1、Designation: G 152 06Standard Practice forOperating Open Flame Carbon Arc Light Apparatus forExposure of Nonmetallic Materials1This standard is issued under the fixed designation G 152; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, the year of last 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 the basic principles and operatingprocedures for using open flame carbon-arc ligh
3、t and 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 exposu
4、re. A 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 G 151 describes performance criteria for all exposuredevices that use laboratory light sources. This practice replaces
5、PracticeG23, which describes very specific designs for devices used for carbon-arc exposures. The apparatus described in Practice G23is covered by thispractice.1.2 Test specimens are exposed to filtered open flamecarbon arc light under controlled environmental conditions.Different filters are descri
6、bed.1.3 Specimen preparation and evaluation of the results arecovered in methods or specifications for specific materials.General guidance is given in Practice G 151 and ISO 4892-1.More specific information about methods for determining thechange in properties after exposure and reporting these resu
7、ltsis described in Practice D 5870.1.4 The values 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 h
8、ealth practices and determine the applica-bility 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.1.6 This practice is technically similar to
9、ISO 4892-4.2. Referenced Documents2.1 ASTM Standards:2D 3980 Practice for Interlaboratory Testing of Paint andRelated Materials3D 5870 Practice for Calculating Property Retention Indexof PlasticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodG23 Prac
10、tice for Operating Light-Exposure Apparatus(Carbon-Arc Type) With and Without Water for Exposureof Nonmetallic Materials3G113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use
11、 Laboratory Light Sources2.2 CIE Standard:CIE-Publ. No. 85: Recommendations for the IntegratedIrradiance and the Spectral Distribution of SimulatedSolar Radiation for Testing Purposes42.3 ISO Standards:ISO 4892-1, PlasticsMethods of Exposure to LaboratoryLight Sources, Part 1, General Guidance4ISO 4
12、892-4, PlasticsMethods of Exposure to LaboratoryLight Sources, Part 4, Open-Flame Carbon Arc Lamp43. Terminology3.1 DefinitionsThe definitions given in TerminologyG113are applicable to this practice.3.1.1 As used in this practice, the term sunlight is identicalto the terms daylight and solar irradia
13、nce, global as they aredefined in Terminology G 113.4. Summary of Practice4.1 Specimens are exposed to repetitive cycles of light andmoisture under controlled environmental conditions.1This practice is under the jurisdiction of ASTM Committee G03 on Weatheringand Durability and is the direct respons
14、ibility of Subcommittee G03.03 onSimulated and Controlled Exposure Tests.Current edition approved March 15, 2006. Published May 2006. Originallyapproved in 1997. Last previous edition approved in 2005 as G 152 05.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cu
15、stomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from American National Standards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.1Copyright ASTM International, 100 Ba
16、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.1 Moisture usually is produced by spraying the testspecimen with demineralized/deionized water or by condensa-tion of water vapor onto the specimen.4.2 The exposure condition may be varied by selection of:4.2.1 Light s
17、ource 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 model of apparatus should not be made unlessreprodu
18、cibility 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 be tested.5. Significance and Use5.1 The use o
19、f 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 to simulate the deterioration causedby localiz
20、ed weather phenomena, such as atmospheric pollu-tion, biological attack, and saltwater exposure. Alternatively,the exposure may simulate the effects of sunlight throughwindow glass. Typically, these exposures would include mois-ture in the form of humidity.5.2 CautionsRefer to Practice G 151 for ful
21、l cautionaryguidance applicable to all laboratory weathering devices.Variation in results may be expected when operating conditionsare varied within the accepted limits of this practice. Noreference, therefore, shall be made to results from the use ofthis practice unless accompanied by a report deta
22、iling thespecific operating conditions in conformance with Section 10.It is recommended that a similar material of known perfor-mance, a control, be exposed simultaneously with the testspecimen to provide a standard for comparative purposes. It isrecommended that at least three replicates of each ma
23、terialevaluated be exposed in each test to allow for statisticalevaluation of results.6. Apparatus6.1 Laboratory Light SourceOpen flame carbon arc lightsources typically use three or four pairs of carbon rods, whichcontain a mixture of rare-earth metal salts and have a metalcoating such as copper on
24、 the surface. An electric current ispassed between the carbon rods which burn and give offultraviolet, visible, and infrared radiation. The carbon rod pairsare burned in sequence, with one pair burning at any one time.Use carbon rods recommended by the device manufacturer.6.1.1 Filter TypesRadiation
25、 emitted by the open flamecarbon arc contains significant levels of very short wavelengthUV (less than 260 nm) and must be filtered. Two types of glassfilters are commonly used. Other filters may be used by mutualagreement by the interested parties as long as the filter type isreported in conformanc
26、e with the report section in PracticeG 151.6.1.2 None of these filters changes the spectral powerdistribution of the open flame carbon arc to make it matchdaylight in the long wavelength UV or the visible light regionsof the spectrum.6.1.3 The following factors can affect the spectral powerdistribut
27、ion of open flame carbon arc light sources:6.1.3.1 Differences in the composition and thickness offilters can have large effects on the amount of short wavelengthUV radiation transmitted.6.1.3.2 Aging of filters can result in changes in filtertransmission. The aging properties of filters can be infl
28、uencedby the composition. Aging of filters can result in a significantreduction in the short wavelength UV emission of a burner.6.1.3.3 Accumulation of dirt or other residue on filters canaffect filter transmission.6.1.3.4 Differences in the composition of the metallic saltsused in he carbon rods ca
29、n affect the spectral power distribu-tion.6.1.4 Spectral Irradiance:6.1.4.1 Spectral Irradiance of Open Flame Carbon Arc withDaylight FiltersDaylight filters are used to reduce the shortwavelength UV irradiance of the open flame carbon arc in anattempt to provide simulation of the short wavelength U
30、Vregion of daylight.5The data in Table 1 is representative of the5Fischer, R., Ketola, W., Murray, W., “Inherent Variability in AcceleratedWeathering Devices,” Progress in Organic Coatings, Vol 19 (1991), pp. 165179.TABLE 1 Typical Relative Ultraviolet Spectral Power Distributionof Open-Flame Carbon
31、-Arc with Daylight FiltersA,BSpectral BandpassWavelength l in nmTypicalPercentCBenchmark SolarRadiation PercentD,E,Fl 290290 # l # 320 2.9 5.8320 l # 360 20.4 40.0360 l # 400 76.7 54.2AData in Table 1 are the irradiance in the given bandpass expressed as apercentage of the total irradiance from 290
32、to 400 nm. Annex A1 states how todetermine relative spectral irradiance.BThe data in Table 1 is representative and is based on the rectangularintegration of the spectral power distributions of open flame carbon arcs withdaylight filters. There is not enough data available to establish a meaningfulsp
33、ecification.CFor any individual spectral power distribution, the calculated percentage forthe bandpasses in Table 1 will sum to 100 %. Test results can be expected to differbetween exposures using open flame carbon arc devices in which the spectralpower distributions differ by as much as that allowe
34、d by the tolerances typical fordaylight filters. Contact the manufacturer of the carbon-arc devices for specificspectral power distribution data for the open flame carbon-arc and filters used.DThe benchmark solar radiation data is defined in ASTM G 177 and is foratmospheric conditions and altitude c
35、hosen to maximize the fraction of shortwavelength solar UV. While this data is provided for comparison purposes only, alaboratory accelerated light source with daylight filters to provide a spectrum thatis a close match to this the benchmark solar spectrum.EPrevious versions of this standard used so
36、lar radiation data from Table 4 ofCIE Publication number 85. See Appendix X2 for more information comparing thesolar radiation data used in this standard with that for CIE 85, Table 4.FFor the benchmark solar spectrum, the UV irradiance (290-400 nm) is 9.8 %and the visible irradiance (400-800 nm) is
37、 90.2 % expressed as a percentage ofthe total irradiance from 290 to 800 nm. The percentages of UV and visibleirradiances on samples exposed in open flame carbon-arc devices may vary dueto the number and reflectance properties of specimens being exposed. This isbased on measurements in xenon-arc dev
38、ices but similar measurements have notbeen made in open flame carbon-arc devices.G152062spectral irradiance received by a test specimen mounted in thespecimen plane of an open flame carbon arc equipped withdaylight filters.NOTE 2The typical spectral irradiance for open-flame carbon arc withdaylight
39、filters was obtained using a borosilicate glass filter.6.1.4.2 Spectral Irradiance of Open Flame Carbon Arc WithWindow Glass FiltersWindow glass filters use a heat resis-tant glass to filter the open flame carbon arc in a simulation ofsunlight filtered through single strength window glass.6Thedata i
40、n Table 2 is representative of the spectral irradiancereceived by a test specimen mounted in the specimen plane ofan open flame carbon arc equipped with window glass filters.6.1.4.3 Spectral Irradiance of Open Flame Carbon arc WithExtended UV filters Filters that transmit more short wave-length UV a
41、re sometimes used to accelerate test results.Although this type of filter has been specified in many testsbecause of historical precedent, they transmit significant radi-ant energy below 300 nm (the typical cut-on wavelength forterrestrial sunlight) and may result in aging processes notoccurring out
42、doors.5The spectral irradiance for an open flamecarbon arc with extended UV filters shall comply with therequirements of Table 3.NOTE 3The most commonly used type of extended UV filters aremade from Potash-Lithia glass and are commonly known as Corex Dfilters.6.2 Test ChamberThe design of the test c
43、hamber mayvary, but it should be constructed from corrosion resistantmaterial, and in addition to the radiation source, may providefor means of controlling temperature and relative humidity.When required, provision shall be made for the spraying ofwater on the test specimen or for the formation of c
44、ondensateon the exposed 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 G 151.6.3 Instrument CalibrationTo ensure standardization andaccuracy, the instruments associ
45、ated with the exposure appa-ratus, for example, timers, thermometers, wet bulb sensors, drybulb sensors, humidity sensors, UV sensors, radiometers,require periodic calibration to ensure repeatability of testresults. Whenever possible, calibration should be traceable tonational or international stand
46、ards. Calibration schedule andprocedure should be in accordance with manufacturers in-structions.6.4 ThermometerEither insulated or uninsulated black orwhite panel thermometers may be used. Thermometers shallconform to the descriptions found in Practice G 151. The type6Ketola, W., Robbins, J. S., “U
47、V Transmission of Single Strength WindowGlass,” Accelerated and Outdoor Durability Testing of Organic Materials, ASTMSTP 1202, Warren D. Ketola and Douglas Grossman, Eds., American Society forTesting and Materials, Philadelphia, 1993.TABLE 2 Typical Relative Spectral Power Distribution for OpenFlame
48、 Carbon Arc With Window Glass Filters (RepresentativeData)Ultraviolet Wavelength RegionIrradiance as a Percentage of Total Irradiance from 300 to 400 nmBandpass (nm)Open Flame Carbon Arcwith Window Glass FiltersAEstimated Window GlassFiltered SunlightB250270 0 % 0 %271290 0 % 0 %291300 0 % 0 %301320
49、 2.1 % 0.11.5 %321340 8.1 % 9.414.8 %341360 13.2 % 23.223.5 %361380 27.3 % 29.632.5 %381400 49.3 % 30.934.5 %Ultraviolet and Visible Wavelength Region Irradiance as a Percentage of TotalIrradiance from 300 to 800 nmCIrradiance as a Percentage of Total Irradiance from 300 to 800 nmCBandpass (nm)Open Flame Carbon Arcwith Window Glass FiltersEEstimated Window GlassFiltered SunlightD300400 22.734.1 % 9.011.1 %401700 51.167.3 % 71.373.1 %*Data from 701 to 800 nm is not shownACarbon Arc DataThis data are for a typical spectral power distribution for anop
