1、Designation: C 1442 06Standard Practice forConducting Tests on Sealants Using Artificial WeatheringApparatus1This standard is issued under the fixed designation C 1442; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers three types of laboratory weather-ing exposure procedures for evaluating the effect of actinicradi
3、ation, heat, and moisture on sealants.1.2 The exposure sources used in the three types of artificialweathering devices are the filtered xenon arc, fluorescentultraviolet lamps, and open flame carbon arc based on PracticesG 155, G 154, and G 152, respectively.1.3 The values stated in SI units are to
4、be regarded as thestandard. The values given in parentheses are provided forinformation only.1.4 The ISO standard related to this Practice is ISO 11431.Significant differences exist between the procedures. The ISOspecimens are exposed through glass and are elongated prior toexamination for loss of a
5、dhesion or cohesion, or both, follow-ing exposure.1.5 This standard does not purport 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 r
6、egulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 717 Terminology of Building Seals and SealantsG113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 141 Guide forAddressing Variability in Exposure Testingof Nonmetallic MaterialsG
7、 147 Practice for Conditioning and Handling of Nonme-tallic Materials for Natural and Artificial Weathering TestsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 152 Practice for Operating Open Flame CarbonArc LightApparatus for Exposu
8、re of Nonmetallic MaterialsG 154 Practice for Operating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic MaterialsG 155 Practice for Operating Xenon Arc Light Apparatusfor Exposure of Non-Metallic Materials2.2 ISO Standard:ISO 11431 Building ConstructionSealants: Determina-tion of Adhesion/
9、Cohesion Properties After Exposure toHeat and Artificial Light Through Glass and to Moisture33. Terminology3.1 DefinitionsDefinitions of the following terms arefound in Terminology C 717: compound, cure, sealant, sub-strate. Definitions of the following terms are found in Termi-nology G113: actinic
10、radiation, control material, file speci-men, fluorescent ultraviolet lamps, irradiance, open flamecarbon arc, radiant exposure, sample, solar radiation-ultraviolet, solar radiation-visible, spectral power distribution,xenon arc.4. Summary of Practice4.1 The test sealant may be applied to a variety o
11、f types ofsubstrates or tested as a free film. The configuration depends onthe properties to be evaluated following exposure. At least fourreplicates of each sealant being tested are required. Aftercuring, one replicate of each sealant being tested is retained asan unexposed file specimen and three
12、replicates are exposed toactinic radiation, heat, and moisture.At the end of the exposureperiod, the test sealant is examined for property change incomparison with the unexposed file specimen and the perfor-mance is compared with that of an exposed control material, ifused.4.2 It is recommended that
13、 a similar material of knownperformance under use conditions (a control) be exposedsimultaneously with the test specimen for evaluation of theperformance of the test materials relative to that of the controlunder the same laboratory exposure conditions. It is preferable1This practice is under the ju
14、risdiction of ASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.40 onWeathering.Current edition approved Jan. 1, 2006. Published February 2006. Originallyapproved in 1999. Last previous edition approved in 2003 as C 1442 03.2For referenced ASTM sta
15、ndards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floo
16、r, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.to use two control materials, one with relatively poor durabilityand the other with good durability.5. Significance and Use5.1 This practice determines the effects
17、 of actinic radiation,elevated temperature, and moisture on sealants and theirconstituents under controlled laboratory artificial weather testconditions.5.2 When conducting exposures in devices which use labo-ratory light sources, it is important to consider (1) how well theartificial test condition
18、s will reproduce property changes andfailure modes caused by end-use environments on the sealantbeing tested and (2) the stability ranking of sealants. Refer toPractice G 151 for full cautionary guidance regarding labora-tory weathering.5.3 Because of differences in the spectral power distribu-tions
19、 of the exposure sources (xenon arc, fluorescent UVlamps, and open flame carbon arc), as well as other conditionsused in the three types of laboratory weathering tests, includingtemperature, type and amount of moisture, and test cycles,these three procedures may not result in the same performanceran
20、king or types of failure modes of sealants. Further, differentexposure durations may be required for testing the weatheringperformance of sealants by the three types of exposures.Comparisons should not be made of the relative stability ofsealants exposed in the different types of apparatus.5.4 Varia
21、tions in results may be expected when operatingconditions are varied within the accepted limits of this practice.Therefore, all test results using this practice must be accom-panied by a report of the specific operating conditions asrequired in Section 10. Refer to Practice G 151 for detailedinforma
22、tion on the caveats applicable to use of results obtainedaccording to this practice.5.5 No laboratory exposure test can be specified as a totalsimulation of actual use conditions in outdoor environments.The relative durability of materials in actual use conditions canvary in different locations beca
23、use of differences in UVradiation, time of wetness, relative humidity, temperature,pollutants, and other factors. Results obtained from theselaboratory accelerated exposures can be considered as repre-sentative of actual use exposures only when the degree of rankcorrelation has been established for
24、the specific materials beingtested and when the failure mode is the same. Exposure of asimilar material of known outdoor performance, a control,along with the test specimens provides for evaluation in termsof relative durability under the test conditions, which alsogreatly improves the agreement in
25、test results among differentlaboratories.5.6 The acceleration factor relating the exposure time in alaboratory accelerated test to exposure time outdoors requiredto produce equivalent degradation is material dependent andcan be significantly different for each material and for differentformulations
26、of the same material. Therefore, the accelerationfactor determined for one material cannot be assumed to beapplicable to other materials.5.7 Results of this procedure will depend on the care that istaken to operate the equipment according to Practices G 152,G 154, and G 155. Significant factors incl
27、ude regulation of theline voltage, freedom from salt or other deposits from water,temperature control, humidity control, where applicable, con-dition and age of the burners and filters in xenon arc equip-ment, and age of lamps in fluorescent UV equipment.NOTE 1Additional information on sources of va
28、riability and onstrategies for addressing variability in the design, execution and dataanalysis of laboratory accelerated exposure tests is found in Guide G 141.6. Test Specimens6.1 The size and configuration of the specimens are deter-mined by the specifications of the test method used to evaluatet
29、he effect of exposure on the specimens. Where practical, it isrecommended that specimens be sized to fit the sample holderssupplied with the apparatus.6.2 Some common specimen configurations may includeslab, tensile bar, H-block aymar samples, patties, sheets,drawdowns, preformed joint sealants, pre
30、vulcanized elasto-meric joint materials, beads, channels, and so forth.6.3 Specimens configured for movement during exposure toartificial weathering conditions also may be used.6.4 Follow the procedures described in Practice G 147 foridentification and handling of specimens prior to, during andafter
31、 exposure.6.5 When destructive tests are used to evaluate weatheringstability, ensure that sufficient unexposed file specimens areretained so that the property of interest can be determined onunexposed file specimens each time exposed materials areevaluated.7. Apparatus7.1 Test ChamberChoice of appa
32、ratus and exposure con-ditions selected shall be by mutual agreement among theinterested parties. Because the different types of exposures mayproduce different test results, they cannot be used interchange-ably without supporting data that demonstrates equivalency ofthe procedures for the materials
33、tested. The procedures shall beas described in 7.2, 7.3, and 7.4, which are based on testprocedures in ASTM and ISO standards and on parametersused in round robin tests on sealants.7.1.1 The operational fluctuations are allowable deviationsfrom the specified set points for irradiance, temperature an
34、drelative humidity during equilibrium operation. They do notimply that the user is allowed to program a set point higher orlower than that specified. If the operational fluctuations aregreater than the maximum allowable after the equipment hasstabilized, discontinue the test and correct the cause of
35、 theproblem before continuing.7.2 Procedure for Exposure in Xenon Arc LightApparatusUnless otherwise specified, use the followingoperating conditions and see Practices G 151 and G 155 forrequirements that are not given below:7.2.1 The xenon arc shall be used with daylight type filtersto simulate dir
36、ect exposure to solar radiation and conform withthe spectral power distribution in Practice G 155.7.2.2 The irradiance shall be set at a level not less than 0.35nor greater than 0.51 W/(m2 nm) at 340 nm. The maximumallowable operational fluctuation is 60.02 W/(m2 nm). Forequivalent broadband irradia
37、nce levels and maximum allow-able operational fluctuations at 300400 nm and 300800 nm,consult the manufacturer of the apparatus.C14420627.2.2.1 The irradiance level of 0.51 W/(m2 nm) at 340 nmis preferred for reasons given in Appendix X1.1. However, toaccommodate users who are required to operate th
38、e machine at0.35 W/(m2 nm) at 340 nm for other tests carried outsimultaneously, the lower irradiance level is an option. The testduration is specified in terms of radiant exposure and the timeis adjusted according to the formula in Annex A1.2 to obtainthe same radiant exposure at different irradianc
39、e levels. SeeAppendix X2 for discussion on effect of variation in irradiancelevel.7.2.3 The default exposure cycle shall be 102 minutes lightonly followed by a wet period of 18 minutes light with wettingeither by water spray on the front surface or immersion inwater. The water spray temperature is t
40、ypically 21 6 5C, butmay be lower if ambient water temperature is low and aholding tank is not used to store purified water. For immersionwater temperature specifications, consult the manufacturer ofthe test apparatus.NOTE 2Water spray and immersion in water are different kinds ofmoisture exposures
41、and can produce different results.7.2.4 The exposure cycle of 2 h light only followed by 2 hlight plus wetting either by water spray on the front surface orimmersion in water can be used by agreement betweenconcerned parties.NOTE 3The test cycle in 7.2.3 has been used by historical conventionand may
42、 not adequately simulate the effects of outdoor exposure ofsealants. Other cycles can be used by mutual agreement of all concernedparties. The cycle specified in 7.2.4, which provides more thoroughwetting than the cycle in 7.2.3, was evaluated in ruggedness tests onsealants.7.2.5 The uninsulated bla
43、ck panel temperature (BPT) shallbe set at 70C with a maximum allowable operational fluctua-tion of 62.5C during the dry period of exposure to theradiation. For the equivalent insulated black panel temperature(black standard temperature, BST), consult the manufacturer ofthe apparatus.7.2.6 In equipme
44、nt that provides for adjustment of thechamber air temperature, the latter shall be set at 48C with amaximum allowable operational fluctuation of 62C.7.2.7 In xenon arc apparatus that allows for control ofrelative humidity, it shall be set at 50 % during the dry periodof exposure to light. The maximu
45、m allowable operationalfluctuation is 65%.7.3 Procedure for Exposure in Fluorescent UV ApparatusUnless otherwise specified, use the following operating condi-tions and see Practices G 151 and G 154 for requirements thatare not given below:7.3.1 Use fluorescent UVA-340 lamps that comply with thespect
46、ral power distribution specifications in Practice G 154.7.3.2 In apparatus with irradiance control, irradiance shallbe set at 0.89 W/(m2 nm) at 340 nm.NOTE 4The irradiance setting is an attempt to provide irradiancesimilar to that measured in the fluorescent UV apparatus without irradi-ance control,
47、 when operated at a temperature of 60C. In previous editionsof C 1442, the irradiance set point was 0.77 W/(m2 nm) at 340 nm. Dueto an error in calibration by one manufacturer, the actual irradiance was0.89 W/(m2 nm) when the specific manufacturers equipment was set at0.77 W/(m2 nm). Therefore, the
48、correct setting for the recalibratedequipment is 0.89 W/(m2 nm). However, for users of equipment made byother manufacturers that had been correctly calibrated, running at the newset point will result in a change in the actual irradiance of the test. If indoubt, users should consult the manufacturer
49、of their device for clarifica-tion. There can be differences in test results when using differentirradiance levels. Refer to Appendix X2 for information regarding theeffect of irradiance.7.3.3 Seal any holes larger than 2 mm in specimens and anyopening larger than 1 mm around irregularly shaped specimensto prevent loss of water vapor. Attach porous specimens to asolid backing, such as aluminum, that can act as a vaporbarrier.7.3.4 For specimens that are less than 20 mm thick, includ-ing support dimensions, the exposure cycle shall be8hUVatan uninsulated blac
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