1、Designation: D 4799 08Standard Practice forAccelerated Weathering Test Conditions and Procedures forBituminous Materials (Fluorescent UV, Water Spray, andCondensation Method)1This standard is issued under the fixed designation D 4799; the number immediately following the designation indicates the ye
2、ar oforiginal adoption or, in the case of revision, 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 describes test conditions and procedure
3、sfor fluorescent UV and condensation exposures conductedaccording to Practices G 151 and G 154 for bituminous roofingand waterproofing materials that have a minimum softeningpoint of approximately 95C (200F) as determined by TestMethod D36. (Also see Terminology G113.)1.2 The values stated in SI uni
4、ts are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 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 pra
5、ctices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D36 Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus)D 1669 Practice for Preparation of Test Panels for Acceler-ated and Outdoor Weathering of Bituminous Coati
6、ngsD 1670 Test Method for Failure End Point in Acceleratedand Outdoor Weathering of Bituminous MaterialsG113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 141 Guide forAddressing Variability in Exposure Testingof Nonmetallic MaterialsG 147 Practice for Cond
7、itioning and Handling of Nonme-tallic Materials for Natural and Artificial Weathering TestsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 154 Practice for Operating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic Materials3
8、. Summary of Test Method3.1 Thin films of bitumen are uniformly applied to alumi-num panels. Shingles and similar materials are cut to size andexposed to specified cycles of temperature, light, and water. Achoice of three test cycles is given along with options fordetermining the period of exposure
9、and evaluating results.4. Significance and Use4.1 This weathering apparatus is used for comparing theweathering characteristics of bituminous materials against acontrol material for which the outdoor weathering characteris-tics are known. It is not possible to establish a precisecorrelation between
10、accelerated and natural weathering be-cause (1) there are geographical climatic variations, localweather variations, and variations in local pollutants, and (2)the relation between accelerated and natural weathering ismaterial dependent. Acceleration factors differ between mate-rials as well as betw
11、een formulations of the same material.Guide G 141 provides guidance regarding this issue.NOTE 1This practice can be used for other than bituminous materials,but the significance and use have not been evaluated.5. Apparatus5.1 The fluorescent UV and condensation apparatus usedshall conform to the req
12、uirements defined in Practices G 151and G 154.5.2 LampsUnless otherwise specified, the lamps shall befluorescent UVA-340 lamps as described in 6.1.3.1 of PracticeG 154.5.2.1 Other fluorescent UV lamps meeting the size andelectrical characteristics in 5.2 may be used if mutually agreedupon and provid
13、ed that the lamp and spectral energy distribu-tion are reported in conformance with Section 9.5.3 MoistureIt is permitted to expose the test specimensto moisture in the form of water spray, condensation, or highhumidity.5.3.1 Water SprayIt is permitted to equip the test chamberwith a means to introd
14、uce intermittent water spray onto the testspecimens under specified conditions. The spray shall be1This practice is under the jurisdiction ofASTM Committee D08 on Roofing andWaterproofing and is the direct responsibility of Subcommittee D08.02 on PreparedRoofings, Shingles and Siding Materials.Curre
15、nt edition approved Feb. 1, 2008. Published February 2008. Originallyapproved in 1988. Last previous edition approved in 2003 as D 4799 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
16、 information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.uniformly distributed over the samples. The spray system shallbe made from corrosion resistant materials th
17、at do not con-taminate the water used.5.3.1.1 Spray Water QualitySpray water shall have aconductivity 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 spray water can cause significantdeposits on the surface of test
18、 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 shall be reported. See Practice G 151 for detailedwater quality instructi
19、ons.6. Test Specimens6.1 Unless otherwise agreed upon, test specimens shall beapproximately 3 by 6 in. (75 by 150 mm). Bituminousmaterials shall be applied as uniform coatings on aluminumpanels in accordance with Practice D 1669. Fabricated materi-als such as bituminous roofing, shingles, and simila
20、r productsshall be cut to size and their weather surfaces exposed. If theseare too flexible to sustain their own weight in a verticalposition, they may be mounted on aluminum panels.6.1.1 Replicate specimens are desirable to provide a recordof degradation at different time intervals. Retention of an
21、unexposed specimen is recommended as it is difficult to maska specimen to prevent exposure to condensation.6.1.2 Follow the procedures described in Practice G 147 foridentification, conditioning, and handling of specimens of testand control materials prior to, during, and after exposure.7. Procedure
22、7.1 Proceed in accordance with Section 9 of Practice G 154.7.2 Apparatus shall be operated continuously, except forintervals for repositioning of samples or inspection of samples,according to one of the following cycles. The temperaturespecifications are for an uninsulated black panel thermometer.Fo
23、r equipment that requires an irradiance setting for itsoperation, it shall be 0.89 6 0.02 W/(m2nm) at 340 nm.Specimens shall be confined to an exposure area in which theirradiance is at least 90 % of the irradiance at the center of theexposure area. Unless it is known that irradiance uniformitymeets
24、 this requirement, use one of the procedures described inPractice G 154, Section 9.5, to ensure equal radiant exposureon all specimens or to compensate for differences within theexposure chamber. If the specimens do not completely fill all ofthe spaces, fill the empty spaces with blank panels of cor
25、rosionresistant material to maintain the test conditions within thechamber.Cycle A4hUVat606 2.5C, alternating with 4 h condensationat 50 6 2.5C.Cycle B 20 h UV at 60 6 2.5C, alternating with 4 h condensationat 50 6 2.5C.Cycle C 20 h UV at 80 6 2.5C, alternating with 4 h condensationat 50 6 2.5C.Cycl
26、e D4hUVat606 2.5C, 15 min water spray, alternating with3.75 h condensation at 50 6 2.5C.Cycle E 20 h UV at 60 6 2.5C, 15 min water spray, alternating with3.75 h condensation at 50 6 2.5C.Cycle F 20 h UV at 80 6 2.5C, 15 min water spray, alternating with3.75 h condensation at 50 6 2.5C.7.3 If inspect
27、ion of the panels is to be performed at anystage in the cycle, the interruption of the test procedure shalltake only sufficient time to allow for such inspection. The timetaken for inspection of the samples shall not be counted as partof the exposure.NOTE 2The cycle to be employed shall be specified
28、 in the productstandard.NOTE 3The operational fluctuations, that is, the positive and negativedeviations from the specified set points for the irradiance and temperature,are allowable deviations from the set points during equilibrium operationof the equipment. They do not imply that the user is allo
29、wed to programa set point higher or lower than that specified. Operate the apparatus tomaintain the allowable operational fluctuations. If the latter are greaterthan the maximum allowable after the equipment has stabilized, discon-tinue the test and correct the cause of the problem before continuing
30、.8. Period of Exposure and Evaluation of Results8.1 The duration of the exposure under this practice shall beone of the following:8.1.1 A mutually agreed upon number of hours of exposure,8.1.2 The number of hours of exposure required to producea mutually agreed upon minimum amount of change in the t
31、estspecimen, or8.1.3 The number of hours required to produce mutuallyagreed upon minimum acceptable change in either the testspecimen or a mutually agreed upon standard sample.8.2 It is permitted to evaluate changes in the exposedsamples visually each day by comparing them with unexposedsamples, or
32、in terms of the number of hours exposure requiredto produce physical or chemical changes as determined by TestMethod D 1670.9. Report9.1 In addition to the items specified in Practice G 151, thereport shall include the following:9.1.1 Test cycle employed (in accordance with 7.2),9.1.2 Manufacturer a
33、nd designation of the fluorescent lampemployed, and9.1.3 Coating thickness employed.9.1.4 Method of sample repositioning, if used, or othermeans of assuring equal radiant exposure on all specimens orcompensation for differences in irradiance within the exposurechamber.D47990829.1.5 Type of fluoresce
34、nt/condensation device used, that is,irradiance controlled or non-controlled.10. Precision and Bias10.1 PrecisionThe repeatability of results obtained inexposures conducted according to this practice will vary withthe materials being tested, the material property being mea-sured, and the specific te
35、st conditions and cycles that are used.It is essential to determine reproducibility of the exposure/property measurement process when using the results fromexposures conducted according to this practice in productspecifications.10.2 BiasBias cannot be determined because no accept-able standard weath
36、ering reference materials are available.11. Keywords11.1 accelerated weathering; bituminous materials; degrada-tion; exposure; fluorescent UV and condensation; light expo-sure; roofing; ultraviolet; waterproofingASTM International takes no position respecting the validity of any patent rights assert
37、ed in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by t
38、he responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive
39、 careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM Interna
40、tional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D4799083
