1、Designation: F2657 07 (Reapproved 2012)An American National StandardStandard 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 ad
2、option or, in the case of revision, 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 polye
3、thylene (PEX) tubing produced 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 te
4、sting and reporting.NOTE 1While 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
5、not designed for outdoor use. 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 asst
6、andard. No other units of measurement 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 wi
7、th its use. It isthe responsibility 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
8、 Time-to-Failure of Plastic PipeUnder Constant Internal PressureD1600 Terminology for Abbreviated Terms Relating toPlasticsF412 Terminology Relating to Plastic Piping SystemsF876 Specification for Crosslinked Polyethylene (PEX)TubingF2023 Test Method for Evaluating the Oxidative Resistanceof Crossli
9、nked Polyethylene (PEX) Tubing and Systems toHot 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 wit
10、h Termi-nology D1600, unless 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
11、 Equator.3.2.3 solar UV radiation, 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 CentralAr
12、izona, 5 off horizontal exposure 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 Discussion
13、UV Energy for Central Arizona 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 S
14、ystems and is the direct 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/F2657-12.2For referenced ASTM standards, visit the ASTM website, www.a
15、stm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume 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.4. Summ
16、ary of Test Method4.1 PEX 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 condit
17、ion in accor-dance with 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 base
18、d on acomplete Test Method 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, a
19、lternately, tested in accordance 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 radia
20、tion prior to being shielded 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
21、 a result of solar UV radiation 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
22、 they should notbe used 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
23、 be in a hot, dry climate (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 o
24、f 5 to 45 inclusive.6.3 Backing specimens 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 an
25、d Specimen Preparation7.1 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 ofn
26、ominal size12 in., SDR 9, and shall be a minimum of 380mm (15 in.) in length for the UV exposure portion of thismethod.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 wi
27、ll be used for calculationin 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
28、 for UV exposure and fivefor the non UV-exposed portion of this method.7.3.2 Post-Exposure Testing to Stabilizer Functionalityaminimum 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 singleNomina
29、l Exposure Time Period (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 suffic
30、ient specimens inaccordance with Section 7.8.2 Preparationcondition and prepare specimens in ac-cordance with Practice G147 prior to exposure testing.Samples to be used for non-UV exposed testing, when re-quired, shall be shielded from any UV exposure source (forexample, sunlight, fluorescent lighti
31、ng, HID lamps, etc.) withopaque 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.8.3.3 Tub
32、ing Bowbowed 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 inwardTABLE 1 Total UV (T
33、UV) Energy 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-Oc
34、tober9 months 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)2rel
35、ative to the plane of the rack. See Fig. 2. Tubing orientationshall not permit containment of water.8.3.4 Markings Positioning any 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.
36、3.8.4 UV Exposure Expose 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 particu
37、larcompound being evaluated.8.5 Handling Exposed Specimens exposed specimensshall be handled in accordance with G147. Exposed specimensshall be shielded from any UV exposure source (for example,sunlight, fluorescent lighting, HID lamps, etc.) with opaquecovering.9. Post UVExposure Testing9.1 Test UV
38、-Exposed Specimens generated 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 alls
39、pecimens to failure. All 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 dat
40、a set inaccordance with 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 si
41、x UV-exposed specimens in 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 U
42、V exposure, test a minimum 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
43、 UV-exposure testing per 9.2,calculate the average of the failure times in hours for theUV-exposed specimens (XUV Exposed).10.2 When performing non UV-expose testing per 9.4,calculate the average of the failure times in hours for thenon-exposed samples (Xnon UV-exposed).10.3 When existing oxidative
44、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)FIG. 1 North-South Polar OrientationFIG. 2 Bowed Tubing RackingF2657 07 (2012)3for
45、the same temperature and 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 ca
46、lculated value from 10.3:% decrease in failure time 5 1 2 XUV 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 designat
47、ion,11.1.4 Tubing lot number (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 Conditions report the exposure conditionsin accordan
48、ce with Standard Practice D1435 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 orie
49、ntation,11.2.9 Marking position, and11.2.10 Tubing bow position (crown up or crown down).11.3 Oxidative Resistance Test report 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.12. Precision and Bias12.1 Precisio
