ASTM D3949-99(2004) (R1999)

1.1 This specification covers woven glass fabric coated with fully cured oleoresinous varnish, epoxy resin, polyurethane resin, or polyester resin. Excluded are coated polyester-glass fabric and glass fabric coated with silicone resins and silicone elastomers.

1.2 It is recognized that several properties, notably breaking strength and dielectric strength, are related to the style of base fabric used for any particular thickness. This specification has been developed for materials using fabrics woven from relatively coarse-filament yarns and in some cases from relatively open-weave constructions, and property values are frequently somewhat lower than if finer filament yarns or closer weave constructions were used. The user is therefore alerted that significantly higher levels of performance test values may be obtained through the use of these latter types of alternate base constructions.

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

This specification covers woven glass fabric coated with fully cured oleoresinous varnish, epoxy resin, polyurethane resin, or polyester resin. Excluded are coated polyester-glass fabric and glass fabric coated with silicone resins and silicone elastomers. Materials are identified according to the type of coating applied, as follows: Type 1, black oleoresinous varnish; Type 2, yellow oleoresinous varnish; Type 3, epoxy resin; Type 4, polyurethane (isocyanate) resin; and Type 5, polyester resin. Glass fabrics shall meet specified values for electrical (dielectric strength at room temperature after bending, and breakdown voltage after aging at an elevated temperature), mechanical (breaking strength, oil resistance, and temperature index), and dimensional (nominal thickness, width, and length) property requirements.