ASTM D4226-00

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An American National Standard
Designation: D 4226 – 00
Standard Test Methods for
Impact Resistance of Rigid Poly(Vinyl Chloride) (PVC)
Building Products
This standard is issued under the fixed designation D 4226; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope * Insulating Materials for Testing
D 883 Terminology Relating to Plastics
1.1 These test methods cover the determination of the
D 1898 Practice for Sampling of Plastics
energy required to crack or break rigid poly(vinyl chloride)
D 3679 Specification for Rigid Poly(Vinyl Chloride) (PVC)
(PVC) plastic sheeting and profile flat sections used in building
Siding
products, as well as extruded or molded test samples, under
E 178 Practice for Dealing with Outlying Observations
specified conditions of impact from a freefalling standard
weightstrikinganimpactorwitheitheroftwoconfigurationsin
3. Terminology
contact with the specimen.
3.1 Definitions— Definitions are in accordance with Termi-
1.2 Two test procedures are included:
nology D 883, unless otherwise indicated.
1.2.1 Procedure A, used to determine minimum impact
3.2 Definitions of Terms Specific to This Standard:
energy required to cause failure (hole, crack, split, shatter, or
3.2.1 failure (of test specimen)—signifiedbythepresenceof
tear).
a punched hole, crack, split, shatter, or tear that was created in
1.2.2 Procedure B, used to determine minimum impact
the target area by the impact of the falling weight and is clearly
energy required to cause brittle failure.
visible to the naked eye when the sample is held up to the light
1.3 The values in inch-pound units are to be regarded as the
(see Fig. 1).
standard.
3.2.2 brittle failure—a punched hole, split, or shatter where
NOTE 1—There is no similar or equivalent ISO standard.
a piece of the specimen separates from the main part of the
specimen or a crack that has a 0° angle at the tip as measured
1.4 The text of this standard references notes and footnotes
which provide explanatory material. These notes and footnotes by the naked eye (see Fig. 1).
(excluding,thoseintablesinfigures)shallnotbeconsideredas 3.2.3 mean failure height (Procedure A)—the height from
which the falling weight will cause 50 % of the specimens to
requirements of this standard.
1.5 This standard does not purport to address all of the fail.
3.2.4 mean failure energy (mean impact resistance), ( Pro-
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- cedure A)—energy required to produce 50 % failures; the
product of the weight and mean failure height.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific precau- 3.2.5 normalized mean failure energy (normalized mean
impact resistance)—the mean failure energy per unit (average)
tionary statements are given in Section 8.
specimen thickness (Procedure A).
2. Referenced Documents
3.2.6 mean brittle failure height—the height from which the
2.1 ASTM Standards: falling weight will cause 50 % brittle failures in specimens
D 374 Test Methods for Thickness of Solid Electrical Insu- (Procedure B).
lation 3.2.7 mean brittle failure energy (mean energy of ductile-
D 618 Practice for Conditioning Plastics and Electrical to-brittle transition), (Procedure B)—energy required to pro-
duce 50 % brittle failures; the product of the weight and mean
brittle failure height.
These test methods are under the jurisdiction of ASTM Committee D20 on
Plastics and are the direct responsibility of Subcommittee D20.24 on Plastic
Building Products. Annual Book of ASTM Standards, Vol 08.01.
Current edition approved Dec. 10, 2000. Published February 2001. Originally Annual Book of ASTM Standards, Vol 03.06.
published as D 4226 - 83. Last previous edition D 4226 - 99.
Annual Book of ASTM Standards, Vol 08.04.
2 6
Annual Book of ASTM Standards, Vol 10.01. Annual Book of ASTM Standards, Vol 14.02.
*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.
D 4226
FIG. 1 Types of Failures of the Specimen
3.2.8 normalized mean brittle failure energy (normalized a stand that has a 0.64-in. (16.3-mm) hole. The falling weight
mean energy of ductile-to-brittle transition), (Procedure B)— impacts on the impactor head tending to drive it through the
the mean brittle failure energy per unit (average) specimen specimen into the hole of the stand.
thickness. 4.5 The technique used to find 50 % failure level in both
3.2.9 outlier—an observation that appears to deviate mark- procedures is commonly called the Bruceton Staircase Method
edly from other members of the sample in which it occurs. or Up-and-Down Method. Testing is concentrated near the
mean, reducing the number of specimens required to obtain a
4. Summary of Test Method
reasonably precise estimate.
4.1 The building product profile is cut apart, if necessary, to
5. Significance and Use
obtain a flat specimen at least 0.75 in. (19 mm) wide.
4.2 Procedure A establishes the height from which a stan- 5.1 The impact strength values obtained on the flat sections
dard falling 8-lb (3.6-kg) weight will cause 50 % of the of a building product profile are relevant only to the flat section
specimens to fail. thathasbeentestedandthesevaluesdonotnecessarilyindicate
4.3 Procedure B establishes the height from which a stan- theimpactresistanceofthewholeproduct,whichisaffectedby
dard falling 8-lb (3.6-kg) weight will cause 50 % of the the configuration of the profile (that is, corners, ribs, etc).
specimens to fail in a brittle mode. 5.2 Constant weight and variable height, employed in these
4.4 Both procedures employ either of two configurations of test methods, allow the velocity of impact to vary and,
impactor heads resting on the specimen. The specimen lays on therefore, by Procedure B, can determine the energy of
D 4226
ductile-to-brittle transition, which cannot be determined if a 6. Interferences
variable weight is dropped from a constant height.
6.1 The results obtained are greatly influenced by the
5.3 These test procedures have been found to be useful
qualityofthetestspecimens.Cracksusuallystartatthesurface
elements in rigid poly(vinyl chloride) (PVC) building product
in tension; the surface opposite the one that is struck by the
characterization. Compound qualification, finished product
impactor head. The composition of this surface layer and the
quality control, environmental and weatherability research and
degree of orientation introduced during the formation of the
development studies, and fabrication tolerance prediction con-
specimen are very important variables. Flaws in this surface
stitute useful applications.
will also affect results. Because of these factors, sometimes
5.4 Choice of the specific impactor head configuration used
additional information about the sample is achieved by testing
is related to a variety of product attributes, such as specimen
the sample from a variety of locations in a product or testing
thickness and product toughness as well as abstract factors,
from both sides of a flat section.
suchastheanticipatedmodeoffailureinaspecificapplication.
The geometric uniqueness of the impactor head configurations
7. Apparatus
prevents any comparison or correlation of testing results on
samples tested with differing impactor head configurations. In
7.1 Testing Machine— The apparatus shall be constructed
general, the conical impactor, C.125, is useful to ensure failure
essentiallyasshowninFig.2andFig.3andshallconsistofthe
thicker specimens where the H.25 impactor caused no failure.
following: suitable base to withstand the impact shock; steel-
rod impact weight weighing 8 6 0.2 lb (3.6 6 0.1 kg);
NOTE 2—Equivalent surface conditions are more likely to occur when
hardened steel impactors as specified in 7.1.1; a slotted guide
specimens are prepared by compression molding or extrusion than by
injection molding.
tube 40 in. (1.0 m) in length in which the impact weights slide,
having an internal diameter sufficient so that friction does not
5.5 When comparing different samples tested with the same
reduce the weight velocity, and having graduations in inch-
impactor head configuration, impact resistance can be normal-
pound (newton-metre) increments, or multiples thereof. A
ized for average specimen thickness over a reasonably broad
bracket is used to hold the tube in a vertical position by
range (for example, 1 to 3 mm). However, this should only be
attaching it to the base and also to hold the hand knob, which
done when the surface conditions listed in 6.1 are essentially
is a pivot-arm alignment for the impactor, about 2 in. (50 mm)
equivalent.
under the tube. The top edge of the opening in the specimen
supportplateshouldberoundedtoa0.031-in.(0.8-mm)radius.
O.R. Weaver, “Using Attributes to Measure a Continuous Variable in Impact
Fig. 3 shows the specimen support configuration for this test.
Testing Plastic Bottles,” Materials Research & Standards, MR & S, Vol. 6, No. 6,
June, 1996, pp. 285-291.
7.1.1 Impactor Configurations:
FIG. 2 Impact Tester
D 4226
FIG. 3 Impactor Head Configuration H.25 Specimen Support Detail
7.1.1.1 Impactor C.125 shall be constructed, as is shown in cotterpin to prevent rebound. The cotterpin must be located
Fig. 4, of tough, hardened (Rockwell C 50-55), scratch well above the penetration depth of the impactor head.
resistantsteel.Itshouldhaveaconical(40-°)configurationand
0.125-in. (3.18-mm) radius hemispherical tip. 9. Sampling
7.1.1.2 Impactor H.25 shall be constructed, as is shown in
9.1 Select samples in accordance with Practice D 1898. The
Fig. 3, of tough, hardened (Rockwell C 50-55) scratch resistant
samples shall be representative of the lot under study.
steel. It should have a 0.25-in. (6.35-mm) radius hemispherical
tip (see Fig. 3andFig. 4 ).
10. Test Specimen
7.1.1.3 The surface of the impactor head shall be polished
10.1 Flat test specimens at least 0.75-in. (19-mm) wide can
free of nicks, scratches, or other surface irregularities.
betested.Thespecimensshallbefreeofobviousimperfections
7.2 Supporting Base—In order to minimize the energy
unless they constitute variables under study.
absorption, compression, and deflection of the support the
10.2 When the approximate mean failure height for a given
tester shall be firmly fixed to a dense, solid, block or base.
sample is known, 20 specimens usually yield sufficiently
7.2.1 The main body of said block or base shall have
precise results. If the mean failure height cannot be approxi-
maximum dimensions of 16 in. (h) 3 30 in. (w) 3 30 in. (d)
mated, six or more specimens should be used to determine the
and shall have a minimum weight of 400 lbs. This block shall
appropriate starting point of the test.
be placed at a height that facilitates equipment usage. It is not
NOTE 4—Specimen quantity, as small as five, often yields sufficiently
necessary to bolt blocks or bases of this weight to the floor.
reliable estimates of the mean failure height. However, the estimated
NOTE 3—The required block weight and dimensions conform to com-
standard deviation will be relatively large.
mercially available butcher block type tables.
11. Conditioning
7.2.2 Alternative supporting bases or those lighter than 400
11.1 Unless otherwise specified, condition the test speci-
lbs should be bolted to a concrete floor. Mean failure energy
mens at 73.4 6 3.6°F (23 6 2°C) and 50 6 5 % relative
comparisons shall be made between these alternative supports
humidity for not less than 40 h prior to test in accordance with
and one where the tester is bolted directly to the concrete floor.
Procedure A of Methods D 618. In cases of disagreement, the
If mean failure energy differences between the concrete floor
tolerance shall be 61.8°F (61°C) and 62 % relative humidity.
and the alternative support are found statistically nonsignifi-
11.2 Quality Control Tests—Condition the test specimens at
cant, use of the lighter support shall be allowed.
73.4 6 3.6°F (23 6 2°C) for4hinair.
7.2.3 Use of rubber mats either under the tester or the
supporting base is prohibited.
12. Procedure
7.3 Micrometer, for measurement of specimen thickness. It
should be accurate to1%ofthe average thickness of
12.1 Procedure A:
specimensused.SeeTestMethodsD374forsuitablemicrome-
12.1.1 Measure and record the thickness of each specimen
ters.
at the anticipated area of impact. Average the values for all
8. Safety Precautions
8.1 Shieldingdevicesshallbeprovidedtoprotectpersonnel.
Brownless, K. A., Hodges J. L., Jr., and Rosenblatt, Murray, “The Up-and-
8.2 Atube can contain the impactor head if it rebounds after
Down Method with Small Samples,” American Statistical Association Journal,
striking a specimen, or the impactor head may be drilled for a JSTNA, Vol. 48, 1953, pp. 262-277.
D 4226
FIG. 4 Impactor Head Configuration C.125
specimens in a sample and use this average thickness in 12.1.6 Raise the weight in the tube to the approximate
calculating normalized mean failure energy. failure energy value for the specific sample and release it so
that the weight drops on the impactor. If the approximate
NOTE 5—When using a large specimen, such as PVC sliding, measure
failure energy value for the sample is unknown, run about six
the thickness at five points uniformly across the width of the specimen.
Use the average of these five values as the average thickness to calculate impact tests at varying energy levels to bracket the approxi-
the normalized mean failure energy.
mate failure energy level before initiating the test series of
12.1.2 Choose a specimen at random from the sample. impacts.
Determine the order of testing by using a set of random
12.1.7 Remove the specimen and examine it to determine
numbers.
whether it has failed. See 3.2.1 for criteria of failure.
12.1.3 Selecttheproperimpactor-headconfiguration(C.125
12.1.8 If the first impact of the specimen results in failure,
or H.25) specified for the test and install on the apparatus.
decrease the drop height one increment. If the first impact of
Adjust the guide arm so that each impactor head is visually
the specimen does not cause failure, increase the drop height
centeredandachievestheproperdepthofpenetration.Depthof
one increment. Then test a second specimen or
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