1、Designation: D 3771 03 (Reapproved 2007)Standard Specification forRubber Seals Used in Concentrating Solar Collectors1This standard is issued under the fixed designation D 3771; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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 specification covers the general requirements formaterials used in rubber seals of concentrating solar col
3、lectors.Particular applications may necessitate other requirements thatwould take precedence over these requirements when speci-fied.1.2 Design requirement pertains only to permissible deflec-tions of the rubber during thermal expansion or contraction ofthe seal in use and the tolerances in dimensio
4、ns of molded andextruded seals.1.3 This specification does not include requirements per-taining to the fabrication or installation of the seals.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 The following safety hazards
5、 caveat pertains only to thetest methods portion, Section 9, of this specification: Thisstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determ
6、ine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2C 661 Test Method for Indentation Hardness ofElastomeric-Type Sealants by Means of a DurometerC 717 Terminology of Building Seals and SealantsC 719 Test Method for Adhesion and Cohesion of Elasto
7、-meric Joint Sealants Under Cyclic Movement (HockmanCycle)D 395 Test Methods for Rubber PropertyCompressionSetD 412 Test Methods for Vulcanized Rubber and Thermo-plastic ElastomersTensionD 865 Test Method for RubberDeterioration by Heatingin Air (Test Tube Enclosure)D 1149 Test Methods for Rubber De
8、teriorationCrackingin an Ozone Controlled EnvironmentD 1229 Test Method for Rubber PropertyCompressionSet at Low TemperaturesD 1349 Practice for RubberStandard Temperatures forTestingD 1415 Test Method for Rubber PropertyInternationalHardnessD 1566 Terminology Relating to RubberD 2137 Test Methods f
9、or Rubber PropertyBrittlenessPoint of Flexible Polymers and Coated FabricsD 2240 Test Method for Rubber PropertyDurometerHardnessD 3182 Practice for RubberMaterials, Equipment, andProcedures for Mixing Standard Compounds and Prepar-ing Standard Vulcanized SheetsD 3183 Practice for RubberPreparation
10、of Product Piecesfor Test Purposes from ProductsG7 Practice for Atmospheric Environmental ExposureTesting of Nonmetallic MaterialsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 155 Practice for Operating Xenon Arc Light Apparatusfor
11、Exposure of Non-Metallic Materials2.2 Other Standards:RMA Handbook Rubber Products: Molded, Extruded,Lathe Cut, and Cellular33. Terminology3.1 Refer to the definitions of terms in Terminology C 717and Terminology D 1566.4. Classification4.1 Types:4.1.1 Type C, intended for use in cold climates(below
12、 10C in winter).4.1.2 Type W, intended for use in warm climates(above 10C in winter).4.2 Grades1This specification is under the jurisdiction ofASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.37 on Coated Fabrics, RubberThreads and Seals.Current edition approved Nov.
13、1, 2007. Published January 2008. Originallyapproved in 1979. Last previous edition approved in 2003 as D 3771 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 information, refer to the
14、 standards Document Summary page onthe ASTM website.3Available from the Rubber Manufacturers Association (RMA), 444 MadisonAve., New York, NY 10022.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2.1 Grade designations represent di
15、ffering degrees ofhardness in accordance with Test Methods D 1415 and D 2240as follows:4.2.1.1 Grade 2, hardness of 20 6 5.4.2.1.2 Grade 3, hardness of 30 6 5.4.2.1.3 Grade 4, hardness of 40 6 5.4.2.1.4 Grade 5, hardness of 50 6 5.4.2.1.5 Grade 6, hardness of 60 6 5.4.2.1.6 Grade 7, hardness of 70 6
16、 5.4.2.1.7 Grade 8, hardness of 80 6 5.NOTE 1The grade to be used in a particular application depends onthe design of the seal and must be specified by the designer.4.3 Classes:4.3.1 Seals shall be classified as follows:4.3.1.1 Class PS, preformed rubber seal.4.3.1.2 Class SC, sealing compound.NOTE
17、2Class SC material should not be used in designs where theseal is under mechanical stress.5. Materials and Manufacture5.1 Resistance to solar radiation can be determined by oneof the following:5.1.1 Desert outdoor exposure, in accordance with recom-mended Practice G7using the exposure rack at an ang
18、le of 45for unbacked exposure of the specimens. Desert outdoorexposure shall be for at least six months including at least onemonth preceding and following the summer solstice.5.1.2 Xenon arc laboratory exposure, in accordance withrecommended Practice G 151 and G 155 using daylight filtersand operat
19、ing conditions as described below:5.1.2.1 The irradiance level shall be maintained at 0.55 60.02 W/(m2nm) at 340 nm at the control point. For equivalentbroad band irradiance levels and tolerances at 300 to 400 nmand 300 to 800 nm, consult the manufacturer of the apparatus.5.1.2.2 The default exposur
20、e cycle shall be 102 min lightonly followed by 18 min light plus either water spray on thefront surface or immersion in water. The water spray tempera-ture is typically 21 6 5C, but may be lower if ambient watertemperature is low and a holding tank is not used to storepurified water. The immersion w
21、ater is kept at a constanttemperature, which shall be less than 40C.NOTE 3Water spray and immersion in water are different kinds ofmoisture exposures and may produce different results.5.1.2.3 The uninsulated black panel temperature (BPT) shallbe maintained at 63 6 2.5C at the control point during th
22、e dryperiod of exposure to light. For the equivalent insulated blackpanel temperature (black standard temperature (BST), consultthe manufacturer of the apparatus.5.1.2.4 Relative humidity shall be maintained at 60 6 10 %at the control point during the dry period of exposure to lightin xenon arc appa
23、ratus that uses water spray for wetting.5.1.2.5 The chamber air temperature shall be maintained at48 6 2C at the control point in equipment that uses waterspray for wetting and provides for adjustment of the chamberair temperature.5.1.2.6 The exposure duration shall be by agreement be-tween the part
24、ies concerned.The exposure time shall be at least1000 h, but long enough to produce a substantial change in theproperty of interest in the least stable formulation of the type ofmaterial being evaluated.NOTE 4The set point is the target condition for the control sensor asprogrammed by the user. When
25、 a Standard calls for a particular set point,the user programs the exact number. The tolerances specified with the setpoint do not imply that the user is allowed to program a set point higheror lower than the exact set point specified. Tolerance is determined by themachine variables. The tolerance s
26、pecified is the maximum deviationallowable from the set point at the control sensor during equilibriumconditions.5.2 After exposure, slight surface chalking and dulling arepermitted. Brittleness, cracking, loss of elongation, tackiness,or other deterioration affecting serviceability shall not beperm
27、itted.6. Requirements6.1 Class PS material shall conform to the requirementsgiven in Table 1.6.2 Class SC material shall conform to the requirementsgiven in Table 2.7. Dimensions7.1 The design of the seal shall not permit the rubber todeflect more than 25 % in any direction during thermalexpansion a
28、nd contraction of the solar collector.NOTE 5If the thermal coefficient of linear expansion for the rubber isnot known, a value of 0.0003/K may be assumed for design purposes.7.2 The tolerances in dimensions shall conform to thefollowing designations in the RMA Handbook:7.2.1 Molded Seals:7.2.1.1 Com
29、mercial DimensionsRMA-F3-T.032.7.2.1.2 Critical DimensionsRMA-F3-T.032.7.2.2 Extruded Seals:7.2.2.1 Commercial DimensionsRMA-F3.8. Workmanship, Finish, and Appearance8.1 Class PS seals shall be free of blisters, checks, cracks,and other imperfections that can affect their ability to make ormaintain
30、a watertight seal.8.2 Class SC material shall be uniform in composition andbe free of defects that may affect serviceability, such aspartially vulcanized lumps.9. Test Methods9.1 Class PS MaterialPrepare the specimens in accor-dance with Practice D 3183 and test the specimens in accor-dance with the
31、 test methods given in Table 1. For control ofproduction, specimens may be taken from standard test sheetsprepared in accordance with Practice D 3182, using the sameunvulcanized material used to prepare the seals and vulcaniz-ing the material at the same temperature used for the seals to anequivalen
32、t state of vulcanization.9.2 Class SC MaterialPrepare five sheets approximately150 by 150 by 2 mm in accordance with the instructionssupplied with the sealing material. Also, prepare five adhesionspecimens in accordance with Test Method C 719. Preferably,prepare each sheet and adhesion specimen from
33、 material in aD 3771 03 (2007)2different container. Condition the sheets and adhesion speci-mens for 14 days at a temperature of 23C and relativehumidity of 50 %. Test the material in accordance with the testmethods given in Table 2.9.3 Determine volatiles lost from the difference in mass ofthe spec
34、imens before and after heating for 166 h at thetemperature given in Table 1 or Table 2 and in accordance withTest Method D 865.9.4 Determine volatiles condensible at 23C from the dif-ference in mass of the outlet tubes before and after heating thespecimens for 166 h at the temperature given in Table
35、 1 orTable 2 and in accordance with Test Method D 865.Ifnecessary, cool the exposed portion of the outlet tube with astream of air to maintain a temperature of 23 6 2C. If anyvolatiles condense on the inlet tube or other parts of theapparatus, add the mass of this condensed material to the massof th
36、e material on the outlet tube.10. Inspection and Rejection10.1 Class PS MaterialManufacturers of preformed sealsmay use their quality-control systems for production inspectionto ensure the seals conform with this specification, providedappropriate records are kept. In case of dispute regarding thequ
37、ality of a delivered product, a sample of five seals shall betaken from the lot and tested for compliance with this specifi-cation. If one of the five seals does not conform, a secondsample of five seals may be taken and tested. If two or more ofthe ten seals do not conform, the lot may be rejected.
38、10.2 Class SC MaterialManufacturers may use theirquality-control systems to ensure production conforms withthis specification. In case of dispute regarding the quality of adelivered product, five test sheets and five adhesion specimensshall be prepared, preferably from five different packages, inacc
39、ordance with the instructions supplied with the sealingmaterial. If one of the five sheets or adhesion specimens doesTABLE 1 Requirements for Class PS Material Used to Seal Solar CollectorsPropertyGradeASTM Method345678Ultimate elongation, min, % 350 300 250 200 150 100 D 412Compression set, max, %:
40、after 70 h at MSTA30 30 30 30 30 30 D 395Bafter 166 h at 10C 60 60 60 60 60 60 D 1229CResistance to heating (for 166 h at MSTA): D 865Hardness change, max 10 10 10 10 10 10 D 1415 or D 2240Ultimate elongation change, max, % 30 30 30 30 30 30 D 412Tensile strength change, max, % 20 20 20 20 20 20 D 4
41、12Volatiles lost, max, % 111111se9.3Volatiles condensible, max, % 0.1 0.1 0.1 0.1 0.1 0.1 see 9.4Resistance to ozone, 100 mPa,Dfor166hat40Cno cracking D 1149Resistance to low temperature, Type C only,max, C40 40 40 40 40 40 D 2137AThe test temperature is based on the maximum service temperature (MST
42、) which normally occurs when the collector is under stagnation conditions and is receivingthe maximum radiation flux to which it will be exposed. The test temperature listed in Practice D 1349 that is between 25 and 49C above the maximum service temperatureis used. These temperatures are: 150, 175,
43、200, 225, and 250C.BMethod B.CSet to be measured at 10 s after release. Lubricated plates or polytetrafluoroethylene film is recommended if the rubber adheres to the metal compression plates duringthe test.D100 mPa of ozone partial pressure is equivalent to 100 pphm at standard atmospheric pressure
44、(100 kPa). See new terminology on ozone content expressionsdescribed in Test Methods D 1149.TABLE 2 Requirements for Class SC Material Used to Sieal Solar CollectorsPropertyGradeASTM Method234Ultimate elongation, min, % 200 150 100 D 412Resistance to heating (for 166 h at MSTA): D 865Hardness change
45、, max 10 10 10 C 661Ultimate elongation change, max, % 30 30 30 D 412Tensile strength change, max, % 20 20 20 D 412Volatiles lost, max, % 1 1 1 see 9.3BVolatiles condensible, max, % 0.1 0.1 0.1 see 9.4BResistance to ozone, 100 mPa,Cfor 166 h at 40C no cracking D 1149Resistance to low temperature, Ty
46、pe C only, max, C 40 40 40 D 2137Adhesion loss (max, cm2)D999C 719EAThe test temperature is based on the maximum service temperature (MST) which normally occurs when the collector is under stagnation conditions and is receivingthe maximum radiation flux. The test temperature listed in Practice D 134
47、9 that is between 25 and 49C above the maximum service temperature is used. Thesetemperatures are: 150, 175, 200, 225, and 250.BThis test is not required if the design precludes condensing of the volatiles on the cover plate(s) of the solar collector.C100 mPa of ozone partial pressure is equivalent
48、to 100 pphm at standard atmospheric pressure (100 kPa). See new terminology on ozone content expressionsdescribed in Test Methods D 1149.DThe combined loss in bond and cohesion areas for the three specimens tested shall not exceed 9 cm2.EThe temperature in 6.3 of Test Method C 719 shall be modified
49、to the MST (see footnoteA).D 3771 03 (2007)3not conform, an additional five sheets or adhesion specimensmay be prepared and tested. If two or more of the ten sheets oradhesion specimens do not conform, the lot may be rejected.11. Product Marking11.1 The following information shall be marked either onthe seal, packaging, label, or tag:11.1.1 Name, brand, or trademark of the manufacturer,11.1.2 Type and grade,11.1.3 Compliance with Specification D 3771, and11.1.4 Other information required by the manufacturer orpurchaser.1
