ASTM C1257-06a(2012)
(Test Method)Standard Test Method for Accelerated Weathering of Solvent-Release-Type Sealants
Standard Test Method for Accelerated Weathering of Solvent-Release-Type Sealants
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.
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.
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Standards Content (Sample)
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Designation: C1257 − 06a(Reapproved 2012)
Standard Test Method for
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 3.1.1 Refer to Terminology C717 and G113 for definitions
of terms used in this test method.
1.1 This test method includes two laboratory accelerated
exposure procedures for predicting the effects of ultraviolet or
4. Summary of Test Method
ultraviolet/visible radiation, heat, and moisture on color,
chalking, cracking, and adhesion of solvent-release sealants. 4.1 Four test specimens are prepared in U-shaped aluminum
channels. After curing, three of the specimens are exposed in
1.2 The values stated in SI units are to be regarded as the
the laboratory accelerated weathering device and the fourth
standard. The values given in parentheses are for information
specimen is stored under standard conditions as an unexposed
only.
file specimen.At the end of the exposure period, the specimens
1.3 This standard does not purport to address all of the
are examined for chalking, color change, center cracking, edge
safety concerns, if any, associated with its use. It is the
cracking, and loss of adhesion versus the unexposed file
responsibility of the user of this standard to establish appro-
specimen.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
5. Significance and Use
1.4 Thecommitteewithjurisdictionoverthisstandardisnot
5.1 It is difficult to establish a precise correlation between
aware of any comparable standards published by other orga-
laboratory accelerated and natural weathering because of (1)
nizations.
geographical climatic variations, local weather variation from
normal, and local pollutants and (2) the fact that the accelera-
2. Referenced Documents
tion factor is material dependent, varying with the type of
2.1 ASTM Standards:
material as well as its formulation. This test method is used to
C717 Terminology of Building Seals and Sealants
determine the resistance of a sealant to laboratory accelerated
C1442 Practice for Conducting Tests on Sealants Using
weathering and, if a control material with known outdoor
Artificial Weathering Apparatus
weathering performance is used, the relative weathering per-
G113 Terminology Relating to Natural andArtificial Weath-
formance of the sealant against that of the control material.
ering Tests of Nonmetallic Materials
5.2 Thistestmethodisconductedusingaluminumchannels.
G151 Practice for Exposing Nonmetallic Materials inAccel-
Other substrate materials may show different results.
erated Test Devices that Use Laboratory Light Sources
G154 PracticeforOperatingFluorescentLightApparatusfor
6. Apparatus
UV Exposure of Nonmetallic Materials
G155 Practice for Operating XenonArc LightApparatus for
6.1 Exposure Apparatus:
Exposure of Non-Metallic Materials
6.1.1 Fluorescent UV/Condensation Apparatus, that con-
forms to the requirements in Practices G151 and G154 with
3. Terminology
UVA-340 type lamps.
6.1.2 Xenon-Arc Apparatus, that conforms to the require-
3.1 Definitions:
ments in Practices G151 and G155 with daylight type filters.
6.2 Four-Mill Finish Aluminum U-Channels, 76 mm long
ThistestmethodisunderthejurisdictionofASTMCommitteeC24onBuilding
3 3
by 19 mm wide by 9.5 mm deep (3 by ⁄4 by ⁄8 in.) inside
Seals and Sealantsand is the direct responsibility of Subcommittee C24.40 on
dimensions. Additional substrate materials may be specified.
Weathering.
Current edition approved Dec. 1, 2012. Published December 2012. Originally
6.3 Steel Spatula.
approved in 1994. Last previous edition approved in 2006 as C1257-06a. DOI:
10.1520/C1257-06AR12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 7. Procedure
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
7.1 Condition sufficient compound in an original closed
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. container for at least 24 h at standard conditions. Standard
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C1257 − 06a (2012)
conditions are to be a temperature of 23 6 2°C (73 6 3.6°F) 7.4.1 Procedure for Fluorescent UV/Condensation
and relative humidity of 50 65%. Apparatus—Operate the device in accordance with the proce-
dure in Section 7.3 of Practice C1442. Remove the specimens
7.2 Prepare four sealant test specimens in aluminum
from the apparatus after a minimum of 1000 h of exposure.
U-channels.
7.4.2 Procedure for Xenon-Arc Apparatus—Operate the de-
7.2.1 Thoroughly clean channels using a suitable solvent
vice in accordance with the procedure in Section 7.2 of
such as methyl ethyl ketone (MEK).Allow to dry before filling
Practice C1442. When operated at the preferred irradiance
with sealant.
level of 0.51 W(m · nm) at 340 nm, remove the specimens
7.2.2 Block the ends of the U-channels with masking tape
from the apparatus after a minimum of 1000 h (1835 kJ/(m ·
and overfill the entire channel with conditioned compound
nm) at 340 nm). See Annex A1 in C1442 for determining the
from the bottom up being careful to avoid air entrapment.
exposure time required to provide the same radiant exposure at
Strike the channel off flat with a spatula. Do not remove the
other irradiance levels.
masking tape. It is to stay in place for the entire test. Removing
it may disturb the uncured or cured sealant. 7.5 Condition the samples at 23 6 2°C (73 6 4°F) and 50
6 5
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