Wool and merino wool are excellent insulating fabrics (Figure 93-2, online). The core of the wool fiber absorbs moisture and redistributes it to the fabric surface, where evaporation occurs. This moderate affinity for absorbing moisture is countered by excellent regain—the fabric retains warmth and does not feel cool or wet when damp. Wool feels wet when saturated. Traditional wool can be highly irritating to the skin. Wool fibers have barbs in the epicuticle, or outer layer of the fiber. Merino wool is a finer fiber with fewer barbs in the epicuticle. Ultrafine merino wool fibers are 17.5 µm in diameter, allowing for lightweight fabrics and exceptionally tight weaves. (For comparison, a human hair is 60 µm in diameter.) Merino wool is machine washable with minimal shrinkage and is highly elastic. It retains its shape well with repeated wearing and washing. The antibacterial properties of wool contribute to decreased body odor retention—a very desirable quality when faced with multiple days of wear. The bacteria that metabolize sweat do not flourish; therefore less odor-producing metabolites are present.

FIGURE 93-2 Icelandic sheep.

Wool, including merino wool, is spun from the fleece of sheep. Alpaca and llamas are camelids, originally from South America (Figure 93-3). Cashmere is spun from the undercoats of cashmere goats. Although technically not wool, these wool-like fibers share similar properties with Merino wool.

FIGURE 93-3 A, Peruvian llama overlooking Machu Picchu. B, Peruvian llama.

Silk is used most commonly in base layers. Conventional, untreated silk retains moisture, although not to the degree of cotton. The majority of silk used for outdoor clothing is treated and wicks reasonably well. Silk is frequently blended with other fibers to smooth the texture of the fabric.

Down

Down is the fluffy undercoating that keeps geese, ducks, and other waterfowl warm (Figure 93-4). It consists of clusters of filaments growing from a central quill point. Land fowl do not produce down. Goose down is superior to duck down in its loft and therefore ability to insulate. Down is an excellent insulator when dry. Unfortunately, the low moisture regain and hydrophilic nature of down make it almost useless when wet. The insulative value of down is measured in fill power. Each company uses a slightly different measurement, making across-the-board comparisons difficult. Generally, the higher the fill power, the greater the insulative value. Fill power is the volume that a specific weight of down occupies. In other words, the number of cubic inches displaced by a given ounce of down (in³/oz) is the fill power.

FIGURE 93-4 Down puff.

The highest-quality down has a fill power of 800 or greater and is usually goose down. Lower-quality products use duck down. A 600–fill power garment may be as warm as an 800–fill power garment, but more down is needed to achieve the same warmth, thus the garment will be heavier. Down is the preferred insulation in cold, dry environments when rain is highly unlikely.

Fur, Leather, and Hides

Historically, protective clothing was made from animal products. Hides, feathers, and even intestines have been used to make garments. Northern indigenous peoples continue to use fur and pelts for outerwear. Pelts and hides are water resistant, warm, and physically protective. However, they are heavy and may be considered cumbersome. They demonstrate little flexibility or stretch. Fur trim may still be used around hoods and the sleeve cuffs but has largely been replaced with wool fleece or synthetic fibers. These trims trap air, which stagnates and warms, forming an insulating area around the face and wrists.

Leather is the finished product of tanned hides. It may be made from any animal, with cow, goat, and sheep being the most common. Leather, depending on the finishing process, can be exceptionally soft, supple, and thin, or it can be tough, thick, and abrasion resistant. Leather is commonly used in the manufacture of footwear and gloves, capitalizing on its durability. However, synthetics have replaced leather in most outdoor clothing. Abrasion-resistant nylon is now used on the cuffs, shoulders, and elbows, where leather may have been used in the past. Leather jackets and pants are still very common for motorcycle gear, and thick leather pants or chaps are still used by woodsmen. Leather is not water resistant and becomes readily saturated unless treated with agents such as mink oil, Sno-Seal, or other oil-based products.

Synthetic Fibers

Polyester is the general term for any petroleum-based fiber. It is widely used in the outdoor industry and highly versatile. Fibers are extruded or formed, not spun as are natural fibers. The fibers can be formed into nearly any thickness or configuration. Polyester fabrics insulate well because the fibers do not conduct heat efficiently. The fibers do not actually absorb any moisture. The moisture travels along the surface of the fiber and out to the surface of the fabric. Polyester fabric dries very quickly. These properties are used to their full advantage when polyester is made into fleece and sheets of insulation. Fleece is soft, washable, and durable. Bulky fleece traps air and is exceptionally warm for its weight. When fleece is tightly woven, wind and water resistance improve, but insulative value is diminished.

Polyester that is formed into sheets of insulation may be sewn into the layers of a garment. Polyester insulation has high moisture regain and good evaporative qualities; however, it is not as light or compressible as down. The fibers may deteriorate and break down with repeated use and washing and thereby lose the insulative value. Both down and synthetic insulations must be stored noncompressed. Prolonged compression damages both down and synthetic fibers, causing loss of loft and insulation.

Polypropylene was one of the first synthetic fabrics used for base layers. It wicks moisture well, has low thermal conductance, and is durable. Unfortunately, it demonstrates high odor retention and stains very easily. Other polyester fabrics, such as Capilene, Polartec, Coolmax, and REI MTS, have largely replaced it.

Nylon, like polyester, absorbs little water, which permits rapid evaporation. It has high moisture regain, is highly abrasion resistant, and melts easily. Nylon can be formed into large-diameter fibers and woven into highly durable fabrics, which are frequently used to reinforce wear points. Nylon must be tightly woven to protect against wind and water. This comes at the expense of breathability.

Blends

Manufacturers blend fiber types to use the benefits of each fabric. For example, spandex may be blended with the primary fiber, such as wool or cotton, to improve stretch and retention of shape. Wool may be blended with polyester to improve durability and fit (Tables 93-1 and 93-2).

TABLE 93-1 Comparison of Synthetic Fabric, Wool, and Silk

TABLE 93-2 Comparison of Down with Synthetic

	Down	Synthetic
Compressibility	Excellent	Good
Insulative quality when wet	Poor	Good
Weight	Lighter per volume	Heavier than down
Durability	Will last longer if cared for properly	Will eventually break down even with ideal care
Care	Requires careful laundering	No special product required
Warmth	Greater warmth-to-weight ratio
Allergenic properties	Possible	None
Expense	High	Moderate
Drying time	Slow	Fast

Waterproof/Breathable Fabrics

Waterproof/breathable fabrics are designed to repel precipitation and allow perspiration, in the form of water vapor, to escape. These actions help to regulate body heat by keeping clothing dry and preventing perspiration from accumulating within the clothing during exertion in rainy environments. Fabrics are made waterproof/breathable through the application of laminates, coatings, and durable water-repellent (DWR) finishes.

Laminates

Laminate fabrics are designed by bonding a waterproof/breathable membrane to the underside of the garment’s exterior. They are commonly bound to nylon. If there are only two layers, the fabric is designated “two-ply.” The laminate may be sandwiched between two layers, thus creating a three-ply material, which is more durable but heavier than two ply. W. L. Gore and Associates produced the first waterproof/breathable membrane—Gore-Tex. This trade name is commonly, and incorrectly, used to refer to the entire category of laminate clothing (Figure 93-5). Although many manufacturers and laminate types now exist, the basis of laminate technology is the membrane. The membrane is formed of stretched or expanded polytetrafluoroethylene (ePTFE). The process of expanding the PTFE introduces microtears or holes in the laminate. These openings are small enough to allow water vapor of perspiration to escape (breathability), while not allowing water droplets to enter from the environment (water resistance). The pores of the ePTFE are 20,000 times smaller than the smallest raindrop, yet large enough to allow water vapor to pass to the outside. Water can only penetrate ePTFE if it is applied with a great deal of force or if the surface of the ePTFE is contaminated or soiled, leading to leakage. Two of the predominant manufacturers, Gore and eVent, use different methods to address soilage. Gore applies a microthin layer of polyurethane to the laminate. It is designed to be porous and not affect breathability of the fabric. eVent uses a proprietary method employing integration of a substance into the laminate itself. By preventing soilage, the waterproof and breathable properties of the fabric are sustained.

FIGURE 93-5 Arc’teryx Alpha LT hard-shell jacket is a lightweight and fully waterproof jacket with the harness HemLock feature, ideal for use with a climbing harness. A light, three-layer Gore-Tex shell.

(From http://www.arcteryx.com.)

Coated Fabrics

Coatings are liquid solutions, predominately polyurethane, that are applied to the interior of the garment. Microporous coatings are formed of microscopic channels that are too small for droplets to penetrate yet porous enough to allow vapor to escape. These channels form as the coating adheres to the surface of the fabric, either secondary to foaming agents that form interconnected pores or to introduced solids that cause microscopic cracks in the coating. Monolithic coating agents form a hydrophilic layer that transports moisture to the surface. Microporous and monolithic coating methods are virtually indistinguishable. Some manufacturers use both methods. Coated fabrics are not as breathable as laminates and are generally not as durable. However, they are more compressible and significantly less expensive than laminate fabrics.

Rubberized nylon is coated with a robust polyurethane lining that is not breathable but is waterproof. This fabric is ideal for marine environments and sedentary activities, when sweat accumulation is less of an issue for temperature control.

Soft-Shell Fabrics

Soft-shell fabrics are the most newly developed fabrics in the outdoor clothing industry. This fabric type excels in breathability and flexibility yet still demonstrates moderate water resistance. Soft-shell fabrics have a tightly woven outer layer and an inner lining of varying insulative quality and may additionally employ a windproof or highly water-resistant laminate (Figure 93-6, online). They combine the properties of both an insulating middle layer with a protective outer layer. Soft-shell garments are highly effective for both temperature and moisture management in environments where rain is unlikely. They are moderately water resistant due to the tightly woven exterior surface and DWR finish. These garments excel when used during highly aerobic activities and in conditions where rain is not a concern. Soft-shell garments may function as both an insulating (middle) and outer (protective) layer.

FIGURE 93-6 The Arc’teryx Gamma AR jacket is a highly breathable, insulated, soft-shell jacket with anatomic shaping for maximum mobility.

(From http://www.arcteryx.com.)

Durable Water-Repellent Finish

A DWR finish is applied to all waterproof/breathable fabrics after the garment is completed. It does not change breathability of the fabric but enhances water resistance by causing water to bead up and roll off the garment’s exterior. The finish bonds to the fibers and does not fill the interstitial spaces of the fabric. An ideal DWR finish forms a dense chemical buffer on the outer surface of the garment. Microscopically, the finish forms an upright, spiky, and brush-like texture. Water thereby has a high contact angle with the finish, forming a spherical droplet. Were the contact angle to be low, water droplets would flatten into a more dome-like shape. This would allow the water to cling to the surface of the fabric and eventually seep in (Figure 93-7).

FIGURE 93-7 Watertight zipper and fabric with durable water-repellent finish.

Layering

Dressing in layers enhances one’s ability to adapt to a changing environment. Each layer should maximize the properties of the fabric from which it is made. Layering allows for addition and subtraction of clothing as needed, adjusting for changes in body temperature and metabolic output, resulting in more efficient maximization of metabolic heat and enhancement of energy conservation. Adjustment of layers in response to changes in the environmental or travel conditions can prevent sweating and overheating, while preventing loss of heat that might lead to undesired cooling. In anticipation of increased body heat and sweating when traveling uphill, layers can be preemptively removed and zippers unzipped to enhance ventilation. Clothing that becomes saturated in sweat is not only uncomfortable, but loses its insulative properties as the fibers become soaked with moisture. This is clearly important in a cold environment, where loss of insulation or long drying times may lead to hypothermia. Removing layers in response to increased work also serves to conserve energy and moisture. In contrast to removing layers to prevent sweating, adding clothing layers as the workload decreases or the environment cools allows heat to be trapped in the insulative layers. The simple actions of managing a personal layering system conserve valuable energy for outdoor endeavors (Figure 93-8, online).

FIGURE 93-8 Sarah Hueniken keeping warm layered up in Outdoor Research clothing between climbs.

An efficient layering system allows rapid response to changing environmental conditions. It is easier to replace a single garment that has become soiled or saturated than to replace an entire suit of clothing. Through layering, it becomes possible to not only pack fewer garments, but still be more comfortable across a wider range of environmental conditions and activity levels. When packing for any wilderness excursion, the unexpected needs to be considered, such as precipitation in the form of rain or snow, a sudden change in temperature, or the unexpected night out. When dressing in layers, fit is very important. The base layer should be snug but not confining. The middle layer should fit over the base layer comfortably. The outer layer needs to be large enough to fit over both base and middle layers without compressing. Compressing the middle layer reduces its insulative properties. Harness or pack straps should not rub or chafe on any seam or fold of fabric. Testing the fit, comfort, and effectiveness of the layering system before venturing into the wilderness will help prevent not only the discomfort of poor-fitting layers, but ensure that the purpose of the layering system is fulfilled—keeping one warm and conserving energy (Box 93-2).

BOX 93-2 Insulating Value of Clothing

The insulating value of clothing is measured in clo. Clo was first defined in 1941 as a more descriptive measure of thermal resistance for clothing. One clo is the amount of clothing necessary for a sedentary person to be comfortable in an environment with an ambient temperature of 21.1° C (70° F), a relative humidity of less than 50%, and normal ventilation (air movement measured at about 0.5 mph). A lightweight business suit has an approximate clo value of 1.0. The lowest clo value is 0.0 and is that of a naked individual. The highest practical clo value (4) is that of Eskimo fur clothing. Today’s manufacturers rarely use clo as a comparative unit. Polartec grades its fleece by 50, 100, 200, and 300; other manufacturers grade garments by light, mid, and heavy weight. Comparing garment type is more practical for most users. What follows are some generalities about different layer types.

	Approximate clo Range	Garment Example
Base	0.15-0.3	Silk weight, cotton T-shirt
Lightweight	0.30-0.50	Polartec 100, Patagonia R1
Midweight	0.75-0.85	Polartec 200, MontBell Thermawrap parka
Heavyweight	0.90-0.11	Polartec 300, Patagonia Polarguard Delta pullover
Expedition	1.40 and greater	Patagonia down pullover and most high-loft insulation

Base Layer

The base layer is next to the skin. It may be as sparse as briefs and a sports bra or as extensive as full-coverage long underwear. The primary function of the base layer is to regulate body temperature by retaining heat and transferring moisture away from skin (Figure 93-9). Moisture management is accomplished by the wicking properties of the fabric. Moisture is drawn away from the skin surface by the hydrophilic properties of the fiber. The hydrophobic properties of the fiber transfer, or “wick,” moisture to the outer surface to be evaporated. This layer must fit without binding seams or wrinkles, allowing for ease of movement without restrictions. Usual base-layer fabrics are supple and flex easily with motion. Most good insulative base-layer garments are made of polyester, merino wool, silk, or a blend of fiber types. Poor base-layer garments are made of fabrics that lose their insulative properties when wet, such as cotton.

FIGURE 93-9 Changing daytime temperatures and varying levels of physical exertion mandate being able to add and remove layers. Dr. Scott McIntosh, Super Sherpa Expedition, Mt Everest.

Base layers are available in ultralight, light-, mid-, and expedition weights. The weight of a garment is a relative measure and varies among manufacturers (see Box 93-2). The choice depends on the activity and environmental conditions. In mild and moderate conditions, a lightweight or midweight layer is appropriate. In conditions of extreme cold, a heavier base layer that maximizes heat retention is preferred. Base layers may have zippers for ventilation. If aerobic, vigorous, and heat-producing activity is likely, consider choosing a top with a zipped neck. This allows increased air movement around the neck and can be rapidly closed to restore protection. Bottom layers are available with zippers or overlapping flaps of fabric to facilitate heat and moisture elimination. With a properly fit system, significantly less skin is exposed to the cold, and harnesses do not need to be removed. One-piece base layers cover both top and bottom with a single garment. Most are designed with long zippers to allow ventilation and elimination. Generally these garments are suited only for extreme cold, where even the chance of exposure through a waistline gap would be dangerous.

In a hot environment, the base layer continues to serve as a key tool for temperature regulation. The choice of a predominantly hydrophilic fabric, such as cotton, enhances evaporative cooling. Cotton’s moisture retention and slow drying time are negative qualities in a cool or cold environment but can be ideal in a hot environment. Base layers employed in hot weather should be loose fitting so as not to retain excess body heat.

Middle Layer

The purpose of the middle layer is insulation. As with the base layer, it is chosen with consideration of the environment, activities being performed, and personal metabolic needs. The middle layer may consist of multiple garments. This is most common when highly variable conditions are expected. A heavy shirt and vest or two midweight garments are significantly more versatile than a single fleece jacket. Wool is a soft and warm material, providing reliable warmth and retaining most of its insulative value when wet. Fleece and other synthetics dry relatively quickly and have a higher warmth-to-weight ratio than wool, but tend to be bulkier. The middle layer retains heat by trapping air next to the body. Fleece fabrics do this well. Down and synthetic fill jackets operate on the same principle. Air is trapped in the space between the down or polyester fibers. Down performs superbly in a dry, cold environment but is useless when wet. Synthetic fiber insulation retains much of its insulative properties when wet and dries quickly.

Overall design and special features should be considered. Zippers augment ventilation by exposing the neck, or in the case of a full zipper, the entire torso. Zippers add weight but make it much easier to add or subtract the layer without removing boots or crampons. Pockets are useful for carrying small items; however, they need to fasten closed to prevent item loss. Vests warm the core while leaving the arms less encumbered. Insulating pants are commonly available in fleece or other synthetic blends. The durability of fleece is improving, and many garments are manufactured with reinforced knees, ankles, and seats.

The fit of the insulating layer determines comfort and functionality. The garments need to fit well, without excess wrinkles or folds, and allow unrestricted movement. Zippers should line up, or at least be accessible, when attempting to reach inner layers. The fit of packs and harnesses should be considered.

Outer Layer

The outer layer provides protection from dirt, dust, wind, rain, and snow. Protection from wind and water does not depend on fabric thickness, but upon tightness of weave. Unfortunately, the tighter the weave, the less breathable the fabric. Moisture does not wick or ventilate away from the skin or middle layers. Protective outer-shell fabrics, commonly called “hard-shell,” are tightly woven and abrasion resistant. These laminated fabrics are designed to allow water vapor to pass through their micropores, while not allowing water droplets to penetrate through from the outside. The fabric’s breathability can be overcome if used during vigorous exercise. Sweat may condense on the inner surface of the garment. Similarly, if exposed to very heavy rain, the garment may fail to be completely water repellent. To combat condensation of sweat, outer layers are designed to ventilate excess moisture through vents and armpit zippers. When a person is sedentary, or little physical activity is expected, a coated nylon rain shell is an option. Polyurethane and rubberized nylon are essentially waterproof but allow no ventilation through the fabric.

Jacket and parka choices range from light wind-shells to heavy down parkas. The garment needs to fit loosely enough to not compress the middle layers, but without excess bulk that may bind in packs or harnesses. Pockets should zip closed and be roomy enough to hold essential items. Chest pockets need to be accessible while wearing a pack. Zippers may have storm flaps to prevent air from entering through the gaps in the teeth. Many garments are now manufactured with sealing zippers that do not require flaps and thereby conserve weight and bulk. All zippers should be easily accessible, and the wearer should be able to operate them with gloves on. Drawstrings and cuffs prevent wind and snow from entering the garment. Most parkas are hooded. Some have hoods that zip off; others have collars into which the hoods may fold. The hood needs to fit over the head without restricting neck movement. A hood that is too bulky may block peripheral vision. Manufacturers may sew in shock cords to customize fit of the hood across the back of the head and neck. A hood that can be adjusted is ideal in the situation of helmet use. Worn over a helmet, the hood can be fully expanded.

Pants should be loose enough to permit unrestricted movement and have no excess fabric to get caught or tangled in straps, crampons, or brush. Full-length zippers permit removing pants without taking off boots. Hand pockets are rare in technical garments; however, if they are present, they should not rub or chafe. Accessory pockets on the thighs should fasten closed and have minimal bulk. The waistband optimally has little bulk and should not interfere with backpack hip belts or harnesses (Figure 93-10, online). Bibs are another choice. They keep the chest and torso warmer and protect against wind and snow. As with the base and middle layers, many garments have a full fly that zips through to the back of the garment.

FIGURE 93-10 The Arc’teryx Alpha SV Bib for frigid alpine expeditions and absolute weather protection. These high-rising bibs have Gore-Tex Pro Shell fabric from the waist down and a tall Schoeller Dynamic GNS stretch-woven bib for breathable warmth and mobility.

(From http://www.arcteryx.com.)

Multilayered Garments

Manufacturers promote many types of multilayered garments. Soft-shell garments are the most common. These garments are excellent for vigorous exercise when rain is not expected. In wet conditions, soft-shell garments do not perform well. They are water resistant because of a dense weave and DWR finish, but prolonged precipitation will overcome the garment. This necessitates a rain shell to protect the layer. These garments may not provide adequate insulation once the participant is no longer moving. This is not unique to soft-shell clothing. Several manufacturers have designed insulated waterproof garments that combine a down or synthetic loft layer with a waterproof outer layer. These garments are excellent for inclement weather and minimal vigorous exercise.

Accessories

Headgear

Adequate headgear is necessary regardless of the climate, whether to protect from the environment or prevent heat loss through the scalp. Brimmed hats and caps shade the face, ears, and neck from the sun, which is necessary in sunny environments, especially when there are reflective sources such as water or snow. Hats for sun protection need to have a broad enough brim to shade the face, ears, and neck. Ball caps, cowboy hats, and fishing “bucket hats” are common. In mild conditions, thin skull caps and bandanas may be fashioned into headgear. Insulating headgear is manufactured out of most fabrics. As with all other layers, the anticipated environment, activities, and length of excursion need to be considered. Knit hats are made from both wool and/or synthetic yarns and may vary in thickness from microweight to heavy weight. Hats may be lined with a wind-resistant or insulating layer or made exclusively from fleece fabrics. Hats need to fit snugly enough to keep from shifting and blowing off, but not so snugly as to constrict and be uncomfortable. Earflaps and tassels must not interfere with helmet fit; the hat needs to fit comfortably under the hood of an outer layer (Figure 93-11).

FIGURE 93-11 The Arc’teryx Firee Hoody demonstrates a well-fitting attached hood. Shock cords allow maximum adjustability, creating a snug fit around the face and back of the head. Peripheral vision, with or without a helmet, is not blocked. Hoods are attached, detachable, or may roll up into the collar of the jacket.

(From http://www.arcteryx.com.)

Neckwear

Scarves, neck gaiters, and balaclavas are common forms of neckwear. Scarves may range from a cotton bandana to a long woven or knit wrap. Long scarves are useful for full neck, face, and head protection. However, they may be cumbersome and are not appropriate if they may get caught in hardware. Neck gaiters are tubes of fleece, wool, or other knit fabric designed to pull over the head and encircle the neck (Figure 93-12). Neck gaiters retain heat and protect the neck from sun, wind, and cold. Similar to headgear, they need to fit well, not be too snug, and allow for helmets and other protective gear to be worn comfortably. The balaclava is an integrated head and neck layer, perhaps best described as a very long hat with an opening for the face (Figure 93-13). It is a versatile accessory and when pulled down around the neck has no openings around the neck or scalp to allow escape of warmth or entry of cold air. Hats may have an integrated skirting or tails to cover the neck and ensure that there is still adequate airflow.

FIGURE 93-12 The Arc’teryx Rho LTW Neck Gaitor (95% wool, 5% Spandex) keeps snow out and retains warmth.

(From http://www.arcteryx.com.)

FIGURE 93-13 Outdoor Research WS Gorilla Balaclava.

(From http://www.outdoorresearch.com.)

Eyewear

See Chapter 94.

Handwear

Gloves and mittens provide physical protection from cuts and scrapes and environmental protection from frostbite and sunburn. Handwear ranges from thin cotton, wool, or synthetic “liner gloves” to abrasion-resistant, waterproof, and insulated gloves or mittens for environmental extremes. Gloves with separated fingers allow for increased dexterity but are not as warm as mittens. Mittens separate only the thumb, providing maximal warmth (Figure 93-14).

FIGURE 93-14 A, The Arc’teryx Alpha SV Glove is an advanced Gore-Tex Pro Shell layering system designed for backcountry performance. Engineered with patent-pending Tri-Dex technology, the outer shell and liner feature a unique finger construction with aggressive articulation for an unparalleled anatomic fit. A removable Polartec Wind Pro liner features low-profile microseams and a snow-shedding laminated cuff that remains open for easy donning during transitions. Supple leather reinforces high-wear zones. B, The Arc’teryx Alpha SV Mitt is an advanced backcountry layering system made with waterproof/breathable Gore-Tex Pro Shell. Removable fleece liner has a double layer of high-loft fleece on the back of the hand for extra warmth, as well as a snow-shedding laminated cuff that remains open for easy donning during transitions. Patent-pending Tri-Dex technology along with aggressive articulation creates an unparalleled anatomic fit. Supple leather reinforces high-wear zones.

(From http://www.arcteryx.com.)

Liner gloves are thin, permitting maximal dexterity and some protection from the environment. In extreme cold, this thin layer may protect against frostbite during brief exposures. If the liner snags or tears, it should be repaired or replaced. Liners are commonly worn under heavier gloves or mittens. This follows the principles of layering but also provides a measure of protection if the outer layer must be removed for tasks requiring more dexterity (Figure 93-15, online).

FIGURE 93-15 Outdoor Research W’s PL Gloves have a smooth, stretch nylon that gives these liners a snug, stretchy fit that conforms to the hand without being restrictive. A polyester fleece interior retains warmth. Wear as a base layer or as a lightweight glove liner.

(From http://www.outdoorresearch.com.)

Gloves vary tremendously. Hybrids of synthetic and natural materials are used, such as a soft-shell or laminate body and a leather palm (Figure 93-16). Fleece gloves provide excellent insulation and may have a wind-stopper laminate. Hard-shell, laminate gloves are available both as shells to be worn over other glove layers and with integrated insulation. Neoprene gloves are manufactured for marine and extremely wet conditions. It is common to have multiple pairs of gloves on any trip, although an efficient combination of glove and mitten layers may minimize number of pairs and maximize protection.

FIGURE 93-16 The Arc’teryx Bolt AR Glove is built for technical activities; these weather-resistant and breathable gloves feature two distinct Polartec Power Shield textiles: a high-loft version insulates the fingers, whereas a regular-loft version on the cuff and back of the hand enhances breathability and mobility. Aggressive articulation provides exceptional digital dexterity, supple leather reinforces the palm and fingers, and a trim-fit cuff reduces layering bulk.

(From http://www.arcteryx.com.)

Footwear

Well-fitting and appropriate footwear is essential for any excursion. All footwear must fit snugly enough to prevent slippage and loosely enough to permit adequate circulation. Socks are manufactured from most fibers, including wool, synthetics, and blends. They may be worn in a layered fashion, with a thin wool or polyester sock as the liner or base layer. This provides an initial layer to wick perspiration away from the skin, and, if well fit, minimize friction that may cause blisters. A thicker, insulating sock must not bunch or wrinkle. This will cause hot spots or blisters and in extreme cold may sufficiently inhibit circulation to promote frostbite. Socks must fit well with the specific shoes or boots to be used. It is imperative to determine the fit of socks and boots before the adventure.

Boots and shoes have become very specialized. Professional fitting is ideal when acquiring footwear. A well-fit boot or shoe has no heel rise and adequate room at the toes to move or wiggle them. The foot does not slide forward, and there are no pressure points or painful areas (Figure 93-17, online). Some people require custom orthotics or boot liners to achieve a good fit. The sole is constructed of a rubberized polymer with a tread pattern. The tread maximizes traction on uneven surfaces. Trail shoes are designed with a flexible sole (Figure 93-18, online). Hiking and mountaineering boots may have a metal shank in the sole to provide additional stability on uneven surfaces, with full-shank boots being the most stable (Figure 93-19).

FIGURE 93-19 A, LaSportiva Thunder II GTX. A midweight hiking boot suitable for a day hike or multiday excursion. Heel is designed of molded rubber for increased stability and protection—providing ankle support while traveling over uneven terrain. The combination leather/Cordura leather upper with Gore-Tex lining repels water and is abrasion resistant. B, La Sportiva Nepal EVO GTX. This boot aptly demonstrates the qualities of a mountaineering boot: designed with a silicone-impregnated leather upper for durability and abrasion resistance, lined with Gore-Tex for warmth and water resistance, full shank provides stability on unstable surfaces.

(From http://www.sportiva.com.)

FIGURE 93-17 La Sportiva Boulder X. Approach shoes are designed to offer support of the foot while providing for traction and flexibility on the approach to climbing sites. Although originally used just to approach rock faces, approach shoes are commonly worn by hikers who know that their route will take them over boulder fields and across uneven surfaces. Additional padding underfoot enhances overall comfort, the leather upper provides abrasion resistance, and the rubber toe rand offers durable protection from rough surfaces.

(From http://www.sportiva.com.)

FIGURE 93-18 La Sportiva Imogene. Trail running shoes must be designed to support the foot with strategically placed cushioning and supportive features, yet maintain the necessary flexibility to navigate uneven trails.

(From http://www.sportiva.com.)

Footwear is constructed from a wide range of materials, and most are available with a waterproof breathable membrane. Fabric or mesh construction is the norm for trail shoes or light hiking boots. Leather is commonly sewn over points of stress or common areas for abrasion. More substantial boots are designed with more leather or a synthetic analog to increase stability and durability. Mountaineering boots are usually constructed of plastic or a semirigid synthetic (Figure 93-20). Boots designed for extreme cold and high altitude have removable and, in many cases, custom-molded boot liners. Double boots are designed to be maximally insulating and still allow for dexterity while walking and climbing (Figure 93-21).

FIGURE 93-20 Ski touring in Whistler, British Columbia.

FIGURE 93-21 La Sportiva Olympus Mons EVO. This boot is designed for the extreme climates experienced at high altitudes. A double boot, it has a lightweight thermal insulating inner boot coupled with a thermo-reflective outer boot. The integrated gaiter protects the boot from wear and prevents debris from entering. This boot has seven layers, contributing to its durability and insulative qualities, yet remains lightweight and highly stable on rough terrain.

(From http://www.sportiva.com.)

Gaiters and overboots are designed to protect and insulate footwear. Constructed of abrasion-resistant nylon with or without a waterproof/breathable laminate, gaiters are tube-like constructions that either pull over or zip around the lower leg (Figure 93-22). They keep dirt, stones, mud, and snow out of shoes and boots. Supergaiters cover the entire boot, with a rubber rand that covers the boot rand. In addition to the protective qualities of standard gaiters, many have a quilted lining and provide additional thermal insulation for the feet. Supergaiters leave the boot sole free so that traction is maintained and crampons do not need to be refit. Overboots cover the entire boot, providing further insulation from the cold ground. Generally, overboots have a fabric sole and do not provide any traction. Crampons need to be fit to accommodate overboots (Table 93-3).

FIGURE 93-22 Outdoor Research Verglas Gaiters. Use over leather hiking boots to plastic mountaineering boots. Waterproof/breathable three-layer 50-denier ripstop Ventia fabric leg section. Coated 500-denier Cordura boot section.

(From http://www.outdoorresearch.com.)

TABLE 93-3 Common Footwear and Their Uses

Shoe Type	Common Use	Advantages and Disadvantages
Sandals	Water sports	Well ventilated and quick drying
		Provides protection to the sole of the foot
		Does not protect the toes or top of the foot
Running shoes	Trail running	Good underfoot support and traction
		Lightweight and ventilated
		Poor ankle support
Rock shoes	Rock climbing	Sticky rubber soles for traction on vertical surfaces
Rock shoes	Rock climbing	Specialized sport shoe, not practical for other uses
Water shoes	Kayaking, boating	Neoprene shoes for insulation in the water
		Rubber soles for traction on wet surfaces
		Little use outside the sport
Approach shoes	Walking, easy hiking, approach to more strenuous climbs	Lightweight with adequate traction
Approach shoes	Walking, easy hiking, approach to more strenuous climbs	Not designed for strenuous hikes or unstable ground
Hiking boots	Hiking, backpacking	Extensive range of design and materials from lightweight material to heavy leather
		Full and half shank for stability
		Excellent traction
Mountaineering boots	Mountaineering, ice climbing	Double or single boots
		Crampon compatible
		Well insulating
		Heavy and not suitable for hiking
Pac boots, Sorels	Insulated, water-resistant winter boots	Well insulated and water resistant
Pac boots, Sorels	Insulated, water-resistant winter boots	Good for activities that do not require traction or maximal support (e.g., after ski, shoveling snow)

Care and Storage of Clothing

Proper care and storage of outdoor clothing will prolong item life and maintain properties of insulation, water resistance, and breathability. Technical fabrics do not have universal care guidelines. The manufacturer’s care instructions should be followed.

Any contaminant on the fabric will diminish effectiveness. Soot, grease, sunscreen, dirt, and body oils contribute to garment failure. N,N-diethyl-3-methylbenzamide (DEET) may physically damage rayon or spandex fibers. It does not damage wool or cotton. The insect repellent picaridin does not damage fibers. Soiled fabric is more susceptible to pilling. The fraying or abrasion of the fibers will attract more soil. Ultimately this forms a small “ball” or “pill” of matted fiber, dirt, and other compounds. Pilling frequently begins in areas of friction, such as the armpits, sleeves, and waistline. Contaminants affect the fabric’s ability to wick and change the surface of the garment, diminishing both water resistance and breathability.

Laundering

A front-loading washer is preferable, because the central agitator of a top-loading unit may damage clothing. Garments should be prepared by closing all zippers and sealing all hook and loop closures. Carefully empty all pockets. An inadvertently retained stick of lip balm or energy bar can ruin a garment. Spot treat all stains by gently massaging with a proper cleaning solution. Turning the garment inside out decreases the chance of damage by abrasion. Choice of laundry solution is important. Mass-market products contain surfactants that are designed to bind and lift away grease. Unfortunately, they do not rinse away completely and leave a behind a residue. This residue decreases the waterproof/breathable properties of a fabric and diminishes the effectiveness of the DWR finish. Specialty detergents for technical fabrics are designed to rinse away completely and have no surfactants or fragrances to bind to the fibers. If nonspecialty products are used, select products labeled “clear,” “Earth-friendly,” or “free,” because these tend to leave less residue. However, they still require an extra rinse cycle. Do not use a fabric softener. Fabric softeners are designed to leave behind oils and fragrance, both of which decrease the garment’s ability to wick away moisture and adversely affect water repellency and breathability. This applies to both liquid softener and dryer sheets.

Drying

Adhere to manufacturer’s instructions. If garments are not line dried, use a low heat setting, and do not allow the clothing to sit in the dryer when the cycle is complete. The fins of some dryers become excessively hot and may melt synthetic fabric. Be aware of the possibility of shrinkage with wool and wool-blend garments. Cotton garments that are not preshrunk will shrink if washed in hot water or placed in a hot dryer. Preshrunk garments may still experience 2% to 3% shrinkage.

Durable Water-Repellent Finish

All waterproof/breathable fabric is treated with a DWR finish. For the fabric to continue to be effective, manufacturers recommend washing at least yearly, and more frequently when there is obvious buildup of dirt, oils, or other products. Sunscreens, body oils, and lotions that rub off onto the garment decrease the effectiveness of the finish. Smoke specifically decreases water repellency. DWR finish requires maintenance when water no longer beads up on the surface of the garment. If the garment is clean, 10 to 15 minutes in a dryer on a low heat setting will restore the finish. The DWR finish, on a microscopic level, resembles upright columns or spikes. With soil, use, and abrasion, the columns are no longer standing upright. Heat restores the upright structure of the finish. If this is ineffective, the finish may have worn off because of repeated washings or excessive soilage. Reapplication of the DWR finish is possible with after-market products, such as ReviveX, Sport-Wash, or Nikwax. If the garment has a laminate membrane, spray-on products are more effective. If there is no membrane, use a wash-in product.

Footwear

Boots and shoes should be well cleaned before storing. Dirt and organic material can mechanically break down both leather and synthetic materials and decrease longevity. Footwear should never be stored damp or wet. Newspaper stuffed into a damp boot will help absorb moisture, but do not leave damp paper behind. Never put footwear in a clothes dryer. Air-drying is best. After-market treatments should be used only at the manufacturer’s suggestion. Boots may require seam sealing and renewal of waterproofing after extended use. Leather boots require conditioners on a periodic basis. Mink oil, Sno-Seal, or similar products can restore water resistance to both the leather and seams.

Storage

Outdoor clothing and technical fabrics should be stored uncompressed and in a dry environment. A damp basement or garage is not a good location, because the moisture may lead to formation of mold and mildew, damaging the fabric. Down or synthetic insulating layers lose loft when stored compressed. Insects can damage clothing if an infestation occurs. Moths are especially damaging to wool. Cedar is a natural repellent and may be found as blocks or rounds to place with the garments. Cedar-lined chests and drawers are options. Cedar does not guarantee moths will not attack clothing. Mothballs may be necessary. Mothballs are formed of the pesticides naphthalene or 1,4-dichlorobenzene, or of camphor. Camphor occurs naturally, found in the wood of the camphor laurel, a large evergreen tree found in Asia, or synthetically produced from oil of turpentine. Mothballs work in an airtight environment by sublimating to the vapor form and killing both larvae and adult moths. Both chemicals are toxic and may be carcinogenic. Allow garments to air out for at least 1 day before using. If wool is stored in an airtight garment bag, ensure that it is completely dry before sealing to prevent mildewing.

Repair

Even with careful use, clothing sustains damage. Patch kits are available from manufacturers and will better maintain the integrity of the garment than do improvised fixes like duct tape. Ideally, repairs should be made professionally to protect laminates, sealed seams, and specialty zippers. Most manufacturers offer repair if the garment is sent to them. In the field, stopgap measures include tape, fabric glue, and safety pins. Seams can be temporarily repaired using a needle and polyester thread.

Special-Use Clothing

Sun Protection Clothing

Protection from the sun is important to reduce skin damage from ultraviolet radiation (UVR) exposure and to decrease radiant heat gain in hot environments. With rare exception, clothing protects the skin from UVR by simply covering the surface. Special sun protection or “UV-blocking” garments employ a tight weave to prevent any radiation from reaching the skin. Any property that blocks sun, such as a tight weave or thicker fiber, improves sun protection. Stretchy garments create spaces through which UVR can penetrate. Wet garments are not as effective as dry garments at blocking UVR. Sun protective clothing tends to be white or pastel colored to capitalize on reflective qualities.

Clothing manufacturers report an ultraviolet protection factor (UPF) determined by using one of several rating systems. For comparative value, a plain white T-shirt has a UPF value between 5 and 9, whereas a sun protection garment has a UPF of 30 or more (Table 93-4).

TABLE 93-4 Ultraviolet Protection Factor Ratings

General Rating	UPF Rating	UV Light Blocked (%)
Good	15-20	93.3-95.8
Very good	25-35	95.9-97.4
Excellent	40+	Above 97.5

Insect-Repellent Clothing

Mechanical protection offered by clothing is the first barrier against insects. Clothing that is loosely fitted prevents insects from biting or stinging through the fabric, and elasticized cuffs and wrists prevent insects from migrating under clothes onto the skin. Insect-repellent chemicals can be impregnated into the garment. The most common agent is permethrin, an odorless chemical synthesized to mimic a compound found in chrysanthemums. Permethrin is insecticidal and kills insects by prolonging sodium channel depolarization of presynaptic neurons. Permethrin eventually washes off and is usually expected to last 20 to 25 washings. After-market products are available, lasting between 4 and 6 washings. Permethrin can be applied as an aerosol spray or a soak-in product to garments and bed nets. It is essential to follow product instructions to maximize effectiveness.

Fire-Resistant Clothing

Nomex is the proprietary fabric used in the manufacture of much fire-resistant clothing and is a structural variant of Kevlar. Flight suits and some rescue gear are also made from this product. Fire resistance may be intrinsic to the fiber itself (Nomex) or secondary to an externally applied retardant agent. The base fiber in fire-resistant clothing must not melt. Wool is a naturally fire-resistant material. It is still flammable but tends to burn out quickly. Nylon-based fabrics melt, causing burns from the fabric as well as from flames.

Vapor Barrier Clothing

Application of vapor barrier clothing is limited to extremely cold environments. Most clothing is designed to wick perspiration into the middle layers and away from the skin. In extreme cold, the middle layer may not dry, creating problems with insulation. The premise of a vapor barrier is to keep the insulating layer dry. Sweat is wicked into the base layer and remains there because it cannot pass the vapor barrier. This creates damp clothing next to the skin but preserves dryness of the insulating layers. The discomfort of a damp base layer is outweighed by the continued effectiveness of the insulating layer.

Sport-Specific Clothing

Sport-specific clothing is not necessarily better than general outdoor clothing. The basic principles of construction and fabric utilization are the same, but the clothing has design properties specific to the sport. For example, outer layers for mountaineering and ice climbing have less fabric around the waist or a much shorter torso rise to accommodate a harness. Gloves must both insulate and allow dexterity. Pockets are situated on the chest, and hand-warmer pockets are frequently eliminated. Kayaking jackets have tight-fitting or neoprene cuffs and waistbands to reduce water entry into the garment. Rock-climbing clothing is snug fitting to prevent fabric from catching in gear. Specialty rock shoes are required (Figure 93-23). Desert environments require increased sun and heat protection. Jungle and snake-ridden areas demand protective boots and snug-fitting ankle and wrist cuffs.

FIGURE 93-23 La Sportiva Katana Lace. Climbing shoes are the most specialized piece of rock-climbing clothing. The shoes fit snugly and may place the foot in a pointed position to better enable insertion into cracks. The shoe’s rubber rand permits the climber to stand on dime-thin edges. A good climbing shoe is able to balance fit, comfort, dexterity, and stability.

(From http://www.sportiva.com.)

Climate-Specific Clothing

When preparing for any excursion, the expected environment is one of the principal factors determining clothing choice. Different clothing systems are needed for each environment, but the basic principles of thermoregulation and moisture management through layering always apply. In addition to anticipating climate and weather extremes, physical features of the environment and the activity to be pursued are important considerations. A hike or backpacking trip though an open forest, tundra, or grassland will not subject clothing to the type of damage made likely by bushwhacking and scrambling over rocks. For all climates, nylon and cotton-polyester blends offer the most abrasion-resistant fabrics. Fleece and any fabric with a loose weave will snag and tear. The need for a garment to tolerate abrasion must be balanced with the considerations for insulation (Table 93-5).

TABLE 93-5 Climates

Hot

Hot and extremely hot environments require clothing that protects from the sun and enhances cooling. Hot climates are those with sustained temperatures over 38° C (100.4° F). Extremely hot climates have temperatures over 46° C (114.8° F); typically, the latter is a desert environment.

Fabrics and design of hot-weather clothing must be able to both protect from the sun and keep the wearer cool (Figure 93-24). Air needs to circulate freely across the skin, while the clothing shields from UVR. A fabric’s ability to protect from the sun is rated as either the ultraviolet protection factor (Australia) or the clothing protection factor (United Kingdom). The fabrics are tested with a spectrometer to measure the ability to block UVR. Not all fabrics receive UV protective ratings, but they still provide a degree of sun protection. Tightly woven fabrics are more protective than materials with a loose weave. Wet fabrics lose protective value, as do worn or abraded fabrics. Air circulation optimizes both convective and evaporative cooling. Strategically placed vents and mesh panels combined with a loose fit maximize ventilation. Many garments are designed to be “convertible,” with zip-off pant legs and easily rolled-up sleeves, offering the wearer maximum versatility for changing conditions (Figure 93-25, online).

FIGURE 93-24 Outdoor Research Sun Runner Cap has a removable, adjustable skirt that gives shelter from harsh rays or can be removed when one just needs ball-cap coverage. The lightweight fabric provides UPF 30 sun protection. Mesh side panels let air flow over the sides of one’s head.

(From http://www.outdoorresearch.com.)

FIGURE 93-25 The Outdoor Research Venture Pants. Lightweight Supplex nylon provides 30+ UPF protection throughout the day. A durable water-repellent finish sheds early morning moisture and dries quickly at the end of the day. Articulated knees and a gusseted crotch allow comfortable movement on steep trails. The cuffs can be rolled up and held in place with button hooks, making these pants ideal for stream crossings and warm-weather adventures.

(From http://www.outdoorresearch.com.)

Thermoregulation cannot be managed by clothing alone. Behavior modifications are the best strategies for cooling in conditions of extreme heat and humidity. If the environment is dry and hot, moistening the fabric enhances evaporative cooling. Exposing arms and legs promotes more rapid evaporation and convection, but sunscreen must be applied. In extreme heat, seeking shade and not performing heavy physical activities during the hottest parts of the day are necessary precautions.

Temperate

Mild temperatures, ranging between freezing and body temperature, characterize temperate climates. This broad range of environmental conditions requires clothing that accommodates the perspiration of activity during the day and provides warmth during cool nights. Unless it is exceptionally humid or rainy, most clothing dries quickly.

Lightweight, quick-drying nylon clothing provides protection from the sun and from abrasion caused by brambles and brush. Polyester-cotton blends are also highly abrasion resistant and dry relatively quickly. Long sleeves and pants may be necessary for cooler evenings or rainy conditions. A lightweight middle layer, such as fleece or a heavy shirt, coupled with gloves and hat, will stave off evening chill. Wind and water protection are accomplished with a lightweight outer layer. A jacket constructed of a waterproof/breathable laminate is most versatile. If extremely wet conditions are expected and the chance of perspiration is low, consider a coated nylon garment (Figure 93-26).

FIGURE 93-26 Stream crossing in Outdoor Research gear.

Cold

Daytime low temperatures that drop below freezing characterize cold climates. Layering systems must accommodate both the relative midday warmth and the potential for precipitation in the form of rain and snow (Figure 93-27, online). Clothing does not dry readily in these conditions. Efficient moisture management is imperative to maintain warmth as temperature drops. The base layer should accommodate the warmth of the day and not contribute to overheating. A light or midweight pair of long underwear is preferable over heavyweight garments. Insulating middle layers that can be easily shed or added are key to maintaining comfort. Careful consideration of the garment’s properties, such as the ability to vent through neck and leg zippers and ease of putting the garment on over boots, harnesses, or helmets, enhances efficiency of the layering system. The outer, protective layer must be both wind- and water-resistant.