Staying Warm

Norwegian polar explorer Roald Amundsen said, “There is no such thing as bad weather, only bad clothing.” Following this logic and considering the fabric and technology available today, our employees should never be cold if they are properly dressed.

The new buzzword among those using extreme cold weather (ECW) clothing is “ensemble.” In reality, the idea of the ECW ensemble mimics good, old-fashioned layering with the latest insulating and wicking materials that already have been in use for winter sports.

When choosing cold-weather clothing, there are three main principles to follow to keep warm. First, the clothing should work together as a unit. Dress to meet the expected conditions. The amount and duration of physical work that will be done and the weather conditions that will be encountered are important factors. For example, an employee working in freezing rain will have different clothing requirements than an employee working in a dry, cold environment.

Second, it is helpful to understand the role of each layer of clothing.

• Inner layer: Dry skin tends to be more comfortable and feel warmer than damp or wet skin, so sweat should be transferred from the skin to the middle and outer layers of clothing. It is important that the inner layer be permeable to sweat or allow sweat to move through the fabric. Moisture remaining in the inner layer’s material can decrease the layer’s ability to insulate by as much as 30 to 50 percent because wet clothing transfers more heat. Materials that are commonly used as the inner layer include polyester and silk.

• Middle layer: This layer is mainly for insulation to trap warm air close to the body. Materials that lend themselves well to being used in the middle layer include fleece, pile, wool or thick polyester. A good way to increase the insulating ability of the middle layer is to use multiple thin layers of material instead of a single thick layer.

• Outer layer: The main function of the outer layer is to provide protection against wind and moisture. By keeping the inner layers of clothing dry, the outer layer allows the clothing to keep the wearer warmer and more comfortable. Good material choices for the outer layer include Gortex, 60/40 cloth, polytetrafluoroethelyne (PTFE) laminate and nylon.

It is important to remember that, when working with electricity, it may be necessary to factor in the need for fire-retardant clothing. This potential need is important when choosing the material for all layers. Natural fibers should be used (cotton, wool and silk), and synthetics should be avoided.

The third, and perhaps most important, factor of staying warm is to minimize the accumulation of moisture in the clothing. To accomplish this, wear layers of clothing that serve the right purposes. The appropriate layers need to be designed with plenty of ventilation. The outer layer of clothing should have a way to ventilate and allow sweat to be released. Ventilation is typically accomplished through “pit zips” (zippers placed in the armpit area), opening sleeve ends and front zippers.

Layering can be the key to employees staying comfortable, warm and dry throughout the workday. Typically, an employee will start the workday straight from home and will have piled on the layers. Once physical work begins, the employee will begin to heat up, and sweat and moisture will accumulate in the clothing. At some point, the employee gets too hot and removes layers to cool down. The remaining layers are wet with sweat and will cause a rapid and uncomfortable heat loss. The employee may then redress in the discarded layers of clothing. He or she may heat up again, and the process repeats.

Avoid this cycle by proactively layering clothing. When starting the day, don’t put on all the layers or remove a few knowing that once work begins the body will naturally heat up and a comfortable temperature will be reached with a minimum of moisture accumulation. As the day unfolds, the number of layers can be adjusted to match weather changes as well as changes in employee activity level.

Maintenance is the key to keeping the layers of the ECW in good shape for the long haul. All layers should be dried or allowed to dry thoroughly before they are worn again. Any physical problem or damage to the material of a garment will decrease its effectiveness in keeping the body warm and dry. If possible, the damage should be repaired, or the piece of clothing should be removed from service. It also is important to consult manufacturer’s recommendations for special care instructions. Many materials used for the outer layer, e.g., Gortex, need to be washed periodically to remove dirt from the pores in the material, so it can work properly.

By following these simple ideas on layering, our employees can stay warm, comfortable and safe throughout the coldest of winters.

KELLY is a safety and health specialist with Intec, a safety consulting, training and publishing firm that offers on-site assistance and produces manuals, training videos and software for contractors. She can be reached at 800.745.4818 and Joe O’Connor edited this article.

About the Author

Diane Kelly

Safety Columnist
Diane Kelly is a safety and health specialist with Intec, a safety consulting, training and publishing firm that offers on-site assistance and produces manuals, training videos and software for contractors. She can be reached at 800.745.4818 or dkell...

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