vane ratio (of a grille)
[EN 12792:2003, 382]:ratio of the chord length to the vane pitch.
Continue reading →main-glossary
vapour barrier
[AIVC, Air infiltration and ventilation glossary, 1992]:a moisture impervious layer applied to the surfaces enclosing a space or to the surface of thermal insulation to limit moisture migration through the surface.
Continue reading →vapour barrier (duct)
[EN 12792:2003, 383]:vapour resistant coating applied to the exterior of the thermal insulation used on ductwork through which air flows at sub-ambient temperature. Also used for the same purpose in other building constructions. Its purpose is to avoid migration of … Continue reading →
variable air volume (VAV)
[AIVC, Air infiltration and ventilation glossary, 1992]:a ventilation system that controls the dry bulb temperature within a space by varying the volume of supply air, rather than the supply air temperature.
Continue reading →variable blade pitch control (of a fan)
(See fan control methods variable speed control)
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