ASTM E997-01(2009)
(Test Method)Standard Test Method for Structural Performance of Glass in Exterior Windows, Curtain Walls, and Doors Under the Influence of Uniform Static Loads by Destructive Methods
Standard Test Method for Structural Performance of Glass in Exterior Windows, Curtain Walls, and Doors Under the Influence of Uniform Static Loads by Destructive Methods
SIGNIFICANCE AND USE
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.
A standard test frame shall be used when it is desired to evaluate the probability of breakage of glass specimens with edge support conditions held constant.
A test frame designed to represent a specific glazing condition shall be used when it is desired to evaluate the probability of breakage of glass specimens in the specified glazing system.
Loads on glass in windows, curtain walls, and doors may vary greatly in magnitude, direction, and duration. Any load (wind, snow, etc.) that can be transformed into a 60-s duration equivalent uniform design load can be considered. Load transformation techniques are addressed in the literature (1, 2, 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 test method is a procedure to determine if the probability of breakage of glass specimens tested is significantly greater than, significantly less than, or not significantly different than the specified probability of breakage when exposed to a specified 60-s duration equivalent design load. 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 60-s duration 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.
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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 7.
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Designation: E997 – 01 (Reapproved 2009)
Standard Test Method for
Structural Performance of Glass in Exterior Windows,
Curtain Walls, and Doors Under the Influence of Uniform
Static Loads by Destructive Methods
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
1.1 This test method is a procedure to determine if the 2.1 ASTM Standards:
probability of breakage of glass specimens tested is signifi- E1300 Practice for Determining Load Resistance of Glass
cantly greater than, significantly less than, or not significantly in Buildings
different than the specified probability of breakage when
3. Terminology
exposed to a specified 60-s duration equivalent design load. It
3.1 Definitions:
isnotintendedtobeadesignstandardfordeterminingtheload
resistance of glass. Practice E1300 shall be used for this 3.2 coeffıcient of variation, n—ratio of the standard devia-
tion of the breakage load to the mean breakage load.
purpose.
1.2 This test method describes apparatus and procedures to 3.3 equivalent design load, n—the specified uniform design
load converted to a 60-s duration (see 4.2).
select and apply a 60-s duration proof load to glass specimens,
todeterminethenumberofglassspecimenstobetested,andto 3.4 glass specimen, n—the glass to be tested, for example,
a single pane, an insulating glass unit, laminated glass, etc.
evaluate statistically the probability of breakage. This test
method may be conducted using the standard test frame (does not include test frame).
3.5 glass specimen breakage, n—the fracture or cracking of
specified herein or a test frame of the user’s design.
1.3 Proper use of this test method requires a knowledge of any glass component of a glass specimen.
3.6 negative load, n—an outward-acting load that results in
the principles of pressure measurement and an understanding
of recommended glazing practices. the indoor side of a glass specimen being the high-pressure
1.4 The values stated in inch-pound units are to be regarded side.
3.7 positive load, n—an inward-acting load that results in
as standard.
1.5 This standard does not purport to address all of the the outdoor side of a glass specimen being the high-pressure
side.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.8 probability of breakage, n—the probability that a glass
specimen will break when tested at a given load. General
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific precau- industry practice is to express the probability of breakage as
lites per 1000 lites.
tionary statements are given in Section 7.
3.9 proof load, n—a magnitude of uniform load at which
glass specimens shall be tested.
This test method is under the jurisdiction of ASTM Committee E06 on
Performance of Buildings and is the direct responsibility of E06.51 on Performance
of Windows, Doors, Skylights and Curtain Walls. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2009. Published January 2010. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1984. Last previous edition approved in 2001 as E997–01. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E0997-01R09. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E997 – 01 (2009)
3.10 proof load factor, a, n—the constant which, when pressure and shall be so located that the reading is minimally
multiplied by the equivalent design load, determines the proof affected by the velocity of the air supply to or from the test
load. chamber or any air movement.The air supply opening into the
3.11 specifying authority, n—professional(s)responsiblefor test chamber shall be arranged so that the air does not impinge
determiningandfurnishinginformationrequiredtoperformthe directly on the glass specimen with any significant velocity.A
test. means of access into the test chamber may be provided to
facilitate adjustments and observations after the specimen has
4. Summary of Test Method
been installed.
4.1 This test method consists of individually glazing glass 6.2.3 Air System, a controllable blower, compressed air
specimens in a test frame that is mounted into or against one supply, exhaust system, reversible blower, or other device
face of a test chamber and supplying air to, or exhausting air designed to apply the proof load to the glass specimen with
from, the test chamber so that each glass specimen is exposed required control.
to a 60-s duration proof load. Load-time records shall be kept 6.2.4 Pressure Measuring Apparatus, to record continuous
for each glass specimen. Each glass specimen break shall be
test chamber pressures within an accuracy of 62%.
recorded.
6.2.5 Temperature Measuring Apparatus, to measure the
4.2 After testing the required number of glass specimens, it
ambient temperature within an accuracy of 61°F (0.6°C).
isdeterminediftheprobabilityofbreakageissignificantlyless
6.2.6 Relative Humidity Apparatus, to measure the relative
than, significantly greater than, or not significantly different
humidity within an accuracy of 62%.
than the specified probability of breakage.
7. Safety Precautions
5. Significance and Use
7.1 Proper precautions to protect observers in the event of
5.1 Glass specimens to be tested shall be mounted in a
glass breakage should be observed. At the pressures used in
standardtestframewithfoursidessupported,orinatestframe
this test method, considerable energy and hazard are involved.
designed to represent specific glazing conditions.
In cases of breakage, the hazard to personnel is less with an
5.1.1 Astandard test frame shall be used when it is desired
exhaust system, as the specimen will tend to blow into rather
toevaluatetheprobabilityofbreakageofglassspecimenswith
thanoutofthetestchamber.Personnelshouldnotbepermitted
edge support conditions held constant.
in such chambers during tests.
5.1.2 A test frame designed to represent a specific glazing
condition shall be used when it is desired to evaluate the
8. Sampling and Glass Specimens
probability of breakage of glass specimens in the specified
8.1 Surfacecondition,cutting,fabrication,andpackagingof
glazing system.
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
8.2 All glass specimens shall be visually inspected for edge
load (wind, snow, etc.) that can be transformed into a 60-s
or surface irregularities prior to testing, and all questionable
duration equivalent uniform design load can be considered.
glass specimens shall not be tested.
Load transformation techniques are addressed in the literature
8.3 Glass specimens shall be handled carefully at all times
(1, 2, 3).
5.3 The strength of glass varies with many different factors because the strength of glass is influenced by its surface and
edge conditions.
including surface condition, load duration, geometry, relative
humidity, and temperature (4). A thorough understanding of
9. Calibration
those strength variations is required to interpret results of this
test method.
9.1 Pressure-measuring systems should be routinely
checked. If calibration is required, the manufacturer’s recom-
6. Apparatus
mendations or good engineering practices should be followed.
6.1 The description of apparatus is general in nature. Any
equipment capable of performing the test procedure within the
10. Required Information
allowable tolerances is permitted.
10.1 The specifying authority shall provide the magnitude
6.2 Major Components:
of the equivalent design load (positive or negative), the
6.2.1 Test Frame,inwhichglassspecimensaremountedfor
orientation of the glass specimen to the test chamber, the
testing. The test frame shall provide either standardized sup-
allowable probability of breakage for the glass specimens, and
port conditions or specified support conditions. Specifications
the coefficient of variation of the breakage loads typical of the
of standardized support conditions are presented inAnnexA1.
glass specimens tested.
6.2.2 Test Chamber, sealed, with an opening in which or
10.2 The specifying authority shall state whether the glass
against which the test frame is installed. At least one static
specimens shall be glazed in a standard test frame (seeAnnex
pressure tap shall be provided to measure the test chamber
A1) or in a test frame designed to simulate a specific glazing
system. If the test frame is to simulate a specific glazing
system, complete glazing details and support conditions shall
The boldface numbers in parentheses refer to a list of references at the end of
this standard. be provided by the specifying authority.
E997 – 01 (2009)
TABLE 1 Required Sample Size (n = 0.10) TABLE 2 Required Sample Size (n = 0.15)
Proof Load Factor, a Proof Load Factor, a
1.2 1.3 1.3 1.4 1.5 1.6
0.010 11 0.010 15
0.009 12 0.009 16
0.008 12 0.008 18 10
0.007 13 0.007 20 11
Equivalent Design Load 0.006 15 Equivalent Design Load 0.006 22 12
Probability of Breakage 0.005 17 Probability of Breakage 0.005 26 13
0.004 19 0.004 31 15
0.003 24 0.003 40 19 11
A
0.002 31 10 0.002 55 26 14
A A
0.001 53 15 0.001 106 47 24 13
A A
Testing is not recommended because of excess expense. Testing is not recommended because of excess expense.
thereisapossibilitythatitwillsignificantlyrestrictdifferential
11. Selection of Proof Load and Sample Size
movement between the glass specimen and the test frame.
11.1 The glass specimens shall be tested with a proof load
12.5 Apply the proof load to the glass specimen in a period
that is larger than the equivalent design load.The proof load is
from 40 to 60 s, maintain the proof load for a period of 60 s,
found by multiplying the design load by the proof load factor,
and then vent the test chamber. Continuous load-time records
a, as follows:
shall be kept for the duration of the loading.
q 5 aq (1)
p d
12.6 If the glass specimen does not break, remove it from
thetestframe,anddiscardit.Selectanewglassspecimen,and
where:
repeat procedures in 12.2-12.5. If the glass specimen does
q = proof load,
p
break, record the break and continue.
a = proof load factor, and
q = equivalent design load. 12.7 Inspect the test frame for permanent deformation or
d
other failures of principal members. If failure of the standard
11.1.1 If the glass specimens are to be tested in a standard
test frame occurs, it shall be appropriately stiffened and
testframe,theproofloadfactor, a,isfoundinTables1-4,given
strengthened and the test restarted. If failure occurs in a user
the equivalent design load probability of breakage and the
specified test frame, the proof load shall be reduced or the test
appropriate coefficient of variation, n.The proof load factor, a,
frame appropriately stiffened or strengthened and the test
corresponding to the minimum sample size or the maximum
restarted.
capacity of the loading apparatus, shall be selected.
12.8 Select a new glass specimen and repeat procedures in
11.1.2 If the glass specimens are to be tested in a test frame
that is representative of a specific glazing system, the maxi- 12.2-12.5.
mumallowableproofloadthatcanberesistedbythetestframe
13. Interpretation of Results
shall be determined using engineering principles. The proof
load factor, a, is then determined by dividing the maximum 13.1 Ifnospecimenbreaksduringthetest,theprobabilityof
allowable proof load by the equivalent design load. Tables 1-4
breakage at the equivalent design load is judged to be signifi-
are then entered with the calculated value of a, the specified cantly less than the specified probability of breakage.
coefficient of variation, n, and the equivalent design load
13.2 If more than four glass specimens break, the probabil-
probability of breakage to determine the number of glass ity of breakage at the equivalent design load is judged to be
specimens to be tested. If the corresponding entry inTable 1 is significantly greater than the specified probability of breakage.
blank, then the proof load factor should be reduced to a value 13.3 If one to four glass specimen breaks occur, the prob-
based upon a minimum sample size. ability of breakage at the equivalent design load is judged to
11.2 Rationale to developTables 1-4 is presented inAppen- not be significantly different than the specified probability of
dix X1. breakage.
12. Procedure 14. Report
12.1 Measure and record the ambient temperature and the 14.1 The report shall include the following information:
relative humidity. 14.1.1 The date of the test, the date of the report, the
12.2 Install glass specimens in the test frame in accordance ambient temperature, and the relative humidity.
with recommendations presented in Annex A1 for standard 14.1.2 Identification of the glass specimens (manufacturer,
supportconditionsorasspecifiedforaspecificglazingsystem. source of supply, dimensions both nominal and measured,
12.3 Apply one half of the proof load to the glass specimen manufacturer’s designation, materials, and other pertinent
andholdfor10s.Reducethetestpressuretozeroandventthe information).
test chamber for a period from 3 to 5 min before the 14.1.3 Detaileddrawingsoftheglassspecimens,testframe,
pressure-measuring apparatus is adjusted to zero. andtestchamberindicatingorientationoftheglassspecimento
12.4 If air leakage around the glass specimen is excessive, thetestchamber.Acompletedescriptionofpressure-measuring
tapemaybeusedtocoveranycracksandjointsthroughwhich apparatus, and a statement that the test was conducted using a
leakage is occurring. However, tape shall not be used when standard test frame or a test frame of the user’s design.
E997 – 01 (2009)
TABLE 3 Required Sample Size (n = 0.20)
Proof Load Factor, a
1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2
0.010 15 10
0.009 16 11
0.008 18 12
Equivalent 0.007 20 13
Design Load 0.006 23 15 10
Probability of 0.005 27 18 12
Breakage 0.004 33 21 15 10
0.003 45 29 19 13 10
A
0.002 66 41 27 19 13 10
A A A
0.001 142 88 57 39 27 19 14 11
A
Testing is not recommended because of excess expense.
TABLE 4 Required Sample Size (n = 0.25)
Proof Load Factor, a
1.5 1.6 1
...
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