ASTM D4204-00
(Practice)Standard Practice for Preparing Plastic Film Specimens for a Round-Robin Study
Standard Practice for Preparing Plastic Film Specimens for a Round-Robin Study
SCOPE
1.1 This practice covers the preparation of test sets of plastic film specimens for subsequent use in an interlaboratory round-robin study to evaluate the precision of a test method. Note 1-There is no similar or equivalent ISO standard.
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Designation:D4204–00
Standard Practice for
Preparing Plastic Film Specimens for a Round-Robin Study
This standard is issued under the fixed designation D 4204; 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 * 3.1.6 test unit—a specified number of film specimens from
which an equal number of test specimens is to be prepared and
1.1 Thispracticecoversthepreparationoftestsetsofplastic
tested in a short-time span to yield one test result for each
film specimens for subsequent use in an interlaboratory round-
property.
robin study to evaluate the precision of a test method.
3.2 Symbols:
NOTE 1—There is no similar or equivalent ISO standard.
2. Referenced Documents
RR = round-robin study,
2.1 ASTM Standards: p = number of laboratories participating in the RR,
q = number of samples to be used in the RR,
E 691 Practice for Conducting an Interlaboratory Study to
r = number of replicate test results to be obtained on
Determine the Precision of a Test Method
different days by each laboratory for each sample in
3. Terminology
the RR (Note 1),
n = specified number of film specimens in a test unit,
3.1 Definitions of Terms Specific to This Standard: 1
n = number of additional film specimens in each test set,
3.1.1 film specimen—one piece of a sample obtained by
p = number of additional “latent” laboratories provided
cutting across the width of the sample and to a length such that
for in the specimen preparation procedure,
one test specimen can subsequently be prepared.
L = film-specimen length appropriate for preparing one
NOTE 2—For any sample in a laboratory, n test specimens are tested to
1 test specimen,
produce a single test result in a short-time period, while replicate test
L = length of film from a sample from which can be
results are obtained over a longer time period. Thus, there are within-
obtained (p + p ) film specimens; L =(p + p )
1 2 2 1 2
laboratory components of variability for both short-term and long-term
(L ),
testing. This practice calls these within-day and between-day components
SD = component standard deviation for a single source of
of variability, inasmuch as round-robin protocols often specify that
variability for one given sample,
replicate test results be obtained on different days.
S = SD for within-laboratory within-day variability of a
3.1.2 sample—a quantity of film of a width appropriate to
test value,
the test method under study and of a length sufficient to yield
S = SD for within-laboratory between-day variability of
the total number of film specimens needed for the planned
a test result,
round-robin study.
S = SD for between-laboratory variability of a test result,
3.1.3 test result—the value (usually, the arithmetic average)
S = SD for within-sample variability,
of the property derived from one test unit.
S = within-laboratory standard deviation of a single test
r
3.1.4 test set—a group of several film specimens, in a
result for one given sample on any day, and
number greater than that specified for a test unit.
S = between-laboratory standard deviation of a single
R
3.1.5 test specimen—the unit, usually of specified dimen-
test result for one given sample on any day.
sions, that is to be cut from one film specimen and tested, to
4. Significance and Use
produce one value of the property, or properties, by the test
method under study.
4.1 This practice is intended to assist task groups participat-
ing in a round-robin study with the preparation of test sets of
film specimens from film samples in the form of rolls on a
This practice is under the jurisdiction ofASTM Committee D20 on Plastics and
cardboard core.
is the direct responsibility of Subcommittee D20.19 on Film and Sheeting.
4.2 This practice assumes that the essential features of the
Current edition approved March 10, 2000. Published June 2000. Originally
round-robin protocol have already been established by follow-
published as D 4204 – 82. Last previous edition D 4204 – 95.
Annual Book of ASTM Standards, Vols 06.03 and 14.02. ing the guidance of Practice E 691. In particular, it is assumed
*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.
D4204–00
that the following are known: (1) the number of film samples an occasional film specimen with a defect which, properly,
to be used, (2) the number of participating laboratories, (3) the should not be used; then, when a defective film specimen is
number of replicate test results to be generated by each found, it can be discarded and an additional film specimen,
laboratory for each sample, and (4) the number of test already at hand, can be substituted. Thus, n must be at least 2
specimens required to yield one test result for each sample. and, preferably would be 3 or 4. The total number of film
4.3 In accordance with this practice, samples are partitioned specimensinatestsetwouldthenbe(n + n ),fromwhichone
1 2
into test sets so that real within-sample variability will not test result would be obtained.
unduly distort the conclusions drawn from statistical analyses
6.2 Select a value of p for the RR. On a practical basis, it
of the data generated in the round-robin study.
is advisable to set p equal to roughly one half of p . Then, if
2 1
mailed test sets are lost in transit, if after-the-fact recheck
5. Sample Selection
testing is needed in one or more laboratories, or if there are
5.1 Select q samples that would be expected to be uniform
late-entering laboratories into the study, additional test sets will
(for which S would be small). The larger the value of S , the
be at hand, as needed. For test set preparation, consider the
4 4
greater will be the adverse effect upon conclusions drawn from
total number of laboratories to be (p + p ).
1 2
round-robin data regarding test method precision.
6.3 Select a value of L appropriate for the test to be
5.1.1 For any sample, the total observed variability will
conduc
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