BSI - BS 493
Specification for Airbricks and gratings for wall ventilation
|Publication Date:||15 April 1995|
|ICS Code (Walls. Partitions. Façades):||91.060.10|
Class 1 units for external use, and class 2 units for internal use, in concrete, clay, copper, aluminium, steel, thermoplastics and plaster (internal only). Overall dimensions, shape of apertures, unobstructed air space, wall hold, screening, testing of plaster units, impact test for thermoplastics airbricks.