ASTM C1392-00

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:C1392–00
Standard Guide for
Evaluating Failure of Structural Sealant Glazing
This standard is issued under the fixed designation C 1392; 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 evaluation program. For example, if statistical and finite
element analyses are being incorporated into the evaluation
1.1 This guide covers a screening approach to detect failure
program, then the authority should be knowledgeable and
(adhesive or cohesive) of a structural sealant in a structural
experienced in these areas.
sealant-glazed window, curtain wall, or other similar system.
3.1.2 competent person, n—a person experienced in the
Presently, only a silicone-sealant that is specifically formu-
operation of the testing equipment and with an understanding
lated, tested, and marketed as a structural glazing sealant is
of the construction of the wall system. This person may carry
allowed for structural sealant glazing.
out the field testing under the supervision of the qualified
1.2 The values stated in either acceptable metric units or in
authority.
other units shall be regarded separately as the standard. The
values stated in each system may not be exact equivalents;
4. Summary of Guide
therefore,eachsystemmustbeusedindependentlyoftheother,
4.1 This guide uses deflection measurements obtained from
without combining values in any way.
localized applied loads to determine locations of sealant failure
1.3 There are no ISO standards similar or equivalent to this
in an installed structural sealant glazing system.
ASTM standard.
4.2 Initially, the deflection of an existing lite that is fully
1.4 This standard does not purport to address all of the
adhered by a structural sealant is measured when a discrete
safety concerns, if any, associated with its use. It is the
edge of the lite is loaded laterally. Subsequently, at a few
responsibility of the user of this standard to establish appro-
selected lites, the structural sealant is cut intentionally to
priate safety and health practices and determine the applica-
simulatefailure,andthedeflectionoftheliteismeasuredatthe
bility of regulatory limitations prior to use.
same lateral load. This provides the basis for determining
2. Referenced Documents during subsequent tests of other lites in the system whether the
sealant has failed.
2.1 ASTM Standards:
4.3 Additional lites are evaluated and their deflections
C 717 Terminology of Building Seals and Sealants
measured to determine the extent of any structural sealant
3. Terminology
failure. Structural sealant failure is determined by comparing
the measured deflections with the initial measurements of
3.1 Definitions: Refer to Terminology C 717 for the follow-
deflection with and without failed (intentionally cut) sealant.
ing definitions and description of terms used in this guide:
adhesive failure; cohesive failure; deflection; glazing; joint;
5. Significance and Use
lite; modulus; silicone sealant; structural sealant; structural
5.1 This guide suggests a simple means of evaluating the
sealant glazing; and substrate.
extent of any failure of a structural sealant in an installed
3.1.1 qualified authority, n—a person with a recognized
structural sealant glazing system.
degree or professional certificate and extensive knowledge and
5.2 A qualified authority should specify the criteria de-
experience in the particular fields necessary for the evaluation
scribed in Sections 8 and 9 and should interpret the results and
program.The authority’s qualification level that is necessary to
judge their significance for the structural sealant glazing
specify the evaluation criteria and interpret the significance of
system.
the results depends upon the level of sophistication of the
5.3 The evaluation program measures deflection of loaded
lites and does not measure directly any structural sealant
ThisguideisunderthejurisdictionofASTMCommitteeC24onBuildingSeals failure. Consequently, the qualified authority interpreting the
and Sealants and is the direct responsibility of Subcommittee C24.10 on Specifi-
datashouldalsoevaluatethesourceofanyincreaseddeflection
cations, Guides and Practices.
that is measured. Increased deflection may be due to structural
Current edition approved Jan. 10, 2000. Published April 2000. Originally
sealant adhesive or cohesive failure, but may also be due to a
published as C 1392 – 98. Last previous edition C 1392 – 98.
Annual Book of ASTM Standards, Vol 04.07.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1392–00
decrease in sealant modulus, a change in sealant joint dimen- the applied load magnitude, the locations of the applied loads
sions, or other nonfailure mechanisms. Selective destructive on the lite, and the criteria for failure length. The following
sampling of areas with increased deflections can assist in this describes various approaches that can be used to select these
evaluation. parameters, depending upon the sophistication of the evalua-
tion program and the desired results. Depending upon the
6. Suggested Apparatus
parameters selected the procedure can be used as a crude
6.1 Field Loading Device, provides a frame that can span
screening tool or can be correlated to the actual stresses within
beyond the edges of the loaded lite, while supported by suction
the structural sealant joint under an applied load and used as a
cups on the face of adjacent lites or by other means that do not
rational means of assessing areas of failure that require repair.
adversely affect the stresses in the tested structural sealant and
Using the deflection magnitudes and locations, the initial
lite (Fig. 1 and Fig. 2). To permit application of a force
evaluation establishes the relationship between loaded lite
perpendicular to the surface of the lite, mount a loading piston
deflections with intact structural sealant and those with failed
on the lite, with a suction cup or other means near the edge of
structural sealant.
thelite.Placealoadcellbetweenthesuctioncupandtheframe
8.2 Applied Load Magnitude—The qualified authority
to monitor the applied load. Calibrate the field loading device
specifies the magnitude of the applied load.The load should be
and the load cell prior to use on a project and immediately after
large enough to produce significant differences in deflection
any changes or damage to the device.
between intact and failed sealant areas, that is, the failure
6.2 Deflection Measurement Device, either an extensometer
length criteria. The applied load can be derived from the
with a dial gage mounted on an adjacent lite or a straight edge
glazing system’s lateral design loads through computer mod-
with feeler gages, of length equal to the length of the edge of
eling (finite element analysis), if it is necessary to relate the
the lite. The device should be accurate to within 10 % of the
testing to a design load and stress.
measured deflection.
8.2.1 An initial evaluation will determine whether the ap-
plied load is large enough to produce significant differences in
7. Sampling
deflectionbetweenareaswithintactstructuralsealantandthose
7.1 The qualified authority should specify the locations,
with failed structural sealant. Excessive loads may crack the
distribution, and number of applied loads for the structural
glazing material.
sealant glazing system. Sections 8 and 9 discuss various
8.3 Applied Load Locations on a Lite—The evaluation
approaches to this selection process.
procedure involves application of a local load to a discrete
8. Establishing Deflection and Sealant Failure
portion of the edge of a lite. Therefore, a single application
Relationship
doesnotnecessarilyevaluateastructuralsealantjointalongthe
entire edge of a lite. The stress distribution in the structural
8.1 Summary of Procedure—Establishing the deflection/
sealant from the applied load is a function of many variables,
failure relationship requires the specifying authority to select
including the relative stiffness of the sealant and glazing
material, the location of the suction cup, and any resistance
from setting blocks or similar items. The qualified authority
should specify the extent of testing that is appropriate along
each edge of a lite.This determination can be influenced by the
degre
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