ASTM F725-03
(Practice)Standard Practice for Drafting Impact Test Requirements In Thermoplastic Pipe And Fittings Standards
Standard Practice for Drafting Impact Test Requirements In Thermoplastic Pipe And Fittings Standards
SCOPE
1.1 This practice describes a procedure for setting up impact test requirements on the basis of test data obtained by Test Method D 2444.
1.2 This practice is applicable to thermoplastic pipe and fittings.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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An American National Standard
Designation: F 725 – 03
Standard Practice for
Drafting Impact Test Requirements In Thermoplastic Pipe
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And Fittings Standards
This standard is issued under the fixed designation F 725; 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 3.1.5 probability graph paper—commercially available
graph paper that provides straight-line plots when the distribu-
1.1 This practice describes a procedure for setting up impact
tion of attributes is normal. For a discussion on the use of
test requirements on the basis of test data obtained by Test
proability graph paper, see Test Method D 2444 Appendix X2.
Method D 2444.
3.1.6 specification format—the rules set forth by the test
1.2 This practice is applicable to thermoplastic pipe and
requirement, including the number of specimens to be tested
fittings.
and the minimum acceptable number of passes.
1.3 This standard does not purport to address all of the
3.1.7 standard deviation—a statistical term that relates to
safety concerns, if any, associated with its use. It is the
the size of the expected variation in test results.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
NOTE 2—The terms “mean,” “normal distribution,” and “standard
bility of regulatory limitations prior to use. deviation” are dealt with in elementary statistics textbooks.
2. Referenced Documents 4. Summary of Practice
2.1 ASTM Standards: 4.1 Round-robin tests of representative pipe and fittings
D 2444 Test Method for Impact Resistance of Thermoplas- specimens are performed to identify the energy levels at which
2
tic Pipe and Fittings by Means of a Tup (Falling Weight) 90 % or more of the specimens in acceptable lots will pass. A
preferred test format is listed. The B-tup and the V-block
3. Terminology
holder, and room-temperature conditioning and tests are pre-
3.1 Definitions of Terms Specific to This Standard:
ferred choices.
3.1.1 binomial probability equation—the equation that de-
5. Significance and Use
fines the chance for exactly r specimens to pass, when n are
tested, given p, the chance that a single specimen chosen at 5.1 This practice is used for drafting impact test specifica-
random will pass. It is expressed as follows: tion requirements, and it presupposes no special familiarity
with statistical methods. It provides for specification values
n!
r n2r
P 5 p ~1 2 p! (1)
r n that will pass acceptable lots with a high degree of certainty.
r!~n–r!!
The impact test requirement is intended to discriminate be-
tween acceptable materials and manufacturing methods and
NOTE 1—The factorial of zero is one.
those which are not; it is not a simulated service test.
3.1.2 binomial test—a test that has only two possible results
6. Procedure
(for example, pass or fail, heads or tails, true or false).
3.1.3 mean strength—the average strength of the total
6.1 Test thermoplastic pipe or fittings specimens in accor-
population (see Note 2).
dance with Test Method D 2444, and plot the test results on
3.1.4 OC curve (operating characteristic curve)—a graph
probability graph paper.
that illustrates the chance of success or failure when a given
6.2 It will be clear, from the probability paper plot, that the
specification format is employed, given any quality level from
energy level where 98 % or 99 % of all specimens would pass
0 to 1 (0 to 100 % passing in the lot from which test specimens
will be low. On the one hand, when the test format requires that
are selected).
five of five, or six of six, or nine or ten of ten tested shall pass,
or the lot rejected, then the specified energy levels must
correspond to these levels (see Fig. 1, the operating character-
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This practice is under the jurisdiction of ASTM Committee F17 on Plastic
istic (OC) curve for the “nine or ten of ten” test format). On the
Piping Systems and is the direct responsibility of Subcommittee F17.40on Test
Methods.
other hand, five of five, six of six, and nine or ten of ten tests
Current edition approved April 10, 2003. Published May 2003. Originally
at low energy levels will not screen marginal or poor lots
approved in 1981. Last previous edition approved in 1996 as F 725 – 89 (1996).
2 effectively. (See Fig. 1 again).
Annual Book of ASTM Standards, Vol 08.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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