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January 3, 2007

Technical Clothing

What is technical clothing, and why should I care?

Technical clothing, sometimes called high-performance clothing, is designed to keep the wearer dry and at a comfortable temperature (a characteristic known as thermoregulation) regardless of weather conditions.

To illustrate the benefits of technical clothing, consider the standard cotton t-shirt worn practically as a Saturday uniform in some areas. It feels great against the skin when you put it on, but as soon as it becomes damp with perspiration or rain and is allowed to cool (particularly in the shade), it becomes clammy and uncomfortable. In comparison, a shirt made from a synthetic fabric like polyester or nylon will wick moisture away from the skin to the surface of the fabric where it evaporates, keeping the wearer dry and comfortable.

 
What’s the big deal with layering?

Technical clothing works best when worn in layers. Layering simply means to wear a number of garments in place of a single heavy garment. This strategy provides great flexibility, as layers can be added or removed to accommodate a wide range of temperatures. In contrast, a heavy coat is really comfortable only when the temperature is very cold. Layering is used for both the upper and lower body, so don’t neglect your legs. Generally speaking, a layering system has three components: a base layer, an insulating layer, and an outer layer, though you may be able to skip one or two, depending on the weather.

1) Base layer

Description: This layer lies directly against the skin, where it wicks moisture to the surface of the fabric. In many cases, the base layer hugs the body to facilitate the wicking process. Lighter-weight fabrics are perfect for cool days when the wearer is highly active, while heavier base layers work best on very cold days when the wearer is still (such as watching a December football game in Green Bay, Wisconsin).

 Materials: Synthetic fabrics like polyester and nylon are popular base layers due to their wicking abilities, but over the last several years, Merino wool products have impressed the experts. Wool, unlike its synthetic counterparts, remains warm against the skin when wet (though it does take a long time to dry). Unlike traditional wool, the extremely fine fibers of Merino wool do not feel itchy against the skin.

 2) Insulating layer

Description: Most of the warmth in a layering system comes from this garment, which can come in the form of a sweater, pullover, vest, or jacket. If the temperature outside is mild, you may skip the insulating layer altogether, and for slightly colder temperatures, an insulating vest may do the trick, but in truly cold conditions, an insulated jacket or pullover is best.

 Materials: The most popular insulating layer material these days is synthetic fleece. This fuzzy and lightweight polyester material was invented over 25 years ago by Massachusetts-based Malden Mills, and has undergone considerable refinement over the years.

 If you think your fleece jacket may occasionally act as an outer layer, consider one made with a wind-resistant fleece fabric. These products incorporate an additional breeze-blocking membrane, making them perfect for spring or fall walks along the lake.

For cold conditions, consider insulating materials like goose down and high-loft polyester fiber. Each is very warm, but down can't be beat for warmth-to-weight ratio. However, unlike unlike polyester insulation, down loses most of its insulating value when wet.

3) Outer layer
 
Description: The outer layer, sometimes called a shell, is a thin jacket designed to keep wind and water out while remaining “breathable” (i.e., they permit moist air from within the jacket to escape through the fabric). There are two types of outer layers:

 Hard Shell: Hard shells excel at blocking exterior wind and water, while allowing perspiration to escape through the fabric as vapor. If heavy precipitation is in the forecast, a hard shell is the best choice. Unfortunately, even the most breathable of hard shells can become uncomfortable in cold weather when perspiration condenses on the inner surface of the jacket. Some manufacturers add a napped inner surface to minimize the clammy feel.

Hard Shell Materials:

Hard shells are made of two or three thin layers of material laminated together, one of which is a semi-permeable membrane. Perhaps the best-known hard shell laminate is Gore-Tex®, but a number of competitors have emerged, such as, eVentT, ConduitT, and HyVentT. Whether one laminate brand is more effective than any other is debated at length by outdoor enthusiasts.

Soft Shell: Soft shells, in contrast, while exceptionally breathable, are unable to repel heavy rains. Water beads on the surface of soft shells in light showers, but saturates the fabric in a downpour. Unless you live in an area where it rains every day, a soft shell is a great choice. They are more comfortable to wear and make less of a rustling noise as you walk than hard shells, and in some cases, are warm enough to eliminate the need for an insulating layer.

Soft Shell Materials:

For information on soft shell fabric choices, read Soft Shells: We love 'em! by outdoor retailer The Alpineer. There are many high-tech soft shell fabrics available, and The Alpineer provides a great summary of the soft shell materials available and their suitability for different situations.

 
What should I look for when buying technical clothing?

• Fit:  Make sure the garment is fit appropriate for its use. Don’t buy a form-fitting hard shell for winter (no room for layering) or a too-baggy base layer (perspiration can’t wick efficiently if your base layer isn’t close to the skin).

•  Ventilation: If you will be active while wearing the garment, make sure the item’s fabric breathes well (e.g., is a soft shell) or that it can zip open to allow a breeze to enter. Specifically, look for “pit zips” (see Figure 2) near the underarm of jackets, or outer seam zips on pants, each of which facilitates air movement.

•  Waterproof zippers and sealed seams: If a shell garment is designed to be waterproof, the manufacturer should take precautions to keep water from entering through zippers or seams.

•  Durable Water Repellent (DWR) coating: Many technical insulating layers and soft shells gain their water resistance through DWR, a fabric coating which causes water to bead on the surface.

 
Resources

• Outdoor Clothing & Footwear Recommendations by Mark Verber. An outdoor enthusiast’s specific recommendations for layering technical clothing.

Posted by moetting at 10:07 AM