1、Designation: G152 13Standard Practice forOperating Open Flame Carbon Arc Light Apparatus forExposure of Nonmetallic Materials1This standard is issued under the fixed designation G152; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the 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 open flame carbon-arc light
3、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 exposure
4、. 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 G151 describes performance criteria for all exposuredevices that use laboratory light sources. This practice replaces Pra
5、cticeG23, 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 filtered open flamecarbon arc light under controlled environmental conditions.Different filters are described
6、.1.3 Specimen preparation and evaluation of the results arecovered in methods or specifications for specific materials.General guidance is given in Practice G151 and ISO 4892-1.More specific information about methods for determining thechange in properties after exposure and reporting these resultsi
7、s described in Practice D5870.1.4 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 health
8、 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 ISO 4
9、892-4.2. Referenced Documents2.1 ASTM Standards:2D3980 Practice for Interlaboratory Testing of Paint andRelated Materials (Withdrawn 1998)3D5870 Practice for Calculating Property Retention Index ofPlasticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Metho
10、dG23 Practice for Operating Light-Exposure Apparatus(Carbon-Arc Type) With and Without Water for Exposureof Nonmetallic Materials (Withdrawn 2000)3G113 Terminology Relating to Natural and Artificial Weath-ering Tests of Nonmetallic MaterialsG151 Practice for Exposing Nonmetallic Materials in Accel-e
11、rated Test Devices that Use 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
12、 1, General Guidance4ISO 4892-4 PlasticsMethods of Exposure to LaboratoryLight Sources, Part 4, Open-Flame Carbon Arc Lamp43. Terminology3.1 DefinitionsThe definitions given in Terminology G113are applicable to this practice.3.1.1 As used in this practice, the term sunlight is identicalto the terms
13、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 onSimulatedand Controlled Exposure Tests.Current edition approved July 1, 20
14、13. Published July 2013. Originally approvedin 1997. Last previous edition approved in 2006 as G152 06. DOI: 10.1520/G0152-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
15、 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.*A Summary of Changes se
16、ction appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Practice4.1 Specimens are exposed to repetitive cycles of light andmoisture under controlled environmental conditions.4.1.1 Moistur
17、e 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 source filter,4.2.2 The type of moisture exposure,4.2.3 The timing of the light and moisture
18、 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 unlessreproducibility has been established among devices for thematerial to be tested.4.4 Comparison of
19、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 of this apparatus is intended to induce propertychanges associated with the end use conditio
20、ns, 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 localized weather phenomena, such as atmosphericpollution, biological attack, and saltwater exposu
21、re.Alternatively, the exposure may simulate the effects of sunlightthrough window glass. Typically, these exposures would in-clude moisture in the form of humidity.NOTE 2Caution: Refer to Practice G151 for full cautionary guidanceapplicable to all laboratory weathering devices.5.2 Variation in resul
22、ts may be expected when operatingconditions are varied within the accepted limits of this practice.No reference, therefore, shall be made to results from the useof this practice unless accompanied by a report detailing thespecific operating conditions in conformance with Section 10.5.2.1 It is recom
23、mended that a similar material of knownperformance, a control, be exposed simultaneously with thetest specimen to provide a standard for comparative purposes.It is best practice to use control materials known to haverelatively poor and good durability. It is recommended that atleast three replicates
24、 of each material evaluated be exposed ineach test to allow for statistical evaluation 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
25、as copper on 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 Ty
26、pesRadiation 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 i
27、n conformance with the report section in PracticeG151.6.1.2 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 pow
28、erdistribution 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
29、can be influencedby 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 car
30、bon rods can 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 anTABLE 1 Typical Relative Ultraviolet Spectra
31、l Power Distributionof Open-Flame Carbon-Arc with Daylight FiltersA,BSpectral BandpassWavelength in nmTypicalPercentCBenchmark SolarRadiation PercentD,E,F 290290 # # 320 2.9 5.8320 # 360 20.4 40.0360 # 400 76.7 54.2AData in Table 1 are the irradiance in the given bandpass expressed as apercentage of
32、 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 distributions of open flame carbon arcs with daylight filters.There is not enough data availa
33、ble 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 using open flame carbon arc devices in which the spectralpower distributions
34、differ by as much as that allowed 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 G177 and is foratmosp
35、heric conditions and altitude chosen 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 ve
36、rsions of this standard used solar radiation data from Table 4 of CIEPublication number 85. SeeAppendix X2 for more information comparing the solarradiation 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 % andthe visi
37、ble irradiance (400-800 nm) is 90.2 % expressed as a percentage of thetotal irradiance from 290 to 800 nm. The percentages of UV and visible irradianceson samples exposed in open flame carbon-arc devices may vary due to thenumber and reflectance properties of specimens being exposed. This is based o
38、nmeasurements in xenon-arc devices but similar measurements have not beenmade in open flame carbon-arc devices.G152 132attempt to provide simulation of the short wavelength UVregion of daylight.5The data in Table 1 is representative of thespectral irradiance received by a test specimen mounted in th
39、especimen plane of an open flame carbon arc equipped withdaylight filters.NOTE 3The typical spectral irradiance for open-flame carbon arc withdaylight filters was obtained using a borosilicate glass filter.6.1.4.2 Spectral Irradiance of Open Flame Carbon Arc WithWindow Glass FiltersWindow glass filt
40、ers use a heat resis-tant glass to filter the open flame carbon arc in a simulation ofsunlight filtered through single strength window glass.6Thedata in Table 2 is representative of the spectral irradiancereceived by a test specimen mounted in the specimen plane ofan open flame carbon arc equipped w
41、ith window glass filters.6.1.4.3 Spectral Irradiance of Open Flame Carbon arc WithExtended UV filtersFilters that transmit more short wave-length UV are sometimes used to accelerate test results.Although this type of filter has been specified in many testsbecause of historical precedent, they transm
42、it significant radi-ant energy below 300 nm (the typical cut-on wavelength forterrestrial sunlight) and may result in aging processes notoccurring outdoors.5The spectral irradiance for an open flamecarbon arc with extended UV filters shall comply with therequirements of Table 3.NOTE 4The most common
43、ly 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 chamber mayvary, but it should be constructed from corrosion resistantmaterial, and in addition to the radiation source, may providefor means of contro
44、lling temperature and relative humidity.When required, provision shall be made for the spraying ofwater on the test specimen or for the formation of condensateon 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
45、 specimen facecomplies with the requirements in Practice G151.6.3 Instrument CalibrationTo ensure standardization andaccuracy, the instruments associated with the exposureapparatus, for example, timers, thermometers, wet bulbsensors, dry bulb sensors, humidity sensors, UV sensors,radiometers, requir
46、e periodic calibration to ensure repeatabilityof test results. Whenever possible, calibration should betraceable to national or international standards. Calibration5Fischer, R., Ketola, W., Murray, W., “Inherent Variability in AcceleratedWeathering Devices,” Progress in Organic Coatings, Vol 19 (199
47、1), pp. 165179.6Ketola, W., Robbins, J. S., “UV 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 Rela
48、tive Spectral Power Distribution for OpenFlame 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 SunlightB25
49、0270 0 % 0 %271290 0 % 0 %291300 0 % 0 %301320 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 dat
