Cold stress hypothermia

Extremes of either heat or cold can be more than uncomfortable—they can be dangerous. Heat stress, cold stress, and burns are major concerns of in the processing industry. Employees who work outside during the summer on surfaces that heat up and store heat will get very hot. They will be around metal equipment and vessels that are hot and radiate large amounts of heat. The opportunity for heat stress will be present. Also, winter conditions on a processing unit in Colorado or Alaska will present the opportunity for frostbite or hypothermia. The prudent process employee will seek to understand the types of heat and cold stress and how to avoid them. 

Cold stress occurs when temperatures go down the body maintains its temperature by reducing blood flow to the skin. This causes a maiked decrease in skin temperature. The most severe effect is on the extranities (fingers, toes, earlobes, and nose). When hands and fingers become cold, they become numb and insensitive, and there is an increased possibility of accidents. If the restriction of blood flow to the skin is not adequate to maintain temperature, then shivering occurs. If this is not adequate to warm the body, then a marked decrease in temperature (hypothermia) may occur. Workers who may be at ino-eased risk are... 

The stress of cold produced increased urinary excretion of norepinephrine but not of epinephrine or vasopressin (K8). Cold in the form of accidental hypothermia also resulted in increased serum creatine phos-phokinase (M2). Mental stress (problem solving) resulted in increases of urinary vasopressin from 33 to 47.6 units, epinephrine from 5.5 to 11.3 mg, and norepinephrine from 17 to 21 mg (K8). 

Climate is most stressful in cold weather when there are low ambient temperatures, high wind speeds, and absence of solar radiation. The humidity content is very low in freezing cold and therefore not an important factor. However, wet cold at ambient temperatures just above the freezing point can form a considerable cold stressor since water takes away the body heat more quickly through convection. Body cooling occurs more rapidly when people are wet (Thompson and Hayward, 1996). Therefore, hypothermia is more apparent in wet cold than in dry cold. 

Prolonged exposure to freezing temperatures can result in health problems as serious as trench foot, frostbite, and hypothermia. When body temperature drops even a few degrees below its normal temperature of 98.6°F, the blood vessels constrict, decreasing peripheral blood flow to reduce heat loss from the surface of the skin. The four environmental factors that contribute to cold-related stress include low temperatures, high/cool winds, dampness, and cold water. Wind chill, a combination... 

Personnel exposed to higji temperatures, alone or in conjimction with high humidity, can suffer from heat stress. Cold environments with high eiir velocities can cause frostbite or hypothermia. ASHRAE [11] has established comfort zone standards identifying the temperature and humidity ranges in which individuals can work comfortably and safely. Areas that must operate outside these comfort zones should be... 

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