1、Designation: D 4799 03Standard 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 D 36. (Also see Terminology G 113.)1.2 The values stated in SI u
4、nits 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 p
5、ractices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 36 Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus)2D 1669 Practice for Preparation of Test Panels for Acceler-ated and Outdoor Weathering of Bituminous Co
6、atings2D 1670 Test Method for Failure End Point in Acceleratedand Outdoor Weathering of Bituminous Materials2G 113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic Materials3G 141 Guide for Addressing Variability in Exposure Testingof Nonmetallic Materials3G 147 Practice
7、 for Conditioning and Handling of Nonme-tallic Materials for Natural and Artificial Weathering Tests3G 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light Sources3G 154 Practice for Operating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic
8、 Materials33. 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
9、of exposure and evaluating results.4. Significance and Use4.1 This weathering apparatus is used for comparing theweathering characteristics of bituminous materials against areference material in which the outdoor weathering character-istics are known. It is not possible to establish a precisecorrela
10、tion between accelerated and natural weathering be-cause of geographical climatic variations, local weather varia-tion from normal, and local pollutants. Guide G 141 providesguidance regarding this issue.5. Apparatus5.1 The fluorescent UV and condensation apparatus usedshall conform to the requireme
11、nts defined in Practices G 151and G 154.5.2 LampsUnless otherwise specified, the lamps shall befluorescent UV-B lamps as described in 6.1.3.3 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 provided that t
12、he 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 introduce inter
13、mittent 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 that do not con-taminate the water used.5.3.1.1 Spray Water QualitySpray water shall have aconductivity be
14、low 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 significant1This practice is under the jurisdiction of ASTM Committee D08 on Roofing andWaterproofing and is the direct responsibility of Subcommi
15、ttee D08.02 on PreparedRoofings, Shingles, and Siding Materials.Current edition approved Jan. 10, 2003. Published February 2003. Originallyapproved in 1988. Last previous edition approved in 2000 as D 4799 00.2Annual Book of ASTM Standards, Vol 04.04.3Annual Book of ASTM Standards, Vol 14.04.1Copyri
16、ght ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.deposits on the surface of test 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-tive
17、ly produce water of the required quality. The pH of thewater used shall be reported. See Practice G 151 for detailedwater quality instructions.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 un
18、iform coatings on aluminumpanels in accordance with Practice D 1669. Fabricated materi-als such as bituminous roofing, shingles, and similar 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 mounte
19、d on aluminum panels.6.1.1 Replicate specimens are desirable to provide a recordof degradation at different time intervals. Retention of anunexposed 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 14
20、7 foridentification, conditioning, and handling of specimens of test,control, and reference materials prior to, during, and afterexposure.7. Procedure7.1 Proceed in accordance with Section 9 of Practice G 154.7.2 Apparatus shall be operated continuously except forintervals for rotation or inspection
21、 of samples according to oneof the following cycles:Cycle A4hUVlight at 60C, alternating with 4 h condensation at 50C.Cycle B 20 h UV light at 60C, alternating with 4 h condensation at 50C.Cycle C 20 h UV light at 80C, alternating with 4 h condensation at 50C.Cycle D4hUVlight at 60C, 15 min water sp
22、ray, alternating with 4 h con-densation at 50C.Cycle E 20 h UV light at 60C, 15 min water spray, alternating with 4 h con-densation at 50C.Cycle F 20 h UV light at 80C, 15 min water spray, alternating with 4 h con-densation at 50C.7.3 If inspection of the panels is to be performed at anystage in the
23、 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 1The cycle to be employed shall be specified in the productstandard.8. Period of Exposure and Evalu
24、ation 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 testspecimen, or8.1.3 The number
25、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 in terms of the number of hours
26、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 and designation of the fluorescen
27、t lampemployed, and9.1.3 Coating thickness employed.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 test conditions and cycles
28、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 weathering reference materials
29、 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 asserted in connection with any
30、 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 the responsible technical
31、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 careful consideration at
32、 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 International, 100 Barr Harbor D
33、rive, 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).D4799032
