5.1 Heat buildup in PVC exterior building products due to absorption of the energy from the sun may lead to distortion problems. Heat buildup is affected by the color, emittance, absorptance, and reflectance of a product. Generally, the darker the color of the product, the more energy is absorbed and the greater is the heat buildup. However, even with the same apparent color, the heat buildup may vary due to the specific pigment system involved. The greatest heat buildup generally occurs in the color black containing carbon black pigment. The black control sample used in this test method contains 2.5 parts of furnace black per 100 parts of PVC suspension resin. The maximum temperature rise above ambient temperature for this black is 90°F (50°C) for a 45° or horizontal surface when the sun is perpendicular to the surface and 74°F (41°C) for a vertical surface assuming that the measurements were done on a cloudless day with no wind and heavy insulation on the back of the specimen.3 See Appendix X1.

5.2 This test method allows the measurement of the temperature rise under a specific type heat lamp, relative to that of a black reference surface, thus predicting the heat buildup due to the sun's energy.

5.3 The test method allows prediction of heat buildup of various colors or pigment systems, or both.

5.4 This test method gives a relative heat buildup compared to black under certain defined severe conditions but does not predict actual application temperatures of the product. These will also depend on air temperature, incident angle of the sun, clouds, wind velocity, insulation, installation behind glass, etc.

1.1 This test method covers prediction of the heat buildup in rigid and flexible PVC building products above ambient air temperature, relative to black, which occurs due to absorption of the sun's energy.

Note 1: This test method is expected to be applicable to all types of colored plastics. The responsible subcommittee intends to broaden the scope beyond PVC when data on other materials is submitted for review.

Note 2: There are no ISO standards covering the primary subject matter of this test method.

1.2 Rigid PVC exterior profile extrusions for assembled windows and doors are covered in Specification D4726.

1.3 Rigid PVC exterior profiles for fencing are covered in Specification F964.

1.4 Rigid PVC siding profiles are covered in Specification D3679.

1.5 Rigid PVC soffit profiles are covered in Specification D4477.

1.6 Rigid PVC and Rigid CPVC plastic building products compounds are covered in Specification D4216.

1.7 The text of this test method references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of this test method.

1.8 Units—The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.9 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific safety hazard statements are given in Section 7.

1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.