The exposed surface of a wall or masonry unit. The surface of a unit designed to be exposed in the finished masonry. In concrete block masonry construction - application of mortar to all vertical and horizontal edges of the face shells of hollow masonry units.
Most buildings rely on some form of ventilation system to exhaust contaminated air.
This system may run continuously, or may be operated automatically or manually. Even in a balanced system, the amount of air may be increased or decreased relative to the amount being exhausted, increasing or decreasing the inside pressure accordingly. The expanse of wall between openings, corners, etc., principally composed of stretchers. A hollow, vitrified clay masonry unit, sometimes salt-glazed, designed for trickling filter floors in sewage disposal plants. See ASTM Specification C 159.