1. 1 Rochester Institute of Technology Heat & Cold Stress

2. 2 Rochester Institute of Technology This material was produced under grant number 46B4-HT15 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

3. 3 Rochester Institute of Technology Heat & Cold Stress HEAT Heat & Cold Stress HEAT INTRODUCTION INTRODUCTION –Since 1936, according to the National Safety Council, 30,000 people have died from heat related illnesses. –On the average, 384 people die each year from heat stroke. –Heat related injuries seem to occur often with the elderly, people who are not in good physical condition, or those who are not acclimatized to the heat.

4. 4 Rochester Institute of Technology Relative to workload, health and physical factors, metabolism, type of clothing, direct contact, prior injury or predisposition. Relative to workload, health and physical factors, metabolism, type of clothing, direct contact, prior injury or predisposition. Control is related to reducing stress. Control is related to reducing stress. Susceptibility varies Susceptibility varies Heat & Cold Stress STRESS

5. 5 Rochester Institute of Technology Heat & Cold Stress Sources of Heat: Metabolic (Internal) Metabolic (Internal) Environmental (External) Environmental (External) Body Maintains balance by sweating: Body Maintains balance by sweating: H + E = M +/- R +/- C

6. 6 Rochester Institute of Technology Heat & Cold Stress Hot Environments Heat Disorders Heat Disorders –Heat fatigue: stress from lack of acclimatization –Heat stress/ cramps: electrolyte balance –Heat strain/exhaustion: headache, nausea, weakness, etc. –Heat stroke: temp regulation failure (temp gets to above 41°C (105.8°F)) –Ranges from elevated temperature to syncope (fainting) to complex heat stroke

7. 7 Rochester Institute of Technology Heat & Cold Stress Treatment Remove to cool area, and remove outer clothing, wet skin and ventilate for evaporative cooling. If heat stroke evident, professional measures must be taken to rapidly bring down body temp. Remove to cool area, and remove outer clothing, wet skin and ventilate for evaporative cooling. If heat stroke evident, professional measures must be taken to rapidly bring down body temp.

8. 8 Rochester Institute of Technology Heat & Cold Stress Preventing Heat-Related Health Problems Heat & Cold Stress Preventing Heat-Related Health Problems Acclimation - accustom yourself to the weather prior to long durations of physical activity. Acclimation - accustom yourself to the weather prior to long durations of physical activity. Maintain Body Fluids - Fluid intake must be maintained throughout the course of physical activity. Maintain Body Fluids - Fluid intake must be maintained throughout the course of physical activity. –Do not rely on thirst as an indicator of dehydration because your body loses water faster than you realize. –Alcohol should be avoided because it is a diuretic, which increases dehydration and can interfere with heat loss.

9. 9 Rochester Institute of Technology Heat & Cold Stress Preventing Heat-Related Health Problems (cont’d) Proper Diet – Eat light and stay away from heavy foods. They increase metabolic heat production and also increase water loss. Eat smaller, well- balanced meals more often. Proper Diet – Eat light and stay away from heavy foods. They increase metabolic heat production and also increase water loss. Eat smaller, well- balanced meals more often. Rest Periods – Pace your work activities at a slower rate during high temperatures, take frequent rest periods in a shaded area, and drink plenty of fluids. Rest Periods – Pace your work activities at a slower rate during high temperatures, take frequent rest periods in a shaded area, and drink plenty of fluids.

10. 10 Rochester Institute of Technology Heat & Cold Stress Preventing Heat-Related Health Problems (cont’d) Dress Light – Lightweight, light-colored clothing reflects heat and sunlight and helps your body maintain normal temperatures. Dress Light – Lightweight, light-colored clothing reflects heat and sunlight and helps your body maintain normal temperatures. Wear loose-fitting clothes such as cotton, which lets air move over your body. Wear loose-fitting clothes such as cotton, which lets air move over your body. Wide brimmed hats should also be worn. Wide brimmed hats should also be worn.

11. 11 Rochester Institute of Technology HOW HOT IS IT?

12. 12 Rochester Institute of Technology ACGIH Guidelines Workers should rest when deep body temp reaches 38°C (100.4°F). Workers should rest when deep body temp reaches 38°C (100.4°F).

13. 13 Rochester Institute of Technology Work/rest regimen LightModerateHeavy Continuous work 30.0°C (86°F) 26.7°C (80°F) 25.0°C (77°F) 75% Work, 25% rest, each hour 30.6°C (87°F) 28.0°C (82°F) 25.9°C (78°F) 50% Work, 50% rest, each hour 31.4°C (89°F) 29.4°C (85°F) 27.9°C (82°F) 25% Work, 75% rest, each hour 32.2°C (90°F) 31.1°C (88°F) 30.0°C (86°F) *Values are in °C and °F, WBGT. These TLVs are based on the assumption that nearly all acclimatized, fully clothed workers with adequate water and salt intake should be able to function effectively under the given working conditions without exceeding a deep body temperature of 38°C (100.4° F). They are also based on the assumption that the WBGT of the resting place is the same or very close to that of the workplace. Where the WBGT of the work area is different from that of the rest area, a time-weighted average should be used (consult the ACGIH 1992-1993 Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices (1992). These TLVs apply to physically fit and acclimatized individuals wearing light summer clothing. If heavier clothing that impedes sweat or has a higher insulation value is required, the permissible heat exposure TLVs in Table III:4-2 must be reduced by the corrections shown in Table III:4-3.

14. 14 Rochester Institute of Technology SUGGESTED HEAT WORK PROCEDURES Temperature Danger Category Heat Syndrome Procedures > 130 Extreme Danger Heat Stroke Imminent When the heat index is in this zone employees in the affected area should be dismissed. 105 - 129 Danger Heat Cramps or heat exhaustion likely. Heat Stroke possible with prolonged exposure and activity When the heat index is in this zone, non critical work activities should be suspended. Critical work activities shall be evaluated and schedule changes of affected employees should be made. Management must specifically approve employees working in heat index danger areas. 91 - 104 Extreme Caution Heat cramps or heat exhaustion possible with prolonged exposure and activity When the heat index is in this zone management shall discuss the situation with supervisors and make schedule/work adjustments to accommodate for the heat. Specific approval must be granted for working under extreme heat conditions. 77 - 90 Caution Fatigue Possible Normal work day, no alerts posted.

15. 15 Rochester Institute of Technology Heat & Cold Stress Control of Heat Stress Acclimatization Acclimatization Breaks Breaks Ventilation Ventilation Auxiliary Control Auxiliary Control Cooling Cooling –Drinks –Clothes

16. 16 Rochester Institute of Technology Heat & Cold Stress Cold Stress Reaction by: Reaction by: –Constriction of blood vessels –Shivering –Glucose production

17. 17 Rochester Institute of Technology Heat & Cold Stress Cold Stress Disorders: Hypothermia - slows down reactions, speech, etc. Hypothermia - slows down reactions, speech, etc. Watch sedatives Watch sedatives Blood vessel abnormalities Blood vessel abnormalities –Raynaud’s phenomenon –Acrocyanosis –Thromboangiities Obliterans Frostbite Frostbite

18. 18 Rochester Institute of Technology Wind-chill Calculation of wind speed, (humidity &) temperature Calculation of wind speed, (humidity &) temperature

19. 19 Rochester Institute of Technology Heat & Cold Stress Prevention Acclimatization Acclimatization Dehydration Dehydration Electrolytes (Salt) Electrolytes (Salt) Control measures - shielding Control measures - shielding Personal Protective Equipment Personal Protective Equipment