Issue link: https://hi.iaq.net/i/248503
www.epa.gov/iaq/moisture Glossary Term Definition Air barrier Any material, combination of materials or manufactured assemblies that are intended, by design, to control the movement of air across an exterior wall system or assembly. Air handler Equipment that includes a blower or fan, heating or cooling coils and related equipment such as controls, condensate drain pans and air filters. Does not include ductwork, registers or grilles, or boilers and chillers. Alligatoring Shrinkage cracking of the bituminous surface of built-up or smooth surface roofing, producing a pattern of deep cracks resembling alligator hide. ASHRAE American Society of Heating, Refrigeration, and Air-Conditioning Engineers, Inc. Asphalt A highly viscous hydrocarbon produced from the residue left over after the distillation of petroleum. Asphalt is used to water-proof built-up roofs. ASTM American Society for Testing and Materials. Ballast An anchoring material such as rock, gravel or pavers used to resist wind uplift forces on roof membranes. Bitumen A generic term for asphalt or coal tar pitch roofing. Blister A spongy raised portion of a roofing membrane as a result of pressure of entrapped air or water vapor. Built-up roofing (BUR) A continuous semi-flexible roof covering consisting of laminations or piles of saturated or coated felts alternated with layers of bitumen. Cant strip A continuous strip of triangular cross-section fitted into the angle formed by a structural deck and a wall or other vertical surface. Used to provide a gradual transition for base flashing and horizontal roof membrane. Capillary break A slot or groove intended to create an opening too large to be bridged by a drop of water in order to eliminate the passage of water by capillary action. Chase A groove or indentation cut into masonry to accommodate electric or plumbing lines. Cladding A panel applied to a structure to provide durability, weathering, corrosion and impact resistance. CMU Concrete masonry unit. Commissioning Start-up of a building that includes testing and adjusting HVAC, electrical, plumbing and other systems to ensure proper functioning and adherence to design criteria; also includes the instruction of building representatives in the use of the building systems. Coping The material or units used to form a cap or finish on top of a wall, pier, pilaster or chimney; a protective cap at the top of a masonry wall. It should be waterproof, weather resistant and sloped to shed water. Crack A break in a roofing membrane as a result of flexing, often occurring along a ridge or wrinkle. H-1