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12100-2
REPORT
First edition
1992-12-15
Safety of machinery - Basic concepts, general
principles for design -
Part 2 :
Technical principles and specifications
S&wit4 des machines - Notions fondamen tales, principes gkntkaux de conception -
Partie 2 : Principes et spkcifications techniques
Reference number
lSO/TR 12100-2 : 1992 (E)
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ISO/TR 12100-2 : 1992 (E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 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, govern-
mental and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
The main task of IS0 technical committees is to prepare International Standards. In ex-
ceptional circumstances a technical committee may propose the publication of a
Technical Report of one of the following types:
-
type 1, when the required support ca nnot be obta ined for the publication of an
efforts;
International Standard, despite repeated
-
type 2, when the subject is still under technical development or where for any
other reason there is the future but not immediate possibility of an agreement on an
International Standard;
-
type 3, when a technical committee has collected data of a different kind from
that which is normally published as an International Standard (“state of the art”, for
example).
Technical Reports of types 1 and 2 are subject to review within three years of publica-
tion, to decide whether they can be transformed into International Standards.
Technical Reports of type 3 do not necessarily have to be reviewed until the data they
provide are considered to be no longer valid or useful.
0 IS0 1992
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
means, electronic or mechanical, including photocopying and microfilm, without permission in
writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
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ISO/TR 12100-2 : 1992 E)
In its resolution 6 (November 19911, Technical Committee ISO/TC 199, Safety of
machinery, endorsed the contents of European Standard EN 292-2 : 1991 prepared by
Technical Committee CEN/TC 114, Safety of machinery. It recommended further that
this European Standard be published as an IS0 Technical Report of type 2 and be im-
plemented with the highest priority throughout ISO/IEC and publicized as widely as
possible.
This document is being issued in the type 2 Technical Report series of publications (ac-
cording to part 1 of the ISO/IEC Directives) as a “prospective standard for provisional
application” in the field of safety of machinery because there is an urgent need for
guidance on how standards in this field should be used to meet an identified need.
This document is not to be regarded as an “International Standard”. It is proposed for
provisional application so that information and experience of its use in practice may be
gathered. Comments on the content of this document should be sent to the IS0 Cen-
tral Secretariat.
A review of this type 2 Technical Report will be carried out not later than three years
after its publication with the options of: extension for another three years; conversion
into an International Standard; or withdrawal.
ISO/TR 12100 consists of the following parts, under the general title Safety of
machinery - Basic concepts, general principles for design :
- Part I: Basic terminology, methodology
Part 2: Technical principles and specifications
Annexes A, B, C and D of this part of lSO/TR 12100 are for information only.
. . .
Ill
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ISO/TR 12100-2: 1992 (E)
TECHNICAL REPORT
EUROPEAN STANDARD
EN 29202:1991
NORME EUROPEENNE
EUROPAISCHE NORM
September 1991
UDC 62-78:614.8:331.454
Descriptors:
Safety of machines, design, accident prevention,
generalities, specifications, human factors
engineering, I safety, control devices, safety
information, indexes (documentation)
devices,
English version
Safety of machinery - Basic concepts, general
principles for design - Part 2: Technical
principles and specifications
Skcurite des machines - Notions Sicherheit von Maschinen -
Grundbegriffe, allgemeine
fondamentales, principes generaux de
conception - Partie 2: Principes Gestaltungsleits3tze - Teil 2:
techniques et specifications Technische Leitsatze und
Spezifikationen
This European Standard was approved by CEN on 1991-09-20
CEN members are bound to comply with the'CENKENELEC 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 Central Secretariat 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
responslbllity of a CEN member into its own language and notified to the
Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Denmark,
Flnland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg,
Sweden, Switzerland and United Kingdom.
Netherlands, Norway, Portugal, Spain,
CEN
European Committee for Standardization
Comiti! Europeen de Normalisation
Europaisches Komitee fur Normung
Central Secretariat: rue de Stassart 36, B-1050 Brussels
(c) CEN 1991 Copyright reserved to all CEN members
Ref. No. EN 292-2:1991 E
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Page 2
EN 292-2: 199 1
ISO/TR 12100-2 : 1992 (E)
Page
Contents list
Foreword
4
0 Introduction
4
1 Scope
6
2 Normative references
6
3 Risk reduction by design
.
31 Avoiding sharp edges and corners, protruding parts, etc
7
32 . Making machines inherently safe by virtue of.
a
33 . Taking into account design codes, data about material
properties, etc.
8
34 . Using inherently safe technologies, processes, energy
supplies
9
35 .
Applying the principle of the positive mechanical action of a
component on another component 9
36 . Observing ergonomic principles 9
37 . Applying safety principles when designing control systems 11
38 . Preventing hazards from pneumatic and hydraulic equipment 15
39 Preventing electrical hazard
15
3’10 Limiting exposure to bards through reliability of equipment 16
3’11 . Limiting exposure to hazards through mechanization and automation of
loading/unloading operations 16
3.12 Limiting exposure to hazards through location of the mqjority of setting
and maintenance points outside the danger zones 16
4 Safeguarding 16
41 . Selection of guards and safety devices 17
42 . Requirements for the design and construction of guards and safety devices 20
5 Information for use
23
51 . General requirements
23
52 . Location and nature of information for use
23
53 . Signals and warning devices
24
54 . Markings, signs (pictograms), written warnings
24
55 . Accompanying documents
25
6 Additional precautions
28
61 . Precautions in view of emergency situations
28
62 .
Equipment, systems and arrangements contributing to safety 29
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ISO/TR 12100-2 : 1992 (E)
EN 292-2: 199 1
Page
32
Annex A (informative) Annex I of the “Machinery Directive”
Al Annex I of the Council Directive of 14 June 1989 on the
approximation of the laws of the Member States relating to machinery
(89/392EEC) : Essential health and sqfiity requirsmsnts duting to the
designandwnstmctimof machinery 32
A.2 Amendments to Annex I of the Directive 89/392/EEC according to
Directive 91/368/EEC published on 22 July 1991 44
B (informative) Bibliography 45
Annex
C (informative) Main teminological discrepancies between
Annex
46
EN 292 and Machinery Directive (89/392/EEC)
47
Annex D (informative) Trilingual alphabetical index
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EN 292-Z: 199 1 ISO/TR 12100-2 : 1992 (E)
Foreword
This standard has been prepared by CEN/‘TC 1WWG 1 “Basic concepts”.
Part 1 of this standard deals with “Basic terminology, methodology” (see clause 0
“Introduction” for more detailed explanations).
NOTE : At several places EN 292-2 refers to specific clauses of
EN 60 204-l: 1985 “Electrical equipment of industrial machines, Part 1 - Genera1
requirements”.
It is important to note that this electrical standard has undergone a major revision
and that a draft prEZN 60 204-l ‘Safety of machinery - Electrical equipment of
requirements”
machines, Part 1 - General should be submitted to the Unique
in 1991. It is therefore likely that, by the time EN 292 is
Acceptance Procedure (UAP)
in use, there will be a new version of EN 60 204-l available which should be used.
To avoid cortfhion in the interim period, the table below indicates the subclauses of
ECN 292-2 which refer to EN 60 204-1:19&S (column 1) and the corresponding
subclauses of EN 60 204.1:1985 (column 2) and prEN 60 204.1:1991 (column 3).
Table 1
5.4 to 5.8, 6, 7, 8 7.5 and 8 to 13
6.1.1 5.6.1 9.2.5.4 and 10.7
53 .
6.2.2 5.6.2
I
0 Introduction
This standard has been produced to assist designers, manufacturers and other interested
bodies to interpret the essential safety requirements in order to achieve conformity with
European Legislation on machinery safety.
It is the ffrst in a programme of standards produced by CENICENELEC u. der mandates from
CEC and EFTA. This programme has been divided into several categories to avoid
duplication and to develop a logic which will enable rapid production of standards and easy
cross-reference between standards.
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ISO/TR 12100-2 : 1992 (E) EN 292-Z: 199 1
The hierarchy of standards is as follows :
a) Type A standards (fundamental safety standards) giving basic concepts, principles for
design, and general aspects that can be applied to all machinery.
B standards safety standards) dealing with one safety aspect or one type of
W (group
safety related devi ce that can be used across a wide range of machi nery :
- type Bl standards on particular safety aspt?CtS e. . safety distances, surface
( g
temperature, noise),
- type B2 standards on safety related devices e. . two-hand controls, interlocking
( I3
devices, pressure sensitive devices, guards).
m C standards (machine safety standards) giving detailed safety requirements for a
Cl
particular machine or group of machines.
The primary purpose of EN 292 is to provide designers, manufacturers, etc. with an overall
framework and guidance to enable them to produce machines that are safe for their intended
use. It also provides a strategy for standard makers producing type C standards, in
coqjunction with ENV . . . . . “Terminology” and EN 414 “Rules for the drafting and presentation
of safety standards”. In addition, this strategy is also a useful guide for designers and
manufacturers of machines when no C standard exists ; it can also assist designers to use the
type B standards to best advantage and to prepare the construction file.
The programme of standards is continuously evolving and some clauses of EN 292 are now
the subject of type A or B standards being prepared. Where such a type A or B standard
exists, a reference to this standard will be added to the relevant clause heading of EN 292. It
is intended that, where another type A or a type B standard covering a specifk clause of
EN 292 exists, it takes precedence over EN 292.
NOTE : In particular, any definition of term(s) given in other type A or in type Bl
and B2 standards has precedence over the corresponding definition given in EN 292.
EN 292 consists of two parts :
- Part 1 “Safety of machinery - Basic concepts, general principles for design - Basic
terminology, methodologyN expressing the basic overall methodology to be followed
when producing safety standards for machinery, together with the basic terminology
related to the philosophy underlying this work,
- Part 2 “Safety of machinery - Basic concepts, general principles for design - Technical
principles and speci&zations” giving advice on how this philosophy can be applied using
available techniques.
The overall purpose of EN 292 is to provide manufacturers, designers, etc. with the strategy
or framework necessary to achieve conformity with the European Legislation in the most
pragmatic way. An essential element in this process is an understanding of the underlying
legal framework, which is expressed in the essential safety requirements of the Machinery
Directive and the equivalent EFTA agreements. Therefore, it has been decided to reprint
annex I of the Directive 89/392/EEC as an annex to EN 292-2.
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ISO/TR 12100-2 : 1992 (E)
EN 292-2: 199 1
It is intended to revise EN 292 at an early date to take account of subsequent standards and
legislation.
1 Scope
This European standard defines technical principles and specifications to help designers and
manufacturers in achieving safety in the desim of machinery (see 3.1 in EN 292-l) for
professional and non-professional purposes. It may also be used for other technical products
having similar hazards.
Parts 1 and 2 should be used together when considering the solution to a specific problem.
They can be used independently of other documents, or as a basis for the preparation of
other type A standards or type B and C standards.
EN 292-Z in cory’unction with part 1 would also assist in a preliminary assessment of
machines with regard to their safety, where there is no relevant me CJ standard available.
It is recommended that this standard is incorporated in training courses or in manuals to
convey technical principles and specifkations to designers, etc.
2 Normative references
This European Standard incorporates, by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and
the publications are listed hereafter. For dated references, subsequent amendments to or
revisions of any of these publications apply to this European Standard only when
incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies.
Safety of machinery - Basic concepts, general principles for design - Part 1 :
EN 292-1
Basic terminology, methodology
294 Safety of machinery - Safety distances to prevent danger zones being reached
EN
by the upper limbs
EN 349 1) Safety of machinery - Minimum distances to avoid crushing of parts of the
human body
EN 418 2) Safety of machinery - Emergency stop equipment - Functional aspects
3)
EN . . . . . Safety of machinery 0’ Guards (ilxed, movable.)
4)
EN . . . . . Safety of machinery - Two-hand control device
5)
EN . . . . . Safety of machinery - Pressure sensitive safety devices - Mats and floors
1) Draft standard submitted to CENKENELEC inquiry in 1991.
2) Draft standard submitted to CEN/CE!!VELEC inquiry in 1991.
3) Draft standard prepared by CEN/TC 114/WG 11.
4) Draft standard prepared by CEN/TC 114-CLC/TC44X/.IVVG7.
5) Draft standard prepared by CEN/TC 114.CLC/TC44X/JWG8.
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EN 292-2: 199 1
lSO/TR 12100-2 : 1992 (E)
6)
EN . . . . . Safety of machinery - Interlocking devices with and without guard locking -
General principles and specifications’ for design
7)
EN . . Q. Safety of machinery - Principles for the design of safety related control systems
8)
EN . . . . . Safety of machinery - Safety requirements for fluid power systems and
components - Hydraulics
9)
EN . . . . . Safety of machinery - Safety requirements for fluid power systems and
components - Pneumatics
10)
machinery - Electrosensitive protective devices
EN . . . . . Safety of
Part 1 : General requirements
11)
Safety of machinery - Ergonomic design principles
EN . . . . .
Part 1 : Terminology and general principles
Part 2 : Interaction between machinery design and work tasks
12)
. . . . . Safety of machinery - Ergonomic requirements and data for the design of
EN
displays and control actuators
Part 1 : Human interaction with displays and control actuators
Part 2 : Displays
Part 3 : Control actuators
EN 50 020: 1977/Al: 1979/A2: 1985 Electrical apparatus for potentially explosive atmospheres -
Intrinsic safety V
EN 60 204-l: 198513) Electrical equipment of industrial machines
Part 1 : General requirements
IS0 447:19&4 Machine tools - Direction of operation of controls
3 Risk reduction by,design
Risk reduction by design consists in following actions, used separately or combined :
- avoiding or reducing as many of the hazards as possible by suitable choice of design
features (see 3.1 to 3.9), and
- limiting persons exposure to hazwds by reducing the ne4 for operator intervention
in danger zones (see 3.10 to 3.12).
3.1 Avoiding sharp edges and comers, protruding parts, etc.
In so far as their purpose allows, accessible parts of the machinery shall have no sharp
edges, no sharp angles, no rough surfaces, no protruding parts likely to cause injury, and no
openings which may “trap” parts of the body or clothing In particular, sheet metal edges
shall be deburred, flanged or trimmed, open ends of tubes which may cause a “trap” shall be
capped, etc.
6) Draft standard prepared by CEN/TC 1lWG 10.
7) Draft standard prepared by CEN/TC 114-CLC/lC44X/JWG6~
Draft standard prepared by CEIWC 114/WG 12.
8)
9) Draft standard prepared by CEN/TC 114/WG 12.
10) Draft standard prepared by CLC/TC 44WWG 2.
11) Draft standard prepared by CEN/TC 122/WG 2.
12) Draft standard prepared by CEN/TC 122/WG 6.
13) See Foreword.
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12100-2: 1992 (E)
EN 292-2: 199 1 ISO/TR
3.2 Making machines inherently safe by virtue of :
- the shape and the relative location of their me&anicall component parts ; for
instance, crushing and shearing hazards are avoided by increasing the minimum space
between the moving parts, such that the part of the body under consideration can enter
the gap safely, or by reducing the gap so that no part of the body can enter it
(see EN 349 “Minimum distances to avoid crushing of parts of the human body” and EN
294 “Safety distances to prevent danger zones being reached by upper limbs”).
- the limit&on of the actuating force to a s&ficiently low value, so that the element
does not generate a mechanical hazardla),
- the limitation of the ~JUW and/or velocity of the movable elements, and hence of
their kinetic energy Is),
the limitation by design of noise and vibration,
- etc.
3.3 Taking inti account des es, data about material properties and, in a more
general way, all prsftion es design and construction
(e.g. calculation rules, etc.)
a) Mechanical &resses :
For example :
- stress limitation by implementation of correct calculation, construction and
fastening methods as regards, for example, bolted assemblies, welded assemblies, etc.,
- stress limitation by overload prevention, (“fusible” plugs, pressure-limiting valves,
breakage points, torque-limiting devices, etc.),
- avoiding fatigue in elements under variable stresses (notably cyclic stresses),
static and dynamic balancing of rotating elements.
b) Materials :
For example, consideration of :
material properties,
corrosion, ageing,, abrasion and wear,
material homogeneity,
to, icity of materials.
.
14) When such a limitation does not hinder the intended tinction.
15) When such a limitation does not hinder the intended function.
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EN 292-2: 199 1
ISO/TR 12100-P: 1992 (E)
3.4 Using inherently s&e techologi~, proc-, power supplies
For example :
- on machines intended for use in explosive atmospheres :
. fully pneumatic or hydraulic control system and actuators, or
. “intrinsically Safien electrical quipment (see EN 50 OZO),
- electrical supply under “hctional extra-low voltage” (see 5.1.2.3 of EN 60 204-P)),
- use of fire resistant and non-toxic fluids in hydraulic equipment of machines.
3.5 Applying the principle of the p&tive mechanical action of a component on another
component
If a moving mechanical component inevitably moves another component along with it, either
by direct contact or via rigid elements, these components are said to be connected in the
positive mode (or positively). The same applies to a component which prevents any
movement of another component purely by virtue of its presence.
On the contrary, where a mechanical component moves and thus allows another one to move
freely (by gravity, by spring force, etc.), there is no positive mechanical action of the first
one on the other one.
3.6 Observing ergonomic principles (See also draft standards prepared by CEN/TC 122
others, EN . . . . . “Ergonomic design principles”
“Ergonomics* and, among and
EN . . . . . “Ergonomic requirements and data for the design of displays and control actuators**)
The observance of ergonomic principles in designing machinery contributes to increasing
safety by reducing stress and physical effort of operator, and thus improving the
performance and reliability of the operation, thereby reducing the probability of errors at all
stages of machine use.
Note shall be taken of these principles when allocating finctions to operator and machine
(degree of automation) in the basic design.
Account shall be taken of body sizes likely to be found in European countries, strengths and
postures, movement amplitudes, frequency of cyclic actions, to avoid hindrance, strain,
physical or psychic damage.
All elements of the woperator-machine” interf~ such as controls, signalling or data display
elements, shall be designed in such a way that clear and unambiguous interaction between
the operator and the machine is possible.
Designers’ attention is especially drawn to following ergonomic aspects of machine design :
3.6.1 Avoiding stressfjll postures and movements during use of the machine, maintenance,
etc. (for instance by providing facilities to adjust the machine to suit the various operators,
etc).
3.6.2 Adapting machines, and more especially hand-held machines, to human effort and
displacement characteristics and to hand, arm, leg, . . . anatomy.
16) See Foreword.
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EN 292-Z: 199 1 ISO/TR 12100-2 : 1992 (E)
3.6.3 Avoiding as far as possible noise, vibration, thermal effects (extreme temperatures),
etc.
3,6.4 Avoiding linking the operator’s working rythm to an automatic succession of cycles.
3.6.5 Providing local lighting on the machine for the illumination of the working area and of
acijusting, setting-up, and maintenance zones when the design features of the machine and/or
its guards render inadequate the ambient lighting of normal intensity ; flicker, dazzling,
shadows and stroboscopic effects shall be avoided if they may cause a risk ; if the position of
the lighting source has to be adjusted, its location shall be such that it does not cause any
hazard to persons making the acQustment.
3.6.6 Designing, locating and identifying manual controls (actuators) so that :
- they are clearly visible and identifiable and appropriately marked where necessary
(see 5.4),
- they can be safely operated without hesitation or loss of time and without ambiguity,
(e.g a standard layout of controls reduces the possibility of error when an opemtos
changes from a machine to another one of similar type having the same pattern of
operation),
- their location’ (for push-buttons) and their movement (for levers and handwheels) are
consistent with their effect (see IS0 447).
- their operation cannot cause additional risk.
Where a control is designed and constructed to perform several different actions, namely
where there is no one-to-one correspondence (e.g. keyboards, etc.), the action to be
performed shall be clearly displayed and subject to confirmation where necessary.
Controls shall be so arranged that their layout, travel and resistance to operation are
compatible with the action to be performed, taking account of ergonomic principles.
Constraints due to the necessary or foreseeable use of personal protection equipment (such
as footwear, gloves, etc.) shall1 be taken into account.
3.6.7 Designing and locating indicators, dials and visual display units so that :
they fit within the parameters and characteristics of human perception,
- information displayed can be detected, identified and interpreted conveniently ; i.e.
long lasting distinct, unambiguous and understandable with respect to the operators
requirements and the intended use,
- the operator is able to perceive them from the control position,
- from the main control position, the operator is able to ensure that there are no
exposed persons in the danger zones ; if this is impossible, the control system shall be
designed and constructed so that an acoustic and/or visual warning signal is given
whenever the machinery is about to start and so that the exposed person has the time
and the means to take action to prevent the machinery starting up.
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EN 292-2: 199 1
ISO/TR 12100-2: 1992 (E)
3.7 Applying safety principles when designing control systems (see also EN . . . . . “Principles
for the design of safety related control systems”)
Insufficient attention to the design of machine control systems can lead to unforeseen and
potentially hazardous machine behaviour.
Typical causes of hazardous machine behaviour are :
- an unsuitable design or a deterioration (accidental or deliberate) of the control
system logic,
- a tempomry or permanent defect or failure of one or several components of the
control system,
- a variation or a failure in the power supply of the control system,
- a wrong design or location of controls
Typical examples of hazardous machine behaviour are :
- unintended/unexpected start
UP,
- uncontrolled speed change,
- failure to stop moving parts,
- dropping or ejection of a mobile part of the machine or of a workpiece clamped by
the machine,
- inhibition of safety devices.
Control systems shall be provided with the means to enable operator interventions to be
carried out safely and easily ; this requires :
- systematic analysis of start and stop conditions,
- provision for specific operating modes (e.g. start-up &er normal stop, restart after
cycle interruption or tier emergency stop, removal of the workpieces contained in the
machine, operation of a part of the machine in case of a failure of a machine element,
etc.),
- clear display of the faults when using an electronic control system and a visual
display unit,
- taking into account the particular requirements of complex machinery.
In order to prevent hazardous machine behaviour and to achieve safety functions, the design
of control systems shall comply with following principles and/or methods, applied singly or
combined as appropriate to the circumstances :
3.7.1 The primary action for starting or accelerating the movement of a mechanism should
be performed by application or increase of voltage or fluid pressure, or, if binary logic
elements are considered, by passage from state 0 to state 1 (if state 1 represents the highest
energy state).
On the contrary, the primary action for stopping or slowing-down shall be performed by
removal or reduction of voltage or fluid pressure, or, if binary logic elements are considered,
by passage from state 1 to state 0 (if state 1 represents the highest energy state).
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ISO/TR 12100-2: 1992 (E)
EN 292-Z: 199 1
3.7.2 The spontanwus restart of a machine when it is re-energized after power interruption,
if such a restart may generate a hazard, shall be prevented (for instance, by use of a self-
maintained relay, contxtor or valve).
3.7.3 Component reliability comidered as the basig of the integrity of the safety fimctions :
this principle is applied whenever, in order to fulfil a tinction, the miscarriage of which
would compromise safety (safety function), components are used which are able to withstand
all disturbances and stresses associated with the usage of the equipment in the conditions of
intended use, for the period of time fuced for the use, without failures generating a
hazardous malfunctioning of the machine.
NOTE : Environmental stresses which are to be taken into consideration are, for
instance : impact, vibration, cold, heat., moisture, dust, aggressive substances, static
electricity, magnetic and electric fields.
Disturbances which may be generated by those stresses are, for instance : insulation
failures, temporary or permanent failures in the function of control system
components.
See also 3.10
3,7.4 Use of RorienCed ftiure mode” compnents or i.e. of components or sy
...