Standardization News

Color and appearance are two of the leading qualities that a homeowner looks for when considering vinyl siding. A new ASTM standard will enable manufacturers of color plastic vinyl siding to enhance the color and appearance retention of their products.

ASTM D7856, Specification for Color and Appearance Retention of Solid and Variegated Color Plastic Siding Products Using CIELab Color Space, will be used by siding manufacturers, developers and suppliers of color systems and outdoor weathering laboratories. In addition, the new standard will be referenced by third-party color retention certificate programs.

ASTM D7856 is a successor to two ASTM specifications:

ASTM D7856 combines elements from both ASTM D6864 and ASTM D7251, and replaces use of the Hunter Lab color space for measurement of colors and evaluation of color change with the CIE 1976 L*a*b* color space, as specified by the International Commission on Illumination. The CIElab color space describes all the colors visible to the human eye.

According to ASTM member David Johnston, senior director, technical, Vinyl Siding Institute Inc., VSI had based the color retention requirements of its Product Certification Program on the standards that reference the Hunter Lab color space, which is no longer frequently used. D7856 was developed to reflect the more common use of CIELab Color Space in current testing procedures. Johnston notes that VSI is now in the process of converting its color retention requirements for siding certification to reference ASTM D7856.

"All building materials undergo changes when exposed to outdoor conditions from the effects of, among other things, solar radiation, temperature, moisture and atmospheric pollution," says Philip Ledgerwood, ASTM member and research and development scientist, Americhem Inc. "For exterior plastic siding products, the chief concern has always been changes in color."

Ledgerwood notes that the development of ASTM standards for color retention has been a major driver of technology to identify pigments and compounding technology that have improved siding color retention performance.

"ASTM D7856 enhances the ability to measure color change correlating to human perception and use two-year outdoor weathering to estimate long-term color retention performance," says Ledgerwood. "It will also aid in applying acceptability criteria that reflect how people view color change on their houses. This will help manufacturers develop products that increase overall satisfaction and can take advantage of the darker and more chromatic colors that consumers want."

ASTM D7856 was developed by Subcommittee D20.24 on Plastic Building Products, part of ASTM International Committee D20 on Plastics.

To purchase ASTM standards, visit www.astm.org and search by the standard designation, or contact ASTM Sales (phone: 877-909-ASTM; sales@astm.org).

CONTACT Technical Information: David Johnston, Vinyl Siding Institute • Washington, D.C. • Phone: 202-587-5102 | Subcommittee D20.24 Contact: Alan Kupfer, Axiall Corp. • Plaquemine, La. • Phone: 225-685-1257 | ASTM Staff: Alyson Fick • Phone: 610-832-9710 | Upcoming Meeting: Nov. 9-12, 2014 • November Committee Week • New Orleans, La.