ASTM D3777-97(2002)

Standard Practice for Writing Specifications for Textiles (Withdrawn 2008)

SCOPE
1.1 This practice covers general methods for specifying textile product characteristics that may be measured or counted.
1.2 There are many different types of acceptance samplings plans. This practice describes five types. (See 1.5.)
1.3 This practice describes general methods for writing the sampling plans of the types named in whose characteristics may be measured or counted. The requirements are described in terms of what the basic unit is and what limit constitutes a nonconforming item. Tables are provided from which appropriate sampling plans can be designed. Numerical examples illustrate the design of sampling plans and the construction of their consequent operating characteristic curves.
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.
1.5 This practice includes the following sections:SectionScope1Referenced Documents2Terminology3Significance and Use4Organizational Form for Specifications5Introductory Sections6Requirements Section7Sampling8Test Methods9Sampling Plans10Operating Characteristic Curve11Keywords12
1.6 The annexes include:Topic TitleAnnex NumberTypes of Sampling Plans:Single-Sample Fraction-Nonconforming Attribute DataAnnex A1Single-Sample Nonconformances-per-UnitAnnex A2Single-Sample by Variables to Control Fraction-Non-conforming with Standard Deviation KnownAnnex A3Single-Sample by Variables to Control Fraction-Non-conforming with Standard Deviation UnknownAnnex A4Chain SamplingAnnex A5
WITHDRAWN RATIONALE
This practice covers general methods for specifying textile product characteristics that may be measured or counted.
This practice is being withdrawn with no replacement because D13 no longer has the expertise to maintain and statistical standards are being maintained by committee E11.
Formerly under the jurisdiction of Committee D13 on Textiles, this practice was withdrawn in July 2008.

General Information

• Status: Withdrawn
• Publication Date: 09-Sep-1997
• Withdrawal Date: 16-Oct-2008
• ICS: 59.080.01 - Textiles in general
• Technical Committee: D13 - Textiles

Relations

• Replaces: ASTM D3777-97 - Standard Practice for Writing Specifications for Textiles
• Effective Date: 10-Sep-1997

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D 3777 – 97 (Reapproved 2002)
Standard Practice for
Writing Specifications for Textiles
This standard is issued under the fixed designation D3777; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
Single-Sample by Variables to Control Fraction-Non- Annex A4
conforming with Standard Deviation Unknown
1.1 This practice covers general methods for specifying
Chain Sampling Annex A5
textile product characteristics that may be measured or
2. Referenced Documents
counted.
1.2 There are many different types of acceptance samplings
2.1 ASTM Standards:
plans. This practice describes five types. (See 1.5.)
D123 Terminology Relating to Textiles
1.3 This practice describes general methods for writing the
D2906 Practice for Statements on Precision and Bias for
samplingplansofthetypesnamedin1.5whosecharacteristics
Textiles
may be measured or counted. The requirements are described
D4271 PracticeforWritingStatementsonSamplinginTest
in terms of what the basic unit is and what limit constitutes a
Methods for Textiles
nonconforming item. Tables are provided from which appro-
2.2 Adjunct
priate sampling plans can be designed. Numerical examples
TEX-PAC
illustrate the design of sampling plans and the construction of
NOTE 1—Tex-Pac is a group of PC programs on floppy disks, available
their consequent operating characteristic curves.
through ASTM Headquarters, 100 Barr Harbor Drive, West Consho-
1.4 This standard does not purport to address all of the
hocken, PA19428, USA. The points on the operating characteristic (OC)
safety concerns, if any, associated with its use. It is the
curves described in theAnnexes of this Standard can be calculated using
responsibility of the user of this standard to establish appro- programs in this adjunct.
priate safety and health practices and determine the applica-
2.3 Other Standards:
bility of regulatory limitations prior to use.
ANSI/ASQC Z1.4 Sampling Procedures and Tables for
1.5 This practice includes the following sections: 4
Inspection by Attributes
Section
MIL-STD-105D Sampling Procedures and Tables for In-
Scope 1
spection by Attributes
Referenced Documents 2
Terminology 3 MIL-STD-414 Sampling Procedures and Tables for Inspec-
Significance and Use 4
tion by Variables by Percent Defective
Organizational Form for Specifications 5
Tables of the Binomial Probability Frequency Distribution
Introductory Sections 6
Requirements Section 7
(No. 6 Of the Applied Mathematics Series), National
Sampling 8
Institute of Standards and Technology (NIST)
Test Methods 9
Sampling Plans 10
3. Terminology
Operating Characteristic Curve 11
Keywords 12
3.1 Definitions:
1.6 The annexes include:
Topic Title Annex Number
Types of Sampling Plans: 2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Single-Sample Fraction-Nonconforming Attribute Annex A1
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Data
Standards volume information, refer to the standard’s Document Summary page on
Single-Sample Nonconformances-per-Unit Annex A2
the ASTM website.
Single-Sample by Variables to Control Fraction-Non- Annex A3
PC programs on floppy disks are available through ASTM. For 3 ⁄2 inch disk
conforming with Standard Deviation Known
request PCN:12-429040-18, for a 5 ⁄4 inch disk request PCN:12-429041-18.
American Society for Quality Control, 230 West Wells Street, Milwaukee, WI
53203.
1 5
ThispracticeisunderthejurisdictionofASTMCommitteeD13onTextilesand AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
is the direct responsibility of Subcommittee D13.93 on Statistics. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Current edition approved Sept. 10, 1997. Published August 1998. Originally Available from National Institute of Standards and Technology, NIST, Gaith-
published as D3777–79. Last previous edition D3777–91. ersburg, MD 20899.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 3777 – 97 (2002)
3.1.1 acceptable quality level, (AQL or p ), n—in accep- 3.1.18 single sampling, n—in acceptance sampling, a sam-
tance sampling,themaximumfractionofnonconformingitems pling plan for which the decision to accept or reject a lot is
at which the process average can be considered satisfactory; based on a single sample.
the process average at which the risk of rejection is called the 3.1.19 specification, n—a precise statement of a set of
producer’s risk. requirements to be satisfied by a material, product, system, or
3.1.2 acceptance number, (c), n—in acceptance sampling, service, that indicates the procedures for determining whether
each of the requirements is satisfied.
the maximum for the number of nonconforming items in a
sample that allows the conclusion that the lot conforms to the 3.1.20 type A operating characteristic curve, n—an operat-
ing characteristic curve which describes the operation of a
specification.
sampling plan where the size of the lot being sampled is taken
3.1.3 acceptance sampling, n—sampling done to provide
into consideration.
specimens for acceptance testing.
3.1.21 type B operating characteristic curve, n—an operat-
3.1.4 acceptance testing, n—testing done to decide if a
ing characteristic curve which describes the operation of a
material meets acceptance criteria.
sampling plan where items are drawn at random from a
3.1.5 chain sampling, n—in acceptance sampling, a sam-
theoretically infinite process.
pling plan for which the decision to accept or reject a lot is
3.1.22 For definitions of textile and statistical terms used in
based in part on the results of inspection of the lot and in part
this practice refer to Terminology D123.
on the results of inspection of the immediately preceding lots.
3.1.6 consumer’s risk, (b), n—in acceptance sampling, the
4. Significance and Use
probabilityofacceptingalotwhentheprocessaverageisatthe
4.1 All purchase agreements should be based on a specifi-
limiting quality level.
cation of the material to be purchased which is agreeable to
3.1.7 laboratory sample, n—a portion of material taken to
both parties.The parties should have a common understanding
represent the lot sample, or the original material, and used in
of the quality of material described by the specification. This
the laboratory as a source of test specimens.
practice describes how to write such a specification.
3.1.8 limiting quality level, (LQL or p ), n—in acceptance
4.2 Allpurchaseagreementsshouldcontainasamplingplan
sampling, the fraction of nonconforming items at which the
to use to determine the disposition of lots of material. A
processaveragecanbeconsideredbarelytolerable;theprocess
specification is not complete without a sampling plan. This
average at which the risk of acceptance is called the consum-
practice describes how to write sampling plans which, when
er’s risk. (Syn. lot tolerance fraction nonconforming.)
used as part of a purchase agreement, will give the parties a
3.1.9 lot, n—in acceptance sampling,thatpartofaconsign-
commonunderstandingofthequalityofmaterialdescribed,the
ment or shipment consisting of material from one production
risks connected with the sampling and testing procedures, and
lot.
the procedures to follow when a lot is rejected.
3.1.10 lot tolerance fraction nonconforming, n—see limit-
4.3 It should be clearly understood that no sampling plan,
ing quality level.
including 100% inspection, can make certain that all accepted
3.1.11 nonconforming, adj—a description of a unit or a
lotswillhaveacertainquality.Nomatterwhatthequalitylevel
group of units that does not meet the unit or group tolerance.
a vendor supplies, if the purchaser continues to receive
3.1.12 nonconformity, n—anoccurrenceoffailingtosatisfy
shipments from the same vendor, a portion of the shipments
the requirements of the applicable specification; a condition
will be accepted by the sampling plan.All a sampling plan can
that results in a nonconforming item.
do is increase the probability of acceptance of good lots, and
3.1.13 operating characteristic curve, OC-curve, n—in ac-
decrease the probability of acceptance of bad lots.
ceptance sampling, the curve which has as its abscissa an
4.4 When inspection is inexpensive and not destructive, or
hypothesized lot average, and which has as its ordinate the
whenitisextremelyimportantthatallnonconformingitemsbe
probability of accepting the lot, when the plan is used. (See
detected, conformance to the specification may be determined
also typeAoperating characteristic curveand type B operating
by complete inspection of every item in the lot.
characteristic curve.)
4.5 When neither of the situations described in 4.4 pertain,
3.1.14 producer’s risk, (a), n—theprobabilityofrejectinga
a sampling plan which involves less than 100% inspection
lot when the process average is at the acceptable quality level,
may be used. A plan should be chosen which will divide the
the AQL.
cost of imperfect judgments caused by inspecting only a
3.1.15 rejection number, n—in acceptance sampling, the
portion of the lot between producer and buyer. This practice
minimum number of nonconforming items in a sample that
describes some simple methods for preparing sampling plans.
requires the conclusion that the lot does not conform to the
More complex sampling plans may be justified when the costs
7,8
specification.
of inspection are high. Such plans may be found in Duncan,
3.1.16 sample, n—(1) a portion of a lot of material which is
MIL-STD-105D, and in MIL-STD-414. In any case, sampling
taken for testing or for record purposes; (2) a group of
specimens used, or observations made, which provide infor-
Duncan, Acheson J., Quality Control and Industrial Statistics, Richard D.
mation that can be used for making statistical inferences about
Irwin, Inc., Homewood, IL, 1974.
the population(s) from which they were drawn.
Hahn,GeraldJ.,Schilling,EdwardG.,“AnIntroductiontotheMIL-STD-105D
3.1.17 sampling unit, n—an identifiable discrete unit or
Acceptance Sampling Scheme,” Standardization News, American Society for
subunit of material that could be taken as part of a sample. Testing and Materials, September 1975, pp. 20–26.
D 3777 – 97 (2002)
TABLE 2 Basis for Acceptance Sampling Plan
plans can be compared using their operating characteristic
curves and their costs. Fraction of Lot Out of
Risk Factors
Specification
4.6 Theoperatingcharacteristiccurvesinthispracticeareof
Property Acceptable Limiting
Pro- Con-
thetypeB.Thatis,thatthelotsbeinginspectedareassumedto
Quality Quality
ducer’s sumer’s
be infinitely large. This assumption is convenient, and no Level Level
Component separation 0.01 0.11 0.05 0.10
significant error is introduced, if the lot size is 1000 or more
Tenacity 0.015 0.07 0.04 0.075
items,orifthesamplesizeisnomorethan10%ofthelotsize.
In other cases the consumer’s risk will be somewhat over-
stated. 9.2.1 Use the preferred option of stating that the property
will be tested as directed in an existing test method which is
5. Organizational Form for Specifications
listed in the section on referenced documents. If it is necessary
5.1 The important parts of a specification are: designation to make minor changes in the test method, add a section on
precision and bias as follows: “The precision and bias of this
number, title, scope, reference documents, terminology, re-
quirements, sampling plan, test methods, and operating char- testmethodarenotchangedsignificantlybytheminorchanges
specified above.” (See Practice D2906.)
acteristic curve. See Part B of Form and Style for ASTM
Standards for further information regarding parts and their 9.2.2 If the less desirable option of writing a test method
within the specification is used, the test method cannot be
order of presentation.
referencedinanotherspecification.Inaddition,thetestmethod
6. Introductory Sections of Specifications
must include sections on scope, significance and use, proce-
dure,andprecisionandbiasasrequiredbyPartAof Form and
6.1 Writethesectionsontitle,scope,referenceddocuments,
Style for ASTM Standards. For practical purposes, this option
and terminology in accordance with Form and Style for ASTM
is no easier than writing a separate test method and contains
Standards.
serious drawbacks.
7. Requirements Section of Specification
9.3 If neither a measurement nor a count can be made on a
unit of the sample, state in writing what is to be done and how
7.1 State the requirements for a laboratory sampling unit.
conformance is to be decided. If appropriate, specify that
Requirements may be expressed as attributes or as variables.
physical samples of satisfactory and unsatisfactory materials
Tolerances may be one-sided or two-sided. It is recommended
are to be exchanged by the producer and the buyer.
that the sections specifying the requirements are preceded by a
9.4 In case of a dispute arising from differences in reported
center heading reading Requirements.
testresultsfollowtheproceduredescribedintheapplicabletest
7.2 Table 1 illustrates the requirements and acceptance
method.
criteriaforanattributeandavariablesplan.Thistableisbased
on the examples in Annex A1 and Annex A3.
10. Sampling Plans
7.3 Tabulate the key parameters, specifying the OC-curves
10.1 Single-Sample Fraction-Nonconforming Attribute
ofsamplingplansinatablesimilartoTable2.Table2isbased
Data—Attribute inspections are summarized in terms of frac-
on the examples of Annex A1 and Annex A3.
tionofunitsnotconforming.Simpletwo-pointplansarebased
on two selected points on the operating characteristic curve.
8. Sampling
Single-sampleplansbasethedecisiontoacceptorrejectthelot
8.1 Follow the directions of Practice D4271 in describing
being sampled on one sample only. The plans in this standard
how sampling is to be done.
are based on the binomial frequency distribution. They do not
takeintoaccountinspectionsmadeonpriorlotsfromthesame
9. Test Methods
vendor.ThecalculationofsuchplansisdescribedinAnnexA1.
9.1 Specify a test method for every property for which
10.2 Single-Sample Nonconformances-Per-Item—A single-
requirements are indicated. List the test methods for the
sample nonconformance-per-unit plan consists of one sample
properties in exactly the same order that they are listed in the
of size n and an acceptance number c. If the sample has a total
sectionsandtablesonrequirements.Itisrecommendedthatthe
number of instances of nonconformances less than or equal to
sectionsspecifyingthetestmethodstobeusedarepr
...