1、Designation: G153 13Standard Practice forOperating Enclosed Carbon Arc Light Apparatus forExposure of Nonmetallic Materials1This standard is issued under the fixed designation G153; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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. Scope*1.1 This practice covers the basic principles and operatingprocedures for using enclosed carbon-arc light and
3、waterapparatus intended to reproduce the weathering effects thatoccur when materials are exposed to sunlight (either direct orthrough window glass) and moisture as rain or dew in actualuse. This practice is limited to the procedures for obtaining,measuring, and controlling conditions of exposure. A
4、numberof exposure procedures are listed in an appendix; however, thispractice does not specify the exposure conditions best suitedfor the material to be tested.NOTE 1Practice G151 describes performance criteria for all exposuredevices that use laboratory light sources. This practice replaces Practic
5、eG23, which describes very specific designs for devices used for carbon-arcexposures. The apparatus described in Practice G23 is covered by thispractice.1.2 Test specimens are exposed to enclosed carbon arc lightunder controlled environmental conditions.1.3 Specimen preparation and evaluation of the
6、 results arecovered in various methods or specifications for specificmaterials. General guidance is given in Practice G151 and ISO4892-1. More specific information about methods for deter-mining the change in properties after exposure and reportingthese results is described in ISO 4582.1.4 The value
7、s stated in SI units are to be regarded as thestandard.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
8、 of regulatory limitations prior to use.1.5.1 Should any ozone be generated from the operation ofthe light source, it shall be carried away from the testspecimens and operating personnel by an exhaust system.2. Referenced Documents2.1 ASTM Standards:2D3980 Practice for Interlaboratory Testing of Pai
9、nt andRelated Materials (Withdrawn 1998)3E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodG23 Practice for Operating Light-Exposure Apparatus(Carbon-Arc Type) With and Without Water for Exposureof Nonmetallic Materials (Withdrawn 2000)3G113 Terminology
10、Relating to Natural and Artificial Weath-ering Tests of Nonmetallic MaterialsG151 Practice for Exposing Nonmetallic Materials in Accel-erated Test Devices that Use Laboratory Light Sources2.2 ISO Standards:ISO 4582 PlasticsDetermination of the Changes of Colourand Variations in Properties After Expo
11、sure to DaylightUnder Glass, Natural Weathering or Artificial Light4ISO 4892-1 PlasticsMethods of Exposure to LaboratoryLight Sources, Part 1, General Guidance4ISO 4892-4 PlasticsMethods of Exposure to LaboratoryLight Sources, Part 4, Open-Flame Carbon Arc Lamp42.3 CIE Standards:CIE-Publ. No. 85: Re
12、commendations for the Integrated Ir-radiance and the Spectral Distribution of Simulated SolarRadiation for Testing Purposes53. Terminology3.1 DefinitionsThe definitions that are applicable to thispractice are provided in Terminology G113.3.1.1 As used in this practice, the term sunlight is identical
13、to the terms daylight and solar irradiance, global as they aredefined in Terminology G113.1This practice is under the jurisdiction of ASTM Committee G03 on Weatheringand Durability and is the direct responsibility of Subcommittee G03.03 onSimulated and Controlled Exposure Tests.Current edition appro
14、ved July 1, 2013. Published July 2013. Originally approvedin 1997. Last previous edition approved in 2004 as G153 04(2010). DOI:10.1520/G0153-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
15、volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Avai
16、lable from Secretary, U.S. National Committee, CIE, National Institute ofStandards and Technology, Gaithersburg, MD 20899.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
17、14. Summary of Practice4.1 Specimens are exposed to repetitive cycles of light andmoisture under controlled environmental conditions. Moistureusually is produced by spraying the test specimen withdemineralized/deionized water or by condensation of watervapor onto the specimen.4.2 The exposure condit
18、ion may be varied by selection ofthe following:4.2.1 Filter,4.2.2 The type of moisture exposure,4.2.3 The timing of the light and moisture exposure,4.2.4 The temperature of light exposure, and4.2.5 The timing of a light/dark cycle.4.3 Comparison of results obtained from specimens exposedin same mode
19、l of apparatus should not be made unlessreproducibility has been established among devices for thematerial to be tested.4.4 Comparison of results obtained from specimens exposedin different models of apparatus should not be made unlesscorrelation has been established among devices for the materialto
20、 be tested.5. Significance and Use5.1 The use of this apparatus is intended to induce propertychanges associated with the end use conditions, including theeffects of sunlight, moisture, and heat. These exposures mayinclude a means to introduce moisture to the test specimen.Exposures are not intended
21、 to simulate the deterioration causedby localized weather phenomena, such as atmosphericpollution, biological attack, and saltwater exposure.Alternatively, the exposure may simulate the effects of sunlightthrough window glass. Typically, these exposures would in-clude moisture in the form of humidit
22、y.NOTE 2Caution: Refer to Practice G151 for full cautionary guidanceapplicable to all laboratory weathering devices.5.2 Variation in results may be expected when operatingconditions are varied within the accepted limits of this practice.Therefore, no reference shall be made to results from the use o
23、fthis practice unless accompanied by a report detailing thespecific operating conditions in conformance with Section 10.5.2.1 It is recommended that a similar material of knownperformance, a control, be exposed simultaneously with thetest specimen to provide a standard for comparative purposes.It is
24、 best practice to use control materials known to haverelatively poor and good durability. It is recommended that atleast three replicates of each material evaluated be exposed ineach test to allow for statistical evaluation of results.6. Apparatus6.1 Laboratory Light SourceEnclosed carbon arc lights
25、ources typically use carbon rods which contain a mixture ofmetal salts. An electric current is passed between the carbonrods which burn and give off ultraviolet, visible, and infraredradiation. Use carbon rods recommended by the device manu-facturer.6.1.1 FilterThe most commonly used filters are bor
26、osili-cate glass globes which fit around the carbon burners. Otherfilters may be used by mutual agreement by the interestedparties as long as the filter type is reported in conformance withthe report section in Practice G151.6.1.2 The emission spectra of the enclosed carbon arc showsstrong emission
27、in the long wavelength ultraviolet region.Emissions in the visible, infrared, and short wavelength ultra-violet below 350 nm generally are weaker than in sunlight (seeTable 1).6.1.3 The following factors can affect the spectral powerdistribution of enclosed carbon arc light sources:6.1.3.1 Differenc
28、es in the composition and thickness offilters can have large effects on the amount of short wavelengthUV radiation transmitted.6.1.3.2 Aging (solarization) of filters can result in changesin filter transmission. The aging properties of filters can beinfluenced by the composition. Aging of filters ca
29、n result in asignificant reduction in the short wavelength UV emission of aburner.6.1.3.3 Accumulation of dirt or other residue on filters canaffect filter transmission.6.1.3.4 Differences in chemical composition of carbons.6.1.4 Spectral Irradiance for Enclosed Carbon with Day-light FiltersThe data
30、 in Table 1 are representative of thespectral irradiance received by a test specimen mounted in thespecimen plane.6.2 Test ChamberThe design of the test chamber mayvary, but it should be constructed from corrosion resistantmaterial, and in addition to the radiant source, may provide formeans of cont
31、rolling temperature and relative humidity. WhenTABLE 1 Typical Relative Spectral Power Distribution forEnclosed Carbon-Arc with Daylight FiltersA,BSpectral BandpassWavelength in nmTypicalPercentCBenchmark SolarRadiation PercentD,E,F 290 0.0290 # # 320 0.1 5.8320 # 360 19.9 40.0360 # 400 80.1 54.2ADa
32、ta in Table 1 are the irradiance in the given bandpass expressed as apercentage of the total irradiance from 290 to 400 nm. Annex A1 states how todetermine relative spectral irradiance.BThe data in Table 1 is representative and is based on the rectangular integrationof the spectral power distributio
33、ns enclosed carbon arcs with daylight filters. Thereis not enough data available to establish a meaningful specification.CFor any individual spectral power distribution, the calculated percentage for thebandpasses in Table 1 will sum to 100 %. Test results can be expected to differbetween exposures
34、using enclosed carbon arc devices in which the spectral powerdistributions differ by as much as that allowed by the tolerances typical for daylightfilters. Contact the manufacturer of the enclosed carbon-arc devices for specificspectral power distribution data for the enclosed carbon-arc and filters
35、 used.DThe benchmark solar radiation data is defined in ASTM G177 and is foratmospheric conditions and altitude chosen to maximize the short wavelength UVfraction of solar UV. While this data is provided for comparison purposes only, it isdesirable for a laboratory accelerated light source with dayl
36、ight filters to provide aspectrum that is a close match to this solar spectrum.EPrevious versions of this standard used solar radiation data from Table 4 of CIEPublication Number 85. See Appendix X2 for more information comparing thesolar radiation data used in this standard with that for CIE 85 Tab
37、le 4.FFor the benchmark solar spectrum, the UV irradiance (290 to 400 nm) is 9.8 %and the visible irradiance (400 to 800 nm) is 90.2 % expressed as a percentage ofthe total irradiance from 290 to 800 nm. The percentages of UV and visibleirradiances on samples exposed in enclosed carbon-arc devices m
38、ay vary due tothe number and reflectance properties of specimens being exposed. This is basedon measurements in xenon-arc devices but similar measurements have not beenmade in enclosed carbon-arc devices.G153 132required, provision shall be made for the spraying of water onthe test specimen or for t
39、he formation of condensate on theexposed face of the specimen.6.2.1 The radiant source(s) shall be located with respect tothe specimens such that the irradiance at the specimen facecomplies with the requirements in Practice G151.6.3 Instrument CalibrationTo ensure standardization andaccuracy, the in
40、struments associated with the exposureapparatus, for example, timers, thermometers, wet bulbsensors, dry bulb sensors, humidity sensors, UV sensors andradiometers, require periodic calibration to ensure repeatabilityof test results. Whenever possible, calibration should betraceable to national or in
41、ternational standards. Calibrationschedule and procedure should be in accordance with manu-facturers instructions.6.4 ThermometerEither insulated or uninsulated black orwhite panel thermometers may be used. Thermometers shallconform to the descriptions found in Practice G151. The typeof thermometer
42、used, the method of mounting on specimenholder, and the exposure temperature shall be stated in the testreport.6.4.1 Some specifications may require chamber air tempera-ture control. Positioning and calibration of chamber air tem-perature sensors shall be in accordance with the descriptionsfound in
43、Practice G151.NOTE 3Typically, these devices control by black panel temperatureonly.6.4.2 The thermometer shall be mounted on the specimenrack so that its surface is in the relative position and subjectedto the same influences as the test specimens.6.5 MoistureThe test specimens may be exposed to mo
44、is-ture in the form of water spray, condensation, or high humidity.6.5.1 Water SprayThe test chamber may be equipped witha means to introduce intermittent water spray onto the testspecimens under specified conditions. The spray shall beapplied so that the specimens are uniformly wetted. The spraysys
45、tem shall be made from corrosion resistant materials that donot contaminate the water used.6.5.1.1 Quality of Water for SpraysSpray water must havea conductivity below 5 S/cm, contain less than 1 ppm solids,and leave no observable stains or deposits on the specimens.Very low levels of silica in spra
46、y water can cause significantdeposits on the surface of test specimens. Care should be takento keep silica levels below 0.1 ppm. In addition to distillation,a combination of deionization and reverse osmosis can effec-tively produce water of the required quality. The pH of thewater used should be rep
47、orted. See Practice G151 for detailedwater quality instructions.6.5.1.2 A spray system designed to cool the specimen byspraying the back surface of the specimen or specimensubstrate may be required when the exposure program specifiesperiods of condensation.6.5.2 Relative HumidityThe test chamber may
48、 beequipped with a means to measure and control the relativehumidity. Such instruments shall be shielded from the lightsource.6.6 Specimen HoldersHolders for test specimens shall bemade from corrosion resistant materials that will not affect thetest results. Corrosion resistant alloys of aluminum or
49、 stainlesssteel have been found acceptable. Brass, steel, or copper shallnot be used in the vicinity of the test specimens.6.6.1 The specimen holders typically, but not necessarily,are mounted on a revolving cylindrical rack, which is rotatedaround the light source at a speed dependent on the type ofequipment, and which is centered both horizontally and verti-cally with respect to the exposure area in the specimen holders.6.6.2 Specimen holders may be in the form of an openframe, leaving the back of the specimen exposed, or they mayprovide the specimen
