Technical Glossary
Technical outerwear comes with its own technical vocabulary. You don't need to be an expert to appreciate the world-class comfort and protection offered by our fabrics, but understanding how we define their properties and characteristics can help you make an informed choice.
Click on the links below for definitions.
- air permeability
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The amount of air that flows through a fabric. When this happens, cold air is exchanged for warm air, lowering the temperature inside the clothing. Air permeability is not the same thing as breathability. Breathable fabric allows internal sources of moisture escape the fabric, but does not allow wind to enter.
- body core
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Your head and torso.
- body microclimate
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The 0.04-inch thick layer of air next to our skin. We are most comfortable with a body microclimate of 90°F to 95° F and a relative humidity of 40% to 60%. Even the smallest changes to this microclimate will affect our level of comfort.
- Breathability
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The rate at which water vapor molecules move through a clothing layer. This movement is determined by the difference in concentration of water vapor (or humidity) between the surface of the skin and the air outside the garment, as well as the physical resistance of the fabric layers. The humidity difference is determined by your activity level, which drives sweating, and the climate around you. The fabric resistance is a property of the materials used in the garment and their thickness. Thicker layers offer more resistance and breathe less.
- conductive heat loss
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The heat loss that occurs when sweat is allowed to stay trapped against the skin. Eventually, the sweat turns cold and discomfort results.
- DWR
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An ultra-thin treatment of durable water repellent polymer applied to the outermost fabric layer of Gore laminates. This coating penetrates the fibers and lowers the surface tension of the fabric, causing water to bead up and roll off the garment instead of being absorbed. DWR is not a waterproofing treatment by itself; the GORE-TEX® membrane does that. DWR significantly improves your comfort in the rain by reducing the heat loss through wet fabric.
- ePTFE
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Expanded polytetrafluoroethylene, the hydrophobic, or water-hating, material in the GORE-TEX® membrane.
- GORE-TEX® fabric
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The most durably waterproof, very breathable, totally windproof fabric meeting Gore's Guaranteed to Keep You Dry® standards. Created when the GORE-TEX® membrane is bonded to high-performance textiles to create laminated fabrics. Different GORE-TEX® laminates satisfy the requirements of different types of garments.
- GORE-TEX® membrane
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GORE-TEX® products are based on GORE-TEX® ePTFE membrane technology. The membrane provides a thin, uniform barrier that can provide properties like waterproofness or chemical resistance. A single square inch of the GORE-TEX® membrane contains 9 billion microscopic pores - each 20,000 times smaller than a raindrop but 700 times larger than a molecule of water vapor - so while water can't pass through the fabric, perspiration can. Integrated into the ePTFE structure is an oleophobic, or oil-hating, substance that allows moisture vapor to pass through but is a physical barrier that prevents the penetration of contaminating substances such as oils, cosmetics, insect repellents, and food substances.
- GORE-SEAM® Seam Sealing technology
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GORE-TEX® technology involving the use of seam tape to completely seal every tiny hole created by sewing machine needles when GORE-TEX® fabric is made into garments This technology is one of the reasons why only GORE-TEX® products carry the Guaranteed To Keep You Dry® promise.
- insulating layer
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The mid-layer in a three-layer clothing layering system that consists of a wicking layer, insulating later, and weather protection layer. The insulating layer is worn over the wicking layer. Its role is to trap in warm air to prevent heat loss.
- laminate
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A 'sandwich' created by bonding ePTFE membrane to different fabrics. A 2-layer laminate is made by bonding a shell fabric to the membrane for use on the outside of a garment; a 3-layer laminate is made by bonding a shell fabric to the outside of the membrane and a knit to the inside.
- layering system
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A clothing system in which several layers are worn in order to better protect the body against the elements and keep its temperature stable. Modern clothing systems usually consist of three basic layers: an inner wicking layer, a mid insulating layer and an outer weather protection layer.
- microclimate
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The very thin layer of warm air that exists next to the body's skin. People are most comfortable with a tropical microclimate of 90°F to 95° F and 40% to 60% humidity.
- moisture management
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The process of keeping the body dry - and therefore warm. Clothes said to have good moisture management effectively allow sweat to escape rather than staying on the skin and turning cold, while keeping all external sources of moisture such as rain or snow away from your skin.
- moisture vapor
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In the context of perspiration, moisture vapor is sweat in gas form.
- shell
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Also referred to as a weather protection layer, this is the outer fabric layer of a garment, or the outermost layer in a layered clothing system.
- ventilation heat loss
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The heat loss that occurs when the warm air trapped inside clothing is replaced by cold air typically through movement.
- waterproof fabric
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A truly waterproof fabric must be able to withstand water entry pressure resulting from active use in extended wet weather, including activities like walking in wind-driven rain or kneeling or sitting on a wet surface.
- water repellent fabric
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Not to be confused with 'waterproof.' A water-repellent fabric uses a DWR coating or a dense weave to prevent saturation of a garment's shell layer. Water repellent fabrics shed or repel water; however, they are not waterproof.
- weather protection layer
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Also referred to as a shell, this is the outer fabric layer of a garment, or the outermost layer in a layered clothing system.
- wet out
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A condition that occurs when the exterior fabric of a waterproof garment becomes saturated with water, thereby increasing its ability to transmit heat from the body and creating clamminess or a cooling sensation often confused with water entry or garment leakage.
- wicking
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A term often used with technical clothing. Clothes said to have good wicking abilities physically move liquid moisture away from your body. This prevents sweat from remaining on your skin and turning cold, which can lead to conductive heat loss.
- wicking layer
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The innermost layer of clothing, or the layer of clothing worn directly next to the skin. Its role is to convey liquid moisture away from the skin to prevent you from feeling clammy and cold.
- windchill factor
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A measurement of the cooling effect of moving air and wind on the body. Often expressed as an equivalent temperature in still air that would create the same heat-loss effect.
- windproof fabric
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A fabric that has an air permeability of 1 cfm (cubic feet per minute) or less in a 30 mph wind. A truly windproof garment will prevent heat loss from convection.