1、Designation: D4799/D4799M 08 (Reapproved 2013)1Standard Practice forAccelerated Weathering Test Conditions and Procedures forBituminous Materials (Fluorescent UV, Water Spray, andCondensation Method)1This standard is issued under the fixed designation D4799/D4799M; the number immediately following t
2、he designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEUnits information was editoria
3、lly corrected in July 2013.1. Scope1.1 This practice describes test conditions and proceduresfor fluorescent UV and condensation exposures conductedaccording to Practices G151 and G154 for bituminous roofingand waterproofing materials that have a minimum softeningpoint of approximately 95C 200F as d
4、etermined by TestMethod D36. (Also see Terminology G113.)1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalue
5、s from the two systems may result in non-conformancewith the standard.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 practices and determine the
6、 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)D1669 Practice for Preparation of Test Panels for Acceler-ated and Outdoor Weathering of Bituminous CoatingsD1670 Test Method for
7、Failure End Point inAccelerated andOutdoor Weathering of Bituminous MaterialsG113 Terminology Relating to Natural and Artificial Weath-ering Tests of Nonmetallic MaterialsG141 Guide for Addressing Variability in Exposure Testingof Nonmetallic MaterialsG147 Practice for Conditioning and Handling of N
8、onmetal-lic Materials for Natural and Artificial Weathering TestsG151 Practice for Exposing Nonmetallic Materials in Accel-erated Test Devices that Use Laboratory Light SourcesG154 Practice for Operating Fluorescent Ultraviolet (UV)Lamp Apparatus for Exposure of Nonmetallic Materials3. Summary of Te
9、st 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 and evaluating
10、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 accelerated and
11、 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 between formulation
12、s of the same material.Guide G141 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 requirements define
13、d in Practices G151and G154.5.2 LampsUnless otherwise specified, the lamps shall befluorescent UVA-340 lamps as described in 6.1.3.1 of PracticeG154.1This practice is under the jurisdiction ofASTM Committee D08 on Roofing andWaterproofing and is the direct responsibility of Subcommittee D08.02 on St
14、eepRoofing Products and Assemblies.Current edition approved July 1, 2013. Published July 2013. Originally approvedin 1988. Last previous edition approved in 2008 as D4799 08. DOI: 10.1520/D4799_D4799M-08R13E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custo
15、mer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2.1 Other fluorescent UV lamps meet
16、ing the size andelectrical characteristics in 5.2 may be used if mutually agreedupon and provided that the lamp and spectral energy distribu-tion are reported in conformance with Section 9.5.3 MoistureIt is permitted to expose the test specimens tomoisture in the form of water spray, condensation, o
17、r highhumidity.5.3.1 Water SprayIt is permitted to equip the test chamberwith a means to introduce intermittent water spray onto the testspecimens under specified conditions. The spray shall beuniformly distributed over the samples. The spray system shallbe made from corrosion resistant materials th
18、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
19、 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 G151 for detailedwater quality instructio
20、ns.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 D1669. Fabricated materi-als such as bituminous roofing, shingles, and similar pr
21、oductsshall 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 anunex
22、posed specimen is recommended as it is difficult to maska specimen to prevent exposure to condensation.6.1.2 Follow the procedures described in Practice G147 foridentification, conditioning, and handling of specimens of testand control materials prior to, during, and after exposure.7. Procedure7.1 P
23、roceed in accordance with Section 9 of Practice G154.7.2 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.For equi
24、pment 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 this
25、requirement, use one of the procedures described inPractice G154, Section 9.5, to ensure equal radiant exposure onall 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 corrosionr
26、esistant material to maintain the test conditions within thechamber.Cycle A4hUVat602.5C,alternatingwith4hcondensationat 50 2.5C.Cycle B 20 h UV at 60 2.5C, alternating with 4 h condensationat 50 2.5C.Cycle C 20 h UV at 80 2.5C, alternating with 4 h condensationat 50 2.5C.Cycle D4hUVat602.5C,15minwat
27、erspray,alternatingwith3.75 h condensation at 50 2.5C.Cycle E 20 h UV at 60 2.5C, 15 min water spray, alternating with3.75 h condensation at 50 2.5C.Cycle F 20 h UV at 80 2.5C, 15 min water spray, alternating with3.75 h condensation at 50 2.5C.7.3 If inspection of the panels is to be performed at an
28、ystage 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 in the productstandard.NOTE 3The operatio
29、nal 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 allowed to programa set point higher or lower
30、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.8. Period of Exposure and Evaluation of R
31、esults8.1 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 testspecimen, or8.1.3 The number of hours r
32、equired 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 in terms of the number of hours exposure r
33、equiredto produce physical or chemical changes as determined by TestMethod D1670.9. Report9.1 In addition to the items specified in Practice G151, thereport shall include the following:9.1.1 Test cycle employed (in accordance with 7.2),9.1.2 Manufacturer and designation of the fluorescent lampemploy
34、ed, 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.9.1.5 Type of fluorescent/condensation device used, that is,irradiance cont
35、rolled or non-controlled.D4799/D4799M 08 (2013)1210. Precision and Bias10.1 PrecisionThe repeatability of results obtained inexposures conducted according to this practice will vary withthe materials being tested, the material property beingmeasured, and the specific test conditions and cycles that
36、areused. It is essential to determine reproducibility of theexposure/property measurement process when using the resultsfrom exposures conducted according to this practice in productspecifications.10.2 BiasBias cannot be determined because no accept-able standard weathering reference materials are a
37、vailable.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 asserted in connection with any item
38、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 the responsible technical commit
39、tee 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 careful consideration at a mee
40、ting 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 International, 100 Barr Harbor Drive,
41、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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D4799/D4799M 08 (2013)13
