Standard Test Method for Predicting Heat Buildup in PVC Building Products

Importancia y uso:

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.4

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.

Subcomité:

D20.24

Referida por:

D7990-21

Volúmen:

08.03

Número ICS:

83.140.01 (Rubber and plastic products in general), 83.140.99 (Other rubber and plastic products)

Palabras clave:

heat buildup; PVC building products; sun energy absorption; weathering;