ASTM E2234-09(2013)
(Practice)Standard Practice for Sampling a Stream of Product by Attributes Indexed by AQL
Standard Practice for Sampling a Stream of Product by Attributes Indexed by AQL
SIGNIFICANCE AND USE
4.1 Purpose—This publication establishes lot or batch sampling plans and procedures for inspection by attributes. This publication shall not be interpreted to supersede or conflict with any contractual requirements. The words “accept,” “acceptance,” “acceptable,” etc, refer only to the contractor’s use of the sampling plans contained in this standard and do not imply an agreement by the customer (formerly “Government” in original text) to accept any product. Determination of acceptability by the customer shall be as described in contractual documents. The sampling plans described in this standard are applicable to AQL’s of 0.01 percent or higher and are therefore not suitable for applications where quality levels in the range of parts per million levels can be realized.
4.2 Application—Sampling plans designated in this publication are applicable, but not limited, to inspection of the following: (1) end items, (2) components and raw materials, (3) operations or services, (4) materials in process, (5) supplies in storage, (6) maintenance operations, (7) data or records, (8) administrative procedures. These plans are intended primarily to be used for a continuing series of lots or batches. The plans may also be used for the inspection of isolated lots or batches, but, in this latter case, the user is cautioned to consult the operating characteristic curves to find a plan which will yield the desired protection (see 6.11).
SCOPE
1.1 This practice establishes lot or batch sampling plans and procedures for inspection by attributes using MIL-STD-105E as a basis for sampling a steady stream of lots indexed by AQL.
1.2 This practice provides the sampling plans of MIL-STD-105E in ASTM format for use by ASTM committees and others. It recognizes the continuing usage of MIL-STD-105E in industries supported by ASTM. Most of the original text in MIL-STD-105E is preserved in Sections 4-6 of this practice.
1.3 No system of units is specified in this standard.
1.4 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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Designation: E2234 − 09 (Reapproved 2013) An American National Standard
Standard Practice for
Sampling a Stream of Product by Attributes Indexed by
AQL
This standard is issued under the fixed designation E2234; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 acceptance quality limit (AQL), n—qualitylimitthatis
theworsttolerableprocessaveragewhenacontinuingseriesof
1.1 This practice establishes lot or batch sampling plans and
lots is submitted for acceptance sampling.
procedures for inspection by attributes using MIL-STD-105E
3.1.2.1 Discussion—This definition supersedes that given in
asabasisforsamplingasteadystreamoflotsindexedbyAQL.
MIL-STD-105E.
1.2 This practice provides the sampling plans of MIL-STD-
3.1.3 average outgoing quality (AOQ), n—the average per-
105E in ASTM format for use by ASTM committees and
cent defective of outgoing product including all accepted lots
others. It recognizes the continuing usage of MIL-STD-105E
or batches after any defectives found in them are replaced by
in industries supported by ASTM. Most of the original text in
acceptableunits,plusalllotsorbatcheswhicharenotaccepted
MIL-STD-105E is preserved in Sections4–6 of this practice.
after such lots or batches have been effectively 100 %
1.3 No system of units is specified in this standard.
inspected and all defective units replaced by acceptable units.
E1994
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1.4 average outgoing quality limit (AOQL), n—theAOQL
responsibility of the user of this standard to establish appro-
is the maximum of the AOQ’s for all possible incoming
priate safety and health practices and determine the applica-
percentages defective for the process for a given acceptance
bility of regulatory limitations prior to use.
sampling plan. E1994
3.1.5 classification of defects, n—the enumeration of pos-
2. Referenced Documents
sible defects of the unit of product classified according to their
2.1 ASTM Standards:
seriousness, that is, critical, major, or minor defect.
E456 Terminology Relating to Quality and Statistics
3.1.6 critical defect, n—a defect that judgment and experi-
E1994 Practice for Use of Process Oriented AOQL and
ence indicate would result in hazardous or unsafe conditions
LTPD Sampling Plans
for individuals using, maintaining, or depending upon the
E2586 Practice for Calculating and Using Basic Statistics
product, or a defect that judgment and experience indicate is
2.2 Other Standard:
likely to prevent performance of the function of a major end
MIL-STD-105E Sampling Procedures and Tables for In-
item.
spection by Attributes
3.1.7 defect, n—any nonconformance of the unit of product
with specified requirements.
3. Terminology
3.1.8 double sampling plan, n—a multiple sampling plan in
3.1 Definitions:
which up to two samplings can be taken and evaluated to
3.1.1 For a more extensive list of terms in E11 standards,
accept or reject a lot.
see Terminology E456.
3.1.9 inspection, n—the process of measuring, examining,
testing, or otherwise comparing the unit of product with the
This practice is under the jurisdiction ofASTM Committee E11 on Quality and
requirements.
Statistics and is the direct responsibility of Subcommittee E11.30 on Statistical
3.1.10 inspection by attributes, n—inspection whereby ei-
Quality Control.
Current edition approved April 1, 2013. Published April 2013. Originally
ther the unit of product is classified simply as defective or
approved in 2005. Last previous edition approved in 2009 as E2234 – 09. DOI:
non-defective, or the number of defects in the unit of product
10.1520/E2234-09R13.
is counted, with respect to a given requirement or set of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
requirements.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
3.1.11 inspection lot, n—a collection of units of product
the ASTM website.
produced under conditions that are considered uniform and
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. from which a sample is drawn and inspected.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2234 − 09 (2013)
3.1.12 major defect, n—a defect, other than critical, that is 3.2.9 minor defective, n—a unit of product which contains
likely to result in failure, or to reduce materially the usability one or more minor defects but contains no critical or major
of the unit of product for its intended purpose. defect.
3.1.13 minor defect, n—a defect that is not likely to reduce
3.2.10 percent defective, n—any given quantity of units of
materially the usability of the unit of product for its intended product one hundred times the number of defective units of
purpose, or is a departure from established standards having
product contained therein divided by the total number of units
little bearing on the effective use or operation of the unit. of product, that is:
3.1.14 multiple sampling plan, n—a sampling plan in which
Number of defectives 3100
Percent Defective 5 (2)
successive samples from a lot are drawn and after each sample
Number of units inspected
is inspected a decision is made to accept the lot, reject the lot,
3.2.11 process average (in inspection), n—the average per-
or to take another sample, based on quality level of the
cent defective or average number of defects per hundred units
combined samples.
(whichever is applicable) of product submitted by the supplier
3.1.14.1 Discussion—When the quality is much less or
for original inspection.
much more than theAQL, the decision can be made on the first
3.2.11.1 Discussion—Original inspection is the first inspec-
sample, which is smaller than that of a single sampling plan
tion of a particular quantity of product as distinguished from
with equivalent acceptance quality level. For samples that are
the inspection of product which has been resubmitted after
closetotheAQLinquality,additionalsamplesarerequiredand
prior rejection.
the total sample size will be larger than the corresponding
3.2.12 sample size code letter, n—a device used along with
single sampling plan.
the AQL for locating a sampling plan on a table of sampling
3.1.15 operating characteristic, n—probability of accep-
plans.
tance using a specified acceptance sampling plan, as a function
3.2.13 sampling plan (in inspection), n—a plan that indi-
of parameters describing quality of the lot.
cates the number of units of product from each lot or batch
3.1.16 sample, n—a group of observations, test results,
which are to be inspected (sample size or series of sample
taken from a large collection of observations, test results,
sizes) and the criteria for determining the acceptability of the
whichservestoprovideinformationthatmaybeusedasabasis
lot or batch (acceptance and rejection numbers).
E2586
for making a decision concerning the larger collection.
3.2.14 unit of product, n—thatwhichisinspectedinorderto
3.1.16.1 Discussion—A sample consists of one or more
determine its classification as defective or non-defective or to
units of product drawn from an inspection lot, the units of the
count the number of defects.
sample being selected at random without regard to their
3.2.14.1 Discussion—It may be a single article, a pair, a set,
quality. The number of units of product in the sample is the
a length, an area, an operation, a volume, a component of an
sample size.
end product, or the end product itself. The unit of product may
3.2 Definitions of Terms Specific to This Standard:
or may not be the same as the unit of purchase, supply,
3.2.1 batch (in inspection), n—a collection of units of
production, or shipment.
product produced under conditions that are considered uniform
and from which a sample is drawn and inspected, and may 4. Significance and Use
differ from a collection of units designated as a batch for other
4.1 Purpose—This publication establishes lot or batch sam-
purposes, for example, production, shipment, etc.
pling plans and procedures for inspection by attributes. This
3.2.2 batch size, n—the number of units of product in a
publication shall not be interpreted to supersede or conflict
batch.
with any contractual requirements. The words “accept,”
“acceptance,” “acceptable,” etc, refer only to the contractor’s
3.2.3 critical defective, n—a unit of product which contains
one or more critical defects and may also contain major and/or use of the sampling plans contained in this standard and do not
imply an agreement by the customer (formerly “Government”
minor defects.
in original text) to accept any product. Determination of
3.2.4 defective, n—a unit of product which contains one or
acceptability by the customer shall be as described in contrac-
more defects.
tual documents. The sampling plans described in this standard
3.2.5 defects per hundred units, n—any given quantity of
are applicable to AQL’s of 0.01 percent or higher and are
units of product is one hundred times the number of defects
therefore not suitable for applications where quality levels in
contained therein (one or more defects being possible in any
the range of parts per million levels can be realized.
unitofproduct)dividedbythetotalnumberofunitsofproduct,
4.2 Application—Sampling plans designated in this publi-
that is:
cation are applicable, but not limited, to inspection of the
Number of defects 3100
Defects per hundred units 5 (1) following:(1)enditems,(2)componentsandrawmaterials,(3)
Number of units inspected
operations or services, (4) materials in process, (5) supplies in
3.2.6 lot, n—see batch.
storage, (6) maintenance operations, (7) data or records, (8)
3.2.7 lot size, n—see batch size.
administrative procedures. These plans are intended primarily
3.2.8 major defective, n—a unit of product which contains to be used for a continuing series of lots or batches. The plans
one or more major defects, and may also contain minor defects may also be used for the inspection of isolated lots or batches,
but contains no critical defect. but, in this latter case, the user is cautioned to consult the
E2234 − 09 (2013)
operating characteristic curves to find a plan which will yield 5.8 Defective—A defective is a unit of product which
the desired protection (see 6.11). contains one or more defects.
5.9 Defects per Hundred Units—The number of defects per
5. Definitions
hundred units of any given quantity of units of product is one
hundred times the number of defects contained therein (one or
5.1 Acceptable Quality Level (AQL)—When a continuous
more defects being possible in any unit of product) divided by
series of lots is considered, theAQLis the quality level which,
the total number of units of product, that is:
for the purposes of sampling inspection, is the limit of a
satisfactory process average (see 5.19).
Number of defects 3100
Defects per hundred units 5
5.1.1 A sampling plan and an AQL are chosen in accor- Number of units inspected
dance with the risk assumed. Use of a value of AQL for a
5.10 Inspection—Inspection is the process of measuring,
certain defect or group of defects indicates that the sampling
examining, testing, or otherwise comparing the unit of product
plan will accept the great majority of the lots or batches
with the requirements.
provided the process average level of percent defective (or
5.11 Inspection by Attributes—Inspection by attributes is
defects per hundred units) in these lots or batches be no greater
inspection whereby either the unit of product is classified
than the designated value of AQL. Thus, the AQL is a
simply as defective or non-defective, or the number of defects
designated value of percent defective (or defects per hundred
in the unit of product is counted, with respect to a given
units) for which lots will be accepted most of the time by the
requirement or set of requirements.
sampling procedure being used.
5.12 Lot or Batch—The term lot or batch shall mean
5.1.2 The sampling plans provided herein are so arranged
“inspection lot” or “inspection batch”, that is, a collection of
that the probability of acceptance at the designatedAQL value
units of product from which a sample is to be drawn and
depends upon the sample size, being generally higher for large
inspected and may differ from a collection of units designated
samples than for small ones, for a givenAQL. TheAQL alone
as a lot or batch for other purposes (for example, production,
does not identify the chances of accepting or rejecting indi-
shipment, etc.).
viduallotsorbatchesbutmoredirectlyrelatestowhatmightbe
expected from a series of lots or batches, provided the steps
5.13 Lot or Batch Size—The lot or batch size is the number
indicatedinthispublicationaretaken.Itisnecessarytoreferto
of units of product in a lot or batch.
the operating characteristic curve of the plan to determine the
5.14 Major Defect—A major defect is a defect, other than
relative risks.
critical, that is likely to result in failure, or to reduce materially
5.2 Average Outgoing Quality (AOQ)—For a particular
the usability of the unit of product for its intended purpose.
process average, the AOQ is the average quality of outgoing
5.15 Major Defective—A major defective is a unit of prod-
product including all accepted lots or batches, plus all rejected
uct which contains one or more major defects, and may also
lots or batches after the rejected lots or batches have been
contain minor defects but contains no critical defect.
effectively100percentinspectedandalldefectivesreplacedby
5.16 Minor Defect—A minor defect is a defect that is not
non-defectives.
likely to reduce materially the usability of the unit of product
5.3 Average Outgoing Quality Limit (AOQL)—The AOQL
for its intended purpose, or is a departure from established
is the maximum AOQ for a given acceptance sampling plan.
standards having little bearing on the effective use or operation
FactorsforcomputingAOQLvaluesaregiveninTableV-Afor
of the unit.
each of the single sampling plans for normal inspection and in
5.17 Minor Defective— A minor defective is a unit of
Table V-B for each of the single sampling plans for tightened
product which contains one or more minor defects but contains
inspection.
no critical or major defect.
5.4 Classification of Defects —A classification of defect
...
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