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Module 3: Hazards of Temperature Extremes

Thermal Comfort

• Conduction • Convection • Metabolic heat • Environment heat • Radiant heat

Heat Strain Defined

It is the overall physiological response resulting from heat stress. The heat physiological adjustments are dedicated to dissipating are dedicated to dissipating excess heat from the body. Acclimatization is a gradual physiological adaptation that improves an individual’s ability to tolerate heat stress.

Recognizing Heat Strain

• A sustained rapid heart rate (180 beats per minutes minus the employee’s age in years).

• Core body temperature is greater than 38.5°C. • Recovery rate one minute after a peak work effort is greater than 110

beats per minute. • Sudden and severe fatigue, nausea, dizziness, or light-headedness.

Specific Controls

• Establish engineering controls that reduce the metabolic rate, provide general air movement, reduce process heat and water-vapour release, a shield radiant heat sources, among others.

• Consider administrative controls that set acceptable exposure times, allow sufficient recovery, and limit physiological strain.

• Consider personal protection that has been demonstrated to be effective for the specific work practices and conditions at the location.

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Cold Stress

Excessive exposure to cold can led to hypothermia, which can be fatal.

- When working in a setting in which wind is a factor, reduce the effect of the wind by

I. Erecting a windscreen; II. Wearing wind-breaking clothing.

- When working in a setting in which clothing may get wet, apply one or more of the following strategies:

I. With light work, wear an outer layer of impermeable clothing; II. With heavier work, wear an outer layer that is water repellent, but

not impermeable; III. Select outer garments that are ventilated to prevent internal

wetting from sweat; IV. If clothing is wet before going into cold environment, change first; V. Change socks daily or more often to keep the feet dry;

- When working in a cold setting, use auxiliary heat applied directly to the hands and feet;

- When working in a cold setting, use facial protection to prevent cold stress to the face and lungs.

- If adequate protective clothing is appropriate for the conditions in question is not available, the work should be modified or suspended until conditions changes or the clothing is available.

Burns and Their Effects

Severity of burns

• First degree – are minor and result only in a mild inflammation of the skin, known as erythema.

• Second degree – are easily recognizable from the blisters that form on the skin. If the second-degree burn is superficial, the skin will heal with little or no scarring.

• Third-degree – are very dangerous and can be fatal depending on the amount of body surface affected. A third-degree burn penetrates through both the epidermis and the dermis.

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Chemical Burns

Chemical burns, like thermal burns, destroy body tissue; the extent of destruction depends on the severity of the burn. However, chemical burns continue to destroy body tissue until the chemical are washed away completely.

Effects of Chemical Burns

• Infection • Fluid loss • Shock

First aid for chemical burns

Wash off the chemical by flooding the burn areas with copious amount of water as quickly as possible. This is the only method for limiting the severity of the burn, and the loss of even a few seconds can be vital.