1、Designation: G201 09G201 16Standard Practice forConducting Exposures in Outdoor Glass-Covered ExposureApparatus with Air Circulation1This standard is issued under the fixed designation G201; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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. Scope1.1 This practice covers the basic principles and operating procedures for using outdoor glass-covered
3、 exposure apparatus withair circulation. This practice is limited to the procedures for obtaining, measuring and controlling conditions of exposure.Anumberof exposure procedures are listed in Appendix X1; however, this practice does not specify the exposure conditions best suited forthe material to
4、be tested.1.2 For direct weathering exposures, refer to Practice G7. For exposures behind glass without air circulation, refer to PracticeG24.1.3 Test specimens are exposed to solar radiation filtered through glass under partially controlled environmental test conditions.Different glass types and op
5、erating parameters are described.1.4 Specimen preparation and evaluation of the results are covered in ASTM methods or specifications for specific materials.More specific information for determining the change in properties after exposure and reporting these results is described inPractices D5870, D
6、2244 and Test Method D523.1.5 The values stated in SI units are to be regarded as standard.1.6 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 practi
7、ces and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D523 Test Method for Specular GlossD2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color CoordinatesD5870 Practice for Calculatin
8、g Property Retention Index of PlasticsE903 Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating SpheresE1084 Test Method for Solar Transmittance (Terrestrial) of Sheet Materials Using SunlightG7 Practice for Atmospheric Environmental Exposure Testing of No
9、nmetallic MaterialsG24 Practice for Conducting Exposures to Daylight Filtered Through GlassG113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic MaterialsG141 Guide for Addressing Variability in Exposure Testing of Nonmetallic MaterialsG173 Tables for Reference Solar Sp
10、ectral Irradiances: Direct Normal and Hemispherical on 37 Tilted SurfaceG177 Tables for Reference Solar Ultraviolet Spectral Distributions: Hemispherical on 37 Tilted SurfaceG179 Specification for Metal Black Panel and White Panel Temperature Devices for Natural Weathering TestsG183 Practice for Fie
11、ld Use of Pyranometers, Pyrheliometers and UV Radiometers2.2 Other Document:3WMO No. 8 Guide to Meteorological Instruments and Methods of Observation, Fifth EditionGM 9538P Weathering Exposure Tests for Interior Trims1 This practice is under the jurisdiction of ASTM Committee G03 on Weathering and D
12、urability and is the direct responsibility of Subcommittee G03.02 on Natural andEnvironmental Exposure Tests.Current edition approved Dec. 1, 2009Feb. 1, 2016. Published May 2010February 2016. Originally approved in 2009. Last previous edition approved in 2009 as G201 09. DOI: 10.1520/G020109.10.152
13、0/G0201-16.2 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 World Meteorological Organization
14、 (WMO), 7bis, avenue de la Paix, Case postale 2300, CH-1211 Geneva 2, Switzerland, http:/www.wmo.int.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 technical
15、ly possible to adequately depict 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 C
16、700, West Conshohocken, PA 19428-2959. United States12.3 ISO Standard:4ISO 9060 Solar energy Specification and classification of instruments for measuring hemispherical solar and direct solarradiation3. Terminology3.1 The definitions given in Terminology G113 are applicable to this practice.3.2 Othe
17、r DefinitionsDefinitions:3.2.1 limit temperature, nFor enclosures operated in temperature control mode, the specified black panel temperature at whichthe circulating fan switches on in order to prevent or minimize black panel temperature readings above the set temperature.4. Summary of Practices4.1
18、Specimens are exposed to light, moisture (in the form of humidity) and heat in an outdoor glass-covered enclosure with aircirculation.4.2 The exposure conditions may be varied by selection of:4.2.1 Glass Type:4.2.2 Operation of the circulating fan (whether constantly on during daylight hours or only
19、 on when a specific limit temperatureis reached).4.2.3 Temperature level at which the fan operates.4.2.4 Orientation of the test fixture.5. Significance and Use5.1 As with any accelerated test, the increase in rate of weathering compared to in-service exposure is material dependent.Results from expo
20、sures conducted to this practice may provide good rank correlation to results from actual use conditions for onetype of material or product. It should not be assumed that this will be true for other materials or products. It is always best to verifythe ability of an accelerated exposure test to prop
21、erly rank the durability of materials with actual use conditions. Guide G141provides information about using rank correlation.5.2 Variation in results may be expected when operating conditions are varied within the accepted limits of this practice.Therefore, no reference shall be made to results fro
22、m the use of this practice unless accompanied by a report detailing the specificoperating conditions in conformance with Report Section 8.5.3 The durability of materials in outdoor use can be very different depending on the location of the exposure because ofdifferences in solar radiation, moisture,
23、 heat, pollutants, and other factors. Therefore, it cannot be assumed that results fromexposure in a single location will be useful for determining durability ranking of materials in a different location.5.4 It is strongly recommended that at least one control material be exposed with each test. The
24、 control material should be ofsimilar composition and construction and be chosen so that its failure modes are the same as that of the material being tested. Itis preferable to use two control materials, one with relatively good durability, and one with relatively poor durability. If controlmaterial
25、s are included as part of the test, they shall be used for the purpose of comparing the performance of the test materialsrelative to the controls.6. Apparatus6.1 Enclosure:6.1.1 Exposures shall be conducted in a glass-covered enclosure of any convenient size (see Fig. 1). The enclosure shall beconst
26、ructed of a corrosion-resistant metal, such as anodized aluminum or stainless steel, and be designed to prevent outside airfrom circulating over specimens. Optionally, vents covered with air filter material may be installed in the bottom of the test fixtureif required to limit the black panel temper
27、ature to a specified maximum. Typical enclosure sizes are about 1.8 m wide by 0.9 mhigh by 0.7 m deep (6 ft wide by 3 ft high by 2.3 ft deep). Other sizes may be used. Additional construction information can befound in GM 9538P.6.1.2 The enclosure shall be located where it will receive solar radiati
28、on throughout the day with no shadow on any specimenwhen the suns angle of elevation is greater than 20 degrees. When the enclosure is installed over grass, the distance between thebottom of the enclosure and the ground shall be sufficient to prevent contact with plant growth, or to minimize damage
29、that mightoccur during maintenance.6.1.3 The enclosure shall be equipped with a rack which supports the specimens in a plane parallel to the glass.Alternately, thespecimens can be mounted in an in-service position. Unless otherwise specified, the distance between the exposed surface of flatspecimens
30、 shall be 75 6 25 mm from the back surface of the glass cover.4 Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.G201 1626.1.4 Formed specimens with irregular dimensions may require custo
31、m mounting with varying distances from the glass cover.In such cases, mount the test specimen surface of major interest parallel to the glass cover at a distance of 75 6 25 mm from theglass cover. The mounting frame or plate shall be constructed of a material that is compatible with the test specime
32、ns. In orderto minimize shadowing from the top and sides of the enclosure, the usable exposure area under the glass shall be limited to thatof the glass cover reduced by twice the distance from the cover to the specimens keep specimens away from each edge by adistance of at least twice the differenc
33、e between specimens and glass as shown in Fig. 2. The effective width of the specimenmounting area is L-4X and the effective height of the mounting area is W-4X, where L is the width of the glass cover, W is theheight of the glass cover, and X is the distance between the glass cover and the specimen
34、s. For example, if the specimens are 75mm below the glass, then all specimens shall be at least 150 mm from the top, bottom, and sides.6.1.5 The enclosure shall be capable of being oriented in a manner mutually agreed upon between interested parties. The testreport shall contain the orientation used
35、. Possible exposure orientations are:6.1.5.1 Fixed tilt angle, typically in the range of 5 to 45 degrees, with cabinet facing equator.6.1.5.2 Fixed tilt angle, typically 51 degrees, with tracking in rotation (azimuth).6.1.5.3 Tracking azimuth and elevation in order to maintain the exposure plane nor
36、mal to the suns direct beam.FIG. 1 Diagram of Typical Enclosure with Air CirculationLegend: L = length of glass cover; W = width of glass cover; X = distance between glass cover and specimensFIG. 2 Sample Exposure Area DiagramG201 1636.1.5.4 Any other angle that is mutually agreed on by all interest
37、ed parties may be used. In some instances, exposures facingdirectly away from the equator or some other specific direction may be desired.6.2 Glass Cover:6.2.1 The glass cover shall be flat glass of one of the following types:6.2.1.1 Clear Tempered GlassThe glass cover shall be non-laminated, temper
38、ed, clear flat glass having a nominal thicknessof 3 to 4 mm. The glass thickness used shall be included in the test report.6.2.1.2 Clear Laminated GlassThe glass cover shall be laminated, clear flat glass having a nominal thickness of 5.8 mm andcontaining a PVB (polyvinyl butyral) inner layer with a
39、n approximate thickness of 0.76 mm (.030(0.030 in.). This type of glassis typically used in automotive applications.6.2.1.3 Any other glass type as agreed upon between interested parties.6.2.2 Wash the exterior and interior surfaces of the glass cover every month (or more frequently, if required) to
40、 remove dustparticles and other undesirable material.6.2.3 It is recommended that the spectral transmittance of representative glass samples be measured. If transmittance ismeasured, report the average for at least three representative pieces of the lot of glass being used. Follow the instructions o
41、f theUV-visible spectrophotometer used for measurement of the glass. If a spectrophotometer with an integrating sphere is used, themeasurements shall be performed in accordance with Test Method E903.6.3 Black Panel Thermometer:6.3.1 For enclosures with a temperature-controlled circulating fan, one o
42、f the following black panel thermometer types shall beinstalled in the enclosure:6.3.1.1 Automotive Black PanelThe black panel thermometer shall be constructed of 0.60 6 0.06 mm (24 gauge) sheet steelwith dimensions of approximately 100 by 125 mm (4 by 5 in.). The exposed surface of the black panel
43、shall be primed and paintedwith black high heat spray paint.6.3.1.2 Specification G179 Black PanelThe black panel thermometer shall be constructed in accordance with the requirementsof Specification G179 with dimensions of approximately 100 by 125 mm (4 by 5 in.).6.3.1.3 The type of black panel ther
44、mometer used shall be described in the test report. Regardless of which type of black panelis used, the black panel is exposed parallel to the glass at the same respective depth from the surface of the glass as the exposedsurface of the test specimen. The panel must be mounted on 13 mm (12 in.) thic
45、k plywood, painted black, whose dimensions areat least 110 by 135 mm (438 by 538 in.) with a machined recess to allow space for the temperature sensor, thermocouple and theirrespective lead wires attached to the back of the black panel. The black panel must be fastened to the plywood with small scre
46、wsnear the corners of the panel. The black panel assembly shall be mounted in the plane of the test samples near the top edge of thesample mounting area no closer than 200 mm from the left or right edge of the glass cover as shown in Fig. 3.6.4 Circulating Fan:6.4.1 The test enclosure shall be equip
47、ped with a circulating fan which directs air between the top surface of specimens and theglass cover. This fan can be set to operate continuously during daylight hours, or based on the temperature reading from a blackpanel thermometer. The circulating fan shall be of sufficient air flow to maintain
48、the desired black panel temperature. Unlessotherwise specified, when the circulating fan is switched off and on based on the temperature of a black panel thermometer, setthe controller to turn on at the desired limit temperature and off at a temperature that is 3C less than the limit temperature.6.5
49、 Over Temperature Protection:6.5.1 Unless otherwise specified, test enclosures shall be equipped with over temperature protection to prevent specimenoverheating in the event of a fan failure. The over temperature protection shall be set to operate at a temperature no greater thanFIG. 3 Black Panel LocationG201 1646C above the limit temperature. The over temperature protection shall cover the test enclosure or change the enclosure orientationin order to prevent damage to specimens being exposed.6.6 Climatological Instruments:6.6.1 Within 1000 m of test enclos
