ASTM E2819-11(2021)

Standard Practice for Single- and Multi-Level Continuous Sampling of a Stream of Product by Attributes Indexed by AQL

ABSTRACT
This practice establishes tables and procedures for applying five different types of continuous sampling plans for inspection by attributes using MIL-STD-1235B as a basis for sampling a steady stream of lots indexed by AQL. This practice represents a conversion of MIL-STD1235B to an ASTM-supported standard.
SIGNIFICANCE AND USE
4.1 The reason for preserving military sampling standards is that many organizations throughout the world still use these standards in their current form. MIL-STD-1235B is no longer supported by the U.S. Department of Defense as of the mid-1990s and is out of print, but does exist in the public domain. This practice represents a conversion of MIL-STD-1235B to an ASTM-supported standard.  
4.2 This practice provides the tables and procedures for applying five different types of continuous sampling plans for inspection by attributes. These continuous sampling plans are discussed in Sections 6 – 10 of this practice and each section includes information on:
(1) Initiation of 100 % inspection in use.
(2) Requirements on when to switch to sampling inspection.
(3) Conditions warranting a return to 100 % inspection.
(4) When a change in Code Letter, if desired, can be made.
(5) What to do when the checking inspector finds a defect that was originally found conforming by the screening inspector(s), that is, ineffective screening.
(6) Situations where a defect is found before the switch to 100 % inspection causing excessive periods of 100 % inspection so action must be taken, that is, long periods of screening.  
4.2.1 Section 6 (Section 2 in MIL-STD-1235B) describes specific procedures and applications of the CSP-1 sampling plans – a single-level continuous sampling procedure which provides for alternating between sequences of 100 % inspection and sampling inspection.  
4.2.2 Section 7 (Section 3 in MIL-STD-1235B) describes specific procedures and applications of the CSP-F sampling plans – a variation of the CSP-1 plans in that CSP-F plans are applied to a relatively short run of product, thereby permitting smaller clearance numbers to be used.  
4.2.3 Section 8 (Section 4 in MIL-STD-1235B) describes specific procedures and applications of the CSP-2 sampling plans – a modification of CSP-1 in that 100 % inspection resumes only after a prescribed number of def...
SCOPE
1.1 This practice establishes tables and procedures for applying five different types of continuous sampling plans for inspection by attributes using MIL-STD-1235B as a basis for sampling a steady stream of lots indexed by AQL.  
1.2 This practice provides the sampling plans of MIL-STD-1235B in ASTM format for use by ASTM committees and others. It recognizes the continuing usage of MIL-STD-1235B in industries supported by ASTM. Most of the original text in MIL-STD-1235B is preserved in Sections 6 – 10 of this practice.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2021
• ICS: 03.120.30 - Application of statistical methods
• Technical Committee: E11 - Quality and Statistics
• Drafting Committee: E11.30 - Statistical Quality Control

Relations

• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM E456-13A(2017)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM E456-13A(2017)e3 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM E456-13a - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae2 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae3 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Aug-2013
• Refers: ASTM E1994-09(2013) - Standard Practice for Use of Process Oriented AOQL and LTPD Sampling Plans
• Effective Date: 01-Apr-2013
• Refers: ASTM E2234-09(2013) - Standard Practice for Sampling a Stream of Product by Attributes Indexed by AQL
• Effective Date: 01-Apr-2013
• Refers: ASTM E456-12e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-May-2012
• Refers: ASTM E456-12 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-May-2012
• Refers: ASTM E1994-09 - Standard Practice for Use of Process Oriented AOQL and LTPD Sampling Plans
• Effective Date: 01-Nov-2009
• Refers: ASTM E2234-09 - Standard Practice for Sampling a Stream of Product by Attributes Indexedby AQL
• Effective Date: 01-Nov-2009
• Refers: ASTM E2234-08 - Standard Practice for Sampling a Stream of Product by Attributes Indexedby AQL
• Effective Date: 01-Oct-2008

Overview

ASTM E2819-11(2021) - Standard Practice for Single- and Multi-Level Continuous Sampling of a Stream of Product by Attributes Indexed by AQL provides comprehensive guidelines for the application of continuous sampling plans in quality control processes. This standard is based on the widely used and historically significant MIL-STD-1235B, ensuring continuity for industries that still rely on these military sampling methods. The standard delivers detailed procedures and tables for implementing five distinct types of continuous sampling plans, all indexed by Acceptance Quality Limit (AQL), for the inspection of ongoing production streams.

Key Topics

• Continuous Sampling Plans: Guidance for single- and multi-level continuous sampling methods to inspect products by their attributes, addressing both defect occurrence and process consistency.
• Inspection by Attributes: Focus on classifying products as defective or non-defective based on set criteria, with definitions and classifications for critical, major, and minor defects.
• Transition Criteria: Explicit requirements for when to transition between 100% inspection and sampling inspection, as well as when to return to full inspection based on inspection findings.
• Sampling Plan Types: Coverage of five plan types (CSP-1, CSP-F, CSP-2, CSP-T, CSP-V), each offering unique procedures for quality assurance:
  • CSP-1: Alternates between full and sampling inspection.
  • CSP-F: Suited for shorter production runs.
  • CSP-2: Adds procedures for quicker response to defects.
  • CSP-T: Allows for reduction of sampling frequency with sustained superior product quality.
  • CSP-V: Reduces clearance numbers in high-quality situations.
• Defect Classification and AQL: Features robust definitions for defect types and detailed guidance on establishing acceptance quality limits.
• Process Requirements: Emphasizes stable processes, ease of inspection, and appropriate resource allocation as prerequisites for plan implementation.
• Supplier and Consumer Responsibilities: Outlines roles related to product acceptance, defect correction, and the use of sampling plans.

Applications

ASTM E2819-11(2021) is valuable for:

• Manufacturers and Quality Assurance Teams: Ensures statistical control in continuous production environments such as assembly lines, process industries, and automated manufacturing.
• Procurement and Vendor Management: Maintains consistency and reliability when sourcing materials by adhering to recognized sampling protocols.
• Industries with Legacy Standards: Supports organizations that continue to use MIL-STD-1235B methods, facilitating transition to ASTM-supported practices without disrupting established quality management systems.
• Inspection of Various Products: Applicable to end items, components, raw materials, and even records or data streams, provided the conditions for sampling are met.
• Regulated Markets: Aligns with international standards development principles and supports acceptability in global supply chains.

Typical scenarios include:

• Routine process monitoring and acceptance sampling by attributes.
• Implementation of quality checks on moving product lines.
• Rapid response to detected defects and process deviations.
• Specification of AQLs in contracts and procurement documentation.

Related Standards

Several supporting and referenced standards strengthen the application of ASTM E2819-11(2021):

• MIL-STD-1235B: The foundation for continuous and multi-level sampling plan procedures incorporated into this standard.
• ASTM E2234: Practice for Sampling a Stream of Product by Attributes Indexed by AQL.
• ASTM E1994: Practice for Use of Process-Oriented AOQL and LTPD Sampling Plans.
• ASTM E456: Terminology Relating to Quality and Statistics.
• International Principles: Developed in accordance with the WTO Technical Barriers to Trade (TBT) Committee guidelines for international standardization.

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By adopting ASTM E2819-11(2021), organizations can implement robust, internationally aligned quality inspection processes for ongoing production, ensuring product quality, customer satisfaction, and regulatory compliance. This standard supports modern quality programs while preserving the continuity of proven military sampling procedures.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2819 − 11 (Reapproved 2021) AnAmerican National Standard
Standard Practice for
Single- and Multi-Level Continuous Sampling of a Stream of
Product by Attributes Indexed by AQL
This standard is issued under the fixed designation E2819; 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 2.2 Military Standards:
MIL-STD-1235A1 Functional Curves of the Continuous
1.1 This practice establishes tables and procedures for
Sampling Plans
applying five different types of continuous sampling plans for
MIL-STD-1235B Single- and Multi-Level Continuous Sam-
inspection by attributes using MIL-STD-1235B as a basis for
pling for Attributes
sampling a steady stream of lots indexed by AQL.
3. Terminology
1.2 This practice provides the sampling plans of MIL-STD-
3.1 Definitions:
1235B in ASTM format for use by ASTM committees and
3.1.1 For a more extensive list of terms in Committee E11
others. It recognizes the continuing usage of MIL-STD-1235B
standards, see Terminology E456.
in industries supported by ASTM. Most of the original text in
3.1.2 acceptance quality limit (AQL), n—qualitylimitthatis
MIL-STD-1235B is preserved in Sections 6–10 of this
the worst tolerable process average when a continuing series of
practice.
lots is submitted for acceptance sampling. E2234
1.3 This standard does not purport to address all of the
3.1.3 average outgoing quality (AOQ), n—the average per-
safety concerns, if any, associated with its use. It is the
cent defective of outgoing product including all accepted lots
responsibility of the user of this standard to establish appro-
or batches after any defectives found in them are replaced by
priate safety, health, and environmental practices and deter-
acceptable units, plus all lots or batches which are not accepted
mine the applicability of regulatory limitations prior to use.
after such lots or batches have been effectively 100 % in-
1.4 This international standard was developed in accor-
spected and all defective units replaced by acceptable units.
dance with internationally recognized principles on standard-
E1994
ization established in the Decision on Principles for the
3.1.4 average outgoing quality limit (AOQL), n—the maxi-
Development of International Standards, Guides and Recom-
mum AOQ for a given acceptance sampling plan for all
mendations issued by the World Trade Organization Technical
possible incoming percentages defective for the process.
Barriers to Trade (TBT) Committee.
E1994
3.1.5 continuous sampling inspection, n—a method of sam-
2. Referenced Documents
pling a stream of product in order of production where the
2.1 ASTM Standards:
sampling frequency is adjusted based on ongoing inspection
E456 Terminology Relating to Quality and Statistics
results.
E1994 Practice for Use of Process Oriented AOQL and
3.1.5.1 Discussion—Only those units of product found by
LTPD Sampling Plans
the inspector or screening crew to be nonconforming are
E2234 Practice for Sampling a Stream of Product by Attri-
rejected. The rest of production, uninspected units as well as
butes Indexed by AQL
units found to be conforming, is allowed to continue down the
production line as conforming material.
3.1.6 critical defect, n—a defect that judgment and experi-
This practice is under the jurisdiction ofASTM Committee E11 on Quality and
ence indicate would result in hazardous or unsafe conditions
Statistics and is the direct responsibility of Subcommittee E11.30 on Statistical
for individuals using, maintaining, or depending upon the
Quality Control.
product, or a defect that judgment and experience indicate is
Current edition approved June 1, 2021. Published June 2021. Originally
likely to prevent performance of the function of a major end
approved in 2011. Last previous edition approved in 2015 as E2819 – 11 (2015).
DOI: 10.1520/E2819-11R21.
item. E2234
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
the ASTM website. Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States
E2819 − 11 (2021)
3.1.7 critical defective, n—a unit of product which contains collectively and each unit of product inspected is inspected for
one or more critical defects and may also contain major and each of the defects in the class.
minor, or both, defects. E2234
3.2.6 inspection by individual defect, n—inspection where
3.1.8 defect, n—any nonconformance of the unit of product one sampling plan is associated with inspection for a single
with specified requirements. E2234
defect, or where a sampling plan is applied to each of several
defects independently.
3.1.9 inspection, n—the process of measuring, examining,
testing, or otherwise comparing the unit of product with the
3.2.7 moving product, n—inspection where product is flow-
requirements. E2234
ing past the inspection station.
3.2.7.1 Discussion—In the typical case the product moves
3.1.10 inspection by attributes, n—inspection whereby ei-
on a conveyor belt or line; however, it may be moved in tote
ther the unit of product is classified simply as defective or
boxes, buggies or other conveyances which are operated
non-defective, or the number of defects in the unit of product
manually or by mobile materials-handling equipment.
is counted, with respect to a given requirement or set of
requirements. E2234
3.2.8 multi-level, n—plan consisting of periods of 100 %
3.1.11 major defect, n—a defect, other than critical, that is inspection and of sampling inspection at various rates which
reflect past inspection results.
likely to result in failure, or to reduce materially the usability
of the unit of product for its intended purpose. E2234
3.2.9 one hundred percent (100 %) inspection, n—the in-
3.1.12 major defective, n—a unit of product which contains spection of every unit of product for the defects concerned
one or more major defects, and may also contain minor defects listed for an inspection station.
but contains no critical defect. E2234 3.2.9.1 Discussion—The two terms, screening and 100 %
inspection, are used interchangeably in this practice.
3.1.13 minor defect, n—a defect that is not likely to reduce
materially the usability of the unit of product for its intended
3.2.10 production interval, n—a finite period of production,
purpose, or is a departure from established standards having
N items in length.
little bearing on the effective use or operation of the unit.
3.2.10.1 Discussion—The production interval is normally a
E2234
shift;itcanbeadayifitisreasonablycertainthatshiftchanges
do not affect quality of product, but shall not be longer than a
3.1.14 minor defective, n—a unit of product which contains
day.
one or more minor defects but contains no critical or major
defect. E2234
3.2.11 production interval length, n—N, specified number
of units to which CSP-F is to be applied.
3.1.15 process average (in inspection), n—the average per-
cent defective or average number of defects per hundred units
3.2.12 sampling frequency, n—f, desired ratio between the
(whichever is applicable) of product submitted by the supplier
number of units of product randomly selected and inspected at
for original inspection. E2234
an inspection station and the number of unit passing the
3.1.16 unit of product, n—thatwhichisinspectedinorderto inspection station during periods of sampling inspection.
determine its classification as defective or non-defective or to 3.2.12.1 Discussion—In this practice, each f is expressed as
count the number of defects. It may be a single article, a pair,
a fraction of the form, 1/7, 1/25, 1/50, etc. The procedure used
a set, a length, an area, an operation, a volume, a component of in selecting the sample units should give each unit of product
an end product, or the end product itself. E2234 presented during periods of sampling inspection an equal
3.1.16.1 Discussion—The unit of product may or may not chance of being selected and inspected. Also referred to as
be the same as the unit of purchase, supply, production, or “frequency of sampling”.
shipment.
3.2.13 sampling inspection, n—inspection for the defects
3.2 Definitions of Terms Specific to This Standard: concerned where the units selected for inspection are selected
by sampling.
3.2.1 checking inspection, n—sampling inspection per-
formed by the supplier on units of product which have already
3.2.14 screening, n—100 % inspection where all defective
been100 %inspectedinordertodeterminetheeffectivenessof
units are removed from the production flow.
the screening crew.
3.2.14.1 Discussion—The two terms, screening and 100 %
3.2.1.1 Discussion—This inspection is performed at the
inspection, are used interchangeably in this practice.
sampling rate f or more often.
3.2.15 single-level, n—planconsistingofalternatingperiods
3.2.2 clearance number, n—i, the number of consecutive
of 100 % inspection and sampling inspection wherein the
conforming, that is, defect-free, units in 100 % inspection
sampling rate is constant.
required prior to qualifying for inspection on a sampling basis.
3.2.3 conforming unit, n—a unit that meets the acceptance
4. Significance and Use
criteria established for the characteristic being considered.
4.1 Thereasonforpreservingmilitarysamplingstandardsis
3.2.4 defects concerned, n—defects being inspected for
that many organizations throughout the world still use these
while using the sampling plan.
standards in their current form. MIL-STD-1235B is no longer
3.2.5 inspection by defect class, n—whenonesamplingplan supported by the U.S. Department of Defense as of the
is associated with inspection for several kinds of defects mid-1990s and is out of print, but does exist in the public
E2819 − 11 (2021)
domain. This practice represents a conversion of MIL-STD- producing, or is capable of producing, material whose quality
1235B to an ASTM-supported standard. is stable, and (5) the inspection is non-destructive. The sam-
pling plans designated herein are applicable, but not limited, to
4.2 This practice provides the tables and procedures for
inspection of various entities, viz., end items, components, raw
applying five different types of continuous sampling plans for
materials, data or records, and any other entities, provided that
inspection by attributes. These continuous sampling plans are
the foregoing conditions are satisfied.
discussed in Sections6–10 of this practice and each section
includes information on:
5.3 Classification of Defects:
(1) Initiation of 100 % inspection in use.
5.3.1 Method of Classifying Defects—A classification of
(2) Requirements on when to switch to sampling inspec-
defects is the enumeration of possible defects of the unit of
tion.
product classified according to their seriousness. Defects will
(3) Conditions warranting a return to 100 % inspection.
normally be grouped into one or more of the following classes;
(4) When a change in Code Letter, if desired, can be made.
however, defects may be grouped into other classes, or into
(5) What to do when the checking inspector finds a defect
subclasses within these classes.
that was originally found conforming by the screening
5.3.1.1 Critical Defect—A critical defect is a defect that
inspector(s), that is, ineffective screening.
judgment and experience indicate is likely to result in hazard-
(6) Situations where a defect is found before the switch to
ous or unsafe conditions for individuals using, maintaining, or
100 % inspection causing excessive periods of 100 % inspec-
depending upon the product; or a defect that judgment and
tion so action must be taken, that is, long periods of screening.
experience indicate is likely to prevent performance of the
4.2.1 Section 6 (Section 2 in MIL-STD-1235B) describes
tactical function of a major end item such as a ship, aircraft,
specific procedures and applications of the CSP-1 sampling
tank,missile,orspacevehicle.Notethatforaspecialprovision
plans – a single-level continuous sampling procedure which
relating to critical defects, see 5.8.2.
provides for alternating between sequences of 100 % inspec-
5.3.1.2 Major Defect—Amajor defect is a defect other than
tion and sampling inspection.
critical that is likely to result in failure or materially reduce the
4.2.2 Section 7 (Section 3 in MIL-STD-1235B) describes
usability of the unit of product for its intended purpose.
specific procedures and applications of the CSP-F sampling
5.3.1.3 Minor Defect—Aminor defect is a defect that is not
plans – a variation of the CSP-1 plans in that CSP-F plans are
likely to reduce materially the usability of the unit of product
applied to a relatively short run of product, thereby permitting
for its intended purpose, or is a departure from established
smaller clearance numbers to be used.
standards having little bearing on the effective use or operation
4.2.3 Section 8 (Section 4 in MIL-STD-1235B) describes
of the unit.
specific procedures and applications of the CSP-2 sampling
5.3.2 Method of Classifying Defectives—A defective is a
plans – a modification of CSP-1 in that 100 % inspection
unit of product which contains one or more defects. Defectives
resumes only after a prescribed number of defect-free units
will usually be classified as follows:
separate any two defective sample units.
5.3.2.1 Critical Defective—Acritical defective contains one
4.2.4 Section 9 (Section 5 in MIL-STD-1235B) describes
or more critical defects and may also contain major and minor,
specific procedures and applications of the CSP-T sampling
or both, defects. Note that for a special provision relating to
plans – a multi-level continuous sampling procedure which
critical defectives, see 5.7.2.
provides for reducing the sampling frequency upon demonstra-
5.3.2.2 Major Defective—Amajor defective contains one or
tion of superior product quality.
more major defects, and may also contain minor defects, but
4.2.5 Section 10 (Section 6 in MIL-STD-1235B) describes
contains no critical defects.
specific procedures and applications of the CSP-V sampling
5.3.2.3 Minor Defective—Aminor defective contains one of
plans – a single-level continuous sampling procedure which is
more minor defects but contains no critical or major defects.
analternativetoCSP-Tinthattheseplansprovideforreducing
the clearance number in good quality situations where reduc-
5.4 Acceptable Quality Level (AQL):
tion of sampling frequency has no economic merit.
5.4.1 Definition—For continuous sampling plans, the AQL
is an index to the plans, and has no other meaning.
5. General Description of Sampling Plans
5.4.2 Use—The AQL, together with the Sample Size Code
5.1 This practice establishes continuous sampling plans and
Letter, is used for indexing the plans provided herein. The
procedures for inspection by attributes. When this practice is
plans are also indexed by theAverage Outgoing Quality Limit
referenced in a contract, specification, inspection standard or
(AOQL).
similar document, the provisions of this practice shall govern
5.4.3 Limitation—The designation of an AQL shall not
the application of all attributes type continuous sampling plans
imply that the supplier has the right to supply knowingly any
and procedures. Unless otherwise noted herein, the provisions
defective unit of product.
of this practice shall be carried out by the supplier.
5.4.4 Specifying AQLs—TheAQLshall be designated in the
5.2 Application—The conditions that must exist before contract or by the responsible authority. Different AQLs may
these sampling plans may be used are: (1) moving product, (2) be designated for groups of defects considered collectively, or
ample space, equipment and manpower at or near the site of for individual defects. An AQL for a group of defects may be
inspection to permit rapid 100 % inspection when required, (3) designated in addition to AQLs for individual defects, or
relatively easy and quick inspection, (4) a process which is subgroups, within that group.
E2819 − 11 (2021)
5.4.5 Preferred AQLs—The values of AQLs given in these authority to inspect every unit for critical defects or to follow
tables are known as preferred AQLs. If, for any product, an some other procedure with regard to the inspection of critical
AQLbedesignatedotherthanapreferredAQL,thesetablesare defects.Ifacriticaldefectisfoundonanyunitofproduct,even
not applicable. if that unit has not been selected for inspection for critical
defects, the supplier shall carry out the procedure specified by
5.5 Average Outgoing Quality (AOQ):
the consumer for critical defects.
5.5.1 Definitions:
5.7.3 Disposition of Rejected Product—Units found to be
5.5.1.1 AOQ—The Average Outgoing Quality (AOQ) for a
defective by either the supplier or consumer shall be removed
particular process average is the long run expected percentage
and kept apart from the flow of product. The supplier may
of defective material in the accepted material, if the associated
correct these units, in which case they will be screened and
sampling plan is followed faithfully (see 7.1 for classified
resubmitted to the consumer apart from the regular flow of
meaning for CSP-F).
product. If they are accepted by the consumer, they will be
5.5.1.2 AOQL—The Average Outgoing Quality Limit
returned to the production line right after the inspection station
(AOQL) is the maximum of all the possible values of AOQ if
for the defects concerned.
the associated sampling plan is followed faithfully (see 7.1 for
classified meaning for CSP-F).
5.8 Drawing of Samples:
5.5.2 Limitation—The listing of values of AOQL in this
5.8.1 Sample—Under continuous sampling a sample con-
practice does not imply that the supplier has a right to supply
sists of one unit or product drawn from the production line as
knowingly any defective unit of product.
it passes a given station.
5.6 Submission of Product:
5.8.2 Frequency of Sampling—Certain values of sampling
5.6.1 Lot or Batch—Althoughlotorbatchsizeisnotusedto
frequency, f, are provided for each of the plans.
select a continuous sampling plan, the formation of lots or
5.8.3 Sample Selection—The sample units shall be selected
batches may remain desirable for reasons of homogeneity,
at the chosen sampling frequency (f) so as to give each unit of
shipping convenience, and facilitation of payment.
product an equal chance of being inspected. The inspector
5.6.2 Order of Production—All inspection should be per-
should allow the interval between sample units to vary some-
formed in the order in which the units of product are produced,
whatratherthandrawsampleunitsaccordingtoarigidpattern.
inorderthatthesourcesofqualityproblemscanbemoreeasily
5.9 Sampling Plans:
spotted and corrective action taken. In those situations where
5.9.1 Definition—As used herein, the phrase “sampling
maintaining the order of production is not possible, for
plan” denotes a particular procedure and the size(s) of the
example, when production from two or more identical produc-
clearance number(s) and sampling frequency(ies) associated
tion lines is merged prior to inspection, the plans herein may
with it.
still be used provided that the mixing of product from the lines
is thorough, thereby assuring a random spacing of any defec-
5.9.2 Code Letters—Sampling plans are designated by code
tive units in the flow of product. letters. Table 1 provides permissible code letters based on the
5.6.3 Units of Product Submitted—All units for which
number of units in the production interval.Acode letter and its
deposition is sought must pass each inspection station. This
associated sampling frequency should be selected after consid-
does not prevent process inspection by the supplier prior to
ering such influencing factors as inspection time per units of
arrival of the product at the inspection station, nor does this
product, production rate, and proximity to other inspection
prohibit the supplier from removing or correcting units con-
stations. When idle inspector time is a significant
tainingdefectspriortosubmittaloftheproduct.However,if,in
consideration, a plan with higher sampling frequency and
the opinion of the consumer, the supplier’s method of sched-
lower clearance number is usually preferred.
uling process inspection results in a flow of product during
5.9.3 Obtaining Sampling Plans—The AQL and an appro-
periods of screening inspection which is not representative of
priatecodelettershallbeusedtoobtainthesamplingplanfrom
the flow of product which can be expected to be encountered
Tables 2-A, 3-A, 4-A, 5-A, or 6-A. For CSP-F, it is also
during subsequent sampling inspection, the consumer reserves
necessary to determine N (see 7.2.1).
the right to cause the supplier to modify his method of
5.9.4 Types of Sampling Plans—Five types of sampling
scheduling process inspection.
plans: CSP-1, CSP-F, CSP-2, CSP-T, and CSP-V are provided
5.7 Acceptance and Rejection: in Tables 2-A, 3-A, 4-A, 5-A, or 6-A respectively. A selection
5.7.1 Responsibility—Although both the consumer and sup- of the appropriate plan can be made by a consideration of their
plier may reject nonconforming material of the supplier, only individual features. CSP-1 is the simplest. CSP-F is a CSP-1
plan with clearance number adjusted to handle a shorter run of
the consumer possesses the authority to accept (purchase) the
supplier’s material. However, since the supplier is responsible product. CSP-2 provides advance warning when a screening
crew may have to be assembled. CSP-T provides for a
forprovidingmaterialwhichsatisfiescontractualrequirements,
he will inspect the product through use of a sampling plan reduction in sampling frequency in good quality situations.
indexed by the designatedAQLto determine whether or not to CSP-V provides for a reduction in clearance number in good
submit the product to the consumer. quality situations, and is an alternative to CSP-T in those
5.7.2 Special Reservation for Critical Defects—The sup- situations where a reduction in sampling frequency has no
plier may be required at the discretion of the responsible economic merit.
E2819 − 11 (2021)
5.10 Discontinuation of Inspection: 6.2.2 Sampling Inspection—Sampling inspection normally
is initiated when the following requirements are satisfied:
5.10.1 Long Periods of Screening—When the use of 6.2.6,
7.2.6, 8.2.6, 9.2.6, and 10.2.6 give indication that an exces- 6.2.2.1 All units of product are made according to the same
drawing and specifications under stable conditions of produc-
sively long period of screening has been in progress, corrective
action shall be taken to improve the production process and the tion. This requirement, which is termed homogeneity, is
usually satisfied when the production process is not altered by
consumer reserves the right to suspend product acceptance.
The provisions of 6.2.6, 7.2.6, 8.2.6, 9.2.6, and 10.2.6 do not innovation, significant changes in materials, strikes, retooling
(other than that due to routine changes to compensate for tool
prevent the supplier from taking corrective action to improve
the production process prior to reaching the limits described in wear) or interruptions other than those due to the end of the
shift, day, or week.
the aforementioned paragraphs.
6.2.2.2 At least i consecutive units inspected by the screen-
5.10.2 Ineffective Screening—If, during a period of 100 %
ing crew during 100 % inspection are found free of the defects
inspection, a checking inspector finds a defect, the consumer
concerned.
shall be notified, and corrective action shall be taken to
6.2.2.3 None of the i consecutive units found defect-free by
improve the effectiveness of the screening crew. If a second
the screening crew are found defective by the checking
defect is found by the checking inspector during this period of
inspector(s). When sampling inspection is begun, screening is
100 % inspection, the same action shall be taken by the
terminated and samples are taken at the frequency, f.
supplier, and the consumer will reserve the right to suspend
6.2.3 Return to 100 % Inspection—Sampling inspection
product acceptance. In the case of critical defects, the con-
sumer reserves the right to suspend acceptance upon the shall be terminated and 100 % inspection shall be resumed if
either or both of the conditions described below occur. For
finding of the first critical defect by the checking inspector
during a period of 100 % inspection. critical defects, screening shall begin with the unit of product
just after the last defect-free sample unit. (See 5.7.2 for further
5.11 Estimation of the Process Average:
provisions for critical defects.)
5.11.1 Definition—The process average (PA) is defined as
6.2.3.1 The production process is interrupted for more than
the percent defective of product submitted by the supplier for
three operating days, or the requirement of 6.2.2.1 is otherwise
originalinspection.Originalinspectionisthefirstinspectionof
not satisfied.
a particular quantity of product as distinguished from the
6.2.3.2 Aunit having any of the defects concerned is found
inspection of product which has been previously submitted.
by the sampling inspector.
The phrases “Process Average” and “Percent Defective of
Submitted Product” are used interchangeably. NOTE 1—When 100 % inspection is required, the flow of product is
curtailed until the screening crew can begin 100 % inspection. 100 %
5.11.2 Computation—A reasonably good estimate of the
inspection shall be continued until the requirements of 6.2.2 are met.
process average can be made from the inspection results. If the
6.2.4 Change in Code Letter—If it is necessary or desirable
inspection results used are for a set period of time or a pre-set
to change Sampling Frequency Code Letters, the following
number of units, the process average can be estimated as
applies:
follows:
6.2.4.1 If the change results in an increase in the sampling
100 number of defectives observed
~ !
frequency, f (and, of course, a decrease in the clearance
PA 5 (1)
est
number of units inspected
number, i), the change may be made at the next shift from a
screening sequence to a sampling sequence or during a
5.11.3 Use—The estimate of the process average, besides
giving an indication of what percentage of manufactured sampling sequence, whichever is the earlier.
product is defective, can also be used to consult the curves 6.2.4.2 If the change results in a decrease in the sampling
given in MIL-STD-1235A1. frequency, f (and, of course, an increase in the clearance
number, i), the change may be made at the next shift from a
sampling sequence to a screening sequence or during a
6. CSP-1
screening sequence, whichever is the earlier. (At any time the
6.1 Features of CSP-1—CSP-1 is a single-level continuous
change may be made by initiating a screening sequence whose
sampling procedure which provides for alternating sequences
clearance number, i, will be that associated with the new code
of 100 % inspection and sampling inspection with no limit as
letter.)
to the number of such sequences. CSP-1 requires a return to
6.2.5 Ineffective Screening—Whenever the checking inspec-
100 % inspection whenever a nonconforming unit is discov-
tor finds a defect in the product found conforming by the
ered during sampling inspection. See Fig.A1.1 for a summary
screening crew, the screening crew shall start a new count of
of the operation of CSP-1. Tables 2-A and 2-B list parameters
consecutive defect-free units, and the actions described in
associated with the procedure.
5.10.2 shall be carried out.
6.2 Description of Procedure:
6.2.6 Long Periods of Screening—If, during a period of
6.2.1 Initiation of Production—At the start of production, 100 %inspection,adefectisfoundbeforefindingiconsecutive
each unit of product shall be inspected by the screening crew. conforming units and the number of units screened is equal to
Checking inspection shall be performed concurrently at a or greater than the appropriate value of S in Table 2-B, the
frequency f or more often on the units passed by the screening supplier shall notify the consumer of this occurrence, and
crew (see 6.2.5). corrective action shall be taken to improve the production
E2819 − 11 (2021)
process. The consumer may, at its option, suspend acceptance 7.2.3.1 The production process is interrupted for more than
immediately or at any time thereafter during the period of three operating days, or the requirement of 7.2.2.1 is otherwise
100 % inspection until the supplier corrects the cause(s) of the not satisfied.
high rate of defectiveness.After effective correction action has 7.2.3.2 Any unit having any of the defects concerned is
been taken, 100 % inspection shall be reinitiated. found by the sampling inspector.
7.2.3.3 The units to which the plan was intended to be
applied have reached the point of inspection.
7. CSP-F
NOTE 2—The remaining units to be produced will be broken down into
7.1 Features of CSP-F—CSP-F is a single-level continuous
one or more groups, and the i value for each group will be determined
sampling procedure which provides for alternating sequences
from Table 3-A. For example, suppose that initially the size of a
of100 %inspectionandsamplinginspection.CSP-Fisequiva-
production run is to be 3000 units, and subsequently it is determined that
lent to the application of a CSP-1 plan to a specified number of
the run is to be 4000 units. After 3000 units have passed the point of
units at a time, thereby permitting a smaller clearance number inspection, 100 % inspection will be initiated, with an i value associated
with N = 1000.
to be used. The plan may be applied in situations involving
NOTE 3—When 100 % inspection is required, the flow of product is
short production runs, or it may be applied to one or more
curtailed until the screening crew can begin 100 % inspection. 100 %
production intervals at a time in situations involving time
inspection shall be continued until the requirements of 7.2.2 are met.
consuming inspection operations (for example, inspection with
7.2.4 Change in Code Letter—If it is necessary or desirable
X-ray equipment) where a large clearance number could cause
to change Sampling Frequency Code Letters, the following
a production bottle-neck. See Fig. A1.2 for a summary of the
applies:
operationsofCSP-F.Table3-Alistsparametersassociatedwith
7.2.4.1 If the change results in an increase in the sampling
the procedure. AOQ and AOQL for CSP-F relate to the long
frequency, f (and, of course, a decrease in the clearance
run average and limit, respectively, over many periods of
number, i), the change may be made at the next shift from a
application of the plan, which in fact are the same as the
screening sequence to a sampling sequence or during a
expected values, respectively, for a single application of the
sampling sequence, whichever is the earlier.
plan.
7.2.4.2 If the change results in a decrease in the sampling
7.2 Description of Procedure:
frequency, f (and, of course, an increase in the clearance
7.2.1 Initiation of Period—The period, in terms of number number, i), the change may be made at the next shift from a
of units, N, for which the plan is to be applied, must first be sampling sequence to a screening sequence or during a
determined, and plan parameters determined from Table 3-A. screening sequence, whichever is the earlier. (At any time the
(If N is smaller than the value of i from Table 3-A, inspect all change may be made by initiating a screening sequence whose
units.)At the start of production or of the period for which the clearance number, i, will be that associated with the new code
plan is to be applied, each unit of product shall be inspected by letter.)
the screening crew. Checking inspection shall be performed 7.2.5 Ineffective Screening—Whenever the checking inspec-
tor finds a defect in the product found conforming by the
concurrently at a frequency f or more often on the units passed
by the screening crew (see 7.2.5). screening crew, the screening crew shall start a new count of
consecutive defect-free units, and the actions described in
7.2.2 Sampling Inspection—Sampling inspection normally
5.10.2 shall be carried out.
is initiated when the following requirements are satisfied:
7.2.6 Long Periods of Screening—If, during a period of
7.2.2.1 All units of product are made according to the same
100 %inspection,adefectisfoundbeforefindingiconsecutive
drawings and specifications under stable conditions of produc-
conforming units and the number of units screened is equal to
tion. This requirement, which is termed homogeneity, is
or greater than the appropriate value of S in Table 2-B (before
usually satisfied when the production process is not altered by
N units have reached the point of inspection), the supplier shall
innovation, significant changes in materials, strikes, retooling
notify the consumer of this occurrence, and corrective action
(other than that due to routine changes to compensate for tool
shall be taken to improve the production process. The con-
wear) or interruptions other than those due to the end of the
sumer may, at its option, suspend acceptance immediately or at
shift, day, or week.
any time thereafter during the period of 100 % inspection until
7.2.2.2 At least i consecutive units inspected by the screen-
the supplier corrects the cause(s) of the high rate of defective-
ing crew during 100 % inspection are found free of the defects
ness. After effective corrective action has been taken, 100 %
concerned.
inspection shall be reinitiated.
7.2.2.3 None of the i consecutive units found defect-free by
NOTE 4—If several consecutive periods of some length N each have
the screening crew are found defective by the checking
passed without going to sampling, and without reaching the S value
inspector(s). When sampling inspection is begun, screening is
because N is smaller than S, the consumer reserves the right to cause the
terminated and samples are taken at the frequency, f.
supplier to use another sampling plan.
7.2.3 Return to 100 % Inspection—Sampling inspection
8. CSP-2
shall be terminated and 100 % inspection shall be resumed if
any of the conditions described below occur. For critical 8.1 Features of CSP-2—CSP-2 is a type of single-level
defects, screening shall begin with the unit of product just after continuous sampling procedure which provides for alternating
the last defect-free sample unit. (See 5.7.2 for further provi- sequences of 100 % inspection and sampling inspection with
sions for critical defects.) no limits as to the number of such sequences. CSP-2 requires
E2819 − 11 (2021)
a return to 100 % inspection whenever two defective units are change may be made by initiating a screening sequence whose
found separated by fewer than i consecutive sampled units but clearance number, i, will be that associated with the new code
does not require return to 100 % inspection if i or more
letter.)
consecutive defect-free sample units separate two defective
8.2.5 Ineffective Screening—Whenever the checking inspec-
units. CSP-2 shall not be used for inspection for critical defects
tor finds a defect in the product found conforming by the
(see also 5.7.2). See Fig. A1.3 for a summary of the operation
screening crew, the screening crew shall start a new count of
of CSP-2. Tables 4-A and 4-B list parameters associated with
consecutive defect-free units, and the actions described in
the procedure.
5.10.2 shall be carried out.
8.2 Description of Procedure: 8.2.6 Long Periods of Screening—If, during a period of
100 %inspection,adefectisfoundbeforefindingiconsecutive
8.2.1 Initiation of Production—At the start of production,
conforming units and the number of units screened is equal to
each unit of product shall be inspected by the screening crew.
or greater than the appropriate value of S in Table 4-B, the
Checking inspection shall be performed concurrently at a
supplier will notify the consumer of this occurrence, and
frequency f or more often on the units passed by the screening
corrective action shall be taken to improve the production
crew (see 8.2.5).
process. The consumer may, at its option, suspend acceptance
8.2.2 Sampling Inspection—Sampling inspection normally
immediately or at any time thereafter during the period of
is initiated when the following requirements are satisfied:
100 % acceptance until the supplier corrects the cause(s) of the
8.2.2.1 All units of product are made according to the same
high rate of defectives. After effective corrective action has
drawings and specifications under stable conditions of produc-
been taken, 100 % inspection shall be reinitiated.
tion. This requirement, which is termed homogeneity, is
usually satisfied when the production process is not altered by
9. CSP-T
innovation, significant changes in materials, strikes, retooling
(other than that due to routine changes to compensate for tool
9.1 CSP-T is a multi-level continuous sampling procedure
wear) or interruptions other than those due to the end of the
which provides for alternating sequences of 100 % inspection
shift, day, or week.
and sampling inspection. CSP-T requires a return to 100 %
8.2.2.2 At least i consecutive units inspected by the screen- inspection whenever a nonconforming unit is discovered dur-
ing crew during 100 % inspection are found free of the defects ing sampling inspection, but provides for a reduced sampling
concerned.
frequency upon demonstration of superior product quality.
CSP-T shall not be used for inspection for critical defects (see
8.2.2.3 None of the i consecutive units found defect-free by
also 5.7.2). See Fig. A1.4 for a summary of the operation of
the screening crew are found defective by the checking
CSP-T. Tables 5-Aand 5-B list parameters associated with the
inspector(s). When sampling inspection is begun, screening is
procedure.
terminated and samples are taken at the frequency, f.
8.2.3 Return to 100 % Inspection—Sampling inspection
9.2 Description of Procedure:
shall be terminated and 100 % inspection shall be resumed
9.2.1 Initiation of Production—At the start of production,
upon the occurrence of one or both of the conditions described
each unit of product shall be inspected by the screening crew.
below:
Checking inspection shall be performed concurrently at fre-
8.2.3.1 The production process is interrupted for more than
quency f or more often on the units passed by the screening
three operating days, or the requirement of 8.2.2.1 is otherwise
crew (see 9.2.5).
not satisfied.
9.2.2 Sampling Inspection—Sampling inspection normally
8.2.3.2 Fewer than i consecutive defect-free sample units
is initiated when the following requirements are satisfied:
separate two defective sample units.
9.2.2.1 All units of product are made according to the same
NOTE 5—When 100 % inspection is required, the flow of product is drawings and specifications under stable conditions of produc-
curtailed until the screening crew can begin 100 % inspection. 100 %
tion. This requirement, which is termed homogeneity, is
inspection shall be continued until the requirements of 8.2.2 are met.
usually satisfied when the production process is not altered by
innovation, significant changes in materials, strikes, retooling
8.2.4 Change in Code Letter—If it is necessary or desirable
(other than that due to routine changes to compensate for tool
to change Sampling Frequency Code Letters, the following
wear) or interruptions other than those due to the end of the
applies:
shift, day, or week.
8.2.4.1 If the change results in an increase in the sampling
frequency, f (and, of course, a decrease in the clearance 9.2.2.2 At least i consecutive units inspected by the screen-
ing crew during 100 % inspection are found free of the defects
number, i), the change may be made at the next shift from a
screening sequence to a sampling sequence or during a concerned.
sampling sequence, whichever is the earlier.
9.2.2.3 None of the i consecutive units found defect-free by
8.2.4.2 If the change results in a decrease in the sampling the screening crew are found defective by the checking
inspector(s). When sampling inspection is begun, screening is
frequency, f (and, of course, an increase in the clearance
number, i), the change may be made at the next shift from a terminated and samples are taken at the frequency f. The
sampling sequence to a screening sequence or during a sampling frequency may be reduced subject to the conditions
screening sequence, whichever is the earlier. (At any time the shown on Fig. A1.4.
E2819 − 11 (2021)
9.2.3 Return to 100 % Inspection—Sampling inspection summary of the operation of CSP-V. Tables 6-A and 6-B list
shall be terminated and 100 % inspection shall be resumed if parameters associated with the procedure.
either or both of the conditions described below occur.
10.2 Description of Procedure:
9.2.3.1 The production process is interrupted for more than
10.2.1 Initiation of Production—At the start of production,
three operating days, or the requirement of 9.2.2.1 is otherwise
each unit of product shall be inspected by the screening crew.
not satisfied.
Checking inspection shall be performed concurrently at a
9.2.3.2 Aunit having any of the defects concerned is found
frequency f or more often on the units passed by the screening
by the sampling inspector.
crew (see 10.2.5).
10.2.2 Sampling Inspection—Sampling inspection normally
NOTE 6—When 100 % inspection is required, the flow of product is
is initiated when the following requirements are satisfied:
curtailed until the screening crew can begin 100 % inspection. 100 %
10.2.2.1 Allunitsofproductaremadeaccordingtothesame
inspection shall be continued until the requirements of 9.2.2 are met.
drawings and specifications under stable conditions of produc-
9.2.4 Change in Code Letter—If it is necessary or desirable
tion. This requirement, which is termed homogeneity, is
to change Sampling Frequency Code Letters, the following
usually satisfied when the production process is not altered by
applies:
innovation, significant changes in materials, strikes, retooling
9.2.4.1 If the change results in an increase in the sampling
(other than that due to routine changes to compensate for tool
frequency, f (and, of course, a decrease in the clearance
wear) or interruptions other than those due to the end of the
number, i), the change may be made at the next shift from a
shift, day, or week.
screening sequence to a sampling sequence or during a
10.2.2.2 At least i (or x if appropriate) consecutive units
sampling sequence, whichever is the earlier.
inspected by the screening crew during 100 % inspection are
9.2.4.2 If the change results in a decrease in the sampling
found free of the defects concerned.
frequency, f (and, of course, an increase in the clearance
10.2.2.3 None of the i (or x if appropriate) consecutive units
number, i), the change may be made at the next shift from a
found defect-free by the screening crew are found defective by
sampling sequence to a screening sequence or during a
the checking inspector(s). When sampling inspection is begun,
screening sequence, whichever is the earlier. (At any time the
screening is terminated and samples are taken at the frequency,
change may be made by initiating a screening sequence whose
f.
clearance number, i, will be that associated with the new code
10.2.3 Return to 100 % Inspection—Sampling inspection
letter.)
shall be terminated and 100 % inspection shall be resumed if
9.2.5 Ineffective Screening—Whenever the checking inspec-
either or both of the conditions described below occur. The
tor finds a defect in the product found conforming by the
appropriate clearance number will be determined according to
screening crew, the screening crew shall start a new count of
the procedural rules shown in Fig. A1.5.
consecutive defect-free units, and the actions described in
10.2.3.1 Theproductionprocessisinterruptedformorethan
5.10.2 s
...