Wild Things - Successful Dressing for Cold Weather (Part 2)

The Protection Layer

While all layers are important, the protection layer—coat, pants, or in some cases a one-piece suit—could be the most important layer in cold weather apparel. No matter how well you layer up, and no matter how well the wicking and insulating layers are doing their jobs, if wind or water is allowed to penetrate you’ll lose body heat at a significantly faster rate. The job of this layer is to protect the body from wind, rain, sleet, and snow, which contribute to loss of body heat and speed up discomfort and cold-related injuries. The protection layer helps the body retain its core temperature by blocking precipitation and wind, but must also allow perspiration to escape and evaporate.

 

Protection Layer Fabrics

Depending upon the climate and environment in which it is worn, the protection layer may simply be a synthetic shell treated to guard against the elements, or it could have various levels of insulation. Waxed cotton was used historically (and is still used today by some brands) but can be heavy and clammy to wear. Because there will always be a trade off between breathability and wind and water resistance—the more weather-resistant a garment is the less breathable it is—choosing this piece of technical apparel based on the environment in which it will be worn is of utmost importance to the wearer’s safety and comfort.

 

Gore-Tex® revolutionized cold-weather gear when it developed and patented the use of a thin, porous membrane that blocked liquid water, such as rain, snow, and sleet, but allowed water vapor, such as sweat, to pass through. This membrane – expanded Polytetrafluoroethylene (ePTFE) – is a remarkable polymer with many uses. Since the Gore-Tex® patent has run out, other manufacturers have developed similar technologies using ePTFE such as eVent®, that use technology that place barriers within or on top of tightly woven, synthetic fabrics, making them both completely waterproof and relatively breathable. A key consideration is the relatively fragile nature of ePTFE. Garment designers have engineered some effective ways to protect the membrane, but care must be taken in high abrasion areas not to wear through the membrane or to puncture the garment. In a nutshell, these materials don’t allow water to get in, but allow sweat to get out.

 

Cotton, nylon, polyester and their various blends that are treated with water-repellent or “hydrophobic” coatings resist water, are breathable and comfortable, but are not as waterproof—and ultimately, not as warm in wet weather—as apparel that uses waterproofing technology. But because they are more breathable, they may be more appropriate than Gore-Tex®, eVent®, and similar technologies in dry environments.

 

For cold conditions, a water-resistant shell can be combined with an insulation layer such as PrimaLoft® for increased warmth. These fills are breathable, warm when wet, durable, and easy to care for.

 

Protection Layer Fit

Because fabrics used in outer shells are typically tightly woven to reduce wind permeability, they tend to be static, without stretch. Some shells include a certain amount of stretch in certain parts of the apparel, such as the elbows and knees, to allow for ease of movement. The protection layer should fit loose, for maximum freedom of movement. It should be roomy enough to easily fit over other layers and body armor. Many garments have some adjustability at the waist and wrists so varying amounts of layers are accommodated. The garment should have an adjustable hood so the head can be covered. Venting in the chest area or under the arms is nice to have if you heat up due to exertion. All seams on a waterproof garment should be sealed, and zippers should have waterproof tape or have flaps over them so they remain watertight.  

 

Special Design Features

The technical apparel worn by law and military personnel must not only protect them from the elements, they must also be able to withstand specific physical and environmental challenges.

 

Those in law enforcement and the military often encounter intense working conditions in addition to extreme climates. In addition to managing the cold, water, wind, and snow, law and military personnel may also face fire or extreme heat, intense sun, projectiles, and enemy detection.

 

To meet the physical challenges of law and military personnel, cold weather technical apparel must be light in weight and low in bulk, durable, cleanable, comfortable, and must have a low noise factor.

 

To meet the environmental needs of law and military personnel, cold weather technical apparel must be water and windproof, snow shedding, thermally insulating and breathable. Depending upon the situation, cold-weather technical apparel should also be rot resistant, UV and NIR light resistant, heat resistant or flame resistant, camouflaging, or able to withstand biological or chemical warfare.

 

Thanks to recent textile technology, cold weather technical apparel has more special design features than ever that ensure law and military personnel are protected and comfortable during operations.

 

Wicking Layer

 

Insulation Layer

 

Protection Layer

 

Part IV: Choosing Your Technical Apparel

 

There’s such a large variety of cold weather technical apparel to choose from that choosing the right apparel can be confusing. To add to the confusion you may not need all layers in all environments, and some apparel will be more appropriate in certain conditions than in others. It is best to think in terms of a core assortment of clothing that meets the needs of your activity and the typical conditions of wherever and whenever you are outside. With this foundation in place, you can then add or subtract a few items to allow you to perform in a broad range of climatic conditions. Knowing you are prepared properly for a range of weather conditions is a significant stress reducer. This confidence allows you to focus on what you need to do and greatly increases your ability to get home safely.

 

In this section we’ll discuss particular environments, their challenges, and what kind of cold weather technical apparel will best serve you.

 

High and Dry/Active

Goals and Challenges: The goal is to retain core body temperature, while also ensuring that any perspiration generated during activity evaporates. Apparel should be loose fitting and as light as possible to avoid weight, and to allow for free and easy movement. Because activity levels will vary, the wearer will want the option of removing layers as core body temperature changes. Because moisture is not a problem in this environment, the wearer should choose technical apparel that is as breathable as possible, and need not worry about sacrificing breathability for the ability to repel water.  

 

Wicking Layer

 

Good choices: polyester, and wool, which are warm but also allow perspiration to evaporate. These materials will help keep you dry no matter how much you sweat.

 

Avoid: Cotton. While this natural fabric is breathable and comfortable, is has no wicking ability whatsoever. Any sweat generated will soak into the fabric and remain wet, which will cause the body to lose heat at a faster rate when temperatures drop, or when activity levels decrease.

 

Insulating Layer

 

Good choices: Fleece and wool are excellent choices, as they are breathable and comfortable, dry quickly if perspiration becomes an issue, and also come in a variety of weights depending upon the environment. Insulating layers that include fill materials such as PrimaLoft® are warm, light, thin, and are also fairly breathable if you sweat. Wind treated apparel, such as hard fleece, are good in windy areas.

 

Avoid: Down. Down will retain sweat during activity. Once down is wet, it loses its insulating properties.

 

Protection Layer

 

Good choices: Tightly woven outer shells made with fabrics such as nylon or polyester with a good DWR that are breathable rather than waterproof are the best options. Since water is not an issue, there is no need to sacrifice breathability for the ability to repel water. A tightly constructed fabric will provide wind resistance while retaining breathability. In very cold conditions, you may want to consider a breathable shell that has some form of insulation, such as PrimaLoft® or Climashield®.

 

High and Dry/Sedentary

Goals and challenges: This is one of the least challenging atmospheres to dress for. The focus should be on warmth first, with breathability second. Since the wearer will have less opportunity to generate or maintain body heat through exercise, loose, insulating layers should be the focus.

 

Wicking Layer

 

Good choices: Body hugging polyester, polypropylene, or wool base layer will provide maximum warmth, but will also allow sweat to evaporate if temperatures change and the wearer becomes overheated.

 

Avoid: Cotton. Cotton is not as warm as the other fibers, and should it become moist with sweat, will cause the sedentary wearer to lose body heat at an alarmingly faster rate when temperatures drop.

 

Insulating Layer

 

Good choices: Down has the best warmth-to-weight ratio, is very lightweight, and is easily compressed if it needs to be packed and carried. Non-active wearers don’t have to worry about moisture from perspiration compromising the insulating properties of down. Wool, fleece, and insulating layers made with polyester fill are also good choices.

 

Avoid: There are no insulating layers that need to be avoided in this environment.

 

Protection Layer

 

Good choices: An insulated outer layer, such as ripstop nylon or polyester filled with down, or a layer of insulation such as PrimaLoft® will provide warmth and breathability.

 

Avoid: Shells that completely waterproof aren’t necessary in this environment, and can cause breathability to be compromised.

 

High and Wet/Active

Goals and challenges: The goal of technical apparel for those working in this environment should be to keep the elements out, while also allowing perspiration to evaporate.

 

Wicking Layer

 

Good choices: polyester, wool

 

Avoid: Cotton.

 

Insulating Layer

 

Good choices: Fleece or wool, which disperses water molecules among its fibers and dries quickly. Hard fleece, which combines soft, wicking inner properties of traditional pile fleece with the water-repellant outer properties of a synthetic shell is an excellent choice. Even though it is wet outside, if the wearer is active, the insulating layer does not need to be as thick and warm as when the wearer is sedentary.

 

Avoid: Down, which loses its insulating properties when wet. Synthetic insulation will be too warm during activity but could be an additional layer when exertion stops.

 

Protection Layer

 

Good choices: Waterproof fabrics that put moisture barriers inside the fabric, allow the fabric to be completely waterproof but somewhat breathable. Shells that have been treated with water repelling coatings are also good choices, and are very breathable, particularly for very active wearers. The wearer will have to gauge the particular environment, to determine whether it is worth it to sacrifice some breathability to be completely waterproof.

 

Avoid: Down

 

High and Wet/Sedentary

Goals and challenges: The goal in this situation is to stay warm and dry. Because perspiration is less of an issue, the wearer can feel more comfortable choosing apparel that is completely waterproof.

 

Wicking Layer

 

Good choices: polyester, wool

 

Avoid: Cotton, which will not be able to manage moisture.

 

Insulating Layer:

 

Good choices: Hard fleece, fleece, wool, and synthetic insulation.

 

Avoid: Down

 

Protection Layer

 

Good choices: Outer shells that are completely waterproof, such as those made with Gore-Tex®, eVent®, or other similar technologies. Because the wearer is not maintaining core temperature through activity, a shell with an insulating fill such as PrimaLoft® is ideal.

 

Avoid: Down, due to its inability to maintain insulation when wet, as well as apparel that is water repellant but not completely waterproof. In an environment that is cold and wet, the sedentary wearer should look more toward warmth and dryness than breathability.

 

Maritime Climate/Active

Goals and challenges: This is one of the most challenging environments to dress for, as the goal is to remain dry but also allow sweat to evaporate. In this environment, a mistake made in choosing clothing can make you very uncomfortable.

 

Wicking Layer

 

Good choices: Polyester, or wool for wicking sweat.

 

Avoid: Cotton.

 

Insulating Layer

 

Good choices: Fleece, wool, or hard fleece, all of which are excellent at drying quickly, evaporating perspiration, and retaining insulating properties when wet. Hard fleece is a particularly good option in this environment, as the soft synthetic outer shell provides a barrier against wetness, but also allows perspiration to adequately evaporate.

 

Avoid: Down.

 

Protection Layer

 

Good choices: Synthetic shells treated with water repellant coatings, or waterproof technical fabrics such as Gore-Tex® or eVent®. In maritime environments, it is very important for the wearer to determine the potential degree of moisture encountered, as well as the activity level. Those with very high activity levels in environments that are damp or humid but not soaking wet may want to choose a water-repellant shell that is more breathable, while those in cold, very wet environments may want to sacrifice breathability for apparel that is totally waterproof.

 

Avoid: Down, or plastic. While it may be tempting to layer a completely waterproof plastic shell over a wicking and insulating layer, it’s a poor choice. Plastic will keep you completely dry, but has absolutely no ability to evaporate sweat, making the wearer clammy, cold, and at risk of losing body heat at a faster rate. Technical fabrics are more expensive, but will provide the breathability active wearers need to stay warm and comfortable.

 

Maritime Climate/Sedentary

Goals and challenges: The goal in this environment is to stay dry and warm. Because perspiration is less of an issue, the focus should be on waterproof apparel first.

 

Wicking Layer

 

Good choices: polyester, or wool.

 

Avoid: Cotton

 

Insulating Layer

 

Good choices: Fleece, hard fleece, and wool.

 

Avoid: Down

 

Protection Layer

 

Good choices: Outer shells that are completely waterproof, such as those made with Gore-Tex®, eVent®, or other similar technologies. Because the wearer is not maintaining core temperature through activity, a shell with an insulating fill such as PrimaLoft® is ideal.

 

Avoid: Down or plastic.

 

Windy

Goals and challenges: To minimize exposure to wind, in order to better retain core body temperature in cold weather.

 

Wicking Layer

 

Good choices: polyester, or wool.

 

Avoid: Cotton.

 

Insulating Layer

 

Good choices: Hard fleece puts a tightly woven synthetic, soft shell material over the softer fleece to protect from the wind. Some fleeces also include special hidden membranes designed specifically to deal with wind, such as Windbloc® and Windstopper®. A synthetic fill insulated garment with a water and wind resistant shell fabric. This combination provides warmth and some weather protection.

 

Avoid: Pile fleece, which is very wind-permeable, unless wearing it under a wind layer.

 

Protection Layer

 

Good choices: Tightly woven shell fabrics. Note that some level of air permeability may be a good thing as it will enhance the comfort range of the product. A completely windproof product will be warm as you start to move.

 

Cold Rain

Goals and challenges: The goal is to stay warm and dry. Apparel that is completely waterproof should be chosen over other types of technical apparel. In this situation, you’ll have to sacrifice some breathability in order to stay completely dry from the outside.

 

Wicking Layer

 

Good choices: polyester, wool

 

Avoid: Cotton

 

Insulating Layer

 

Good choices: Hard fleece, fleece, wool.

 

Avoid: Down

 

Protection Layer

 

Good choices: Outer shells that are completely waterproof, such as those made with Gore-Tex®, eVent®, or other similar technologies. Because the wearer is not maintaining core temperature through activity, a shell with an insulating fill such as PrimaLoft® is ideal.

 

Avoid: Down or plastic.

 

 

 

 

 

 

 

 

           

 

 

Sources

 

http://www.manfredkaiser.com/cold_and_body.html

http://www.manfredkaiser.com/cold_and_body.html

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http://www.mayoclinic.com/health/frostbite/DS01164/DSECTION=symptoms

http://www.princeton.edu/~oa/safety/hypocold.shtml

http://www.coolantarctica.com/Antarctica%20fact%20file/science/cold_humans.htm

http://www.uihealthcare.com/topics/medicaldepartments/internalmedicine/acclimatization/index.html

http://blog.peertrainer.com/tip_of_the_day/2010/02/does-cold-weather-cause-your-body-to-store-more-fat.html

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www.exploretextiles.ca

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http://www.millikenmilitary.com/products/Pages/extreme-cold-weather.aspx

www.rei.com