1、Designation: C1392 00 (Reapproved 2009)Standard Guide forEvaluating Failure of Structural Sealant Glazing1This standard is issued under the fixed designation C1392; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. 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 guide covers a screening approach to detect failure(adhesive or cohesive) of a structural sealant in a structuralsealan
3、t-glazed window, curtain wall, or other similar system.Presently, only a silicone-sealant that is specifically formu-lated, tested, and marketed as a structural glazing sealant isallowed for structural sealant glazing.1.2 The values stated in either acceptable metric units or inother units shall be
4、regarded separately as the standard. Thevalues stated in each system may not be exact equivalents;therefore, each system must be used independently of the other,without combining values in any way.1.3 There are no ISO standards similar or equivalent to thisASTM standard.1.4 This standard does not pu
5、rport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C
6、717 Terminology of Building Seals and Sealants3. Terminology3.1 Definitions: Refer to Terminology C717 for the follow-ing definitions and description of terms used in this guide:adhesive failure; cohesive failure; deflection; glazing; joint;lite; modulus; silicone sealant; structural sealant; struct
7、uralsealant glazing; and substrate.3.1.1 qualified authority, na person with a recognizeddegree or professional certificate and extensive knowledge andexperience in the particular fields necessary for the evaluationprogram. The authoritys qualification level that is necessary tospecify the evaluatio
8、n criteria and interpret the significance ofthe results depends upon the level of sophistication of theevaluation program. For example, if statistical and finiteelement analyses are being incorporated into the evaluationprogram, then the authority should be knowledgeable andexperienced in these area
9、s.3.1.2 competent person, na person experienced in theoperation of the testing equipment and with an understandingof the construction of the wall system. This person may carryout the field testing under the supervision of the qualifiedauthority.4. Summary of Guide4.1 This guide uses deflection measu
10、rements obtained fromlocalized applied loads to determine locations of sealant failurein an installed structural sealant glazing system.4.2 Initially, the deflection of an existing lite that is fullyadhered by a structural sealant is measured when a discreteedge of the lite is loaded laterally. Subs
11、equently, at a fewselected lites, the structural sealant is cut intentionally tosimulate failure, and the deflection of the lite is measured at thesame lateral load. This provides the basis for determiningduring subsequent tests of other lites in the system whether thesealant has failed.4.3 Addition
12、al lites are evaluated and their deflectionsmeasured to determine the extent of any structural sealantfailure. Structural sealant failure is determined by comparingthe measured deflections with the initial measurements ofdeflection with and without failed (intentionally cut) sealant.5. Significance
13、and Use5.1 This guide suggests a simple means of evaluating theextent of any failure of a structural sealant in an installedstructural sealant glazing system.5.2 A qualified authority should specify the criteria de-scribed in Sections 8 and 9 and should interpret the results andjudge their significa
14、nce for the structural sealant glazingsystem.5.3 The evaluation program measures deflection of loadedlites and does not measure directly any structural sealantfailure. Consequently, the qualified authority interpreting thedata should also evaluate the source of any increased deflectionthat is measur
15、ed. Increased deflection may be due to structural1This guide is under the jurisdiction ofASTM Committee C24 on Building Sealsand Sealants and is the direct responsibility of Subcommittee C24.10 on Specifi-cations, Guides and Practices.Current edition approved Dec. 1, 2009. Published December 2009. O
16、riginallyapproved in 1998. Last previous edition approved in 2005 as C1392 00(2005).DOI: 10.1520/C1392-00R09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the sta
17、ndards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.sealant adhesive or cohesive failure, but may also be due to adecrease in sealant modulus, a change in sealant joint dimen-sions, or othe
18、r nonfailure mechanisms. Selective destructivesampling of areas with increased deflections can assist in thisevaluation.6. Suggested Apparatus6.1 Field Loading Device, provides a frame that can spanbeyond the edges of the loaded lite, while supported by suctioncups on the face of adjacent lites or b
19、y other means that do notadversely affect the stresses in the tested structural sealant andlite (Fig. 1 and Fig. 2). To permit application of a forceperpendicular to the surface of the lite, mount a loading pistonon the lite, with a suction cup or other means near the edge ofthe lite. Place a load c
20、ell between the suction cup and the frameto monitor the applied load. Calibrate the field loading deviceand the load cell prior to use on a project and immediately afterany changes or damage to the device.6.2 Deflection Measurement Device, either an extensometerwith a dial gage mounted on an adjacen
21、t lite or a straight edgewith feeler gages, of length equal to the length of the edge ofthe lite. The device should be accurate to within 10 % of themeasured deflection.7. Sampling7.1 The qualified authority should specify the locations,distribution, and number of applied loads for the structuralsea
22、lant glazing system. Sections 8 and 9 discuss variousapproaches to this selection process.8. Establishing Deflection and Sealant FailureRelationship8.1 Summary of ProcedureEstablishing the deflection/failure relationship requires the specifying authority to selectthe applied load magnitude, the loca
23、tions of the applied loadson the lite, and the criteria for failure length. The followingdescribes various approaches that can be used to select theseparameters, depending upon the sophistication of the evalua-tion program and the desired results. Depending upon theparameters selected the procedure
24、can be used as a crudescreening tool or can be correlated to the actual stresses withinthe structural sealant joint under an applied load and used as arational means of assessing areas of failure that require repair.Using the deflection magnitudes and locations, the initialevaluation establishes the
25、 relationship between loaded litedeflections with intact structural sealant and those with failedstructural sealant.8.2 Applied Load MagnitudeThe qualified authorityspecifies the magnitude of the applied load. The load should belarge enough to produce significant differences in deflectionbetween int
26、act and failed sealant areas, that is, the failurelength criteria. The applied load can be derived from theglazing systems lateral design loads through computer mod-eling (finite element analysis), if it is necessary to relate thetesting to a design load and stress.8.2.1 An initial evaluation will d
27、etermine whether the ap-plied load is large enough to produce significant differences indeflection between areas with intact structural sealant and thosewith failed structural sealant. Excessive loads may crack theglazing material.8.3 Applied Load Locations on a LiteThe evaluationprocedure involves
28、application of a local load to a discreteportion of the edge of a lite. Therefore, a single applicationdoes not necessarily evaluate a structural sealant joint along theentire edge of a lite. The stress distribution in the structuralsealant from the applied load is a function of many variables,inclu
29、ding the relative stiffness of the sealant and glazingmaterial, the location of the suction cup, and any resistancefrom setting blocks or similar items. The qualified authorityshould specify the extent of testing that is appropriate alongeach edge of a lite. This determination can be influenced by t
30、hedegree of assurance that is required from the evaluationprogram. One approach is to space a number of load applica-tion points periodically along the edge of a lite. At closespacings, this approach can evaluate virtually the entire lengthof the structural sealant joint. However, the duration and c
31、ostof such a program can be substantial. Another approach is tomake a preliminary study of lites with failure to assist inunderstanding the failure mechanisms that have occurred andthen use this information to select applied load locations in theareas most likely to have failed. For example, initial
32、 appliedloads may indicate that failure is related to debonding fromprolonged contact with water. In this case, evaluation may beperformed in the areas likely to collect and trap water againstthe structural sealant joint, such as the horizontal edges of a literather than the vertical edges. If failu
33、re is the result of poorsubstrate cleaning or haphazard or inadequate application ofprimer, then the failure may be distributed randomly and loadapplications at the midpoint of each edge may be appropriate.8.4 Failure Length CriteriaThe qualified authority shouldspecify the extent of failure that is
34、 to be detected. A small,isolated length of failure, such as 25 to 50 mm (1 to 2 in.) forFIG. 1 Schematic of Field Loading DeviceC1392 00 (2009)2a6mm(14 in.) thick glass lite, is difficult to detect, but is notlikely to have a significant adverse impact on overall systemperformance. The length selec
35、tion can be based on a rationalcomputer analysis of the stresses in the sealant that result fromfailure and an attempt to keep the stresses below a certain level,such as a 138 KPa (20 psi) structural sealant design stress. Inother cases, the failure length selection criteria may be basedon detecting
36、 the smallest length possible within the accuracyand other parameters of this evaluation program. Detecting afailure length of less than about 100 mm (4 in.) fora6mm(14in.) thick glass lite with medium-modulus structural sealants isnot likely to be practical. Stiffness of the glazing lite and thestr
37、uctural sealant along with other variables can affect thefailure length criteria.8.5 Suggested Procedures for Initial Testing:8.5.1 Determine the accessibility of the existing structuralsealant joint from the interior and exterior of the building. Ifthe joint is accessible only from the exterior, re
38、move theweatherseal along the entire perimeter of the lite prior toproceeding with the evaluation program.8.5.2 Mount the loading device on adjacent lites and locatethe suction cup with load cell at the specified location along theedge of the lite, with the edge of the suction cup set 6 mm (14in.) f
39、rom the edge of the lite. Arrange the direction of loadapplication to avoid damaging the hermetic seal of an insulat-ing glass unit. For example, apply an outward load from theinterior, rather than from the exterior.8.5.3 Gradually increase the applied load on the suction cupto the specified load wi
40、thin 20 s. Maintain the load for one min.Measure the deflection of the edge of the lite while loaded andrecord the load.8.5.4 Repeat 8.5.3 as many additional times as required toobtain two consecutive tests in which the deflection values donot differ by more than 10 % of the deflection determined in
41、the first of the two consecutive tests. Verify that the structuralseal is fully adhered after completing the test.8.5.5 Intentionally cut through the structural sealant jointover a length equal to the failure length criteria specified by thequalified authority. Center the point of load application o
42、verthe center of the length of the cut.8.5.6 Repeat 8.5.3 and obtain the deflection with the inten-tionally cut sealant.8.5.7 Repeat 8.5.1-8.5.6 at seven (minimum) additionallocations.9. Field Evaluation Program9.1 Extent of Field Evaluation ProgramThe qualifiedauthority should specify the extent of
43、 the evaluation programfor the structural sealant glazing system. Such a determinationdepends on several factors, including the desired degree ofassurance, the funds available, and the nature of any knownproblems with the structural sealant glazing system. With theappropriate evaluation parameters,
44、the data can be analyzedstatistically to predict the reliability of the structural sealantsystem. This may allow the evaluation of a relatively smallnumber of samples to gain initial insight into possible systemreliability. If an analysis indicates that the probable number ofinadequately attached li
45、tes is high compared to the totalnumber of lites, then it is likely to be more cost effective torepair all lites than to invest additional funds in furtherevaluation. If the evaluation program results indicate that theprobable number of inadequately attached lites is small com-pared to the total num
46、ber of lites, then it may be less costly toevaluate all of the lites at the design load to identify those thatrequire remedial action.Asimple comparative economic analy-sis of the evaluation program and the repair costs can guide thequalified authority in selecting the appropriate balance betweeneva
47、luation and repair. An article by Schwartz, et al in ASTMSTP 12863provides additional information on in-service reli-ability evaluation of structural sealant glazing systems.3Schwartz, T.A., Zarghamee, M.S., and Kan, F.W., “Structural Silicone Glazing:In-Service Reliability Evaluation,” Science and
48、Technology of Building Seals,Sealants, Glazing and Waterproofing, ASTM STP 1286, James C. Myers, Ed.,ASTM.FIG. 2 Example of a Field Loading Device Mounted on a WallC1392 00 (2009)39.2 Suggested Field Evaluation ProceduresFor each ap-plied load location required by the specifying authority, repeatste
49、ps 8.5.2 and 8.5.3. Remove structural sealant samples andinvestigate conditions at the applied load locations as requiredto ensure that areas with increased deflection are due tostructural sealant failure and to determine the causes of failure,since the probable cause of failure may affect the scope of theevaluation program.10. Report10.1 Report the following information (Fig. 3):10.1.1 All requirements specified by the qualified authority,including applied load magnitude, applied load locations andquantities, and sealant failure length criteria.10.1.2 Address and age
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