The air permeability of roofing systems constructed from discrete elements, as is the case for clay and concrete tile and slate roof systems, is a critical factor in determining the wind resistance of the roof system. The ability of the roof system to relieve wind-induced uplift pressures as a result of the overall air permeability of the roof assembly relates to the resistance of the roof system to damage induced by wind.

Natural wind conditions differ with respect to intensity, duration, and turbulence; these conditions are beyond the means of this test method to simulate.

1.1 The air permeability of tile roofing systems is a critical factor in determining the wind resistance of tile roofing as applied to a roof. This Standard describes a procedure for measuring the air permeability of clay and concrete tile and slate roof systems when applied to a small section of roof deck in accordance with the manufacturer's instructions.

1.2 This test procedure measures the air permeability of a laid array of unsealed clay or concrete roof tiles or slates. The tiles or slates shall have a thickness between ¹/₈-in. (3-mm) and 2-in. (51-mm).

1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.