Transcript Heat & Cold - Rochester Institute of Technology

Heat & Cold Stress
Rochester Institute of Technology
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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.
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Heat & Cold Stress
HEAT
• 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.
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Heat & Cold Stress
STRESS
• Relative to workload, health and physical
factors, metabolism, type of clothing, direct
contact, prior injury or predisposition.
• Control is related to reducing stress.
• Susceptibility varies
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Heat & Cold Stress
Sources of Heat:
• Metabolic (Internal)
• Environmental (External)
• Body Maintains balance by sweating:
H + E = M +/- R +/- C
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Heat & Cold Stress
Hot Environments
• 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
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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.
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Heat & Cold Stress
Preventing Heat-Related Health Problems
• 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.
– 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.
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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, wellbalanced 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.
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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.
• Wear loose-fitting clothes such as cotton,
which lets air move over your body.
• Wide brimmed hats should also be worn.
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HOW HOT IS IT?
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ACGIH Guidelines
• Workers should rest when deep body temp
reaches 38°C (100.4°F).
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Work/rest regimen
Light
Moderate
Heavy
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.
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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.
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Heat & Cold Stress
Control of Heat Stress
• Acclimatization
• Breaks
• Ventilation
• Auxiliary Control
• Cooling
– Drinks
– Clothes
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Heat & Cold Stress
Cold Stress
• Reaction by:
– Constriction of blood vessels
– Shivering
– Glucose production
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Heat & Cold Stress
Cold Stress Disorders:
• Hypothermia - slows down reactions, speech,
etc.
• Watch sedatives
• Blood vessel abnormalities
– Raynaud’s phenomenon
– Acrocyanosis
– Thromboangiities Obliterans
• Frostbite
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Wind-chill
• Calculation
of wind
speed,
(humidity &)
temperature
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Heat & Cold Stress
Prevention
• Acclimatization
• Dehydration
• Electrolytes (Salt)
• Control measures - shielding
• Personal Protective Equipment
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