1、Designation:E99805 (Reapproved 2011) Designation: E998 12Standard Test Method forStructural Performance of Glass in Windows, Curtain Walls,and Doors Under the Influence of Uniform Static Loads byNondestructive Method1This standard is issued under the fixed designation E998; the number immediately fo
2、llowing the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test meth
3、od is a nondestructive test procedure to establish the nature of stresses induced in glass subjected to uniformstatic loads. A procedure is provided for using this stress information to estimate the probability of breakage of the glass.1.2 This test method is applicable to glass of various degrees o
4、f temper; for example, annealed, heat-strengthened, fullytempered, laminated, insulating, and combinations thereof.1.3 This test method describes a process of applying specific test loads to glass. The test may be conducted using the standardtest frame specified herein or a test frame of the users d
5、esign.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversionsto inch-pound 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 problems, if
6、any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific precautionary statements see Section 67.2. Terminology Referenced Documents2.1 A
7、STM Standards:2E631 Terminology of Building Constructions3. Terminology3.1 Definitions:3.1.1 For definitions of general terms related to building construction used in this test method refer to Terminology E631.3.2 Definitions of Terms Specific to This Standard:3.2.1 aspect ratioa ratio of long side
8、to short side of the glass lite.2.23.2.2 average breaking stress (ABS)the average maximum principal tensile stress (MPTS) at failure, representative of theglass under test. The ABS is dependent on a number of factors including geometry, time history of load, surface condition, andso forth. Glasses w
9、ith residual surface stresses, such as heat-strengthened or fully tempered, must have their residual stresses addedto the state of stress at the specified load. As defined for use in the standard, the ABS is for annealed glass.2.33.2.3 coeffcient of variationthe ratio (decimal fraction) of the stand
10、ard deviation of the maximum principal tensile stress(MPTS) at failure to the ABS.2.43.2.4 equivalent design loada magnitude of a uniform load and the load duration selected by the specifying authority torepresent design loads.2.53.2.5 glass specimenthe glass to be tested, for example, a single lite
11、, an insulating glass unit, laminated glass, and so forth(does not include test frame).1This test method is under the jurisdiction ofASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.51 on Performanceof Windows, Doors, Skylights and Curtain Walls.Cur
12、rent edition approved Oct.April 1, 2011.2012. Published October 2011.May 2012. Originally approved in 1984. Last previous edition approved in 20052011 asE99805.E998 11. DOI: 10.1520/E0998-05R11.10.1520/E0998-12.2The boldface numbers in parentheses refer to the references listed at the end of this te
13、st method.2For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intend
14、ed only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current
15、 versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.63.2.6 maximum principal tensile stress (MPTS) a maximum calculated tensile stress based on strai
16、n gage measurements.2.73.2.7 negative loada load that results in the indoor side of a glass specimen being the high-pressure side.2.83.2.8 permanent set of test framea load-induced permanent displacement from an original position of the test frame.2.93.2.9 positive loada load that results in the out
17、door side of a glass specimen being the high-pressure side.2.103.2.10 probability of breakagethe probability that a glass specimen breaks when tested at a given equivalent design load.General industry practice to express probability as lites per 1000 lites.2.113.2.11 residual stressan initial, state
18、 of stress on unloaded, unglazed glass resulting from the manufacturing process(heat-strengthening, tempering).2.123.2.12 specifying authoritythe professional or professionals responsible for determining and furnishing the informationrequired to perform this test method as described in Section 910.3
19、.Summary of Test Method3.1This test method consists of:3.1.1Glazing the test specimen into a test frame that is mounted on or against a test chamber.3.1.2Supplying or exhausting air from the chamber at a rate required to maintain a test-pressure difference across the testspecimen.3.1.3Measuring and
20、observing deflections, deformations, specimen strains, and the nature of any failures.3.1.4Recording the results in an orderly manner.3.2Methods of loading to nondestructive levels are provided.3.3Test data are used to predict glass structural performance characteristics.4. Summary of Test Method4.1
21、 This test method consists of:4.1.1 Glazing the test specimen into a test frame that is mounted on or against a test chamber.4.1.2 Supplying or exhausting air from the chamber at a rate required to maintain a test-pressure difference across the testspecimen.4.1.3 Measuring and observing deflections,
22、 deformations, specimen strains, and the nature of any failures.4.1.4 Recording the results in an orderly manner.4.2 Methods of loading to nondestructive levels are provided.4.3 Test data are used to predict glass structural performance characteristics.5. Significance and Use4.1This5.1 This test met
23、hod is a standard procedure to determine a stress pattern and estimate a probability of breakage of glasstested under uniform static loads.4.2Loads5.2 Loads on glass in windows, curtain walls, and doors may vary greatly in magnitude, direction, and duration. Anunderstanding of wind loads on the buil
24、ding is required for selection of test loads and interpretation of results with respect toexpected exposure at a particular site.4.3The5.3 The strength of glass varies with many different factors including surface condition, load duration, geometry, relativehumidity, and temperature (1, 2, 3, 4).34.
25、4A5.4 A thorough understanding of the variations of the strength of glass and the nature of loading is required to interpretresults of this test method.4.5The5.5 The proper use of this test method requires a knowledge of the principles of pressure, deflection and strainmeasurement, stress/strain rel
26、ationships, and statistical estimating techniques.5.6. Apparatus5.1The6.1 The description of apparatus is general in nature.Any equipment capable of performing the test procedure within theallowable tolerances shall be permitted.5.26.2 Major Components:5.2.13The boldface numbers in parentheses refer
27、 to the references listed at the end of this test method.E998 1226.2.1 Test Frame, in which glass specimens are mounted for testing. The test frame shall provide either standardized supportconditions or specified support conditions. Specifications of standardized support conditions are presented in
28、Annex A1.5.2.26.2.2 Test Chamber, sealed, with an opening in which or against which the test frame shall be installed. At least one staticpressure tap shall be provided to measure the test chamber pressure and shall be so located that the reading is minimally affectedby the velocity of the air suppl
29、y to or from the test chamber or any other air movement. The air supply opening into the testchamber shall be arranged so that the air does not impinge directly on the glass specimen with any significant velocity. A meansof access into the test chamber shall be permitted to facilitate adjustments an
30、d observations after the specimen has been installed.5.2.36.2.3 Air System, a controllable blower, compressed air supply, exhaust system, reversible blower or other device designed toapply the equivalent design load to the glass specimen with required control.5.2.46.2.4 Pressure Measuring Apparatus,
31、 to record continuously the test chamber pressure within an accuracy of 62%.5.2.56.2.5 Deflection-Measuring System, for measuring deflections within an accuracy of 60.25 mm (0.01 in.).56.2.5.1 The deflection indicator shall be mounted so that deflection of the test chamber or test frame is not inclu
32、ded in thedeflection gage reading. Provisions shall be made to ensure that readings can be made from a safe location.5.2.66.2.6 Strain Gage MeasurementsAppendix X1 describes apparatus and techniques required for proper strain measure-ments on glass.5.2.76.2.7 Temperature Measuring Apparatus, to meas
33、ure the ambient temperature within an accuracy of 60.6C (1F).5.2.86.2.8 Relative Humidity Measuring Apparatus, to measure the relative humidity within an accuracy of 62%.6.Safety Precautions6.1Proper precautions to protect observers in the event of glass specimen failure shall be observed. At the pr
34、essures used in thistest method, considerable energy and hazard are involved. In cases of breakage, the hazard to personnel is less with an exhaustsystem, as the specimen will tend to blow into rather than out of the test chamber. No personnel shall be permitted in such chambersduring tests. All rea
35、sonable precautions shall be exercised during conduct of the test.7. Sampling and Glass Specimens7.1Surface condition, cutting, fabrication, and packaging of the glass specimens to be tested shall be representative of the glasswhose strength is to be evaluated.7.2All glass specimens shall be visuall
36、y inspected for edge or surface irregularities prior to testing, and all questionable glassspecimens shall not be tested. All questionable glass specimens shall be reported to the specifying authority.7.3Glass specimens shall be handled carefully at all times because the strength of glass is influen
37、ced by its surface and edgeconditions. Safety Precautions7.1 Proper precautions to protect observers in the event of glass specimen failure shall be observed. At the pressures used inthis test method, considerable energy and hazard are involved. In cases of breakage, the hazard to personnel is less
38、with an exhaustsystem, as the specimen will tend to blow into rather than out of the test chamber. No personnel shall be permitted in such chambersduring tests. All reasonable precautions shall be exercised during conduct of the test.8. Sampling and Glass Specimens8.1 Surface condition, cutting, fab
39、rication, and packaging of the glass specimens to be tested shall be representative of the glasswhose strength is to be evaluated.8.2 All glass specimens shall be visually inspected for edge or surface irregularities prior to testing, and all questionable glassspecimens shall not be tested. All ques
40、tionable glass specimens shall be reported to the specifying authority.8.3 Glass specimens shall be handled carefully at all times because the strength of glass is influenced by its surface and edgeconditions.9. Calibration89.1 Pressure-measuring systems, deflection-measuring devices, and strain gag
41、es shall be routinely checked. If calibration isrequired, the manufacturers recommendations or good engineering practice shall be followed.9.10. Required Information9.1The10.1 The specifying authority shall provide the magnitude of the equivalent design load (positive or negative) and theallowable p
42、robability of breakage for the glass specimens.9.2The10.2 The specifying authority shall state whether the glass specimens shall be glazed in a standard test frame or in a testframe designed to simulate a specific glazing system. If the test frame is to simulate a specific glazing system, complete g
43、lazingdetails and support conditions shall be provided by the specifying authority.E998 12310.11. Procedure101.1 Measure and record ambient temperature and the relative humidity.101.2 Install strain gages to the low pressure side of the glass specimen according to procedures in Annex A2.101.3 Instal
44、l glass specimens in the test frame in accordance with recommendations in Annex A1 for standard supportconditions or as specified for a specific glazing system by the manufacturer.101.4 Record reference strain reading at no-load conditions.10.5Load11.5 Load specimen to low level pressure, 20 % of de
45、sign load for 1 min. Release load. Allow 3 to 5-min gage andrestoration time.101.6 Apply one-half of the specified design load to the glass specimen. Take initial set of pressure, deflection, and strainreadings at one-half of design load. Reduce the test pressure to 0, and vent the test chamber for
46、a period of 3 to 5 min beforepressure-measuring apparatus is adjusted to zero.10.6.1If11.6.1 If air leakage around the test specimen is excessive, tape shall be permitted to be used to cover any cracks andjoints through which the leakage is occurring. Tape shall not be used when there is a probabili
47、ty that it may significantly restrictdifferential movement between the glass and test frame.101.7 Apply load to the glass specimen in increments of 20 % of specified design load, recording strain gage readings at eachincrement. Maintain the load at each increment of design load until all strain gage
48、 readings are taken. For each increment, the loadshould not be applied for a period under 1 min or longer than 5 min in duration. Continuous load-time records shall be kept forthe duration of the loading.10.8If11.8 If the specimen breaks prior to reaching the specified design load, check for permane
49、nt set of the test frame andchamber damage before testing another specimen.11.12. Report11.1The12.1 The report shall include the following information:112.1.1 Date of the test, the date of the report, the ambient temperature, and the relative humidity.112.1.2 Identification of the glass specimens (manufacturer, source of supply, dimensions, both nominal and measured,manufacturers designation, materials, and other pertinent information).112.1.3 Detailed drawings of the glass specimen, test frame, test chamber, a complete description of pressure-measuringapparat
