1. Ch. 22 – Climate AREAS OF INTEREST: Comfort Stress
Heat stress
Cold stress
Air volume and quality
amount
contaminants
ventilation
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2. Comfort Factors For standard conditions Individual adjustments
_____________________________________________
For standard conditions
_____________________
Individual adjustments
______________________
Adjustments for nonstandard conditions
_____________________
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3. Heat Stress Effects on performance and health
_____________________________________________
Setting environmental limits
Reducing heat stress
Design for comfort because ‘ordinary’ workers (not highly motivated) work less efficiently in hot environments
For health, using multiple criteria is better than a single, but if a single criterion is needed, use body core temp.
WBGT – wet bulb globe temperature. See fig. 25.7, pg. 496
heat balance equation – see pg. 496
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4. Heat Transfer Radiant Convective Evaporative
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Convective
Evaporative
heat transfer – pp
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5. Cold Stress
Cold causes discomfort, reduced mental performance and dexterity, pain, loss of extremities, and death
_____________________________________________
Environmental Limits
Protection
Other Factors in Cold Stress
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6. Air Volume and Quality
Volume of air required is proportional to local contaminants.
Usually not a problem in office buildings, but …
_______________________________________________
For forced-air heating and cooling, ventilation volume may be determined by room temperature.
ASHRAE (American Society for Heating, Refrigeration, and Air conditioning Engineers) provides recommendations for air volume & humidity based on conditions (work level, CO2 levels, odors, smoking, etc.) This is discussed in detail in your text (pg , esp. box 22.2)
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7. Ch. 23 – Chemical environment (a.k.a., toxicology)
Deals with long-term effects of foreign chemicals on the body.
Chemicals affect the body with doses producing a response.
Controls can be engineered, administration, or personal protection.
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8. Effects of Poisons Effects may be permanent or ________
Threshold limit values are based on ___________.
Response may _____ the dose by __________.
Workers tend to ignore hazards with ___________
Financial benefits accrue to _________, heath costs to __________.
___________ cause defects in fetal development.
TLV approach considers humans to be ________________.
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9. Dose/Response
Chemicals can be detected in extremely low concentrations.
The problem is to define “excess.”
Poisoning depends on
_____________________
The Leaky Bucket
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10. Poison Routes To enter the body, a poison must _________________
Poisons may be characterized by ____________________________________
The most important entrance points are _________________.
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11. Entry points Skin Mouth Lungs in general,
__________________________________________
dermatitis
Mouth
Lungs
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12. Poison Interior targets Elimination Threshold limit values (TLV)
__________________________________________
Elimination
Threshold limit values (TLV)
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13. Example of TLV Calculation
Assume worker exposed to acetone for 4 h at 500 ppm, 2 h at 750 ppm, 2 h at 1500 ppm.
TWA = ________________________________
Is this acceptable?
812 > 750, so the exposure is unacceptable.
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14. Controlling Exposure Engineering Controls:
__________________________________________
Personal Protective Equipment
Administrative controls:
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