ASTM C1257-15

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C1257 − 06a (Reapproved 2012) C1257 − 15
Standard Test Method for
1
Accelerated Weathering of Solvent-Release-Type Sealants
This standard is issued under the fixed designation C1257; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
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.
2. Referenced Documents
2
2.1 ASTM Standards:
C717 Terminology of Building Seals and Sealants
C1442 Practice for Conducting Tests on Sealants Using Artificial Weathering Apparatus
G113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
G151 Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources
G154 Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Nonmetallic Materials
G155 Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials
3. Terminology
3.1 Definitions:
3.1.1 Refer to Terminology C717 and G113 for definitions of terms used in this test method.method: standard conditions.
4. Summary of Test Method
4.1 Four test specimens are prepared in U-shaped aluminum channels. After curing, three of the specimens are exposed in the
laboratory accelerated weathering device and the fourth specimen is stored under standard conditions as an unexposed file
specimen. At the end of the exposure period, the specimens are examined for chalking, color change, center cracking, edge
cracking, and loss of adhesion versus the unexposed file specimen.
5. Significance and Use
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
This test method is under the jurisdiction of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.40 on
Weathering.
Current edition approved Dec. 1, 2012March 15, 2015. Published December 2012April 2015. Originally approved in 1994. Last previous edition approved in 20062012
as C1257C1257-06a(2012).-06a. DOI: 10.1520/C1257-06AR12.10.1520/C1257-15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
C1257 − 15
6. Apparatus
6.1 Exposure Apparatus:
6.1.1 Fluorescent UV/Condensation Apparatus, that conforms to the requirements in Practices G151 and G154 with UVA-340
type lamps.
6.1.2 Xenon-Arc Apparatus, that conforms to the requirements in Practices G151 and G155 with daylight type filters.
3 3
6.2 Four-Mill Finish Aluminum U-Channels, 76 mm long by 19 mm wide by 9.5 mm deep (3 by ⁄4 by ⁄8 in.) inside dimensions.
Additional substrate materials may be specified.
6.3 Steel Spatula.
7. P
...