1.1 This specification covers vinyl-coated glass yarns. These yarns are manufactured in two basic classes. These classes have been established that when properly woven into screening, satisfactory strength, durability, and insect protection are obtained. The two classes are as follows:

1.1.1 Class 1 -Nominal thickness 0.292 mm (0.0115 in.).

1.1.2 Class 2 -Nominal thickness 0.330 mm (0.0130 in.).

1.2 This specification shows the values in both SI units and inch-pound units. "SI units" is the technically correct name for a system of metric units known as the International System of Units. "Inch-pound units" is the technically correct name for the customary units used in the United States. The values stated in inch-pound units are to be regarded as the standard. The values in SI units are provided for information only.

1.3 The following precautionary statement pertains only to the test method portions, Sections 12 through 21, of this specification. 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.