Bsi bs en 00418 1992 (1998)

BRITISH STANDARD

Safety of machinery —
Emergency stop
equipment, functional
aspects —
Principles for design

The European Standard EN 418:1992 has the status of a
British Standard

UDC 62-783.5:331.45:614.8

BS EN
418:1992


BS EN 418:1992

Cooperating organizations
The European Committee for Standardization (CEN), under whose supervision
this European Standard was prepared, comprises the national standards
organizations of the following countries:

This British Standard, having
been prepared by the
Machinery and Components
Standards Policy Committee,
was published under the
authority of the Standards
Board and comes into effect on

15 December 1992
© BSI 10-1998
The following BSI references
relate to the work on this
standard:
Committee reference MCE/3
Draft for comment 90/82130 DC
ISBN 0 580 20861 3

Austria

Oesterreichisches Normungsinstitut

Belgium

Institut belge de normalisation

Denmark

Dansk Standardiseringsraad

Finland

Suomen Standardisoimisliito, r.y.

France

Association franỗaise de normalisation

Germany

Deutsches Institut fỹr Normung e.V.

Greece

Hellenic Organization for Standardization

Iceland

Technological Institute of Iceland

Ireland

National Standards Authority of Ireland

Italy

Ente Nazionale Italiano di Unificazione

Luxembourg

Inspection du Travail et des Mines

Netherlands

Nederlands Normalisatie-instituut

Norway

Norges Standardiseringsforbund

Portugal

Instituto Portugs da Qualidade

Spain

Asociación Espola de Normalización y Certificación

Sweden

Standardiseringskommissionen i Sverige

Switzerland

Association suisse de normalisation

United Kingdom

British Standards Institution

Amendments issued since publication
Amd. No.

Date

Comments


BS EN 418:1992

Contents

© BSI 10-1998

Cooperating organizations
National foreword

Page
Inside front cover
ii

Foreword
Text of EN 418:1992
National annex NA (informative) Committees responsible
National annex NB (informative) Cross-references

2
3
Inside back cover
Inside back cover

i


BS EN 418:1992

National foreword
This British Standard has been prepared under the direction of the Machinery
and Components Standards Policy Committee and is the English language

version of EN 418 Safety of machinery — Emergency stop equipment, functional
aspects — Principles for design published by the European Committee for
Standardization (CEN). EN 418 was produced as a result of international
discussions in which the United Kingdom took an active part.
A British Standard does not purport to include all the necessary provisions of a
contract. Users of British Standards are responsible for their correct application.
Compliance with a British Standard does not of itself confer immunity
from legal obligations.

Summary of pages
This document comprises a front cover, an inside front cover, pages i and ii,
the EN title page, pages 2 to 8, an inside back cover and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on
the inside front cover.
ii

© BSI 10-1998


EUROPEAN STANDARD

EN 418

NORME EUROPÉENNE
EUROPÄISCHE NORM

October 1992

UDC 62-783.5:331.45:614.8

Descriptors: Safety of machines, dangerous machines, accident prevention, safety devices, control devices, stopping, emergency
measures, design, specifications

English version

Safety of machinery — Emergency stop equipment,
functional aspects — Principles for design

Sécurité des machines — Equipement d’arrêt
d’urgence, aspects fonctionnels — Principes
de conception

Sicherheit von Maschinen —
Not-Aus-Einrichtung, funktionelle Aspekte —
Gestalgungsleitsätze

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This European Standard was approved by CEN on 1992-10-16. 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 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
responsibility 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, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and
United Kingdom.

CEN
European Committee for Standardization
Comité Européen de Normalisation
Europäisches Komitee für Normung
Central Secretariat: rue de Stassart 36, B-1050 Brussels
© 1992 Copyright reserved to CEN members

Ref. No. EN 418:1992 E


EN 418:1992

Foreword
CEN/TC 114-CLC/TC 44X/JWG 9 has been
entrusted by CEN/TC 114 with the task of
producing standards on emergency stop, safety hold,
isolation and energy dissipation.
This standard is the result of the first part of this
task.
The standard was accepted and in accordance with
the CEN/CENELEC Internal Regulations, the
following countries are bound to implement this
European Standard: Austria, Belgium, Denmark,
Finland, France, Germany, Greece, Iceland,
Ireland, Italy, Luxembourg, Netherlands, Norway,
Portugal, Spain, Sweden, Switzerland, and the

United Kingdom.
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
April 1993, and conflicting national standards shall
be withdrawn at the latest by April 1993.

Contents
Foreword
0
Introduction
1
Scope
2
Normative references
3
Definitions
3.1 Emergency stop (function)
3.2 Emergency stop equipment
3.3 Control device
3.4 Manual control (actuator)
3.5 Machine actuator
4
Safety requirements
4.1 General requirements
4.2 Specific requirements for electrical
equipment
4.3 Operating conditions, environmental
influences
4.4 Shape, colour and arrangement of

emergency stop actuators
4.5 Additional requirements for wires and
ropes, when used as actuators
Figure 1 — Functional aspects of the field of
application of EN 418
Figure 2 — Emergency stop equipment in
machinery

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© BSI 10-1998


EN 418:1992

0 Introduction
This European Standard has been prepared under a
mandate given to CEN by the Commission of the
European Communities and the European Free
Trade Association, and supports essential
requirements of the machinery EC Directive and
associated EFTA regulations.
An essential safety requirement of the Machinery
Directive relating to emergency stopping and
reproduced in subclause 6.1.1 of EN 292-2 specifies
that machinery shall be provided with emergency
stop equipment, except for:
— machines in which an emergency stop
equipment would not lessen the risk, either
because it would not reduce the stopping time or
because it would not enable the special measures
required to deal with the risk to be taken;
— hand-held portable machines and hand-guided
machines.

The purpose of this standard is to specify the
functional requirements the emergency stop

equipment has to comply with, to fulfil the essential
safety requirements of the Machinery Directive.
As a complement to this standard, a standard
dealing with the control device (see 3.3) of electrical
emergency stop equipment is being prepared by
CENELEC/TC 17 B.

1 Scope
This standard specifies design principles for
emergency stop equipment for machinery. No
account is taken of the nature of the energy source.
A functional demarcation of the emergency stop
equipment is shown in Figure 1. Figure 2 illustrates
the location of this equipment in machinery.

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Figure 1 — Functional aspects of the field of application of EN 418

© BSI 10-1998

3


EN 418:1992

2 Normative references

3 Definitions

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.
EN 292-1:1991, Safety of machinery — Basic
concepts — General principles for design —
Part 1: Basic terminology, methodology.
EN 292-2:1991, Safety of machinery — Basic
concepts — General principles for design —
Part 2: Technical principles and specifications.
EN 60204-1:1985, Electrical equipment of industrial
machines — Part 1: General requirements.

For the purposes of this standard, the following
definitions apply.

NOTE EN 60204-1:1985 has undergone a major revision and
the resulting prEN 60204-1:1991 “Safety of machinery —
Electrical equipment of machines — Part 1: General
requirements” has been adopted in February 1992. In order to
help make the transition between EN 60204-1:1985 and its new
version, every reference to a section or sub-section of
EN 60204-1:1985 in the present standard is complemented by a
reference to the equivalent part of prEN 60204-1:1991.

NOTE Functions such as reversal or limitation of motion,
deflection, shielding, braking, disconnecting, etc. may be part of
the emergency stop function. This standard does not deal with
these functions.

EN 60947-5-1:1992 (3rd part), Low-voltage
switchgear and controlgear — Part 5: Control circuit
devices and switching elements —
Chapter 1: Definitions, characteristics, tests —
Section 3: Special requirements for control switches
with positive opening operation.

3.1
emergency stop (function)
function which is intended
— to avert arising or to reduce existing hazards to
persons, damage to machinery or to work in
progress;
— to be initiated by a single human action when
the normal stopping function is inadequate for
this purpose.
hazards for the purpose of this standard are those
which may arise from:
— functional irregularities (malfunctioning of the
machinery, unacceptable properties of the
processed material, human errors ...);
— normal operation.

3.2
emergency stop equipment

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arrangement of components intended to achieve the
emergency stop function (see Figure 2, showing the
parts of a machine those components can belong)
3.3
control device

that component of the emergency stop equipment
which generates the emergency stop signal when
the associated manual control (actuator) is operated
3.4
manual control (actuator)
that component of the control device which, when
operated, activates the control device, and is
designed to be operated by a person (see 4.4.1)
3.5
machine actuator
a power mechanism used to effect motion of a
machine

4

© BSI 10-1998


EN 418:1992

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Figure 2 — Emergency stop equipment in machinery

© BSI 10-1998

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EN 418:1992

4 Safety requirements
4.1 General requirements
4.1.1 The emergency stop function shall be available
and operational at all times, regardless of the
operating mode.
NOTE When emergency stop control devices can be
disconnected (e.g. portable teaching pendants) or when
machinery can be partially isolated, care shall be taken to avoid
confusion between active and inactive control devices.

4.1.2 The control device and its actuator shall apply
the principle of positive mechanical action
(see 3.5 of EN 292-2).
NOTE A control switch with positive opening operation, is an
example of a suitable control device. According to EN 60947-5-1
(3rd part, subclause 2.2), positive opening operation (of a contact
element) is “the achievement of contact separation as the direct
result of a specified movement of the switch actuator through
non-resilient members (e.g. not dependent upon springs)”.

4.1.3 The emergency stop equipment shall neither
be used as an alternative to proper safeguarding
measures nor as an alternative for automatic safety
devices, but it may be used as a back-up measure.
4.1.4 After activation of the actuator, the emergency
stop equipment shall operate in such a way that the
hazard is averted or reduced automatically in the
best possible manner.
NOTE 1 The statement “in the best possible manner” includes
among others:
— choice of optimal deceleration rate;
— selection of the stop category (see 4.1.5 hereunder),
according to the risk assessment.
NOTE 2 “Automatically” means that, after activation of the
emergency stop actuator, the achievement of the emergency stop
function may be the result of a predetermined sequence of
internal functions.

4.1.5 The emergency stop shall function as:
— either stop category 0, i.e. stopping by:
— immediate removal of power to the machine
actuator(s);
— or mechanical disconnection (declutching)
between the hazardous elements and their
machine actuator(s);
and, if necessary, braking (uncontrolled stop);
— or stop category 1, i.e. a controlled stop with
power to the machine actuator(s) available to
achieve the stop and then removal of power when
the stop is achieved.

4.1.7 The emergency stop command shall override
all other commands.
4.1.8 The response of the machine to the emergency
stop command shall not generate any additional
hazard.
4.1.9 The emergency stop function shall not impair
the effectiveness of safety devices or of devices with
safety-related functions.
NOTE For this purpose, it may be necessary to ensure the
continuing operation of auxiliary equipment such as magnetic
chucks or braking devices.

4.1.10 The emergency stop function shall not impair
any facilities designed to release trapped persons.
NOTE The emergency stop function may include initiation of
certain of these facilities.

4.1.11 Any action on the actuator which results in
generating the emergency stop command shall also
result in the latching-in of the control device so that,
when the action on the actuator is discontinued, the
emergency stop command be maintained until the
control device is reset (unlatched). It shall not be
possible for the control device to latch-in without
generating the stop command.
NOTE In case of a failure in the control device (latching-in
means included), the function generating the stop command shall
have priority over the latching-in function.

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4.1.12 Resetting the control device shall only be
possible as the result of a manual action on the
control device itself.

Resetting the control device shall not by itself cause
a restart command.
It shall not be possible to restart the machine until
all control devices which have been actuated are
reset manually, individually and intentionally.
4.1.13 The state the machine is brought into by an
emergency stop command shall not alter
unintendedly (unexpectedly) during the time the
control device is in the actuated condition.
4.2 Specific requirements for electrical
equipment
See EN 60204-1:1985, paragraphs 5.6.1 and 6.2.7
(prEN 60204-1:1991, paragraphs 9.2.2, 9.2.5.4
and 10.7; see note in clause 2).

4.1.6 The emergency stop equipment shall be
designed such that deciding to actuate the
emergency stop actuator shall not require the
operator to consider the resultant effects (stopping
zone, deceleration rate, etc.).

6

© BSI 10-1998

EN 418:1992

4.3 Operating conditions, environmental
influences
The components of the emergency stop equipment
shall be selected, assembled and interconnected so
that this equipment meets the expected operating
conditions and environmental influences. This
includes:
— consideration of the frequency of operation and
the need for periodic testing (especially reliable
switching should be foreseen in the case of
infrequent operation),
— consideration of vibration, shock, temperature,
dust, foreign bodies, moisture, corrosive
materials, fluids, etc.
4.4 Shape, colour and arrangement of
emergency stop actuators
4.4.1 The emergency stop actuators shall be
designed for easy actuation by the operator and
others who may need to operate them. Types of
actuators that may be used include:
— mushroom-type push buttons;
— wires, ropes, bars;
— handles;
— in specific applications, foot-pedals without
protective cover...
4.4.2 The emergency stop actuators shall be

positioned for easy access and for non-hazardous
operation by the operator and others who may need
to operate them.

4.4.4 When machinery is divided into several
“emergency stop zones”, the whole system shall be
designed so that it is easy to see which emergency
stop actuators correspond to which zones.
4.5 Additional requirements for wires and
ropes, when used as actuators
4.5.1 Consideration shall be given to:
— the amount of deflection necessary for
generating the emergency stop signal;
— the maximum deflection possible;
— the minimum clearance between the wire or
the rope and the nearest object in the vicinity;
— the force to be applied to the wire or rope in
order to actuate the control unit;
— making wires or ropes visible for the operators
(e.g. by use of marker flags).
4.5.2 In the event of breaking or disengagement of a
wire or a rope, the emergency stop signal shall be
generated automatically.
4.5.3 Resetting facilities should be placed so that
the whole length of the wire or rope is visible from
those resetting facilities.
NOTE If this is not practicable, the instructions for use should
state that, after actuation and before resetting, the machinery
should be inspected along the whole length of the wire or rope in
order to detect the reason for activation.

NOTE Measures against inadvertent operation should not
impair accessibility.

4.4.3 The emergency stop actuators shall be
coloured red. As far as a background exists behind
the actuator and as far as it is practicable, it shall be
coloured yellow.
NOTE 1 In certain circumstances, it may be useful to provide
labels in addition.
NOTE 2 For electrical equipment, see also subclause 5.6.1.3 of
EN 60204-1:1985 (subclause 10.2.1 of prEN 60204-1:1991;
see note in clause 2).
NOTE 3 When using wires or ropes, it can be useful to improve
their visibility by using marker flags attached to them.

© BSI 10-1998

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BS EN 418:1992
National annex NA (informative)
Committees responsible
The United Kingdom participation in the preparation of this European Standard was entrusted by the

Machinery and Components Standards Policy Committee (MCE/-) to Technical Committee MCE/3, upon
which the following bodies were represented.
Advanced Manufacturing Technology Research Institute
Agricultural Engineers Association
Association for Consumer Research (ACRE)
British Cable Makers’ Confederation
British Compressed Air Society
British Federation of Printing Machinery and Supplies Ltd.
British Rubber Manufacturers’ Association Ltd.
British Textile Machinery Association
Consumer Policy Committee of BSI
Department of Trade and Industry
Engineering Employers’ Federation
Engineering Equipment and Materials Users’ Association
Federation of Bakers
Health and Safety Executive
Institute of Materials Management
Institution of Occupational Safety and Health
Loss Prevention Council
METCOM
Machine Tool Technologies Association
Machinery Safety Equipment Manufacturers’ Association
Ministry of Defence
Society of Laundry Engineers and Allied Trades Limited
Trades Union Congress

National annex NB (informative)
Cross-references
Publication referred to

Corresponding British Standard

EN 292-1:1991
EN 292-2:1991
EN 60204-1:1985

BS EN 292 Safety of machinery. Basic concepts, general principles for design
Part 1:1991 Basic terminology, methodology
Part 2:1991 Technical principles and specifications
BS 2771 Electrical equipment of industrial machines
Part 1:1986 Specification for general requirements

© BSI 10-1998

9


BSI
389 Chiswick High Road
London
W4 4AL

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