ASTM C1253-14(2019)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1253 − 14 (Reapproved 2019)
Standard Test Method for
Determining the Outgassing Potential of Sealant Backing
This standard is issued under the fixed designation C1253; 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 4. Summary of Test Method
4.1 A sample of sealant backing material is placed between
1.1 This test method provides a procedure for determining
nonporoussubstratesinacompressedcondition,simulatingthe
the outgassing potential of a sealant backing when it is
placing of sealant backing on a job site. The sealant backing is
punctured during or after installation, with the puncture occur-
then punctured at intervals along its exposed face. A sealant is
ring before the sealant cures.
applied immediately after puncture, and it is tooled to make a
1.2 The values stated in SI units are to be regarded as the
typical butt joint as described in Guide C1193. After tooling,
standard. The values given in parentheses are for information
the specimen is placed in an air circulating oven at elevated
only.
temperature for 1 h and then removed. The specimen is
1.3 This standard does not purport to address all of the 1
compressed12 ⁄2 %ofitsdiameterandinthecompressedstate
safety concerns, if any, associated with its use. It is the
returned to the oven. The specimen is removed after another
responsibility of the user of this standard to establish appro- 1
hour in the oven and compressed another 12 ⁄2 % and returned
priate safety, health, and environmental practices and deter-
to the oven, where it remains for another 2 h. The specimen is
mine the applicability of regulatory limitations prior to use.
removed from the oven, and the sealant is allowed to finish
1.4 This international standard was developed in accor-
curingatroomtemperature,whileinthecompressedcondition.
dance with internationally recognized principles on standard-
The sealant is then removed from the specimen, and the back
ization established in the Decision on Principles for the
face (the face against the sealant backing) is examined. The
Development of International Standards, Guides and Recom-
sealant is slit in half along its length and the size of any voids
mendations issued by the World Trade Organization Technical
estimated.
Barriers to Trade (TBT) Committee.
5. Significance and Use
5.1 This test method is an indicator of a potential sealing
2. Referenced Documents
problem that could occur if a sealant backing is flawed in
2.1 ASTM Standards:
manufacture or transportation to the job site, or abused during
C717 Terminology of Building Seals and Sealants
the installation. If flawed, some sealant backing materials, in
C1193 Guide for Use of Joint Sealants
combination with certain environmental conditions, can
outgas, generating voids in the applied sealant before the
3. Terminology
sealant cures, thereby potentially compromising the cured
3.1 Definitions—Refer toTerminology C717 for the follow-
sealant’s intended performance.
ing terms used in this test method: sealant, cure, sealant
5.2 Voids are also known to be caused by other means and
backing, joint, substrate, non-sag sealant, tooling, and outgas-
under certain conditions such as air entrapment during sealant
sing.
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
ThistestmethodisunderthejurisdictionofASTMCommitteeC24onBuilding
the field. This test method is limited to identifying the
Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on
outgassing potential of a punctured sealant backing by forma-
General Test Methods.
tion of a void in the soft uncured sealant under conditions of
Current edition approved May 1, 2019. Published May 2019. Originally
approved in 1993. Last previous edition approved in 2014 as C1253–14. DOI: heat and compression.
10.1520/C1253-14R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Apparatus
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 Air Circulating Oven,capableofmaintainingatempera-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ture of 122°F (50°C).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1253 − 14 (2019)
6.2 Test Frame and Stylus, as described in Annex A1. 9.6 Remove the specimens from oven, turn the screws to
compress the joint another 12 ⁄2 % of the original dimension
1 1
7. Test Specimens
[1.6 mm ( ⁄16 in.) for a 12.7-mm ( ⁄2-in.) joint], and place them
back in the oven for another 2 h.
7.1 Sealant backing should be 307.8-mm (12-in.) long and
of a width appropriate for use in 12.7-mm ( ⁄2-in.) wide joints.
9.7 Remove the specimens from the oven and allow the
The proper width will be as specified by the sealant backing
sealant to cure at standard conditions for 2 weeks or for the
manufacturer.
sealant manufacturer’s recommended cure time.
NOTE 1—The test method is specifically for 12.7-mm ( ⁄2-in.) wide
9.8 If a clear sealant was used, bubbles will be evident if
joints and sealant backings used in such joints. The procedure is adapted
they occurred. In all cases, slit the sealant along its entire
easily to either wider or narrower joints if all compression is considered
length at the mid point of the joint width using a sharp razor.
as a percent of the joint width.
9.8.1 If properly performed, the slit will pass through any
voids that have formed. Cut the sealant away from the edge of
8. Conditioning
the substrate (a knife generally works better than a razor).
8.1 Condition all sealant backing and sealants at standard
Remove the two sealant halves from the joint and examine the
conditions in accordance with Terminology C717 for a mini-
size of the voids.
mum of 12 h prior to testing.
10. Report
9. Procedure
10.1 Report the test results and observations on the form
9.1 Prepare the test specimen by placing the sealant backing
shown in Fig. 1.
in the simulated joint apparatus (Fig. A1.1 and Fig.
...