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Thermo Stress Lawrence S. Wong, CIH University of California Office of the President
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Cold Stress
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Cold Environment ► Body’s Energy Used to Keep Internal Temperature Warm Shift Blood Flow From Extremities/Outer Skin to Body Core (Chest & Abdomen) Results in Rapid Cooling of Extremities and Exposed Skin ► Increases Chance for: Hypothermia Frostbite Trench Foot
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Wind Speed ► 16 k/hr (10 mph) Light Flag Fully Extended ► 24 k/hr (15 mph) Raises Newspaper Sheet Off the Ground ► 32 k/hr (20 mph) Wind Capable of Blowing Snow
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Hypothermia - Means “Low Heat” ► Body Heat Lost Faster than Replaced Onset – Body Core Temperature Drops – 95 O F ► Symptoms – Pale & Cold Skin Shiver, Stomp Feet, Lose Coordination, Slurred Speech, Fumble Items with Hands ► Body Temperature Continues to Fall Symptoms Worsen, Shivering Stops, Unable to Walk or Stand Body Temperature of 85 O F - Unconscious Body Temperature of 78 O F – Death Could Occur
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Hypothermia Treatment ► Mild Hypothermia Move to Warm Area & Stay Active Remove Wet Clothes & Replace with Dry Clothes or Blanket & Cover the Head Drink Warm (Not Hot) Sugary Drink Avoid Drinks with Caffeine ► More Severe Hypothermia – Do All Above and: Contact EMS Cover All Extremities Completely & Place Warm Objects on Head, Neck, Chest & Groin Arms & Legs Are Warmed Last
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Severe Hypothermia Treatment ► Treat Victim Very Gently ► Do Not Apply External Heat to Re-Warm ► Hospital Treatment is Required
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Frostbite ► Typically Affects Extremities – Feet & Hands ► Skin Freezes and Loses Water ► Usually Occurs at Temperatures < 30 O F ► Affected Body Part – Cold, Tingling, Stringing or Aching, Followed by Numbness ► Skin Color – Red, Then Purple, Then White Cold to the Touch Severe Cases - Blisters
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Frostbite Treatment ► Do Not Rub Affected Area to Warm It ► Wrap Area in Soft Cloth ► Move to Warm Area & Contact Medical Personnel ► Do Not Pour Water on Affected Part ► If Affected Part May Get Cold Again Do Not Warm Warming & Re-Cooling – Cause Severe Tissue Damage
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Trench Foot ► Feet Immersed in Cold Water at Temperatures Above Freezing for Long Periods of Time ► Similar to Frostbite, But Not as Severe ► Symptoms – Tingling, Itching, or Burning Sensation. Blisters May Be Present ► Soak Feet in Warm Water & Then Wrap with Dry Cloth Bandages ► Drink Warm Sugary Drinks
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Cold Stress Prevention ► Plan for Work in Cold Weather ► Wear Appropriate Clothing – 3 Layers Outer Layer: Gortex® or Nylon – Break the Wind & Allow Some Ventilation Middle Layer: Down or Wool – Absorb Sweat & Provide Insulation Even When Wet Inner Layer: Cotton or Synthetic Weave – To Allow Ventilation ► Layering Creates Air Pockets – Helps Retain Body Heat
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Cold Stress Prevention ► Wear Hat – Exposed Head: Up to 40% Loss of Body Heat ► Insulated Boots or Footwear Wear One Thick or Two Thin Pairs of Socks Too Many Socks Tighten Fit & Restrict Blood Flow ► Hands Loose Dexterity < 59 O F ► Change of Dry Clothing–If Clothes Gets Wet ► Do Not Wear Tight Clothing – Loose Air Pocket Insulation
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Cold Stress Prevention ► Avoid Alcohol and Caffeine Increases Heat Loss Through Vasodilation ► Take Breaks Out of the Cold ► Schedule Work During Warmer Parts of Day ► Older Workers or Certain Medical Conditions May Be More Susceptible ► Radiant Heater ► Shielding Work Areas from Drafts & Wind to Reduce Wind Chill
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Cold Stress Training ► Proper Clothing & Equipment ► Safe Work Practices ► Guidelines for Eating & Drinking ► Risk Factors That Increase Health Effects of Cold Exposure ► How to Recognize Signs & Symptoms of Hypothermia, Frostbite, & Trench Foot ► Appropriate First Aid Treatment, Including Warming Procedures
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Heat Stress
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► Body Produces/Stores More Heat Than You Lose Metabolism/Exercise Heat Absorbed ► Radiant Energy (Sun, Fire) ► Conductive (Direct Contact) ► Primary Heat Loss – Evaporation Sweat/Evaporation Function of Humidity & Temperature
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Heat Illnesses ► Heat Rash Clogged/Irritated Sweat Glands ► Heat Cramps Painful Muscle Spasms–Electrolyte Imbalance ► Heat Exhaustion Heavy Sweating/Pale Clammy Skin Normal Heart Rate/Body Temperature ► Exert ional Heat Illness Stuporous Appearance, Nausea, High Temperature, Headache
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Heat Illnesses ► Heat Stroke High Body Temperature Hot, Red (Gray) Dry Skin, Rapid Pulse Confusion, Loss of Consciousness Death is Imminent ► Heat Stroke First Aid Loosen Tight Clothing Cool with Wet Cloth If Conscious, Slowly Give 4 oz of Water Every 15 Minutes Get Victim to Emergency Room ASAP
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Heat Illness Prevention ► Drink Fluids Water – 4 Cups (1 Quart/Hour) No Alcohol or Caffeine - Diuretics ► Eat Replace Electrolytes Lost by Perspiration
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Heat Illness Prevention ► Acclimation Slow Process for Body to Condition Itself to Heat May Take Up to 10 Days Quickly Lost in a Matter of Days ► Conditioning/General Health Stay in Shape, Exercise Regularly Watch Your Weight
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Cal/OSHA Heat Illness Regulation Title 8 Cal. Code Regs., §3395 ► Several Fatalities Due to Heat Stroke in California Construction Agriculture ► Became Permanent in April 22, 2006 ► Essentially Identical to Emergency Regulation
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Heat Illness Prevention Standard: Application ► All Outdoor Places of Employment ► At Time When Environmental Factors for Heat Illness are Present Air Temperature Relative Humidity Radiant Heat, Conductive Heat Workload Severity/Duration Personal Protective Clothing/Equipment
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Outdoor Environments ► Agriculture ► Construction ► Equipment and Storage Yard ► Loading Docks ► Tents ► Structures with One or More Open Sides Lack of Insulation/Heating From Sun Limited Air Circulation
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Potable Drinking Water ► Sufficient Quantity at Beginning of Work Shift Can Begin Shift with Smaller Quantities if Effective Replenishment Procedures Developed and Implemented ► > 1 Quart/Employee/Hour for Entire Shift >2 Gallons/Employee/8-Hour Shift ► Encourage Frequent Drinking of Water Thirst – Unreliable Indicator of Dehydration
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Access to Shade ► Available for Employee(s): Suffering from Heat Illness; or Believe a Preventive Recovery Period is Needed ► At Least 5 Minutes ► Cool Down (Metabolic Heat/Heart Rate) ► Rehydrate ► Shade is: Open to Air; or Provided with Ventilation or Cooling for a Period of No Less Than 5 Minutes ► Access to Shade Permitted at All Times
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Heat Illness Prevention Training ► Employee Training ► Supervisor Training ► Training Completed Prior to Assignment in Outdoor Environment with a Potential for Heat Illness
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Employee Training ► Risk Factors for Heat Illness Environmental Personal ► Employer’s Preventive Procedures ► Importance of Water Consumption ► Importance of Acclimation ► Types/Signs & Symptoms of Heat Illnesses ► Immediate Reporting Signs/Symptoms to Supervisor ► Employer’s Procedures Responding to Signs & Symptoms ► Emergency Medical Procedures
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Supervisor Training ► Same Information in Employee Training ► Procedures for Supervisor to Implement Heat Illness Prevention Program to Meeting Cal/OSHA Standard ► Procedures Supervisor to Follow: When Employee Exhibits Symptoms of Possible Heat Illness; and For Emergency Response
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