AS'|'l1 D192? '13 — lJ‘?5"l5]:lJ D53‘-l5?? BIJH —
`
`45”’ Designation: D 1922 - 93
`
`AMERICAN SOCIETY FOR TESTING AND MATERMLS
`1916 Race 8!. Phladolphld, Pa19103
`Reprinted from the Annual Book of ASTM standards. copyright ASTM
`it not listed In the current combined Index, will appear h the nets edltlon.
`
`Standard Test Method for
`
`Propagation Tear Resistance of Plastic Film and Thin
`Sheeting by Pendulum Method‘
`
`This standard is issued under the fixed designation D 1922; 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 (t) indicates an editorial change since the last revision or reapproval.
`
`1. Scope
`l.l This test method’ covers the determination of the
`average force to propagate tearing through a specified length
`of plastic film or nonrigid sheeting. After the tear has been
`started using an Elmcndorf-type tearing tester, two speci-
`mens are cited, a rectangular type and one with a constant
`radius testing length. The latter shall be the preferred or
`referee specimen.
`1.2 Because of (I) difficulties in selecting uniformly iden-
`tical specimens, (2) the varying degree of orientation in some
`plastic films, and (3) the difficulty found in testing highly
`extensible or highly oriented materials, or both, the repro-
`ducibility of the test results may be variable and, in some
`cases, not good or misleading. Provisions are made in the test
`method to compensate for oblique directional tearing which
`may be found with some materials.
`1.3 The values stated in SI units are to be regarded as the
`standard. The values given in parentheses are for informa-
`tion only.
`1.4 This standard does not purport to address all of the
`safety problems, if any, associated with its use. It is the
`responsibility of the user of this standard to establish appro-
`priate safety and health practices and determine the applica-
`bility ofregulatory limitations prior to use.
`
`2. Referenced Documents
`
`2.1 ASTM Standards:
`D374 Test Methods for Thickness of Solid Electrical
`Insulation’
`D618 Practice for Conditioning Plastics and Electrical
`Insulating Materials for Testing‘
`
`‘This test method is under the jurisdiction of ASTM Committee D-20 on
`Plastics and is the direct responsibility of Subcommittee D 20.10 on Mechanical
`Properties.
`Omen! edition approved Oct. I5, I993. Published December 1993. Originally
`published as D I922 - 6| T. Last previous edition D 1922 - 89.
`1 This test method has been adapted from TAPPI Standard Method T4l4M-49.
`internal Tearing Resistance of Paper. in testing certain plastic films, problems of
`reproducibility and interpretation of results are encountered which require special
`treatment to make the test method of most value. The test method is revised here
`specifically for use with plastic film and thin sheeting. For more complete
`explanation of certain aspects of the equipment, its calibration and adjustment,
`refer to TAPPI Standard Method T4l4m-49.
`The following additional references may be of interest in connection with this
`lest method:
`Painter, 6. V.. Chu. C. C.. and Morgan, H. M.. “Testing Textiles on the
`Elmendort‘ Tear Tester.” Textile Research Journal, TIUOA, Vol XX, No. 6, June
`1950. PD. 4l0—4l7.
`Elmendorf, A., “Strength Test for Paper," Paper, PPEXA, Vol 26. April 2|.
`I920. p. 302.
`3 Annual Book tJASTM Standards, Vol 10.02.
`‘Annual Book ofASTM Standards, Vol 08.01.
`
`D689 Test Method for Internal Tearing Resistance of
`Paper’
`D1004 Test Method for Initial Tear Resistance of Plastic
`Film and Sheeting‘
`D4000 Classification System for Specifying Plastic
`Materials‘
`
`3. Summary of Test Method
`
`3.1 The force in grams required to propagate tearing
`across a film or sheeting specimen is measured using a
`precisely calibrated pendulum device. Acting by gravity, the
`pendulum swings through an arc, tearing the specimen from
`a precut slit. The specimen is held on one side by the
`pendulum and on the other side by a stationary member.
`The loss in energy by the pendulum is indicated by a pointer.
`The scale indication is a function of the force required to tear
`the specimen.
`
`4. Significance and Use
`
`4.1 This test method is of value in ranking relative tearing
`resistance of various plastic films and thin sheeting of
`comparable thickness. Experience has shown the test to have
`its best reliability on relatively less extensible films and
`sheeting. Variable elongation and oblique tearing effects on
`the more extensible films preclude its use as a precise
`production control tool for these types of plastics. This test
`method should be used for specification acceptance testing
`only alter it has been demonstrated that the data for the
`particular material are acceptably reproducible. This test
`method should be used for service evaluation only after its
`usefulness for the particular application has been demon-
`strated with a number of different films.
`4.2 This test method has been widely used as one index of
`the tearing resistance of plastic film and thin sheeting used in
`packaging applications. While it may not always be possible
`to correlate film tearing data with its other mechanical or
`toughness properties,
`the apparatus of this test method
`provides a controlled means for
`tearing specimens at
`straining rates approximating some of those found in actual
`packaging service.
`4.3 Due to orientation during their manufacture, plastic
`films and sheeting frequently show marked anisotropy in
`their resistance to tearing. This is further complicated by the
`fact that some films elongate greatly during tearing, even at
`the relatively rapid rates of loading encountered in this test.
`The degree of this elongation is dependent in turn on film
`
`5 Annual Book qf/ISTM tfiandards, Vol l5.09.
`5 Annual Book ofASTM Standards, Vol 08.02.
`
`Page 1 of 5
`
`BOREALIS EXHIBIT 1042
`
`

`
`ASTM D1922 ‘I3 — D?5‘l5L.D D53‘-I575 Nil] —
`
`ill}: D1922
`
`43 mm (I.7")
`Radius of Tour
`
`
`
`Precut Silt
`
`FIG. 1 Constant-Radius Test specimen for Tear Resistance Test
`
`orientation and the inherent mechanical properties of the
`polymer from which it is made. These factors make tear
`resistance of some films reproducible between sets of speci-
`mens to :5 % of the mean value, while others may show no
`better reproducibility than :50 %.
`4.4 Data obtained by this test method may supplement
`that from Test Method D1004, wherein the specimen is
`strained at a rate of 50 mm (2 in.) per min. However,
`specimen geometry and testing speed of the two test methods
`are dissimilar. The rate of tearing in this test method, while
`varying as a function of resistance to tear, is in the range of
`from 7.6 to 46 m (300 to 1800 in.)/min.
`4.5 There is not a direct,
`linear relationship between
`tearing force and specimen thickness. Data from this test
`method are expressed as tearing force in millinewtons (or
`grams-force, if desired), with specimen thickness also re-
`ported. But sets of data from specimens of dissimilar
`thickness are usually not comparable. Therefore, only data at
`the same thickness can be compared.
`4.6 For many materials, there may be a specification that
`requires the use of this test method, but with some proce-
`dural modifications that take precedence when adhering to
`the specification. Therefore, it is advisable to refer to that
`material specification before using this test method. Table 1
`of Classification System D 4000 lists the ASTM materials
`standards that currently exist.
`
`5. Apparatus
`
`5.l Pendulum Impulse Type Testing Apparatus,’ con-
`sisting of the following:
`5.1.1 Stationary Clamp.
`5.l.2 Movable Clamp, carried on a pendulum, preferably
`formed by a sector of a wheel or circle, free to swing on a ball
`bearing or other substantially frictionless bearing.
`
`5.1.3 Stop Catch, for holding the pendulum in a raised
`position and for releasing it instantaneously.
`5.1.4 Indicating Device, for registering the maximum are
`through which the pendulum swings when released. The
`pendulum shall carry a circumferential scale, graduated from
`0 to I00 % of the machine capacity so as to read against the
`pointer the average force required to tear a specimen 43 mm
`(1.7 in.). The pointer and scale may be replaced by an
`electronic digital readout. Digital
`readouts are available
`which will give test results directly in millinewtons, directly
`in grams-force, or in percent of pendulum capacity. With the
`pendulum in its initial position ready for test, separate the
`two clamps by an interval of 2.54 mm (0.10 in.). So align
`them that the specimen clamped in them lies in a plane
`perpendicular to the plane of oscillation of the pendulum
`with the edges of the jaws gripping the specimen in a
`horizontal line, a perpendicular to which through the axis of
`suspension of the pendulum is 102.7 :1: 0.05 mm (4.044 t
`0.002 in.) in length and makes an angle of 27.5’ with the
`plane of the lilm specimen. The clamping surface in each jaw
`shall be at least 25.4 mm (1 in.) in width and at least 12.7
`mm (0.5 in.) in depth.
`5.1.5 Capacz'ty—lnstruments of several capacities, 1960,
`3920, 7840, 15 600, 31 360, 62 720 mNs (200, 400, 800,
`1600, 3 200, 6 400 gf), and perhaps others are available.
`These capacities can be achieved by individual instruments,
`interchangeable pendulum sectors, or augmenting weights.
`5.2 Template, Die. or Shear-Type Cutler,‘ for cutting
`specimens.
`5.3 Razor Blades, single-edged,
`where a template is used.
`5.4 Thickness-Measuring Device—A suitable micrometer,
`or other thickness gage, reading to 0.0025 mm (0.000! in.)
`for measuring the thickness of test specimens. The pressure
`exerted by the gage on the specimen being measured shall be
`between 160 and 185 kPa (23 and 27 psi), as prescribed in
`Method C of Test Methods D 374.
`
`for cutting specimens
`
`6. Test Specimens
`l, to
`6.1 Test specimens shall be cut, as shown in Fig.
`form a constant-radius testing length. This shall be the
`preferred or referee specimen type since its geometry auto-
`matically compensates for the problem of oblique tearing
`(Notes 1 and 2). Alternatively, specimens shall be cut to form
`a rectangle 76 mm (3 in.) or more in width by 63 mm (2.5
`in.)
`in length and plainly marked to denote intended
`direction of tear. The 63-mm specimen dimension shall be
`the direction of tear. Two sets of specimens shall be cut from
`each sample so that their sides are parallel to (I) the machine
`direction, and (2) the transverse direction, respectively, of the
`material being tested. Enough specimens shall be cut in each
`direction to provide a minimum of ten tear strength deter-
`minations.
`
`Nora l-Specimens having constant-radius testing lengths are de-
`signed to correct for oblique directional tearing encountered in certain
`anisotropic, elastomeric films, and nonrigid sheeting. For purposes of
`specimen selection, oblique tearing is defined as tearing in a curved or
`
`7 Equipment available from the Thwing-Albert instrument 00.. Philadelphia,
`
`‘The TA63 Sample Cutter. Catalog No. 98, from the Thwing-Albert Instru-
`ment Co., Philadelphia, PA l9l44, has been found satisfactory for cutting
`
`Page 2 of 5
`
`

`
`ASTI1 D]r‘lEE ‘I3 — lJ?5'l5]rD U53liS?"l EB? —
`
`tilts n 1922
`
`straight line that deviates more than 9.5 mm (‘A in.) from the vertical
`line of intended tear.
`.
`NOTE 2.—Certain film and sheeting specimens showing oblique
`tearing may yield data of poor reproducibility because the axis of
`maximum orientation varies as much as 30' from the nominal machine
`direction. When this is suspected, the sample may be examined by
`crossed Polaroid plates to determine this direction of maximum
`orientation and the specimens out along the axis ofanisotropy for testing
`parallel and normal to it.
`
`6.2 Where a metal template is used, the film or sheeting
`shall be placed on a hard surface. The template shall be held
`over it and the specimens cut out using a single—edgcd razor
`
`6.3 When the specimen is cut out, a slit 20 mm (0.8 in.)
`deep may be made at the center of the edge perpendicular to
`the direction to be tested. This leaves exactly 43 mm (1 .7 in.)
`of tearing length between the end of the slit and the opposite
`edge of the specimen. This slit may be cut into the specimen
`after it has been placed in the testing apparatus.
`
`Nora 3—The pendulum apparatus may be fitted with a sharp-loaded
`knife to make this slit in the specimen after it has been clamped in the
`apparatus. The action of the knife must be such as to make a clean slit
`exactly 20 mm (0.8 in.) into the specimen from the edge.
`
`7. Adjustment of Apparatus
`7.l Pendulum Friction:
`7.1.1 Older Instruments—To check the pendulum swing
`for freedom from excess friction,
`level the apparatus and
`draw a pencil line on the base or stop mechanism 25.4 mm
`(1 in.) to the right of the edge of the sector stop. With the
`sector raised to its initial position and the pointer set against
`its stop, on releasing the sector and holding the stop down,
`the sector should make at least 20 complete oscillations
`before the edge of the sector that engages with the stop no
`longer passes to the left of the pencil line. Otherwise, oil and
`adjust the bearing.
`7.1.2 Newer Instruments—ln recent years, a new type of
`frictionless bearing made of synthetic material has been used.
`This hearing will not necessarily allow the pendulum sector
`to make 20 complete oscillations as the older one did. This
`does not mean that there is excess friction in the pendulum
`swing. These newer bearings should not be oiled. Consult the
`instructions supplied with the instrument for guidance.
`7.2 Pointer Friction.-
`
`Z.2.l Check the pointer friction as follows: Set the pointer
`at zero reading on the scale before releasing the sector, and
`after release see that the pointer is not pushed more than
`three scale divisions beyond zero. A reading of more than
`three divisions indicates excessive pointer fiiction and the
`pointer should be removed, the bearing wiped clean, and a
`trace of oil or petroleum jelly applied. When the pointer
`friction has been reduced, finally adjust the pointer stop.
`7.3 Pointer Zero Reading—To check the pointer for its
`zero point, level the apparatus so that, with the sector free,
`the line on the sector
`indicating the vertical point of
`suspension coincides with a corresponding point on the base
`of the apparatus, usually placed on the stop mechanism.
`After leveling, operate the apparatus several
`times with
`nothing in the jaws,
`the movable jaw being closed,
`to
`ascertain whether the pointer registers zero with no load. If
`
`by means of the pointer stop thumb screw until a zero
`reading is obtained.
`
`8. Verification of Scale
`
`8.1 The scale may be verified either by the procedure
`described in Test Method D 689 and repeated here, or by the
`method which uses the elmendorf check weights obtainable
`from the manufacturer. The method in Test Method D 689
`is relatively time-consuming and complicated. The check
`weight method is relatively simple.
`8.2 ASTM Test Method D 689 Procedure.-
`8.2.l To verify the scale, first mark the center of gravity of
`the weight (including means of attaching) by a punched dot
`on the face of the weight. Then clamp a known weight in
`grams, W. to the radial edge of the sector beneath the jaws.
`8.2.2 Raise and set the sector as for tearing a specimen
`and, by means of a suitable scale. measure the height in
`centimetres, h, of the center of gravity of the weight above
`the surface upon which the apparatus rests. Then release the
`sector, allow it
`to swing, and note the pointer reading.
`Without touching the pointer, raise the sector until the edge
`of the pointer just meets with its stop, in which position
`again determine the height in centimetres, H, of the center of
`gravity of the weight above the surface.
`8.2.3 The work done is W(H — h) gram-centimetres. The
`pointer reading noted above should be the same as that
`calculated as follows:
`
`W(H — h)/ I 37.6
`
`8.2.4 Five weights from 75 to 400 g form a suitable range
`for calibration of the apparatus, one or more being clamped
`on the edge of the sector in different positions. Calculate the
`work done in raising each and add together.
`8.2.5 Make a record of deviations of the pointer from the
`calculated readings and make corresponding corrections in
`the test results at the proper points on the scale.
`8.2.6 It is unnecessary to repeat the calibration of the
`instrument provided it is kept in adjustment and no parts
`become changed or worn.
`8.3 Check Weight Method."
`8.3.1 Use a set of three check weights calibrated for scale
`values of 20, 50, and 80 % of the pendulum capacity. Sets of
`check weights of these values are available for each pen-
`dulum capacity. These weights should be so constructed that
`each weight can be inserted in the clamps by the procedure
`used for a test specimen.
`8.3.2 With the pendulum in the raised position, open the
`clamp of the pendulum. Slide the tang of the weight into
`position, and fasten it securely into the clamp. The body of
`the weight must be beneath the clamp. Depress the pen-
`dulum stop, thus releasing the pendulum. Hold down the
`stop until alter the tea: is completed and catch the pendulum
`on the return swing. Read the indicating device to the nearest
`division.
`8.3.3 Repeat
`weights.
`
`this procedure with each of the check
`
`’ Elmendorf calibration check weights are available from the Thwing-Albert
`Instrument Co., Philadelphia, PA l9l44. Use of these weights will permit direct
`calibration of the apparatus in a shorter time.
`
`Page 3 of 5
`
`

`
`AST11 ]>]r‘iEE ‘13 — 0759510 12153115613 3T"! —
`
`$111 D1922
`
`9. Conditioning
`
`9.1 Conditt'om'ng—-Condition the test specimens at 23 ac
`2'C (73.4 :1: 3.6‘F) and 50 :1: 5 % relative humidity for not
`less than 40 h prior to test in accordance with Procedure A of
`Practice D 618 for these tests where conditioning is required.
`In cases of disagreement,
`the tolerances shall be :1:1'C
`(:1:1.8'F) and :1:2 % relative humidity.
`9.2 Test Conditians—Conduct tests in the standard labo-
`ratory atmosphere of 23 : 2°C (73.4 :1: 3.617) and 50 :1: 5 %
`relative humidity, unless otherwise specified in the test
`method. In cases of disagreement, the tolerances shall be
`:l'C (:t1.8°F) and :2 % relative humidity.
`
`10. Procedure
`
`10.1 Test not less than ten specimens in each of the
`principal film or sheeting directions. Measure and record the
`thickness of each specimen as the average of three readings
`across its center in the direction in which it is to be torn.
`Read the thickness to a precision of 0.0025 mm (0.0001 in.)
`or better except for sheeting greater than 0.25 mm (10 mils)
`thickness, which read to a precision of 0.025 mm (0.001 in.)
`or better.
`
`10.2 With the pendulum in its raised position, place the
`specimen midway in the clamps so that its upper edge is
`parallel to the top of the clamps and the initial slit (if it was
`made when the specimen was cut) is at the bottom of and
`between the clamps at right angles to their top.
`10.3 Slit the firmly clamped specimen with the sharp
`spring-loaded knife if it has not been slit during cutting. Lay
`the upper,
`testing portion of the specimen over in the
`direction of the pendulum pivot.
`Nora 4—The work done in tearing a specimen includes a certain
`amount of work to bend continuously the film or sheeting as it is torn, to
`provide for the rubbing of the torn edges of the specimen together, and
`to lift the specimen against the force of gravity. Consequently, it is
`necessary to specify certain empirical requirements for both the appa-
`ratus and the method to lceep the additional work not used for tearing to
`approximately a definite quantity.
`
`10.4 Release the sector stop and tear the specimen. As the
`sector completes its return swing, catch it with the thumb
`and forefinger of the lefl hand, being careful not to disturb
`the position of the pointer.
`10.5 Examine the specimen. If it tore through the con-
`stant-radius section within an approximate angle of 60° on
`either side of the vertical line of intended tear, record the
`pointer reading to the nearest 0.5 unit. If the line of tear was
`more than approximately 60' from the vertical, reject the
`reading and test an extra specimen in its place. If rectangular
`specimens are tested, reject all specimens that tear obliquely
`more than 9.5 mm (3/s in.) from the vertical line of intended
`tear. Test extra specimens to replace those rejected. When
`oblique tearing is frequent, the test may be performed along
`and normal to the axis of maximum orientation (see Note 2)
`instead of along machine and transverse directions.
`
`Nora 5—ln addition to tearing in a curved or oblique direction,
`some specimens may elongate along the line of tear to such an extent
`that the actual
`tearing length may be considerably more than the
`standard 43-mm (1.7-in.) dimension. As the degree or length of this
`elongation cannot be measured, the data cannot be corrected for its
`effect. However, when this has occuned, a note should be included in
`the report of data. This elongation tendency of certain films may cause
`poorer reproducibility.
`
`NOTE 6—The maximum accuracy of the pendulum apparatus lies in
`the scale range between 20 and 60. When thin specimens are being
`tested,
`it may be advisable to test enough specimens sandwiched
`together to produce a scale reading between 20 and 60. However, certain
`specimens in the same sandwich may tear obliquely in opposite
`directions, which may lead to falsely high results When this tearing
`behavior is encountered, single specimens must be tested, even though
`scale readings may be in the range below 20. iftearing loads are in excess
`of 60, the augmenting weight attachment may be used to double the
`capacity of the apparatus or a higher capacity pendulum may be used.
`For thin film, it is recommended that single specimens and a lower
`capacity tester be used rather than several specimens and a higher
`capacity machine. if the scale reading is below 10 on a 200 g pendulum,
`multiple plies may be used. The number of plies used should be the
`number required to bring the reading above 10.
`
`ll. Calculation
`
`11.1 Calculate the average tearing force in milli-newtons
`and, if desired, in grams-force as follows:
`11.1.1 If the standard 1600-gf instrument with 0-100 scale
`is used:
`
`Average tearing ram’ mN = 16 X 9.81 x ave:-‘age scale readi
`
`16 X average scale reading
`It
`
`Average tearing force, gf =
`
`where:
`
`n = 1, or number of plies, if used. See Note 6.
`11.1.2 If an instrument of different grams-force capacity
`with 0-100 scale is used:
`
`Average tearing force, mN
`
`= 16 X 9.81 X average scale reading X gt-capacity
`n X 1600 gt‘
`
`Average tearing force, gt‘
`
`where:
`
`16 X average scale reading X gt-capacity
`nx l600gf
`
`n = 1, or number of plies, if used. See Note 6.
`11.1.3 If an instrument has an S1 metric scale (for
`example, 0-1000 graduations):
`Average tearing force, mN
`
`3 16 X average scale reading X capacity, N
`n X 15.7 N
`
`Average tearing force. gt‘
`
`a 16 x average scale reading X capacity, N
`9.81 X n X 15.7 N
`
`where:
`
`n = 1, or number of plies, if used. See Note 6.
`11.1.4 If an instrument has a direct-reading scale (for
`example, digital read-out) in millinewtons:
`
`Average tearing force, mN =
`
`Average tearing force, gf = "ems;
`fading
`
`where:
`
`n = 1, or number of plies, if used. See Note 6.
`11.1.5 If an instrument has a direct-reading scale (for
`
`Page 4 of 5
`
`

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`ASTH D]a"iEE '13 — |J‘?5"l5]iD 0531156]: E35 —
`
`iilii o 1922
`
`
`
`Average tearing force, mN =
`
`average scale reading X 9.81
`n
`
`_
`.
`
`Average tearing force, gf =- -:mE—-—-éave$2]: madmg
`
`where:
`rt = l, or number of plies, if used. See Note 6.
`A direct proportionality may not always exist between
`tearing force and specimen thickness. Therefore, this test
`method provides for reporting data in millinewtons, or, if
`desired, grams of force required to propagate tearing with
`specimen thickness reported separately.
`11.2 Calculate the arthmetic mean, X, tearing resistance
`in each principal direction of the film or sheeting.
`11.3 Calculate the standard deviation of the tearing resis-
`tance in each principal direction to two significant figures as
`f°"°ws:
`
`5 = ~i(EX’ " H5)/(H - 1)
`
`when;
`s = estimated standard deviation,
`X = value of a single observation,
`number of observations, and
`X = arithmetic mean of the set of observations.
`11.4 The average, standard deviation, maximum, and
`minimum values of the tearing resistance may be obtained
`from the digital readout device, if applicable.
`
`12. Report
`12.1 Report the following information:
`12.1.1 Complete identification of the sample tested in-
`
`eluding source, manufacturer's name and code number,
`method of fabrication, roll or lot number, and date received
`or made,
`12.1.2 Type and direction of specimens tested: rectan-
`gular or constant radius, parallel or normal to the machine
`direction of the film. If tests were performed with reference
`to an axis of maximum orientation that did not coincide
`with the machine or transverse direction of the film, the
`report should also include the location of this axis relative to
`the latter directions,
`12.1.3 Number of specimens tested at one time, and the
`number tested in each principal direction of the film,
`12.1.4 Average, maximum, and minimum values for
`specimen thickness and for machine and transverse tearing
`resistance (if data are obtained from specimens in both
`principal directions), expressed in millinewtons, or grams-
`force, if desired to the nearest whole number,
`12.1.5 Standard deviation from the average(s) of the
`tearing resistance in the machine and transverse directions, if
`both directions are tested, and
`12.1.6 Capacity of the tester.
`
`13. Precision and Bias
`
`13.1 Work is in progress to establish the precision of this
`test method.
`13.2 Bias cannot be determined as there is no absolute
`standard that can be used as a reference of any such patent
`rights, and the risk of infringement of such rights, are entirely
`their own responsibility.
`
`The American society for Testing and Materials takes no position respecting the validity ol any patent rights asserted In connection
`with any item mentioned in this standard. Users oi this standard are expressly emrised that determination of the validity at any such
`patent rights, and the risk ol inirlngement of such rights, are entirely their own responsibility.
`
`This standard is subject to revision at any time by the responsible technical committee and must be reviewed every live years and
`I! not revised, either reepproved or withdrawn. Your comments are invited either for revision oi this standard or lor additional standards
`and should be addressed to ASYM Headquarters. Your comments will receive careful consideration at a meeting oi the responsible
`technical committee, which you may attend. if you ieei that your comments have not received a lair hearing you should make your
`views known to the ASTM Committee on Standards, 1918 Race St.. Philadelphia. PA 19103.
`
`Page 5 of 5