ASTM E997-15(2021)
(Test Method)Standard Test Method for Evaluating Glass Breakage Probability Under the Influence of Uniform Static Loads by Proof Load Testing
Standard Test Method for Evaluating Glass Breakage Probability Under the Influence of Uniform Static Loads by Proof Load Testing
SIGNIFICANCE AND USE
5.1 Glass specimens to be tested shall be mounted in a standard test frame with four sides supported, or in a test frame designed to represent specific glazing conditions.
5.2 Loads on glass in windows, curtain walls, and doors may vary greatly in magnitude, direction, and duration. Any design load (wind, snow, etc.) that can reasonably be applied to the test specimens or transformed into an equivalent uniform design load can be considered. Load transformation techniques are addressed in the literature (1, 2, 3).3
5.3 The strength of glass varies with many different factors including surface condition, load duration, geometry, relative humidity, and temperature (4). A thorough understanding of those strength variations is required to interpret results of this test method.
SCOPE
1.1 This proof load test method is a procedure to determine, with a 90 % confidence level, if the probability of breakage under design loads for a given population of glass specimens is less than a selected value. It is not intended to be a design standard for determining the load resistance of glass. Practice E1300 shall be used for this purpose.
1.2 This test method describes apparatus and procedures to select and apply a proof load to glass specimens, to determine the number of glass specimens to be tested, and to evaluate statistically the probability of breakage. This test method may be conducted using the standard test frame specified herein or a test frame of the user's design.
1.3 Proper use of this test method requires a knowledge of the principles of pressure measurement and an understanding of recommended glazing practices.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 7.
1.6 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.
General Information
Relations
Standards Content (Sample)
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:E997 −15 (Reapproved 2021)
Standard Test Method for
Evaluating Glass Breakage Probability Under the Influence
of Uniform Static Loads by Proof Load Testing
This standard is issued under the fixed designation E997; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 Thisproofloadtestmethodisaproceduretodetermine,
E631Terminology of Building Constructions
with a 90 % confidence level, if the probability of breakage
E1300PracticeforDeterminingLoadResistanceofGlassin
underdesignloadsforagivenpopulationofglassspecimensis
Buildings
less than a selected value. It is not intended to be a design
standard for determining the load resistance of glass. Practice
3. Terminology
E1300 shall be used for this purpose.
3.1 Definitions:
3.1.1 For definitions of general terms related to building
1.2 This test method describes apparatus and procedures to
construction used in this test method refer to Terminology
select and apply a proof load to glass specimens, to determine
E631.
the number of glass specimens to be tested, and to evaluate
3.2 Definitions of Terms Specific to This Standard:
statistically the probability of breakage. This test method may
3.2.1 coeffıcient of variation, v—ratio of the standard devia-
be conducted using the standard test frame specified herein or
tion of the breakage load to the mean breakage load.
a test frame of the user’s design.
3.2.2 design load, n—the specified uniform load and load
1.3 Proper use of this test method requires a knowledge of
duration.
the principles of pressure measurement and an understanding
3.2.3 glass specimen, n—theglasstobetested,forexample,
of recommended glazing practices.
a single pane, an insulating glass unit, laminated glass, etc.
1.4 The values stated in inch-pound units are to be regarded
(does not include test frame).
as standard. The values given in parentheses are mathematical
3.2.4 glass specimen breakage, n—the fracture or cracking
conversions to SI units that are provided for information only
of any glass component of a glass specimen.
and are not considered standard.
3.2.5 negative load, n—an outward-acting load that results
1.5 This standard does not purport to address all of the
in the indoor side of a glass specimen being the high-pressure
safety concerns, if any, associated with its use. It is the
side.
responsibility of the user of this standard to establish appro-
3.2.6 positive load, n—an inward-acting load that results in
priate safety, health, and environmental practices and deter-
the outdoor side of a glass specimen being the high-pressure
mine the applicability of regulatory limitations prior to use.
side.
Specific precautionary statements are given in Section 7.
3.2.7 probability of breakage, n—theprobabilitythataglass
1.6 This international standard was developed in accor-
specimen will break when tested at a given load.
dance with internationally recognized principles on standard-
3.2.8 proof load, n—a uniform load at which glass speci-
ization established in the Decision on Principles for the
mens shall be tested.
Development of International Standards, Guides and Recom-
3.2.9 proof load factor, a, n—the constant which, when
mendations issued by the World Trade Organization Technical
multiplied by the design load, determines the proof load.
Barriers to Trade (TBT) Committee.
3.2.10 specifying authority, n—professional(s) responsible
fordeterminingandfurnishinginformationrequiredtoperform
the test.
This test method is under the jurisdiction of ASTM Committee E06 on
Performance of Buildings and is the direct responsibility of E06.52 on Glass Use in
Buildings. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Aug. 1, 2021. Published August 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1984. Last previous edition approved in 2015 as E997–15. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E0997-15R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E997−15 (2021)
4. Summary of Test Method 6.2.4 Pressure Measuring Apparatus, to record continuous
test chamber pressures within an accuracy of 62%.
4.1 This test method consists of individually glazing glass
6.2.5 Temperature Measuring Apparatus, to measure the
specimens in a test frame that is mounted into or against one
ambient temperature within an accuracy of 61°F (0.6°C).
face of a test chamber and supplying air to, or exhausting air
6.2.6 Relative Humidity Apparatus, to measure the relative
from, the test chamber so that each glass specimen is exposed
humidity within an accuracy of 62%.
to a proof load. Load-time records shall be kept for each glass
specimen. Each glass specimen break shall be recorded.
7. Safety Precautions
4.2 After testing the required number of glass specimens, it
7.1 Proper precautions shall be taken to protect observers in
is determined, with a 90 % confidence level, if the probability
the event of glass breakage. At the pressures used in this test
of breakage under design loads for the given population of
method, considerable energy and hazard are involved. In cases
glassspecimensislessthanaspecifiedallowableprobabilityof
of breakage, the hazard to personnel is less with an exhaust
breakage.
system, as the specimen will tend to blow into rather than out
of the test chamber. Personnel should not be permitted in such
5. Significance and Use
chambers during tests.
5.1 Glass specimens to be tested shall be mounted in a
8. Sampling and Glass Specimens
standardtestframewithfoursidessupported,orinatestframe
designed to represent specific glazing conditions.
8.1 Surfacecondition,cutting,fabrication,andpackagingof
the glass specimens shall be representative of the glass whose
5.2 Loads on glass in windows, curtain walls, and doors
strength is to be evaluated.
may vary greatly in magnitude, direction, and duration. Any
designload(wind,snow,etc.)thatcanreasonablybeappliedto
8.2 All glass specimens shall be visually inspected for edge
the test specimens or transformed into an equivalent uniform
or surface irregularities prior to testing. All glass specimens
designloadcanbeconsidered.Loadtransformationtechniques
with edge or surface irregularities not representative of the
are addressed in the literature (1, 2, 3).
glass whose strength is to be evaluated shall not be tested.
5.3 The strength of glass varies with many different factors
8.3 Glass specimens shall be handled carefully at all times
including surface condition, load duration, geometry, relative
because the strength of glass is influenced by its surface and
humidity, and temperature (4). A thorough understanding of
edge conditions.
those strength variations is required to interpret results of this
9. Calibration
test method.
9.1 Pressure-measuring systems should be verified prior to
6. Apparatus
testing. If calibration is required, the manufacturer’s recom-
6.1 The description of apparatus is general in nature. Any mendations or good engineering practices shall be followed.
equipment capable of performing the test procedure within the
10. Required Information
allowable tolerances is permitted.
10.1 The specifying authority shall provide the design load
6.2 Major Components:
(positive or negative), the orientation of the glass specimen to
6.2.1 Test Frame,inwhichglassspecimensaremountedfor
the test chamber, the design load allowable probability of
testing. The test frame shall provide either standardized sup-
breakage for the glass specimens, and the coefficient of
port conditions or specified support conditions. Specifications
variation of the breakage loads typical of the glass specimens
of standardized support conditions are presented in AnnexA1.
tested.
6.2.2 Test Chamber, sealed, with an opening in which or
against which the test frame is installed. At least one static
10.2 The specifying authority shall state whether the glass
pressure tap shall be provided to measure the test chamber
specimens shall be glazed in a standard test frame (see Annex
pressure and shall be so located that the reading is minimally
A1) or in a test frame designed to simulate a specific glazing
affected by the velocity of the air supply to or from the test
system. If the test frame is to simulate a specific glazing
chamber or any air movement.The air supply opening into the
system, complete glazing details and support conditions shall
test chamber shall be arranged so that the air does not impinge
be provided by the specifying authority.
directly on the glass specimen with any significant velocity.A
11. Selection of Proof Load and Initial Sample Size
means of access into the test chamber may be provided to
facilitate adjustments and observations after the specimen has
11.1 The glass specimens shall be tested with a proof load
been installed.
that is larger than the design load. The proof load is found by
6.2.3 Air System, a controllable blower, compressed air
multiplying the design load by the proof load factor, a,as
supply, exhaust system, reversible blower, or other device
follows:
designed to apply the proof load to the glass specimen with
q 5 aq (1)
p d
required control.
where:
q = proof load,
p
The boldface numbers in parentheses refer to a list of references at the end of
a = proof load factor, and
this standard.
E997−15 (2021)
TABLE 2 Required Zero Break Sample Size (ν=0.15)
q = design load.
d
Proof Load Factor, a
11.1.1 If the glass specimens are to be tested in a standard
1.3 1.4 1.5 1.6
test frame, the proof load factor, a, is found in Table 1 through
0.010 14
Table 4, given the design load allowable probability of break-
0.009 16
age and the appropriate coefficient of variation, ν. The proof 0.008 17
0.007 19 10
load factor, a, is selected with due regard to the maximum
Design Load 0.006 22 11
capacity of the test apparatus. The tables indicate the initial
Probability of Breakage 0.005 25 13
0.004 31 15
sample size, n, of glass specimens to be tested. If the sample
0.003 39 19 10
sizeentryinTable1throughTable4isblankanalternateproof
0.002 26 13
load factor shall be selected.
0.001 47 23 13
11.2 Rationale to develop Table 1 through Table 4 is
presented in Appendix X1.
12. Procedure
design load is less than the allowable probability of breakage.
Ifelectedbythespecifyingauthorityorotherappropriateparty,
12.1 Measure and record the ambient temperature and the
testing may then continue in accordance with procedures in
relative humidity.
12.2 through 12.5.
12.2 Install glass specimens in the test frame in accordance
12.7 If, during the course of testing N samples, a second
with recommendations presented in Annex A1 for standard
break occurs, record the break and, if desired, determine from
supportconditionsorasspecifiedforaspecificglazingsystem.
Table 9 through Table 12 (using the design load probability of
12.3 Apply one half of the proof load to the glass specimen
failure,theappropriatecoefficientofvariation,andtheselected
andholdfor10s.Reducethetestpressuretozeroandventthe
proofloadfactor)the“twobreak”samplesize,N .Thissample
test chamber for a period from 3min to 5 min before the
size represents the total number of tests to be conducted with
pressure-measuring apparatus is adjusted to zero.
only two associated specimen breaks such that there is a 90%
12.4 If air leakage around the glass specimen is excessive,
confidence level that the actual probability of breakage at the
tapemaybeusedtocoveranycracksandjointsthroughwhich
design load is less than the allowable probability of breakage.
leakage is occurring. However, tape shall not be used when
Ifelectedbythespecifyingauthorityorotherappropriateparty,
thereisapossibilitythatitwillsignificantlyrestrictdifferential
testing may then continue in accordance with procedures in
movement between the glass specimen and the test frame.
12.2 through 12.5.
12.5 Apply the proof load to the glass specimen as quickly
12.8 Inspect the test frame for permanent deformation or
aspossible,butnolongerthan15s.Maintaintheproofloadfor
other failures of principal members. If failure of the standard
the same duration as the specified design load, and then vent
test frame occurs, it shall be appropriately stiffened and
the test chamber. Continuous load-time records shall be kept
strengthened and the test restarted. If failure occurs in a user
for the duration of the loading.
specified test frame, the proof load shall be reduced or the test
frame appropriately stiffened or strengthened and the test
12.6 If the glass specimen does not break, remove it from
restarted.
the test frame. Select a new glass specimen, and repeat
procedures in 12.2 through 12.5. If the glass specimen does
12.9 Rationale used to develop Table 5 through Table 12 is
break, record the break and, if desired, determine from Table 5
presented in Appendix X1. Guidance for testing a sample of
through Table 8 (using the design load probability of failure,
glass specimens with more than two breaks is not given in this
the appropriate coefficient of variation, and the selected proof
test method, but may be determined using the principles
load factor) the “one break” sample size, N . This sample size
described in Appendix X1.
represents the total number of tests to be conducted with only
one associated specimen break such that there is a 90%
13. Interpretation of Results
confidence level that the actual probability of breakage at the
13.1 If no specimen breaks during the testing of the initial
sample size, n, given in Table 1 through Table 4, there is a
90%confidencelevelthattheactualprobabilityofbreakageat
TABLE 1 Required Zero Break Sample Size (ν=0.10)
the design load is less than the allowable probability of
Proof Load Factor, a
breakage.
1.2 1.3
0.010 10
13.2 If one specimen breaks during the testing of sample
0.009 11
size, N , given in Table 5 through Table 8, there is a 90%
0.008 12
confidence level that the actual probability of breakage at the
0.007 13
Design Load 0.006 14
design load is less than the allowable probability of breakage.
Probability of Breakage 0.005 16
0.004 19 13.3 If two specimens break during the testing of sample
0.003 23
size, N , given in Table 9 through Table 12
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