Air barrier
Air barriers control air leakage into and out of the building envelope. Air barrier products may take several forms: 

Mechanically-attached membranes, also known as housewraps, usually a polyethylene-fiber or spun-bonded polyolefin, such as Tyvek is a generally accepted moisture barrier and an air barrier (ASTM E2178). Self-adhered membranes, which are typically also a water-resistant barrier and a vapor barrier
Fluid-applied membranes, such as heavy-bodied paints or coatings including polymeric based and asphaltic based materials
Closed-cell medium density spray-applied polyurethane foam, which typically provides insulation as well
Some open-cell spray-applied polyurethane foam that are of high density
Boardstock, which includes 12 mm plywood or OSB, 25 mm extruded polystyrene, etc. Air barriers are divided into air barrier materials, air barrier accessories, air barrier components, air barrier assemblies and air barrier systems. Air barrier materials – Building materials that are designed and constructed to provide the principal plane of airtightness through an environmental separator, which has an air permeance rate no greater than 0.02 L/(s•m2) at a pressure difference of 75 Pa when tested in accordance with ASTM E 2178.