1.1 This procedure describes a method to determine a numerical value indicating the relative rigidity or stiffness of vinyl siding panels. This procedure is not intended for routine quality control inspection during the manufacture of vinyl siding. The rigidity of vinyl siding is believed to be controlled primarily by its configuration and is not believed to be significantly influenced by manufacturing variables.

1.2 Vinyl siding with higher rigidity is often easier to handle and install. It is expected to provide a straighter appearance when installed on walls having an uneven surface.

1.3 All other vinyl siding requirements and test methods can be identified through Specification D3679.

1.4 There is no known ISO equivalent to this standard.

1.5 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.