Wadding: A non-woven ‘mat’ of fibres. Typically used as the insulating layers in synthetic sleeping bags.
Warmth-to-weight: The amount of insulation a material provides for a given weight.
Waterproof: For a fabric to be called waterproof, as opposed to just water or shower resistant, it must prevent water penetration even under pressure. The European Standard that a fabric must meet to be classed as waterproof is a minimum hydrostatic head of 1.5 meters. This is enough to keep out the heaviest possible rain, but is not enough to keep out water under pressure from rucksack straps or kneeling down. High quality waterproof fabrics will greatly exceed this standard (Gore-Tex has a hydrostatic head of 28 meters).
Webbing: A tape woven from polyester, nylon, polypropylene or acrylic yarns. Can be woven as a flat tape, like a car seat belt, or tubular like a sock. Tubular webbings have a far higher strength to weight ratio.
Wicking: The ability of a fabric to move liquid water through it’s structure. An essential function for any fabric worn next to the skin.
Windbloc: A windproof fleece fabric utilising a windproof film typically laminated between 2 layers of lightweight fleece.
Windchill: The dramatic cooling effect the wind has on the human body. For example, an ambient temperature of 10ºC will feel more like -1ºC in a 40km/h wind. Even more noticeable if wet clothing is worn.
Windproof: For a fabric to be called windproof (as opposed to just wind resistant), it can allow no more than 11 litres of air to pass through per second per square meter, in a 50km/h wind. Wind protection is a vital function of outer garments in mild or cold weather conditions.
Windstopper: A windproof fleece fabric utilising a windproof and highly breathable ePTFE membrane, typically laminated between 2 layers of lightweight fleece, or a lightweight fleece outer and mesh inner.