EN ISO 2692:2014

SLOVENSKI STANDARD
01-marec-2015
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Geometrical product specifications (GPS) - Geometrical tolerancing - Maximum material
requirement (MMR), least material requirement (LMR) and reciprocity requirement (RPR)
(ISO 2692:2014)
Geometrische Produktspezifikation (GPS) - Form- und Lagetolerierung - Maximum-
Material-Bedingung (MMR), Minimum-Material-Bedingung (LMR) und
Reziprozitätsbedingung (ISO 2692:2014)
Spécification géométrique des produits (GPS) - Tolérancement géométrique - Exigence
du maximum de matière (MMR), exigence du minimum de matière (LMR) et exigence de
réciprocité (RPR) (ISO 2692:2014)
Ta slovenski standard je istoveten z: EN ISO 2692:2014
ICS:
01.100.20 Konstrukcijske risbe Mechanical engineering
drawings
17.040.30 Merila Measuring instruments
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 2692
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2014
ICS 01.100.20 Supersedes EN ISO 2692:2006
English Version
Geometrical product specifications (GPS) - Geometrical
tolerancing - Maximum material requirement (MMR), least
material requirement (LMR) and reciprocity requirement (RPR)
(ISO 2692:2014)
Spécification géométrique des produits (GPS) - Geometrische Produktspezifikation (GPS) - Geometrische
Tolérancement géométrique - Exigence du maximum de Tolerierung - Maximum-Material-Bedingung (MMR),
matière (MMR), exigence du minimum de matière (LMR) et Minimum-Material-Bedingung (LMR) und
exigence de réciprocité (RPR) (ISO 2692:2014) Reziprozitätsbedingung (RPR) (ISO 2692:2014)
This European Standard was approved by CEN on 16 August 2014.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 2692:2014 E
worldwide for CEN national Members.

Contents Page
Foreword .3
Foreword
This document (EN ISO 2692:2014) has been prepared by Technical Committee ISO/TC 213 "Dimensional
and geometrical product specifications and verification" in collaboration with Technical Committee
CEN/TC 290 “Dimensional and geometrical product specification and verification” the secretariat of which is
held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by June 2015, and conflicting national standards shall be withdrawn at
the latest by June 2015.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 2692:2006.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 2692:2014 has been approved by CEN as EN ISO 2692:2014 without any modification.

INTERNATIONAL ISO
STANDARD 2692
Third edition
2014-12-15
Geometrical product specifications
(GPS) — Geometrical tolerancing
— Maximum material requirement
(MMR), least material requirement
(LMR) and reciprocity requirement
(RPR)
Spécification géométrique des produits (GPS) — Tolérancement
géométrique — Exigence du maximum de matière (MMR), exigence
du minimum de matière (LMR) et exigence de réciprocité (RPR)
Reference number
ISO 2692:2014(E)
©
ISO 2014
ISO 2692:2014(E)
© ISO 2014
All rights reserved. Unless otherwise specified, 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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

ISO 2692:2014(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Maximum material requirement, MMR and least material requirement, LMR .5
4.1 General . 5
4.2 Maximum material requirement, MMR . 6
4.2.1 Maximum material requirement for toleranced features . 6
4.2.2 Maximum material requirement for related datum features . 7
4.3 Least material requirement, LMR . 8
4.3.1 Least material requirement for toleranced features. 8
4.3.2 Least material requirement for related datum features . 9
5 Reciprocity requirement, RPR .10
5.1 General .10
5.2 Reciprocity requirement and maximum material requirement .10
5.3 Reciprocity requirement and least material requirement .10
Annex A (informative) Examples of tolerancing with , and .11
Annex B (informative) Concept diagram .43
Annex C (informative) Relation to the GPS matrix model .44
Bibliography .46
ISO 2692:2014(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 213, Dimensional and geometrical product
specifications and verification.
This third edition cancels and replaces the second edition (ISO 2692:2006), of which subclauses 3.10,
4.1, 4.2.1 (rule D), 4.2.2 (rule G), 4.3.1 (rule K), 4.3.2 (rule N) and Annex A have been revised.
iv © ISO 2014 – All rights reserved

ISO 2692:2014(E)
Introduction
0.1. General
This International Standard is a geometrical product specification (GPS) standard and is to be regarded
as a general GPS standard (see ISO/TR 14638). It influences the chain links 1, 2 and 3 of the chain of
standards on size of linear “features of size” and form of a line (independent/dependent of a datum),
form of a surface (independent/dependent of a datum), orientation and location of derived features
based on “features of size” and datums also based on “features of size”.
The ISO GPS Masterplan given in ISO/TR 14638 gives an overview of the ISO GPS system of which this
document is a part. The fundamental rules of ISO GPS given in ISO 8015 apply to this document and
the default decision rules given in ISO 14253-1 apply to specifications made in accordance with this
document, unless otherwise indicated.
For more detailed information on the relation of this International Standard to the GPS matrix model,
see Annex C.
This International Standard covers some frequently occurring workpiece functional cases in design
and tolerancing. The “maximum material requirement”, MMR, covers “assembleability” and the “least
material requirement”, LMR, covers, for example, “minimum wall thickness” of a part. Each requirement
(MMR and LMR) combines two independent requirements into one collective requirement, which more
accurately simulates the intended function of the workpiece. In some cases of both MMR and LMR, the
“reciprocity requirement”, RPR, can be added.
NOTE In ISO GPS standards, threaded features are often considered as features of size of type cylinder.
However, no rules are defined in this International Standard for how to apply MMR, LMR and RPR to threaded
features. Consequently, the tools defined in this International Standard cannot be used for threaded features.
0.2 Information about maximum material requirement, MMR
The assembly of parts depends on the combined effect of
a) the size (of one or more extracted features of size), and
b) the geometrical deviation of the (extracted) features and their derived features, such as the pattern
of bolt holes in two flanges and the bolts securing them.
The minimum assembly clearance occurs when each of the mating features of size is at its maximum
material size (e.g. the largest bolt size and the smallest hole size) and when the geometrical deviations (e.g.
the form, orientation and location deviations) of the features of size and their derived features (median
line or median surface) are also at their maximum. Assembly clearance increases to a maximum when the
sizes of the assembled features of size are furthest from their maximum material sizes (e.g. the smallest
shaft size and the largest hole size) and when the geometrical deviations (e.g. the form, orientation and
location deviations) of the features of size and their derived features are zero. It therefore follows that
if the sizes of one mating part do not reach their maximum material size, the indicated geometrical
tolerance of the features of size and their derived features may be increased without endangering the
assembly to the other part.
This assembly function is controlled by the maximum material requirement. This collective requirement
is indicated on drawings by the symbol .
0.3 Information about least material requirement, LMR
The least material requirement is designed to control, for example, the minimum wall thickness,
thereby preventing breakout (due to pressure in a tube), the maximum width of a series of slots, etc.
It is indicated on drawings by the symbol . The least material requirement is also characterized by a
collective requirement for the size of a feature of size, the geometrical deviation of the feature of size
(form deviations) and the location of its derived feature.
ISO 2692:2014(E)
0.4 Information about reciprocity requirement, RPR
The reciprocity requirement is an additional requirement, which may be used together with the maximum
material requirement and the least material requirement in cases where it is permitted — taking into
account the function of the toleranced feature(s) — to enlarge the size tolerance when the geometrical
deviation on the actual workpiece does not take full advantage of, respectively, the maximum material
virtual condition or the least material virtual condition.
The reciprocity requirement is indicated on the drawing by the symbol .
0.5 General information about terminology and figures
The terminology and tolerancing concepts in this International Standard have been updated to conform
to GPS terminology, notably that in ISO 286-1, ISO 14405-1, ISO 14660-2:1999 and ISO 17450-1:2011.
vi © ISO 2014 – All rights reserved

INTERNATIONAL STANDARD ISO 2692:2014(E)
Geometrical product specifications (GPS) — Geometrical
tolerancing — Maximum material requirement (MMR),
least material requirement (LMR) and reciprocity
requirement (RPR)
1 Scope
This International Standard defines the maximum material requirement, the least material requirement
and the reciprocity requirement. These requirements can only be applied to features of size.
These requirements are used to control specific functions of workpieces where size and geometry are
interdependent, e.g. to fulfil the functions “assembly of parts” (for maximum material requirement)
or “minimum wall thickness” (for least material requirement). However, the maximum material
requirement and least material requirement are also used to fulfil other functional design requirements.
Considering this interdependence between size and geometry, the principle of independency defined
in ISO 8015 does not apply when the maximum material requirement, least material requirement, or
reciprocity requirement, are used.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 1101:2012, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out
ISO 5459:2011, Geometrical product specifications (GPS) — Geometrical tolerancing — Datums and datum
systems
ISO 14405-1:2010, Geometrical product specifications (GPS) — Dimensional tolerancing — Part 1: Linear
sizes
ISO 14660-2:1999, Geometrical Product Specifications (GPS) — Geometrical features — Part 2: Extracted
median line of a cylinder and a cone, extracted median surface, local size of an extracted feature
ISO 17450-1:2011, Geometrical product specifications (GPS) — General concepts — Part 1: Model for
geometrical specification and verification
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5459:2011, ISO 14405-1:2010,
ISO 14660-2:1999, ISO 17450-1:2011 and the following apply.
3.1
integral feature
geometrical feature belonging to the real surface of the workpiece or to a surface model
Note 1 to entry: An integral feature is intrinsically defined, e.g. skin of the workpiece.
Note 2 to entry: Adapted from ISO 17450-1:2011, definition 3.3.5.
ISO 2692:2014(E)
3.2
feature of size
feature of linear size
geometrical feature, having one or more intrinsic characteristics, only one of which may be considered as
variable parameter, that additionally is a member of a “one parameter family”, and obeys the monotonic
containment property for that parameter
Note 1 to entry: Adapted from ISO 17450-1:2011, definition 3.3.1.5.1. See also ISO 22432:2011, definitions
3.2.5.1.1.1 and 3.2.5.1.1.2 for “one parameter family” and “monotonic containment property”.
EXAMPLE 1 A single cylindrical hole or shaft is a feature of linear size. Its linear size is its diameter.
EXAMPLE 2 Two opposite parallel plane surfaces are a feature of linear size. Its linear size is the distance
between the two parallel planes.
3.3
derived feature
geometrical feature, which does not exist physically on the real surface of the workpiece and which is
not natively a nominal integral feature
Note 1 to entry: A derived feature can be established from a nominal feature, an associated feature, or an extracted
feature. It is qualified respectively as a nominal derived feature, an associated derived feature, or an extracted
derived feature.
Note 2 to entry: The centre point, the median line and the median surface defined from one or more integral
features are types of derived features.
Note 3 to entry: Adapted from ISO 17450-1:2011, definition 3.3.6.
EXAMPLE 1 The median line of a cylinder is a derived feature obtained from the cylinder surface, which is an
integral feature. The axis of the nominal cylinder is a nominal derived feature.
EXAMPLE 2 The median surface of two opposite parallel plane surfaces is a derived feature obtained from the
two parallel plane surfaces, which constitute an integral feature. The median plane of the nominal two opposite
parallel planes is a nominal derived feature.
3.4
maximum material condition
MMC
state of the considered extracted feature, where the feature of size is at that limit of size where the
material of the feature is at its maximum everywhere, e.g. minimum hole diameter and maximum shaft
diameter
Note 1 to entry: The term maximum material condition, MMC, is used in this International Standard to indicate,
at ideal or nominal feature level (see ISO 17450-1), which limit of the requirement (upper or lower) is concerned.
Note 2 to entry: The size of the extracted feature at maximum material condition, MMC, can be defined by default,
or by several special definitions of the size of the extracted feature (see ISO 14405-1).
Note 3 to entry: The maximum material condition, MMC, as defined in this International Standard, can be used
unambiguously with any definition of size of the extracted feature.
3.5
maximum material size
MMS
l
MMS
dimension defining the maximum material condition of a feature
Note 1 to entry: Maximum material size, MMS, can be defined by default or by one of several special definitions of
the size of the extracted feature (see ISO 14405-1 and ISO 14660-2).
Note 2 to entry: In this International Standard, maximum material size, MMS is used as a numerical value, therefore
no specific definition of the extracted size is needed to permit unambiguous use of maximum material size, MMS.
2 © ISO 2014 – All rights reserved

ISO 2692:2014(E)
Note 3 to entry: See Annex A.
3.6
least material condition
LMC
state of the considered extracted feature, where the feature of size is at that limit of size where the
material of the feature is at its minimum everywhere, e.g. maximum hole diameter and minimum shaft
diameter
Note 1 to entry: The term least material condition, LMC, is used in this International Standard to indicate, at the
ideal or nominal feature level (see ISO 17450-1), which limit of the requirement (upper or lower) is concerned.
Note 2 to entry: The size at least material condition, LMC, can be defined by default or by several special definitions
of the size of extracted feature (see ISO 14405-1 and ISO 14660-2).
Note 3 to entry: The least material condition, LMC, as defined in this International Standard, can be used
unambiguously with any definition of size of the extracted feature.
3.7
least material size
LMS
l
LMS
dimension defining the least material condition of a feature
Note 1 to entry: Least material size, LMS, can be defined by default or by one of several special definitions of the
size of the extracted feature (see ISO 14405-1 and ISO 14660-2).
Note 2 to entry: In this International Standard, least material size, LMS, is used as a numerical value, therefore no
specific definition of the extracted size is needed to permit unambiguous use of least material size, LMS.
Note 3 to entry: See Annex A.
3.8
maximum material virtual size
MMVS
l
MMVS
size generated by the collective effect of the maximum material size, MMS, of a feature of size and the
geometrical tolerance (form, orientation or location) given for the derived feature of the same feature
of size
Note 1 to entry: Maximum material virtual size, MMVS, is a parameter for size used as a numerical value connected
to maximum material virtual condition, MMVC.
Note 2 to entry: For external features, MMVS is the sum of MMS and the geometrical tolerance, whereas for
internal features, it is the difference between MMS and the geometrical tolerance.
Note 3 to entry: The MMVS for external features of size, l , is given by Formula (1):
MMVS,e
ll=+δ (1)
MMVS,e MMS
and the MMVS for internal features of size, l , is given by Formula (2):
MMVS,i
ll=−δ (2)
MMVS,i MMS
where
l is the maximum material size;
MMS
δ is the geometrical tolerance.
ISO 2692:2014(E)
3.9
maximum material virtual condition
MMVC
state of associated feature of maximum material virtual size, MMVS
Note 1 to entry: Maximum material virtual condition, MMVC, is a perfect form condition of the feature.
Note 2 to entry: Maximum material virtual condition, MMVC, includes an orientation constraint (in accordance
with ISO 1101 and ISO 5459) of the associated feature when the geometrical specification is an orientation
specification (see Figure A.3). Maximum material virtual condition, MMVC, includes a location constraint (in
accordance with ISO 1101 and ISO 5459) of the associated feature when the geometrical specification is a location
specification (see Figure A.4).
Note 3 to entry: See Figures A.1-A.4, A.6. A.7 and A.10-A.13.
3.10
least material virtual size
LMVS
l
LMVS
size generated by the collective effect of the least material size, LMS, of a feature of size and the
geometrical tolerance (form, orientation or location) given for the derived feature of the same feature
of size
Note 1 to entry: Least material virtual size, LMVS, is a parameter for size used as a numerical value connected to
least material virtual condition, LMVC.
Note 2 to entry: For external features, LMVS is the difference between LMS and the geometrical tolerance, whereas
for internal features, it is the sum of LMS and the geometrical tolerance.
Note 3 to entry: The LMVS for external features of size, l , is given by Formula (3):
LMVS,e
ll=−δ (3)
LMVS,eLMS
and the LMVS for internal features of size, l , is given by Formula (4):
LMVS,i
ll=+δ (4)
LMVS,iLMS
where
l is the least material size;
LMS
δ is the geometrical tolerance.
3.11
least material virtual condition
LMVC
state of associated feature of least material virtual size, LMVS
Note 1 to entry: Least material virtual condition, LMVC, is a perfect form condition of the feature.
Note 2 to entry: Least material virtual condition, LMVC, includes an orientation constraint (in accordance with
ISO 1101 and ISO 5459) of the associated feature when the geometrical specification is an orientation specification.
Least material virtual condition, LMVC, includes a location constraint (in accordance with ISO 1101 and ISO 5459)
of the associated feature when the geometrical specification is a location specification (see Figure A.5).
Note 3 to entry: See Figures A.5, A.8 and A.9.
4 © ISO 2014 – All rights reserved

ISO 2692:2014(E)
3.12
maximum material requirement
MMR
requirement for a feature of size, defining a geometrical feature of the same type and of perfect form,
with a given value for the intrinsic characteristic (dimension) equal to MMVS, which limits the non-ideal
feature on the outside of the material
Note 1 to entry: Maximum material requirement, MMR, is used to control the assemblability of a workpiece.
Note 2 to entry: See also 4.2.
3.13
least material requirement
LMR
requirement for a feature of size, defining a geometrical feature of the same type and of perfect form,
with a given value for the intrinsic characteristic (dimension) equal to LMVS, which limits the non-ideal
feature on the inside of the material
Note 1 to entry: Least material requirements, LMR, are used in pairs, e.g. to control the minimum wall thickness
between two symmetrical or coaxially located similar features of size.
Note 2 to entry: See also 4.3.
3.14
reciprocity requirement
RPR
additional requirement for a feature of size used as an addition to the maximum material requirement,
MMR, or the least material requirement, LMR to indicate that the size tolerance is increased by the
difference between the geometrical tolerance and the actual geometrical deviation
4 Maximum material requirement, MMR and least material requirement, LMR
4.1 General
The maximum material requirement, MMR, and the least material requirement, LMR, can be applied
to a set of one or more feature(s) of size as toleranced feature(s), or datum(s), or both. They create a
combined requirement between the size of feature(s) of size and the geometry requirements (form,
orientation or location) specified for its (their) derived feature(s).
NOTE 1 This edition of this International Standard only covers features of size of type cylinder and type two
opposite parallel plane surfaces. Consequently, the only possible derived features are median lines and median
surfaces.
NOTE 2 In ISO GPS standards, threaded features are often considered as features of size of type cylinder.
However, no rules are defined in this International Standard for how to apply MMR, LMR and RPR to threaded
features. Consequently, the tools defined in this International Standard cannot be used for threaded features.
When maximum material requirement, MMR, or least material requirement, LMR, is used, the two
specifications (size specification and geometrical specification) are transformed into one collective
requirements specification. The collective specification concerns only the integral feature, which in this
International Standard relates to the surface(s) of the feature(s) of size(s).
NOTE 3 In the past, the maximum material requirement, MMR, was referred to as the maximum material
principle, MMP.
When no modifiers ( , , ) are applied to the toleranced feature, the definitions of size of extracted
feature in ISO 14405-1 and ISO 14660-2 apply.
When no modifiers ( , ) are applied to the datum, ISO 5459 applies. The modifier does not apply
to datums.
ISO 2692:2014(E)
4.2 Maximum material requirement, MMR
4.2.1 Maximum material requirement for toleranced features
The maximum material requirement for toleranced features results in four independent requirements:
— a requirement for the upper limit of the local size [see Rules A 1) and A 2)];
— a requirement for the lower limit of the local size [see Rules B 1) and B 2)];
— a requirement for the surface non-violation of the MMVC (see Rule C);
— a requirement for when more than one feature is involved (see Rule D).
When the maximum material requirement, MMR, applies to the toleranced feature, it shall be indicated
on drawings by the symbol placed after the geometrical tolerance of the derived feature of the feature
of size (toleranced feature) in the tolerance indicator.
In this case, it specifies for the surface(s) (of the feature of size) the following rules.
a) Rule A The extracted local sizes of the toleranced feature shall be:
1) equal to or smaller than the maximum material size, MMS, for external features;
2) equal to or larger than the maximum material size, MMS, for internal features.
NOTE 1 This rule can be altered by the indication of reciprocity requirement, RPR, with the symbol
after the symbol (see Clause 5 and Figure A.1).
b) Rule B The extracted local sizes of the toleranced feature shall be:
1) equal to or larger than the least material size, LMS, for external features [see Figures A.2 a),
A.3 a), A.4 a), A.6 a), A.7 a), A.10 and A.11];
2) equal to or smaller than the least material size, LMS, for internal features [see Figures A.2 b),
A.3 b), A.4 b), A.6 b), A.7 b), A.10 and A.11].
c) Rule C The maximum material virtual condition, MMVC, of the toleranced feature shall not be
violated by the extracted (integral) feature (see Figures A.2, A.3, A.4, A.6, A.7, A.10 and A.11).
NOTE 2 Use of the envelope requirement (previously also known as the Taylor Principle) usually leads
to superfluous constraints regarding the function of the feature(s) (assembleability). Use of such constraints
and size definitions reduces the technical and economic advantage of maximum material requirement, MMR.
NOTE 3 The indication 0 applied to a form specification has the same meaning as the envelope
requirement applied to a size.
d) Rule D When the geometrical specification is an orientation or a location relative to a (primary)
datum or a datum system, the maximum material virtual condition, MMVC, of the toleranced feature
shall be in theoretically exact orientation or location relative to the datum or the datum system,
in accordance with ISO 1101 and ISO 5459 (see 3.9 NOTE 2 and Figures A.3, A.4, A.6, and A.7).
Moreover, in the case of several toleranced features controlled by the same tolerance indication, the
maximum material virtual conditions, MMVCs, shall also be in theoretically exact orientation and
location relative to each other [in addition to the possible constraints relative to the datum(s)] (see
Figures A.1, A.10, A.11 and A.13).
NOTE 4 In the case of several toleranced features controlled by the same toleranced indication, the
maximum material requirement, MMR, without any other modifier than has exactly the same meaning as
the same requirement with both and CZ modifiers.
6 © ISO 2014 – All rights reserved

ISO 2692:2014(E)
1)
To specify requirements that apply separately, the SZ modifier shall be used after the modifier.
4.2.2 Maximum material requirement for related datum features
The maximum material requirement for datum features results in three independent requirements:
— a requirement for the surface non-violation of the MMVC (see Rule E);
— a requirement for MMS when there is no geometrical specification or when there is only geometrical
specifications whose tolerance value is not followed by the symbol (see Rule F);
— a requirement for MMS when there is a geometrical specification whose tolerance value is followed
by the symbol and whose “datum” section (third and subsequent compartments) of the tolerance
indicator meets a property defined in Rule G.
When the maximum material requirement, MMR, applies to the datum feature, it shall be indicated on
drawings by the symbol placed after the datum letter(s) in the tolerance indicator.
NOTE 1 The use of after the datum letter is only possible if the datum is obtained from a feature of size.
NOTE 2 When maximum or least material requirement applies to all elements of the collection of surfaces of
a common datum, the corresponding sequence of letters identifying the common datum are indicated within
parentheses (see Figure A.13 and ISO 5459:2011, Rule 9) and maximum material virtual conditions, MMVCs,
are by default constrained in location and orientation relative to each other (see ISO 5459:2011, Rule 7). When
maximum or least material requirement applies only to one surface of the collection of features involved in a
common datum, the sequence of letters identifying the common datum is not indicated within parentheses, and
the requirement applies only to the feature identified by the letter placed just before the modifier.
In this case, it specifies for the surface(s) (of the feature of size) the following rules.
a) Rule E The maximum material virtual condition, MMVC, of the related datum feature shall
not be violated by the extracted (integral) datum feature from which the datum is derived (see
Figures A.6 and A.7).
b) Rule F The size of the maximum material virtual condition, MMVC, of the related datum feature
shall be the maximum material size, MMS, when the related datum feature has no geometrical
specification (see Figure A.6), or has only geometrical specifications whose tolerance value is not
followed by the symbol , or has no geometrical specification complying with Rule G.
NOTE 3 In these cases, the MMVS for external and internal features of size, l , is given by Formula (5):
MMVS
ll= ±=0 l (5)
MMVS MMS MMS
where l is the maximum material size.
MMS
c) Rule G The size of the maximum material virtual condition, MMVC, of the related datum feature
shall be the maximum material size, MMS, plus (for external features of size) or minus (for internal
features of size) the geometrical tolerance, when the datum feature is controlled by a geometrical
specification with the following properties:
1) its tolerance value is followed by the symbol , and
i) it is a form specification and the related datum corresponds to the primary datum of
the tolerance indicator where the symbol is indicated next to the datum letter (see
Figure A.7), or
ii) it is an orientation/location specification whose datum or datum system contains exactly
the same datum(s) in the same order as the one(s) called before the related datum in
1) SZ will be incorporated in the revision of ISO 1101:2012.
ISO 2692:2014(E)
the tolerance indicator where the symbol is indicated next to the datum letter (see
Figure A.12 and Figure A.13).
NOTE 4 In this case, the MMVS for external features of size is as given in Formula (1), and the MMVS for internal
features of size is as given in Formula (2). See 3.8, Note 3.
NOTE 5 When above properties are not observed, Rule F applies.
In the case of Rule G, the datum feature indicator shall be directly connected to that geometrical
tolerance indicator from which maximum material virtual condition, MMVC, of the datum feature is
controlled (see ISO 5459:2011, Rule 1, dash 2).
4.3 Least material requirement, LMR
4.3.1 Least material requirement for toleranced features
When the least material requirement, LMR, applies to the toleranced feature, it shall be indicated on the
drawing by the symbol placed after the geometrical tolerance of the derived feature of the feature of
size (toleranced feature) in the tolerance indicator.
EXAMPLE To fully control the minimum wall thickness, the symbol is applied to the tolerancing of the
features on both sides of the wall. Least material requirement, LMR can be implemented in two different ways, as
follows.
— The location requirements for the two different sides of the wall can refer to the same datum axis or datum
system (see Figure A.8). In this case, applies to the two toleranced features.
— The location requirement of the derived feature for one of the sides of the wall can refer to the derived feature
of the other as the datum. In this case, the tolerance for the toleranced feature and the datum letter are
followed by the symbol (see Figure A.9).
NOTE 1 This possibility only applies if the features on the two sides are features of size.
When the least material requirement, LMR, applies to the toleranced feature, it specifies for the surface(s)
(of the feature of size) the following rules.
a) Rule H The extracted local sizes of the toleranced feature shall be:
1) equal to or larger than the least material size, LMS, for external features;
2) equal to or smaller than the least material size, LMS, for internal features.
NOTE 2 This rule can be altered by the indication of reciprocity requirement, RPR, with the symbol
after the symbol [see 5.3, Figure A.5 e) and Figure A.5 f)].
b) Rule I The extracted local sizes of the toleranced feature shall be:
1) equal to or smaller than the maximum material size, MMS, for external features [see
Figures A.5 a), A.8 and A.9];
2) equal to or larger than the maximum material size, MMS, for internal features [see Figures A.5 b)
and A.8].
c) Rule J The least material virtual condition, LMVC, of the toleranced feature shall not be violated
by the extracted (integral) feature (see Figures A.5, A.8 and A.9).
NOTE 3 Use of the envelope requirement (previously also known as the Taylor Principle) usually leads
to superfluous constraints regarding the function of the feature(s) (minimum wall thickness). Use of such
constraints and size definitions for size reduces the technical and economic advantage of LMR.
d) Rule K When the geometrical specification is an orientation or a location relative to a (primary)
datum or a datum system, the least material virtual condition, LMVC, of the toleranced feature
8 © ISO 2014 – All rights reserved

ISO 2692:2014(E)
shall be in theoretically exact orientation or location relative to the datum or the datum system, in
accordance with ISO 1101 and ISO 5459 (see 3.11 NOTE 2 and Figures A.5, A.8, and A.9). Moreover,
in the case of several toleranced features controlled by the same tolerance indication, the least
material virtual conditions, LMVCs, shall also be in theoretically exact orientation and location
relative to each other [in addition to the possible constraints relative to the datum(s)].
NOTE 4 In the case of several toleranced features controlled by the same toleranced indication, the least
material requirement, LMR, without any other modifier than has exactly the same meaning as the same
requirement with both and CZ modifiers.
2)
To specify requirements that apply separately, the SZ modifier shall be used after the modifier.
4.3.2 Least material requirement for related datum features
When the least material requirement, LMR, applies to the datum feature, it shall be indicated on the
drawing by the symbol placed after the datum letter in the tolerance indicator.
NOTE 1 The use of after the datum letter is only possible if the datum is obtained from a feature of size.
NOTE 2 When maximum or least material requirement applies to all elements of the collection of surfaces of
a common datum, the corresponding sequence of letters identifying the common datum are indicated within
parentheses (see Figure A.13 and ISO 5459:2011, Rule 9) and maximum material virtual conditions, MMVCs,
are by default constrained in location and orientation relative to each other (see ISO 5459:2011, Rule 7). When
maximum or least material requirement applies only to one surface of the collection of features involved in a
common datum, the sequence of letters identifying the common datum is not indicated within parentheses, and
the requirement applies only to the feature identified by the letter placed just before the modifier.
In this case, it specifies for the surface(s) (of the feature of size) the following rules.
a) Rule L The least material virtual condition, LMVC, of the related datum feature shall not be
violated by the extracted (integral) datum feature from which the datum is derived (see Figure A.9).
b) Rule M The size of the least material virtual condition, LMVC, of the related datum feature shall
be the least material size, LMS, when the related datum feature has no geometrical specification
(see Figure A.9), or has only geometrical specifications whose
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