Managing Cold Stress
Cold weather has returned to most parts of the U.S. To help you make it through yet another winter, this Tailgate focuses on how to protect yourself from cold stress-related illnesses and injuries.
How Cold is Too Cold?
Four factors contribute to cold stress: cold temperatures, high or cold wind, dampness and cold water. Cold air, water and snow all draw heat from the body, and a cold environment forces the body to work harder to maintain its temperature. Wind chill – the combination of air temperature and wind speed – also has an influence on cold stress. For example, when you’re outside in an air temperature of 30 F and a wind speed of 20 mph, your skin is exposed to conditions equivalent to an air temperature of 17 F. A wind chill calculator can be used to determine wind chill if the air temperature and wind speed are known.
While it is obvious that below-freezing conditions combined with inadequate clothing may bring about cold stress, it is important to understand that it can also be brought about by temperatures in the 50s coupled with rain and wind.
Your Body’s Reaction to Cold
When in a cold environment, most of your body’s energy is used to keep your internal temperature warm. Over time, your body will begin to shift blood flow from your outer skin and extremities – your hands, feet, arms and legs – to your chest and abdomen. Any exposed skin and your extremities will cool rapidly and the risk of frostbite and hypothermia will increase. When combined with cold water, trench foot may also be a problem.
Hypothermia is a potentially serious health condition that occurs when the body has fallen to a subnormal temperature. It often develops when someone is in a cold environment and body heat is lost faster than it can be replaced. Onset typically begins when the body temperature drops below the normal 98.6 F to around 95 F. The person affected begins to shiver and stomp their feet in order to generate heat. As their body temperature continues to fall, the person will stop shivering and begin to demonstrate slurred speech, lack of coordination and memory loss. Once the body temperature falls to around 85 F, the person may become unconscious. At 78 F, the person could die.
Who’s at Risk?
Cold stress is a risk for anyone working in a cold environment. However, older people may be at greater risk than younger adults since older people are not able to generate heat as quickly.
Preventing Cold Stress
When you’re going to be working in cold weather, planning is your most important defense. Wearing appropriate clothing and being aware of how your body will react to the cold are instrumental in the prevention of cold stress. Avoiding alcohol, certain medications and smoking can also help minimize risks.
Wearing the right clothing is the best way to avoid cold stress. The type of fabric you choose makes a big difference between keeping you warm and allowing you to get too cold. Cotton loses its insulation value when it becomes wet. Wool, on the other hand, retains its insulation even when wet. Electric and gas workers should never wear untreated synthetics such as rayon, nylon or polyester because these fabrics are known to melt into skin exposed to arc or flash. Many new products on the market provide both flame resistance and excellent climate protection.
The following are clothing recommendations to remember when you’re working in cold environments:
• Wear at least three layers of clothing: A flame-resistant outer layer to break the wind and allow ventilation; a middle layer of wool to absorb sweat and provide insulation even when wet; and an inner layer of cotton or flame-resistant synthetic weave to allow ventilation.
• Wear a hat. Up to 40 percent of body heat can be lost when the head is exposed.
• Wear insulated boots or other cold weather protective footwear.
• Keep a change of dry clothing available in case your work clothes become wet.
• Do not wear tight clothing. Loose clothing allows better ventilation.
By incorporating these cold weather basics into your routine and working a good plan, you will keep yourself and your crew safe and free from cold stress-related illnesses and injuries.
About the Author: John Boyle is vice president of safety and quality for INTREN, an electric, gas and telecommunication construction company based in Union, Ill. Boyle has more than 28 years of experience, and has worked in nuclear and wind power generation and electric and gas distribution.