1、Designation: F2657 07 (Reapproved 2012)Standard Test Method forOutdoor Weathering Exposure of Crosslinked Polyethylene(PEX) Tubing1This standard is issued under the fixed designation F2657; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 test method describes the procedure for exposingcrosslinked polyethylene (PEX) tubing produced
3、 in accordancewith Specification F876 to natural (sunlight) ultraviolet (UV)radiation and evaluating the effects of the exposure. This testmethod outlines the requirements for specimen size andpreparation, exposure orientation, minimum UV exposureenergy, post exposure testing and reporting.NOTE 1Whi
4、le other laboratory UV exposure systems are available,this test method relies on natural sunlight as the UV radiation source.Laboratory methods may be added in the future if testing confirms acorrelation between natural sunlight and laboratory exposure.1.2 PEX tubing is not designed for outdoor use.
5、 Data fromshort-term exposure testing per this test method can be used tojudge the relative performance of PEX tubing stored outdoorsfor short periods of time prior to installation completelyshielded from sunlight.1.3 The values stated in SI units are to be regarded asstandard. No other units of mea
6、surement are included in thisstandard.1.4 The following precautionary caveat pertains only to thetest method and post exposure testing portions, Sections 8 and9 of this test method. This standard does not purport to addressall of the safety concerns, if any, associated with its use. It isthe respons
7、ibility of the user of this standard to establishappropriate safety and health practices and determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1435 Practice for Outdoor Weathering of PlasticsD1598 Test Method for Time-to-Failure of Plastic
8、PipeUnder Constant Internal PressureD1600 Terminology forAbbreviated Terms Relating to Plas-ticsF412 Terminology Relating to Plastic Piping SystemsF876 Specification for Crosslinked Polyethylene (PEX) Tub-ingF2023 Test Method for Evaluating the Oxidative Resistanceof Crosslinked Polyethylene (PEX) T
9、ubing and Systemsto Hot Chlorinated WaterG147 Practice for Conditioning and Handling of Nonmetal-lic Materials for Natural and Artificial Weathering Tests3. Terminology3.1 DefinitionsDefinitions are in accordance with Termi-nology F412 and abbreviations are in accordance with Termi-nology D1600, unl
10、ess otherwise indicated.3.2 Definitions of Terms Specific to This Standard:3.2.1 nominal exposure time period, nthe number ofmonths corresponding to the measured TUV as defined inTable 1.3.2.2 polar orientation, nthe longitudinal direction of thespecimens with respect to the Equator.3.2.3 solar UV r
11、adiation, nthe portion of the light spec-trum falling within the range of 295nm to 385nm.3.2.4 total solar UV radiation (TUV), nthe sum of mea-sured UV Energy for the time period specimens are exposed,expressed in MJ/m2. The historical average monthly TUVvalues for CentralArizona, 5 off horizontal e
12、xposure are listedin Table 1.3.2.5 tubing bow, nthe resultant curvature of a tubingsample taken from a coil.3.2.6 UV energy, nthe amount of solar UV radiation perunit time based on a 5 off horizontal specimen placement forCentral Arizona expressed as MJ/m2.3.2.6.1 DiscussionUV Energy for Central Ari
13、zona wasselected as it represents the worst case North Americanlocation based on a 4-year average of 1998 through 2001. Thisinformation was provided by Atlas Material Testing Technol-ogy LLC.1This test method is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct
14、responsibility of Subcommittee F17.40 on TestMethods.Current edition approved March 1, 2012. Published April 2012. Originallyapproved in 2007. Last previous edition approved in 2007 as F265707.DOI:10.1520/F2657-07R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AST
15、M Customer 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 States14. Summary of Test Method4.1 P
16、EX tubing specimens are exposed to solar UV radia-tion for a period of time and then removed. The exposedspecimens are then tested in accordance with one of thefollowing methods:4.2 Potable Water ApplicationsUV exposed specimensare tested at one temperature and pressure condition in accor-dance with
17、 Test Method F2023 to determine the average timeto failure. The average time to failure for the UV-exposedspecimens is then compared to the average time to failure ofnon UV-exposed specimens of the same PEX material or to thepredicted time to failure for the same material based on acomplete Test Met
18、hod F2023 data set. The percentage decreasein the average time to failure for the UV exposed specimensand the TUV of the exposure are reported.4.3 Non-Potable Water Applications PEX tubing for non-potable water applications is post-exposure tested in accor-dance with 4.2 or, alternately, tested in a
19、ccordance with thestabilizer functionality test in Specification F876. The pass orfail result of the stabilizer functionality test and the TUV of theexposure are reported.5. Significance and Use5.1 During shipment, storage and installation, PEX tubingmay be exposed to UV radiation prior to being shi
20、elded fromfurther exposure after installation. The effects of UV exposureon PEX tubing is determined by use of this test method. Byfirst exposing specimens to solar UV radiation and subse-quently testing specimens for oxidative resistance or stabilizerfunctionality, changes as a result of solar UV r
21、adiation expo-sure can be evaluated. This information can be used todetermine the maximum allowable total UV exposure prior topermanent shielding provided by installation.5.2 The results of short-term exposure tests can provide anindication of relative outdoor performance, but they should notbe used
22、 to predict the absolute long-term performance of amaterial. The results of tests conducted for less than twelvemonths will depend on the particular season of the year inwhich they begin.6. Apparatus6.1 Test SiteExposure site shall be in accordance withPractice D1435 and shall be in a hot, dry clima
23、te (for example,Phoenix, AZ).6.2 Specimen RackSpecimen racks shall be in accordancewith Practice D1435 and shall allow for vertical mounting ofsamples free of torsional or tensile stress. The rack shallposition the exposed surface of the specimens at a tilt angle inthe range of 5 to 45 inclusive.6.3
24、 Backingspecimens shall be tested un-backed.6.4 UV Energy Measurement Equipment UV radiationshall be measured using an Ultraviolet Radiometer conformingto the requirements of Practice D1435. Radiometer shall bemounted in the same attitude as the exposed samples.7. Sampling and Specimen Preparation7.
25、1 Samplingspecimens shall be representative of theproduct/material being evaluated. Select a sufficient amount oftubing to satisfy the testing requirements. Specimens can bestraight or can have a bow when cut from a coil.7.2 Test Specimen SizePEX tubing specimens shall be ofnominal size12 in., SDR 9
26、, and shall be a minimum of 380 mm(15 in.) in length for the UV exposure portion of this method.7.3 Number of Test Specimens:7.3.1 Post Exposure Testing to Test Method F2023when acomplete data set exists for the PEX material being evaluatedto Test Method F2023 and that data will be used for calculat
27、ionin accordance with 10.4, a minimum of five specimens arerequired. When no data set exists for the PEX material beingevaluated to Test Method F2023, or the existing data set willnot be used for calculation in accordance with 10.4, a minimumof ten specimens are required, five for UV exposure and fi
28、vefor the non UV-exposed portion of this method.7.3.2 Post-Exposure Testing to Stabilizer Functionality aminimum of six specimens are required when stabilizer func-tionality is used for post UV exposure testing.NOTE 2The minimum specimen requirements are based on a singleNominal Exposure Time Period
29、 (NETP) for the material being evaluated.When the expected NETP for the material is unknown, additionalspecimens may be UV exposed for various levels of NETP and post-exposure test data can be evaluated against non-UV exposed data.8. Procedure8.1 Required Specimensobtain sufficient specimens in ac-c
30、ordance with Section 7.8.2 Preparationcondition and prepare specimens in accor-dance with Practice G147 prior to exposure testing. Samples tobe used for non-UV exposed testing, when required, shall beshielded from any UV exposure source (for example, sunlight,fluorescent lighting, HID lamps, etc.) w
31、ith opaque covering.8.3 Mounting Specimens for UV Exposure:8.3.1 Polar Orientationposition specimens in the North-South orientation with respect to the Equator. See Fig. 1.8.3.2 Mounting mount specimens on the specimen rackvertically free of torsional or tensile stress.TABLE 1 Total UV (TUV) Energy
32、per Monthly Time PeriodANominal ExposureTime PeriodTUV Solar RadiationMJ/m2Highest ConsecutiveUV Month Range1 month 40 June2 months 80 May-June3 months 119 May-July4 months 154 May-August5 months 187 April-August6 months 218 April-September7 months 246 March-September8 months 270 March-October9 mont
33、hs 289 February-October10 months 307 February-November11 months 324 January-November12 months 339 January-DecemberASolar UV radiation is based on Central Arizona 5 off horizontal for the 4 yearperiod of 1998 through 2001 as reported byAtlas andTesting andTechnology LLC.F2657 07 (2012)28.3.3 Tubing B
34、owbowed specimens, such as those cutfrom a coil, shall be positioned with the crown of the bow 906 5 to the plane of the rack. The crown may be positioned inthe up or the down position. All bowed specimens in a rackshall be bowed in the same direction either outward or inwardrelative to the plane of
35、 the rack. See Fig. 2. Tubing orientationshall not permit containment of water.8.3.4 Markings Positioningany print lines, markings orstripes shall be positioned so that no portion of them lie withinthe region of 6 45 from the vertical axis centerline (top deadcenter). See Fig. 3.8.4 UV ExposureExpos
36、e specimens. Once the desiredTUV in accordance with Table 1 is achieved remove speci-mens.NOTE 3Since each PEX compound will have different resistance toUV exposure, exposure at several TUV levels may be required todetermine the maximum TUV that can be tolerated by the particularcompound being evalu
37、ated.8.5 Handling Exposed Specimensexposed specimens shallbe handled in accordance with G147. Exposed specimens shallbe shielded from any UV exposure source (for example,sunlight, fluorescent lighting, HID lamps, etc.) with opaquecovering.9. Post UVExposure Testing9.1 Test UV-Exposed Specimens gener
38、ated in Section 8 toeither 9.2 or 9.3. When required, test non UV-exposed speci-mens in accordance with 9.4.9.2 Oxidative Resistance Testing to Test Method F2023test the exposed specimens at one temperature and pressurecondition in accordance with Test Method F2023. Test allspecimens to failure. All
39、 failures shall be Stage III brittleoxidative failures. See Specification F876.NOTE 4The selection of the temperature and pressure for post-exposure oxidative resistance testing is not critical. However, testing at ahigher temperature will reduce the test duration. When a data set inaccordance with
40、Test Method F2023 exists for the PEX tubing beingevaluated, selecting a temperature and pressure condition of that data setis preferred so that the effects of UV exposure can be directly calculated.9.3 Stabilizer Functionality Testing to Specification F876test a minimum of six UV-exposed specimens i
41、n accordancewith the stabilizer functionality section of Specification F876.9.4 Non UV-Exposed Specimen Testing When no data setin accordance with Test Method F2023 exists for the PEXtubing being evaluated, or when an existing data will not beused to evaluate the effects of UV exposure, test a minim
42、um offive non UV-exposed specimens in accordance with TestMethod F2023 at the same temperature and pressure conditionas for the exposed specimens. Test all specimens to failure. Allfailures shall be Stage III brittle oxidative failures.10. Calculation10.1 When performing post UV-exposure testing per
43、 9.2,calculate the average of the failure times in hours for theUV-exposed specimens (XUV Exposed).FIG. 1 North-South Polar OrientationFIG. 2 Bowed Tubing RackingF2657 07 (2012)310.2 When performing non UV-expose testing per 9.4,calculate the average of the failure times in hours for thenon-exposed
44、samples (Xnon UV-exposed).10.3 When existing oxidative stability data in accordancewith F2023 exists for the material being evaluated and that datais used to evaluate the effects of UV exposure for the samematerial, calculate the expected time to failure (Xnon UV-exposed)for the same temperature and
45、 pressure condition used for theUV-exposed specimens based on the regression equation de-veloped in Test Method F2023 for the PEX material.10.4 Calculate the percentage decrease in average failuretimes of the UV-exposed specimens relative to the non UV-exposed specimens or calculated value from 10.3
46、:% decrease in failure time 512XUV Exposed!/Xnon UV2exposed!*100%(1)11. Report11.1 Material and Sample Identification Report the fol-lowing information:11.1.1 Tubing nominal size and DR or wall thicknessspecification,11.1.2 Tubing manufacturers name,11.1.3 Trade designation,11.1.4 Tubing lot number
47、(if applicable),11.1.5 Resin manufacturers name,11.1.6 Compound designation and lot designation (for in-plant compounded materials, resin manufacturers name maybe omitted), and11.1.7 Cross-linking process.11.2 Exposure Conditionsreport the exposure conditionsin accordance with Standard Practice D143
48、5 and this methodincluding:11.2.1 Total radiant UV exposure (TUV),11.2.2 Total solar radiant exposure,11.2.3 Nominal Exposure Time Period,11.2.4 Dates of exposure,11.2.5 Exposure location and laboratory name,11.2.6 Mounting method ,11.2.7 Racking Angle,11.2.8 Polar orientation,11.2.9 Marking positio
49、n, and11.2.10 Tubing bow position (crown up or crown down).11.3 Oxidative Resistance Testreport as per the require-ments of Section 14 of Test Method F2023. Report the XUVexposed,Xnon-UV exposedand method of calculating, and the %decrease in failure time as calculated in 10.4.11.4 Stabilizer Functionalityreport as per the reportingrequirements of Test Method D1598 and report the pass or failas per the requirement of Specification F876 for stabilizerfunctionality.FIG. 3 Top Dead CenterFIG. 4 Exposure Plane AngleF2657 07 (2012)
