ASTM C1248-08(2012)
(Test Method)Standard Test Method for Staining of Porous Substrate by Joint Sealants
Standard Test Method for Staining of Porous Substrate by Joint Sealants
SIGNIFICANCE AND USE
5.1 Staining of building materials is an aesthetically undesirable occurrence. This test method evaluates the likelihood of a sealant causing an early stain on a porous substrate due to exudation of materials from the sealant. Since this is an accelerated test, it does not necessarily predict that the tested sealants will not stain or discolor porous substrates over longer periods of time.
SCOPE
1.1 This test method covers four types of laboratory tests to determine if a joint sealant has a probability of staining a porous substrate (such as marble, limestone, sandstone, and granite). The tests are on compressed samples and include (1) storage under standard laboratory conditions, (2) storage in an oven, and (3) exposure in a fluorescent UV/condensation device, and (4) exposure in a xenon arc device.
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 problems, 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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Designation: C1248 − 08 (Reapproved 2012)
Standard Test Method for
Staining of Porous Substrate by Joint Sealants
This standard is issued under the fixed designation C1248; 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. Terminology
1.1 This test method covers four types of laboratory tests to 3.1 Definitions:
determine if a joint sealant has a probability of staining a 3.1.1 Refer to Terminology C717 and G113 for definitions
porous substrate (such as marble, limestone, sandstone, and of terms used in this test method.
granite). The tests are on compressed samples and include (1)
4. Summary of Test Method
storage under standard laboratory conditions, (2) storage in an
oven, and (3) exposure in a fluorescent UV/condensation 4.1 In this test method standard joint specimens are com-
device, and (4) exposure in a xenon arc device. pressed and clamped at the manufacturer’s rated movement
capabilityandsubjectedtothefollowingtreatments;(a)fourof
1.2 The values stated in SI units are to be regarded as the
the specimens are stored at standard conditions while under
standard. The values given in parentheses are for information
compression for up to 28 days; (b) four of the specimens are
only.
exposed in an oven while under compression for up to 28 days;
1.3 This standard does not purport to address all of the
(c) four of the specimens are exposed either in a fluorescent
safety problems, if any, associated with its use. It is the
UV/condensation device or in a xenon arc device while under
responsibility of the user of this standard to establish appro-
compression for up to 28 days.
priate safety and health practices and determine the applica-
4.1.1 This test method allows for additional exposure be-
bility of regulatory limitations prior to use.
yond the minimum 28 day exposure period as described in 4.1.
1.4 Thecommitteewithjurisdictionoverthisstandardisnot
If it is desired to extend the exposure period beyond 28 days,
aware of any comparable standards published by other orga-
prepare an additional six specimens for each extended expo-
nizations.
sure period. Of these six specimens prepared, two specimens
each should be stored as described in the three conditions
2. Referenced Documents
named in 4.1.
2.1 ASTM Standards:
4.2 The effects of the test are evaluated by visual inspection
C717 Terminology of Building Seals and Sealants
for changes in surface appearance and average measurements
C1442 Practice for Conducting Tests on Sealants Using
of any stain depth and stain width.
Artificial Weathering Apparatus
4.3 This test method is applicable to any type of elastomeric
G113 Terminology Relating to Natural andArtificial Weath-
joint sealant and any type of porous substrate.
ering Tests of Nonmetallic Materials
G151 Practice for Exposing Nonmetallic Materials inAccel-
5. Significance and Use
erated Test Devices that Use Laboratory Light Sources
5.1 Staining of building materials is an aesthetically unde-
G154 Practice for Operating Fluorescent Ultraviolet (UV)
sirable occurrence.This test method evaluates the likelihood of
Lamp Apparatus for Exposure of Nonmetallic Materials
a sealant causing an early stain on a porous substrate due to
G155 Practice for Operating XenonArc LightApparatus for
exudation of materials from the sealant. Since this is an
Exposure of Non-Metallic Materials
accelerated test, it does not necessarily predict that the tested
sealants will not stain or discolor porous substrates over longer
periods of time.
ThistestmethodisunderthejurisdictionofASTMCommitteeC24onBuilding
Seals and Sealants and is the direct responsibility of Subcommittee C24.40 on
6. Apparatus
Weathering.
Current edition approved Dec. 1, 2012. Published December 2012. Originally
6.1 Forced-Draft Oven.
approved in 1993. Last previous edition approved in 2008 as C1248-08. DOI:
10.1520/C1248-08R12.
6.2 Exposure Apparatus:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.2.1 Fluorescent UV/condensation apparatus that conforms
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
totherequirementsinPracticesG151andG154withUVA-340
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. type lamps.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1248 − 08 (2012)
6.2.2 Xenon-Arc apparatus that conforms to the require-
ments in Practices G151 and G155 with daylight type filters.
6.3 TFE-Fluorocarbon Spacers.
6.4 Masking Tape.
7. Test Specimens
7.1 Substrates shall be 25 by 25 by 75 mm (1 by 1 by 3 in.).
A total of 24 substrates are required to make the twelve test
specimens.
7.1.1 If testing beyond the minimum 28 day exposure
period, prepare an additional twelve substrates to make the six
additional test specimens as required in 4.1.1.
NOTE 1—The precision and bias statement is based on Vermont white
marble and Bethel white granite substrates.
7.2 Primers—Whenaprimerisrecommendedbythesealant
manufacturer, apply the primer to one substrate block of each
test specimen. Apply the primer where the sealant will be in
contact with the substrate.
7.3 Preparation of Test Specimens:
7.3.1 Standard conditions of temperature and relative hu-
midity used throughout this test method are defined as 23 6
2°C (73.4 6 3.6°F) and 50 6 5 %, respectively.
7.3.2 Multi-Component Sealants—Prepare twelve test
specimens for each substrate that is to be used in the test.After
maintaining the unopened sample for at least 24 h at standard
conditions, mix thoroughly for 5 min at least 250 g of base
compound with the appropriate amount of curing agent.Apply
FIG. 1 Stain Test Specimen
1 1
a bead of sealant 13 by 13 by 50 mm ( ⁄2 by ⁄2 by 2 in.)
between parallel 25 by 75 mm (1 by 3 in.) faces of substrates
9.2.1 If testing beyond the minimum 28 day exposure
(see Fig. 1). Use appropriate spacers to form the proper size
period, prepare an additional two compressed specimens at
bead. Use adhesive tape, rubber bands, or clamps to hold the
standard conditions for each extended period, and remove
test specimen together before and after filling it with the
those two compressed specimens at the end of each extended
sealant. In the case of a self leveling sealant, use masking or
period.
other suitable tape to retain the sealant. Use masking tape on
9.3 Placefourcompressedspecimensinanovenat7062°C
the top surface of substrates to prevent sealant from curing on
(158 6 3.6°F). Remove two after 14 days and two after 28
the finished surface. Remove the tape immediately following
days.
filling of the specimen joint cavity.
9.3.1 If testing beyond the minimum 28 day exposure
7.3.3 Single-Component Sealants—Prepare the specimens
period, place an additional two compressed specimens in an
as described in 7.3.2 except that no mixing is required.
oven at 70 6 2°C (158 6 3.6°F) for each extended period, and
Condition the sealed cartridge or bulk container at standard
remove those two compressed specimens at the end of each
conditions for at least 24 h before us
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