ISO 3951-6:2023
(Main)Sampling procedures for inspection by variables — Part 6: Specification for single sampling plans for isolated lot inspection indexed by limiting quality (LQ)
Sampling procedures for inspection by variables — Part 6: Specification for single sampling plans for isolated lot inspection indexed by limiting quality (LQ)
This document specifies an acceptance sampling system of single sampling plans for inspection by variables, primarily designed for use under the following conditions: a) where the inspection procedure is applied to an isolated lot of discrete products all supplied by one producer using one production process; b) where only a single quality characteristic, x, of this process is taken into consideration, which is measurable on a continuous scale; c) where the quality characteristic, x, is distributed according to a normal distribution or a close approximation to a normal distribution; d) where the quality characteristic can be measured without error or with moderate measurement error; e) where a contract or standard defines a lower specification limit, L, an upper specification limit, U, or both; an item is qualified as conforming if and only if its measured quality characteristic, x, satisfies the appropriate one of the following inequalities: 1) x ≥ L (i.e. the lower specification limit is not violated); 2) x ≤ U (i.e. the upper specification limit is not violated); 3) x ≥ L and x ≤ U (i.e. neither the lower nor the upper specification limit is violated). Inequalities 1) and 2) are cases with a single specification limit, whereas inequality 3) is a case with double specification limits. Where double specification limits apply, it is assumed in this document that conformance to both specification limits is equally important to the integrity of the product. In such cases, it is appropriate to apply a single LQ to the combined fraction of a product outside the two specification limits. This is referred to as combined control.
Règles d’échantillonnage pour les contrôles par mesures — Partie 6: Spécification pour les plans d’échantillonnage simples pour les contrôles de lots isolés, indexés d’après la qualité limite (QL)
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INTERNATIONAL ISO
STANDARD 3951-6
First edition
2023-11
Sampling procedures for inspection by
variables —
Part 6:
Specification for single sampling plans
for isolated lot inspection indexed by
limiting quality (LQ)
Règles d’échantillonnage pour les contrôles par mesures —
Partie 6: Spécification pour les plans d’échantillonnage simples pour
les contrôles de lots isolés, indexés d’après la qualité limite (QL)
Reference number
ISO 3951-6:2023(E)
© ISO 2023
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ISO 3951-6:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2023 – All rights reserved
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ISO 3951-6:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 6
5 Choice of a sampling plan . 7
5.1 Choice between variables and attributes . 7
5.2 General . 7
5.3 Choice between the s-method and the σ-method . 8
5.4 Choice of the limiting quality (LQ) . 8
6 Standard procedures for the s-method. 9
6.1 General . 9
6.2 Single specification limits . . 9
6.3 Double specification limits . 9
7 Standard procedures for the σ-method .10
7.1 General . 10
7.2 Single specification limits . . 10
7.3 Double specification limits
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 3951-6
ISO/TC 69/SC 5
Sampling procedures for inspection by
Secretariat: BSI
variables —
Voting begins on:
2023-09-07
Part 6:
Voting terminates on:
Specification for single sampling plans
2023-11-02
for isolated lot inspection indexed by
limiting quality (LQ)
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 3951-6:2023(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2023
---------------------- Page: 1 ----------------------
ISO/FDIS 3951-6:2023(E)
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 3951-6
ISO/TC 69/SC 5
Sampling procedures for inspection by
Secretariat: BSI
variables —
Voting begins on:
Part 6:
Voting terminates on:
Specification for single sampling plans
for isolated lot inspection indexed by
limiting quality (LQ)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: +41 22 749 01 11
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: copyright@iso.org
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 3951-6:2023(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
ii
© ISO 2023 – All rights reserved
NATIONAL REGULATIONS. © ISO 2023
---------------------- Page: 2 ----------------------
ISO/FDIS 3951-6:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 6
5 Choice of a sampling plan . 7
5.1 Choice between variables and attributes . 7
5.2 General . 7
5.3 Choice between the s-method and the σ-method . 8
5.4 Choice of the limiting quality (LQ) . 8
6 Standard procedures for the s-method.
...
ISO/FDIS 3951-6:2023(E)
ISO/TC 69/SC 5
Secretariat: BSI
Date: 2023-07-01xx
Sampling procedures for inspection by variables --— Part 6: Specification for single
sampling plans indexed by limiting quality (LQ)
---------------------- Page: 1 ----------------------
ISO/FDIS 3951-6:2023(E)
© ISO 2023 Formatted: Pattern: Clear
Formatted: Pattern: Clear
All rights reserved. Unless otherwise specified, or required in the context of its
implementation, no part of this publication may be reproduced or utilized otherwise in any
form or by any means, electronic or mechanical, including photocopying, or posting on the
internet or an intranet, without prior written permission. Permission can be requested from
either ISO at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2023 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 3951-6:2023(E)
Contents
Formatted: Font: Cambria, English (United Kingdom)
Foreword iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 6
5 Choice of a sampling plan . 7
5.1 Choice between variables and attributes. 7
5.2 General . 8
5.3 Choice between the s-method and the σ-method . 9
5.4 Choice of the limiting quality (LQ) . 9
6 Standard procedures for the s-method . 9
6.1 General . 9
6.2 Single specification limits . 10
6.3 Double specification limits . 10
7 Standard procedures for the σ-method . 11
7.1 General . 11
7.2 Single specification limits . 11
7.3 Double specification limits . 11
8 The p*-method . 12
9 Relation to ISO 2859-2 . 13
9.1 Similarities . 13
9.2 Differences . 13
10 Allowing for measurement uncertainty . 14
11 Normality, data transformations and outliers . 15
1
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