1、Designation: C1442 11C1442 14Standard Practice forConducting Tests on Sealants Using Artificial WeatheringApparatus1This standard is issued under the fixed designation C1442; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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 practice covers three types of laboratory weathering exposure procedures for evaluating the effect of actinic
3、 radiation,heat, and moisture on sealants.1.2 The exposure sources used in the three types of artificial weathering devices are the filtered xenon arc, fluorescent ultravioletlamps, and open flame carbon arc based on Practices G155, G154, and G152, respectively.1.3 The values stated in SI units are
4、to be regarded as the standard. The values given in parentheses are provided for informationonly.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 to examination for los
5、s of adhesion or cohesion, or both, followingexposure.1.5 This standard does not purport to address all of the safety concerns, if 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 o
6、f regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and SealantsG113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic MaterialsG141 Guide for Addressing Variability in Exposure Testing of Nonmetallic Materia
7、lsG147 Practice for Conditioning and Handling of Nonmetallic Materials for Natural and Artificial Weathering TestsG151 Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light SourcesG152 Practice for Operating Open Flame Carbon Arc Light Apparatus for Exposu
8、re of Nonmetallic MaterialsG154 Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Nonmetallic MaterialsG155 Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials2.2 ISO Standard:ISO 11431 Building ConstructionSealants: Determination
9、of Adhesion/Cohesion Properties After Exposure to Heat andArtificial Light Through Glass and to Moisture33. Terminology3.1 DefinitionsDefinitions of the following terms are found in Terminology C717: standard conditions, compound, cure,sealant, substrate. Definitions of the following terms are found
10、 in Terminology G113: actinic radiation, control material, filespecimen, fluorescent ultraviolet lamps, irradiance, open flame carbon arc, radiant exposure, sample, solar radiation-ultraviolet,solar radiation-visible, spectral power distribution, xenon arc.4. Summary of Practice4.1 The test sealant
11、may be applied to a variety of types of substrates or tested as a free film. The configuration depends on theproperties to be evaluated following exposure. At least four replicates of each sealant being tested are required. After curing, one1 This practice is under the jurisdiction of ASTM Committee
12、 C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.40 on Weathering.Current edition approved April 1, 2011July 15, 2014. Published April 2011August 2014. Originally approved in 1999. Last previous edition approved in 20062011 asC1442 06.C1442 11. DOI: 10.1520/C1
13、442-11.10.1520/C1442-14.2 For 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.3 Available from American National St
14、andards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.This document is not an ASTM standard and is intended 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 dep
15、ict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current 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 19
16、428-2959. United States1replicate of each sealant being tested is retained as an unexposed file specimen and three replicates are exposed to actinic radiation,heat, and moisture. At the end of the exposure period, the test sealant is examined for property change in comparison with theunexposed file
17、specimen and the performance is compared with that of an exposed control material, if used.4.2 It is recommended that a similar material of known performance under use conditions (a control) be exposed simultaneouslywith the test specimen for evaluation of the performance of the test materials relat
18、ive to that of the control under the samelaboratory exposure conditions. It is preferable to use two control materials, one with relatively poor durability and the other withgood durability.5. Significance and Use5.1 This practice determines the effects of actinic radiation, elevated temperature, an
19、d moisture on sealants and their constituentsunder controlled laboratory artificial weather test conditions.5.2 When conducting exposures in devices which use laboratory light sources, it is important to consider (1) how well theartificial test conditions will reproduce property changes and failure
20、modes caused by end-use environments on the sealant beingtested and (2) the stability ranking of sealants. Refer to Practice G151 for full cautionary guidance regarding laboratory weathering.5.3 Because of differences in the spectral power distributions of the exposure sources (xenon arc, fluorescen
21、t UV lamps, andopen flame carbon arc), as well as other conditions used in the three types of laboratory weathering tests, including temperature,type and amount of moisture, and test cycles, these three procedures may not result in the same performance ranking or types offailure modes of sealants. F
22、urther, different exposure durations may be required for testing the weathering performance of sealantsby the three types of exposures. Comparisons should not be made of the relative stability of sealants exposed in the different typesof apparatus.5.4 Variations in results may be expected when opera
23、ting conditions are varied within the accepted limits of this practice.Therefore, all test results using this practice must be accompanied by a report of the specific operating conditions as required inSection 10. Refer to Practice G151 for detailed information on the caveats applicable to use of re
24、sults obtained according to thispractice.5.5 No laboratory exposure test can be specified as a total simulation of actual use conditions in outdoor environments. Therelative durability of materials in actual use conditions can vary in different locations because of differences in UV radiation, timeo
25、f wetness, relative humidity, temperature, pollutants, and other factors. Results obtained from these laboratory acceleratedexposures can be considered as representative of actual use exposures only when the degree of rank correlation has beenestablished for the specific materials being tested and w
26、hen the failure mode is the same. Exposure of a similar material of knownoutdoor performance, a control, along with the test specimens provides for evaluation in terms of relative durability under the testconditions, which also greatly improves the agreement in test results among different laborator
27、ies.5.6 The acceleration factor relating the exposure time in a laboratory accelerated test to exposure time outdoors required toproduce equivalent degradation is material dependent and can be significantly different for each material and for differentformulations of the same material. Therefore, th
28、e acceleration factor determined for one material cannot be assumed to beapplicable to other materials.5.7 Results of this procedure will depend on the care that is taken to operate the equipment according to Practices G152, G154,and G155. Significant factors include regulation of the line voltage,
29、freedom from salt or other deposits from water, temperaturecontrol, humidity control, where applicable, condition and age of the burners and filters in xenon arc equipment, and age of lampsin fluorescent UV equipment.NOTE 1Additional information on sources of variability and on strategies for addres
30、sing variability in the design, execution and data analysis oflaboratory accelerated exposure tests is found in Guide G141.6. Test Specimens6.1 The size and configuration of the specimens are determined by the specifications of the test method used to evaluate theeffect of exposure on the specimens.
31、 Where practical, it is recommended that specimens be sized to fit the sample holders suppliedwith the apparatus.6.2 Some common specimen configurations may include slab, tensile bar, H-block aymar samples, patties, sheets, drawdowns,preformed joint sealants, prevulcanized elastomeric joint material
32、s, beads, channels, and so forth.6.3 Specimens configured for movement during exposure to artificial weathering conditions also may be used.6.4 Follow the procedures described in Practice G147 for identification and handling of specimens prior to, during and afterexposure.6.5 When destructive tests
33、are used to evaluate weathering stability, ensure that sufficient unexposed file specimens are retainedso that the property of interest can be determined on unexposed file specimens each time exposed materials are evaluated.C1442 1427. Apparatus7.1 Test ChamberChoice of apparatus and exposure condit
34、ions selected shall be by mutual agreement among the interestedparties. Because the different types of exposures may produce different test results, they cannot be used interchangeably withoutsupporting data that demonstrates equivalency of the procedures for the materials tested. The procedures sha
35、ll be as described in7.2, 7.3, and 7.4, which are based on test procedures in ASTM and ISO standards and on parameters used in round robin tests onsealants.7.1.1 The operational fluctuations are allowable deviations from the specified set points for irradiance, temperature and relativehumidity durin
36、g equilibrium operation. They do not imply that the user is allowed to program a set point higher or lower than thatspecified. If the operational fluctuations are greater than the maximum allowable after the equipment has stabilized, discontinuethe test and correct the cause of the problem before co
37、ntinuing.7.2 Procedure for Exposure in Xenon Arc Light ApparatusUnless otherwise specified, use the following operating conditionsand see Practices G151 and G155 for requirements that are not given below:7.2.1 The xenon arc shall be used with daylight type filters to simulate direct exposure to sola
38、r radiation and conform with thespectral power distribution in Practice G155.7.2.2 The irradiance shall be set at a level not less than 0.35 nor greater than 0.51 W/(m2 nm) at 340 nm. The maximumallowable operational fluctuation is 60.02 W/(m2 nm). For equivalent broadband irradiance levels and maxi
39、mum allowableoperational fluctuations at 300400 nm and 300800 nm, consult the manufacturer of the apparatus.7.2.2.1 The irradiance level of 0.51 W/(m2 nm) at 340 nm is preferred for reasons given in Appendix X1.1. However, toaccommodate users who are required to operate the machine at 0.35 W/(m2 nm)
40、 at 340 nm for other tests carried outsimultaneously, the lower irradiance level is an option. The test duration is specified in terms of radiant exposure and the time isadjusted according to the formula in Annex A1.2 to obtain the same radiant exposure at different irradiance levels. See AppendixX2
41、 for discussion on effect of variation in irradiance level.7.2.3 The default exposure cycle shall be 102 min light only followed by a wet period of 18 min light with wetting either bywater spray on the front surface or immersion in water. The water spray temperature is uncontrolled, but is typically
42、 21 6 5C.It may be lower if ambient water temperature is low and a holding tank is not used to store purified water. The recirculatedimmersion water temperature is typically 40 6 5C during the test.NOTE 2For sealants in which moisture has a significant effect on weathering, the two types of wetting
43、may produce different test results due todifferences in the water temperature and because water spray and immersion in water are different kinds of moisture exposures.7.2.4 The exposure cycle of 2 h light only followed by 2 h light plus wetting either by water spray on the front surface orimmersion
44、in water can be used by agreement between concerned parties.NOTE 3The test cycle in 7.2.3 has been used by historical convention and may not adequately simulate the effects of outdoor exposure of sealants.Other cycles can be used by mutual agreement of all concerned parties. The cycle specified in 7
45、.2.4, which provides more thorough wetting than the cyclein 7.2.3, was evaluated in ruggedness tests on sealants.7.2.5 The uninsulated black panel temperature (BPT) shall be set at 70C with a maximum allowable operational fluctuationof 62.5C during the dry period of exposure to the radiation. For th
46、e equivalent insulated black panel temperature (black standardtemperature, BST), consult the manufacturer of the apparatus.7.2.6 In equipment that provides for adjustment of the chamber air temperature, the latter shall be set at 48C with a maximumallowable operational fluctuation of 62C.7.2.7 In xe
47、non arc apparatus that allows for control of relative humidity, it shall be set at 50 % during the dry period of exposureto light. The maximum allowable operational fluctuation is 65 %.610 % in accordance with standard conditions as defined inTerminology C717.7.3 Procedure for Exposure in Fluorescen
48、t UV ApparatusUnless otherwise specified, use the following operating conditionsand see Practices G151 and G154 for requirements that are not given below:7.3.1 Use fluorescent UVA-340 lamps that comply with the spectral power distribution specifications in Practice G154.7.3.2 In apparatus with irrad
49、iance control, irradiance shall be set at 0.89 W/(m2 nm) at 340 nm.NOTE 4The irradiance setting is an attempt to provide irradiance similar to that measured in the fluorescent UV apparatus without irradiance control,when operated at a temperature of 60C. In previous editions of C1442, the irradiance set point was 0.77 W/(m2 nm) at 340 nm. Due to an error incalibration by one manufacturer, the actual irradiance was 0.89 W/(m2 nm) when the specific manufacturers equipment was set at 0.77 W/(m2 nm).Therefore, the correct setting for the recalibrat
