| Term | Definition |
| ABRASION RESISTANCE: | The ability of a membrane to resist being worn away by contact with a moving, abrasive surface, such as foot traffic. |
| ACOUSTICAL DECK: | Metal deck panel perforated to absorb sound. |
| ADDITION POLYMERIZATION: | Polymerization in which monomers are linked together without the splitting off of water or other simple molecules. |
| ADHERE: | To cause two surfaces to be held together by the combined strenght of the molecular forces and the mechanical interlocking achieved between adhesive and the bonded surface. |
| ADHESIVE FAILURE: | Failure of the bond between a compound and the surface with which it is in contact, allowing the compound to pull away and create an opening. See cohesive failure. |
| ADIPRENE (Urethane Rubber): | A polyurethane rubber, strong, tough and abrasion-resistant. |
| A-FRAME: | A three-piece rigid structural frame in the shape of the upright capital letter A. See FRAMING. |
| AGGREGATE: | Crushed stone, crushed slag, or water-worn gravel used for surfacing a builtup roof; any granular mineral material. |
| AIR LANCE: | A device used to test, in the field, the integrity of field seams in plastic sheeting. It consists of a wand or tube through which compressed air is blown. |
| ALIPHATIC POLYURETHANE COATING | Normally used as a topcoat, a material that contain a specific class of iscyanates based on a long, straight-chain molecular structure noted for its high tensile strength, high gloss, color-stable properties, and ultraviolet resistance. |
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