1、Designation: D4226 09An American National StandardStandard Test Methods forImpact Resistance of Rigid Poly(Vinyl Chloride) (PVC)Building Products1This standard is issued under the fixed designation D4226; the number immediately following the designation indicates the year oforiginal adoption or, in
2、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. Scope*1.1 These test methods cover the determination of theenergy required to crack or break
3、rigid poly(vinyl chloride)(PVC) plastic sheeting and profile flat sections used in buildingproducts, as well as extruded or molded test samples, underspecified conditions of impact from a freefalling standardweight striking an impactor with either of two configurations incontact with the specimen.1.
4、2 Two test procedures are included:1.2.1 Procedure A, used to determine minimum impactenergy required to cause failure (hole, crack, split, shatter, ortear).1.2.2 Procedure B, used to determine minimum impactenergy required to cause brittle failure.1.3 The values in inch-pound units are to be regard
5、ed as thestandard.NOTE 1There is no similar or equivalent ISO standard.1.4 The text of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding, those in tables in figures) shall not be considered asrequirements of this standard.1.5 This sta
6、ndard 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 applica-bility of regulatory limitations prior to use. Specific precau-tionary st
7、atements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2D374 Test Methods for Thickness of Solid Electrical Insu-lationD618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD3679 Specification for Rigid Poly(Vinyl Chloride) (PVC)SidingE178 Practic
8、e for Dealing With Outlying Observations3. Terminology3.1 Definitions Definitions are in accordance with Termi-nology D883, unless otherwise indicated.3.2 Definitions of Terms Specific to This Standard:3.2.1 failure (of test specimen)signified by the presence ofa punched hole, crack, split, shatter,
9、 or tear that was created inthe target area by the impact of the falling weight and is clearlyvisible to the naked eye when the sample is held up to the light(see Fig. 1).3.2.2 brittle failurea punched hole, split, or shatter wherea piece of the specimen separates from the main part of thespecimen o
10、r a crack that has a 0 angle at the tip as measuredby the naked eye (see Fig. 1).3.2.3 mean failure height (Procedure A)the height fromwhich the falling weight will cause 50 % of the specimens tofail.3.2.4 mean failure energy (mean impact resistance), ( Pro-cedure A)energy required to produce 50 % f
11、ailures; theproduct of the weight and mean failure height.3.2.5 normalized mean failure energy (normalized meanimpact resistance)the mean failure energy per unit (average)specimen thickness (Procedure A).3.2.6 mean brittle failure heightthe height from which thefalling weight will cause 50 % brittle
12、 failures in specimens(Procedure B).3.2.7 mean brittle failure energy (mean energy of ductile-to-brittle transition), (Procedure B)energy required to pro-duce 50 % brittle failures; the product of the weight and meanbrittle failure height.3.2.8 normalized mean brittle failure energy (normalizedmean
13、energy of ductile-to-brittle transition), (Procedure B)the mean brittle failure energy per unit (average) specimenthickness.1These test methods are under the jurisdiction of ASTM Committee D20 onPlastics and are the direct responsibility of Subcommittee D20.24 on PlasticBuilding Products.Current edi
14、tion approved Nov. 1, 2009. Published December 2009. Originallyapproved in 1983. Last previous edition approved in 2000 as D4226 - 05. DOI:10.1520/D4226-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
15、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.9 outlieran observat
16、ion that appears to deviate mark-edly from other members of the sample in which it occurs.4. Summary of Test Method4.1 The building product profile is cut apart, if necessary, toobtain a flat specimen at least 0.75 in. (19 mm) wide.4.2 Procedure A establishes the height from which a stan-dard fallin
17、g 8-lb (3.6-kg) weight will cause 50 % of thespecimens to fail.4.3 Procedure B establishes the height from which a stan-dard falling 8-lb (3.6-kg) weight will cause 50 % of thespecimens to fail in a brittle mode.4.4 Both procedures employ either of two configurations ofimpactor heads resting on the
18、specimen. The specimen lays ona stand that has a 0.64-in. (16.3-mm) hole. The falling weightimpacts on the impactor head tending to drive it through thespecimen into the hole of the stand.4.5 The technique used to find 50 % failure level in bothprocedures is commonly called the Bruceton Staircase Me
19、thodor Up-and-Down Method. Testing is concentrated near themean, reducing the number of specimens required to obtain areasonably precise estimate.5. Significance and Use5.1 The impact strength values obtained on the flat sectionsof a building product profile are relevant only to the flat sectionthat
20、 has been tested and these values do not necessarily indicatethe impact resistance of the whole product, which is affected bythe configuration of the profile (that is, corners, ribs, etc).5.2 Constant weight and variable height, employed in thesetest methods, allow the velocity of impact to vary and
21、,therefore, by Procedure B, can determine the energy ofductile-to-brittle transition, which cannot be determined if avariable weight is dropped from a constant height.5.3 These test procedures have been found to be usefulelements in rigid poly(vinyl chloride) (PVC) building productcharacterization.
22、Compound qualification, finished productquality control, environmental and weatherability research andFIG. 1 Types of Failures of the SpecimenD4226 092development studies, and fabrication tolerance prediction con-stitute useful applications.5.4 Choice of the specific impactor head configuration used
23、is related to a variety of product attributes, such as specimenthickness and product toughness as well as abstract factors,such as the anticipated mode of failure in a specific application.The geometric uniqueness of the impactor head configurationsprevents any comparison or correlation of testing r
24、esults onsamples tested with differing impactor head configurations. Ingeneral, the conical impactor, C.125, is useful to ensure failureof thicker specimens where the H.25 impactor caused nofailure.NOTE 2Equivalent surface conditions are more likely to occur whenspecimens are prepared by compression
25、 molding or extrusion than byinjection molding.5.5 When comparing different samples tested with the sameimpactor head configuration, impact resistance shall be permit-ted to be normalized for average specimen thickness over areasonably broad range (for example, 1 to 3 mm).3However,this should only b
26、e done when the surface conditions listed in6.1 are essentially equivalent.6. Interferences6.1 The results obtained are greatly influenced by thequality of the test specimens. Cracks usually start at the surfacein tension; the surface opposite the one that is struck by theimpactor head. The composit
27、ion of this surface layer and thedegree of orientation introduced during the formation of thespecimen are very important variables. Flaws in this surfacewill also affect results. Because of these factors, sometimesadditional information about the sample is achieved by testingthe sample from a variet
28、y of locations in a product or testingfrom both sides of a flat section.7. Apparatus7.1 Testing Machine The apparatus shall be constructedessentially as shown in Fig. 2 and Fig. 3 and shall consist of thefollowing: suitable base to withstand the impact shock; steel-rod impact weight weighing 8 6 0.2
29、 lb (3.6 6 0.1 kg);hardened steel impactors as specified in 7.1.1; a slotted guidetube 40 in. (1.0 m) in length in which the impact weights slide,having an internal diameter sufficient so that friction does notreduce the weight velocity, and having graduations in inch-pound (newton-metre) increments
30、, or multiples thereof. Abracket is used to hold the tube in a vertical position byattaching it to the base and also to hold the hand knob, whichis a pivot-arm alignment for the impactor, about 2 in. (50 mm)under the tube. The top edge of the opening in the specimensupport plate should be rounded to
31、 a 0.031-in. (0.8-mm) radius.Fig. 3 shows the specimen support configuration for this test.7.1.1 Impactor Configurations:7.1.1.1 Impactor C.125 shall be constructed, as is shown inFig. 4, of tough, hardened (Rockwell C50-55), scratch resistantsteel. It should have a conical (40-) configuration and 0
32、.125-in. (3.18-mm) radius hemispherical tip.3O.R. Weaver, “Using Attributes to Measure a Continuous Variable in ImpactTesting Plastic Bottles,” Materials Research building products; failure energy;falling weight; impact testTABLE 1 Within-Laboratory and Between-Laboratory VariationsMaterials Average
33、 SrSRrREmboss A 92.292 2.206 4.880 6.178 13.665Emboss B 71.157 3.031 4.207 8.486 11.957Emboss C 56.956 3.452 5.704 9.666 15.970Emboss D 61.406 2.538 4.922 7.107 13.782where:Sr= repeatability standard deviationthe standard deviation of test results obtained under repeatability conditionsSR= reproduci
34、bility standard deviationthe standard deviation of test results obtained under reproducibility conditionsr = repeatability limitthe value below which the absolute difference between two individual test results obtained under repeatability conditions may be expectedto occur with a probability of appr
35、oximately 0.95 (95 %).R = reproducibility limitthe value below which the absolute difference between two individual test results obtained under reproducibility conditions may beexpected to occur with a probability of approximately 0.95 (95 %).D4226 097SUMMARY OF CHANGESCommittee D20 has identified t
36、he location of selected changes to this standard since the last issue(D4226 05) that may impact the use of this standard. (November 1, 2009)(1) Section 15 was revised to add a precision and biasstatement for the method used on vinyl siding.ASTM International takes no position respecting the validity
37、 of any patent rights asserted in connection with any 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
38、to revision at any time by the responsible technical 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
39、. Your comments will receive careful consideration at 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
40、 copyrighted by ASTM International, 100 Barr Harbor Drive, 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/).D4226 098
