Class 1 units for external use, and class 2 units for internal use in concrete, clay, cast iron, copper, aluminium steel, plastics and plaster (internal only). Overall dimensions, shape of apertures, unobstructed air space, wall hold, screening, testing of plaster units. Illustrations of typical examples.
BS 493:1970
Original price was: $264.16.$132.00Current price is: $132.00.
Specification for airbricks and gratings for wall ventilation
BSI Group , 12/14/1970
Pages: 20
