ASTM C1253-93(2005)
(Test Method)Standard Test Method for Determining the Outgassing Potential of Sealant Backing
Standard Test Method for Determining the Outgassing Potential of Sealant Backing
SIGNIFICANCE AND USE
This test method is an indicator of a potential sealing problem that could occur if a sealant backing is flawed in manufacture or transportation to the job site, or abused during the installation. If flawed, some sealant backing materials, in combination with certain environmental conditions, can outgas, generating voids in the applied sealant before the sealant cures, thereby potentially compromising the cured sealant’intended performance.
Voids are also known to be caused by other means and under certain conditions such as air entrapment during sealant application, trapped air in the substrate releasing into the uncured sealant, incompatibility of the sealant with the sealant backing or substrate, or inhospitable installation conditions in the field. This test method is limited to identifying the outgassing potential of a punctured sealant backing by formation of a void in the soft uncured sealant under conditions of heat and compression.
SCOPE
1.1 This test method provides a procedure for determining the outgassing potential of a sealant backing when it is punctured during or after installation, with the puncture occurring before the sealant cures.
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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:C1253–93 (Reapproved 2005)
Standard Test Method for
Determining the Outgassing Potential of Sealant Backing
This standard is issued under the fixed designation C 1253; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope compressed12 ⁄2 %ofitsdiameterandinthecompressedstate
returned to the oven. The specimen is removed after another
1.1 This test method provides a procedure for determining
hour in the oven and compressed another 12 ⁄2 % and returned
the outgassing potential of a sealant backing when it is
to the oven, where it remains for another 2 h. The specimen is
punctured during or after installation, with the puncture occur-
removed from the oven, and the sealant is allowed to finish
ring before the sealant cures.
curingatroomtemperature,whileinthecompressedcondition.
1.2 The values stated in SI units are to be regarded as the
The sealant is then removed from the specimen, and the back
standard. The values given in parentheses are for information
face (the face against the sealant backing) is examined. The
only.
sealant is slit in half along its length and the size of any voids
1.3 This standard does not purport to address all of the
estimated.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety and health practices and determine the applica-
5.1 This test method is an indicator of a potential sealing
bility of regulatory limitations prior to use.
problem that could occur if a sealant backing is flawed in
2. Referenced Documents manufacture or transportation to the job site, or abused during
the installation. If flawed, some sealant backing materials, in
2.1 ASTM Standards:
combination with certain environmental conditions, can out-
C 717 Terminology of Building Seals and Sealants
gas, generating voids in the applied sealant before the sealant
C 1193 Guide for Use of Joint Sealants
cures, thereby potentially compromising the cured sealant’s
3. Terminology
intended performance.
5.2 Voids are also known to be caused by other means and
3.1 Definitions—Refer to Terminology C 717 for the fol-
under certain conditions such as air entrapment during sealant
lowing terms used in this test method: sealant, cure, sealant
application, trapped air in the substrate releasing into the
backing, joint, substrate, non-sag sealant, tooling, and outgas-
uncured sealant, incompatibility of the sealant with the sealant
sing.
backing or substrate, or inhospitable installation conditions in
4. Summary of Test Method
the field. This test method is limited to identifying the
outgassing potential of a punctured sealant backing by forma-
4.1 A sample of sealant backing material is placed between
tion of a void in the soft uncured sealant under conditions of
nonporoussubstratesinacompressedcondition,simulatingthe
heat and compression.
placing of sealant backing on a job site. The sealant backing is
then punctured at intervals along its exposed face. A sealant is
6. Apparatus
applied immediately after puncture, and it is tooled to make a
6.1 Air Circulating Oven,capableofmaintainingatempera-
typical butt joint as described in Guide C 1193. After tooling,
ture of 122°F (50°C).
the specimen is placed in an air circulating oven at elevated
6.2 Test Frame and Stylus, as described in Annex A1.
temperature for 1 h and then removed. The specimen is
7. Test Specimens
ThistestmethodisunderthejurisdictionofASTMCommitteeC24onBuilding
7.1 Sealant backing should be 307.8-mm (12-in.) long and
Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on
of a width appropriate for use in 12.7-mm ( ⁄2-in.) wide joints.
General Test Methods.
The proper width will be as specified by the sealant backing
Current edition approved Jan. 1, 2005. Published January 2005. Originally
approved in 1993. Last previous edition approved in 1998 as C 1253–93(1998).
manufacturer.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
NOTE 1—The test method is specifically for 12.7-mm ( ⁄2-in.) wide
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 joints and sealant backings used in such joints. The procedure is adapted
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1253–93 (2005)
easily to either wider or narrower joints if all compression is considered
9.8.1 If properly performed, the slit will pass through any
as a percent of the joint width.
voids that have formed. Cut the sealant away from the edge of
the substrate (a knife generally works better than a razor).
8. Conditioning
Remove the two sealant halves from the joint and examine the
8.1 Condition all sealant backing and sealants at standard
size of the voids.
conditions for a minimum of 12 h prior to testing. Standard
conditions for this procedure are 23 6 2°C (73.4 6 3.6°F) and
10. Report
50 6 5 % relative humidity.
10.1 Report the test results and observations on the form
shown in Fig. 1.
9. Procedure
9.1 Prepare the test specimen by placing the sealant backing
in the simulated joint apparatus (Fig. A1.1 and Fig. A1.2),
which has been adjusted to a 12.7-mm ( ⁄2-in.) wide opening.
Exercise care not to abuse or puncture the sealant backing
during installation.
9.2 Use the stylus (Fig. A1.3) to form six 9.5-mm ( ⁄8-in.)
deep punctures starting 38-mm (1 ⁄2-in.) from the end, spaced
25.4-mm (1-in.) apart, and centered on the width of the sealant
backing. The marks on the channel, used to form the joint, aid
in locating the quick, even placement of the punctures.
9.2.1 If the sealant backing has a tendency to slip down in
the joint during the puncturing, slip a temporary solid form
(such as a length of wood) beneath the backing to hold it in
place. Remove this when the pu
...
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