Medical emergency –Move the victim to a cool shady area –Remove excess clothing –Spray the person with cool water Prevention –Monitor workers in sustained work in severe heat »Drink plenty of water »Drink cool fluids that do not contain caffeine

15. Heat Stress Control Measures –Engineering Controls Reduction of Humidity: –Reduce the temperature and humidity through air conditioning Provide air-conditioned rest areas. Ventilation and Air Conditioning: –Use of air-circulating fans –Better ventilation, to draw heat and steam away from work areas Shielding between workers and heat sources Heat Stress

16. Heat Stress Control Measures –Administrative Controls Changing the rate of work Schedule hot jobs to cooler times of the day. Increase the frequency and length of rest breaks if possible Encouraged employees to take a rest break should any sign of heat stress or heat disorder develop. Allow for slower-paced work during the hottest periods of the day Limiting duration of exposure time –Rotate work activities Heat Stress

17. Heat Stress Control Measures Cont. –Protective Clothing Light summer clothing should be worn to allow free air movement and sweat evaporation. Outside, wear light-colored clothing.

18. Heat Stress Prevention of Heat Stress –Supervisor Identify all hot work environments under his/her authority Ensure that employees have been trained in hot working environments Train workers to recognize signs & symptoms of heat stress disorders and be prepared to give first aid if necessary. Avoid placing employees in hot work environments for extended time periods. Realize individual employees vary in their tolerance to heat stress conditions.

19. Heat Stress Prevention of Heat Stress –Employees Learn to recognize the symptoms of heat stress. Change work location, taking adequate rest periods (in shade or cooler environment). Become familiar with the hazards associated with working in hot environments Use adequate fans for ventilation and cooling, especially when wearing personal protective equipment (PPE). Wear light colored, loose (unless working around equipment with moving parts) clothing. Keep shaded from direct heat where possible (e.g., wear a hat in direct sunlight). Drink plenty of water. In hot environments the body requires more water than it takes to satisfy thirst.

20. Any Questions ??