ASTM C1257-06a(2012)

5.1 It is difficult to establish a precise correlation between laboratory accelerated and natural weathering because of (1) geographical climatic variations, local weather variation from normal, and local pollutants and (2) the fact that the acceleration factor is material dependent, varying with the type of material as well as its formulation. This test method is used to determine the resistance of a sealant to laboratory accelerated weathering and, if a control material with known outdoor weathering performance is used, the relative weathering performance of the sealant against that of the control material.

5.2 This test method is conducted using aluminum channels. Other substrate materials may show different results.

1.1 This test method includes two laboratory accelerated exposure procedures for predicting the effects of ultraviolet or ultraviolet/visible radiation, heat, and moisture on color, chalking, cracking, and adhesion of solvent-release sealants.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 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.

1.4 The committee with jurisdiction over this standard is not aware of any comparable standards published by other organizations.