ASTM D2626-97b

1.1 This specification covers asphalt-saturated and coated organic felt base sheet with fine mineral surfacing on the top side, with or without perforations, for use as the first ply of a built-up roof. When not perforated this sheet may be used as a vapor retarder under roof insulation.

1.2 The values stated in inch-pound units are to be regarded as the standard.