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TECHNICAL
12100-1
REPORT
First edition
1992-12-15
Safety of machinery - Basic concepts, general
principles for design -
Part 1 :
Basic terminology, methodology
- Notions fondamentales, principes g&&aux de conception -
S6curit6 des machines
Partie 7 : Terminologie de base, m6thodologie
Reference number
lSO/TR 12100-l : 1992 (E)
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ISO/TR 12100-I : 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:
0 Ibtained for the publication of an
- type 1, when the required support cannot be
International Standard, despite repeated efforts;
- 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provide are considered to be no longer valid or useful.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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lSO/TR 12100-l : 1992 (E)
In its resolution 6 (November 1991), Technical Committee ISO/TC 199, Safety of
machinery, endorsed the contents of European Standard EN 292-l : 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.
lSO/TR 12100 consists of the following parts, under the general title Safety of
machinery - Basic concepts, general principles for design :
- Part 7: Basic terminology, methodology
Part 2: Technical principles and specifications
Annexes A and B of this part of lSO/TR 12100 are for information only.
. . .
III
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lSO/TR 12100-l : 1992 (E)
TECHNICAL REPORT
EUROPEAN STANDARD
EN 29201:1991
NORME EUROPEENNE
EUROPAISCHE NORM September 1991
UDC 62078:614.8:331.454:001.4
Descriptors: Safety of machlnes, design, definitions, hazards,
safety measures, categories
English version
Basic concepts, general
Safety of machinery -
principles for design -
Part 1: Basic terainology,
methodology
Securite des machines - Notions
Sicherheit von Maschinen -
fondamentales, principes generaux de
Grundbegriffe, allgemeine
conception - Partie 1: Terminologie de Gestaltungsleitsatze - Teil 1:
base, methodologie Grundsatzliche Terminologie,
Hethodologie
This European Standard was approved by CEN on 1991-09-20
CEN members are bound to comply with the CENJCENELEC 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 Austrja, Belgium, Denmark,
Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg,
Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
CEN
European Committee for Standardization
Comite 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 29201:1991 E
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Page 2
EN 29%1:1991 ISO/TR 12100-l : 1992 (E)
Page
Contents list
4
Foreword
4
0
Introduction
5
1 Scope
5
2 Nonnative references
6
3 Basic concepts
6
31 . Machinery (machine)
6
32 . Reliability of a machine
6
33 . Maintainability of a machine
6
34 . Safety of a machine
6
.
33 Hazard
7
36 . Hazardous situation
7
37 . Risk
7
38 . Risk assessment
7
39 Hazardous machine function
7
3’10 Danger zone
7
3’11 Design of a machine
8
3’12 Intended use of a machine
8
Safety functions
3’13
9
3’14 Automatic monitoring
9
3’15 Unexpected (or unintended) start-up
9
3’16 Failure to danger
9
3’17 Fail-safe condition (minimized failure to danger)
10
3’18 Risk reduction by design
10
3’19 Safeguarding .
10
3’20 Information for use
10
3’21 Operator
10
3’22 Guard
12
3’23 Safety device
13
3’24 . Deterring/impedeing device
13
4 Description of hazards generated by machinery
13
41 General
13
4:2 Mechanical hazard
14
43 . Electrical hazard
15
44 . Thermal hazard
15
4.5 Hazards generated by noise
15
Hazards generated by vibration
46
15
417 Hazards generated by radiation
15
48 . Hazards generated by materials and substances
16
49 Hazards generated by neglecting ergonomic principles inmachine design
16
Hazard combinations
4’10 .
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Page 3
EN 292-1:1991
ISO/TR 12100-l : 1992 (E)
Page
5 Strategy for selecting safety measures
16
5.1 Specification of the limits of the machine
18
.
52 Systematic assessment of hazardous situations
19
53 .
Removal of the hazards or limitation of the risk 19
5.4 Safeguarding against hazards which could not be avoided or
sufficiently limited according to 5.3
20
.
55 Informing and warning users about residual hazards
20
.
56 Additional precautions
20
57 .
Remarks
20
6 Risk assessment
22
.
61 Introduction
22
. Factors to be taken into account when assessing a risk
62
22
(informative) General schematic representation of a machine
Annex A
(informative) Trilingual alphabetical index
Annex B
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Page 4
EN 2920 1: 199 1 ISO/TR 12100-l : 1992 (E)
Foreword
This standard has been prepared by CEN/TC 114/WG 1 “Basic concepts“.
Part 2 of EN 292 deals with “Technical princip les and specifications” (see clause 0
“introduction” for more detailed explanations).
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 first in a programme of standards produced by CEN/CENELEC under 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.
The hierarchy of standards is as follows :
a) Qpe A standards (fundamental safety standards) giving basic concepts, principles for
design, and general aspects that can be applied to all machinery.
b) Type B standards (group safety standards) dealing with one safety aspect or one type of
safety related device that can be used across a wide range of machinery :
- type Bl standards on particular safety aspects (e.g. safety distances, surface
temperature, noise),
- type B2 standards on safety related devices (e.g. two-hand controls, interlocking
devices, pressure sensitive devices, guards).
c) ‘Qpe C standards (machine safety standards) giving detailed safety requirements for a
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
conjunction 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 specific 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.
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ISO/TR 121004 : 1992 (E) EN 292~1:1991
EN 292 consists of two parts :
- Part 1 “Safety of machinery - Basic concepts, general principles for design - Basic
~~I-IT&Io~o~~, methodology” 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 specifkations” 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.
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 basic terminology and specifies general design methods, to
help designers and manufacturers in achieving safety in the design of machinery (see 3.1) for
professional and non-professional purposes. It may also be used for other technical products
having similar hazards.
It is recommended that this standard is incorporated in training courses and manuals tc
convey basic terminology and general design methods to designers.
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.
Basic concepts, general principles for design -
EN 292-2 Safety of machinery -
Part 2 : Technical principles and specifications.
ENV . . . .I) Safety of machinery - Terminology
Rules for the drafting and presentation of safety
EN 414 Safety of machinery -
standards
1) Predraft standard under study by CEN/TC 114/WG 3.
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Page 6
EN 292-1:1991
ISO/TR 12100-l : 1992 (E)
2)
EN . . . . .
Safety of machinery - Risk assessment
EN 60 204-l: 19853) Electrical equipment of industrial machines - Part 1 : General
requirements
3 Basic concepts (see also ENV . . . .I) “Terminologyn)
For the purposes of this standard, the following definitions apply :
3.1 Machinery (machine)
An assembly of linked parts or components, at least one of which moves, with the
appropriate machine actuator, control and power circuits, etc., joined together for a specific
application, in particular for the processing, treatment, moving or packaging of a material.
The term machinery also covers an assembly of machines which, in order to achieve one and
the same end, are arranged and controlled so that they function as an integral whole.
Annex A provides the general schematic representation of a machine.
3.2 Reliability
The ability of a machine or components, or equipment, to perform a required function under
specified conditions and for a given period of time without failing.
3.3 Maintainability of a machine
The ability of a machine to be maintained in a state which enables it to fulfil its function
under conditions of intended use (see 3.12), or restored into such a state, the necessary
actions (maintenance) being carried out according to specified practices and using specified
means.
3.4 Safety of a machine
The ability of a machine to perform its function, to be transported, installed, aausted,
maintained, dismantled and disposed of under conditions of intended use (see 3.12) specified
in the instruction handbook (and, in some cases, within a given period of time indicated in
the instruction handbook) without causing injury or damage to health.
3.5 Hazard
A source of possible @jury or damage to health.
NOTE : The word “hazard” is generally used in conjunction with other words defining
its origin or the nature of the expected injury or damage to health : electrical shock
hazard, crushing hazard, shearing hazard, toxic hazard, etc. Hazards generated by
machinery are described in clause 4.
2) Draft standard(s) under study by CEN/TC 114NG 14
3) A revised version of EN 60 204.1:1985 should be submitted, in 1991, to the Unique
Acceptance Procedure (UAP).
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EN 29201:1991
ISO/TR 12100-l : 1992 (E)
3.6 Hazardous situation
Any situation in which a person is exposed to a hazard or to hazards.
3.7 Risk
A combination of the probability and the degree of the possible injury or damage to health
in a hazardous situation.
3.8 Risk assessment
A comprehensive estimation of the probability and the degree of the possible iqjury or
damage to health in a hazardous situation in order to select appropriate safety measures.
NOTE : Clause 6 deals with risk assessment.
3.9 Hazardous machine function
Any function of a machine which generates a hazard when operating.
3.10 Danger zone
Any zone within and/or around machinery in which a penon is exposed to risk of iqjury or
damage to health.
NOTE : The hazard generating the risk envisaged in this definition :
- either is permanently present during the intended use of the machine (motion of
hazardous moving elements, electric arc during a welding phase, etc.),
- or may appear unexpectedly (unintended/unexpected start-up, etc.).
3.11 Design of a machine
A series of actions including :
a) The study of the machine itself, taking into account all phases of its “life” :
1) Construction
2) Transport and commissioning
- assembly, installation,
- adjustment,
3) Use
- setting, teaching/programming or process changeover,
- operation,
- cleaning,
- fault finding,
- maintenance.
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EN 29201:1991 ISO/TR 12100-1 : 1992 (E)
4) De-commissioning, dismantling and, as far as safety is concerned, disposal.
b) The drafting of the instructions relating to all above-mentioned phases of the “life”
of the machine (except construction), dealt with in 5.5 of EN 292-2.
3.12 Intended use of a machine
The use for which the machine is suited according to the information provided by the
manufacturer or which is deemed usual according to its design, construction and function.
Intended use also involves the compliance with the technical instructions laid down notably
in the instruction handbook (see 5.5 in EN 2!32-2), taking into account reasonably foreseeable
misuse.
With regard to foreseeable misuse,
NOTE : the following behaviour should be
particularly taken into account in the risk assessment :
- the foreseeable incorrect behaviours resulting from normal carelessness, but not
resulting from deliberate misuse of the machine,
- the reflex behaviour of a person in case of malfunction, incident, failure, etc. ,
during use of the machine,
- the behaviour resulting from taking the “line of least resistance” in carrying out a
task,
- for some machines (especially machines for non-professional use), the foreseeable
behaviour of certain persons, such as chi dren or disabled.
See also 5.7.1.
3.13 Safety thctions
3.13.1 Safety critical functions
Those functions of a machine, the malfunction of which would immediately increase the risk
of iqjury or damage to health.
There are two categories of safety critical functions :
a) Safety-specific firnctions, which are safety critical *functions specifically intended to
achi.eve safety.
EXAMPLES
- function preventing unintended/unexpected start-up (interlocking device associated
with a guard . .).
- single-cycle function,
- two-hand control function,
- etc.
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ISO/TR 12100-l : 1992 (E) EN 29% 1: 199 1
b) Safety-related hctions, which are safety critical functions other than safety-specific
functions.
EXAMPLES
- manual control of a hazardous mechanism during setting phases, with by-passed
(muted) safety devices (see 3.7.9 and 4.1.4 in EN 292-2),
- speed or temperature control keeping the machine within safe operating limits.
3.132 Back-up safety Functions
Those functions whose failure does not immediately generate a hazard, however it reduces
the level of safety. This covers notably automatic monitoring (see 3.7.6 in EN 292-2) of any
safety critical function (e.g. monitoring of the correct operation of a position switch
belonging to an interlocking device).
3.14 Automatic monitoring
A back-up safety function which ensures that a safety measure is initiated if the ability of a
component or an element to perform its function is diminished, or if the process conditions
are changed in such a way that hazards are generated.
There are two categories of automatic monitoring :
- “continuous” automatic monitoring, whereby a safety measure is immediately initiated
when a failure occurs,
- “discontinuous” automatic monitoring, whereby a safety measure is initiated during a
following machine cycle, if a failure has occurred.
3.15 Unexpected (or unintended) start-up
Any start-up which, because of its unexpected nature, generates a risk to persons.
3.16 Failure to danger
Any failure in the machinery, or in its power supply, that generates a hazardous situation.
3.17 Fail-safe condition (minimized failure to danger)
A theoretical condition which would be reached if a safety function remained unchanged in
the case of a failure of the power supply or of any component contributing to the
achievement of this condition.
In practice, achievement of this condition gets closer as the effect of failures on the
considered safety function is reduced.
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EN 29%1:1991 ISO/TR 12100-l : 1992 (E)
3.18 Risk reduction by design
Safety measures consisting of :
- avoiding or reducing as many of the hazards as possible by suitable choice of design
features, and
- limiting exposure to hazards which are unavoidable or cannot be reduced
sufficiently ; this is achieved by reducing the need for operator intervention in danger
zones.
NOTE : Clause 3 of EN 292-Z deals with risk reduction by design.
3.19 Safeguarding -
Safety measures consisting of the use of specific technical means called safeguards (guards,
safety devices), to protect persons from the hazards which cannot reasonably be removed or
suffkiently limited by design.
NOTE : Clause 4 of EN 292-Z deals with safeguarding.
3.20 Information for use
Safety measures consisting of communication links, such as texts, words, signs, signals,
symbols or diagrams, used separately or in combination, to convey information to the user. It
is directed to professional and/or non-professional users.
NOTE : Clause 5 of EN 292-Z deals with information for use.
3.2 1 Operator
The person or persons given the task of installing, operating, adjusting, maintaining, cleaning,
repairing, or transporting machinery.
3.22 Guard
Part of a machine specifically used to provide protection by means of a physical barrier.
Depending on its construction, a guard may be called casing, cover, screen, door, enclosing
guard, etc.
NOTE 1 : A guard may act :
- alone ; it is then only effective when it is closed,
- in coqjunction with an interlocking device with or without guard locking ; in this
case, protection is ensured whatever the position of the guard.
NOTE 2 : nClosedw means “kept in place” for a !Ixed guard.
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EN 292- 1: 199 1
ISO/TR 12100-l : 1992 (E)
3.22.1 Fixed guard
Guard kept in place (i.e. closed) :
- either permanently (by welding, etc.),
- or by means of fasteners (screws, nuts, etc.) making removal/opening impossible
without using tools.
3.22.2 Movable guard
Guard generally connected by mechanical means (e.g. hinges or slides) to the machine frame
or an aaacent f=ed element and which can be opened without the use of tools.
3.22.3 Aaustable guard
Fixed or movable guard which is adjustable as a whole or which incorporates adjustable
part(s). The acijustment remains fixed during a particular operation.
3.22.4 Interlocking guard
Guard associated with an interlocking device (see 3.23.1), so that :
- the hazardous machine functions “covered” by the guard cannot operate until the
guard is closed,
- if the guard is opened while hazardous machine finctions are operating, a stop
instruction is given,
- when the guard is closed, the hazardous machine functions “covered” by the guard
can operate, but the closure of the guard does not by itself initiate their operation.
3.22.5 Intmlocking guard with guard locking
Guard associated with an interlocking device (see 3.23.1) and a guard locking device so that :
- the hazardous machine functions “covered” by the guard cannot operate until the
guard is closed and locked,
- the guard remains closed and locked until the risk of injury from the hazardous
machine functions has passed,
- when the guard is closed and locked, the hazardous machine functions “covered” by
the guard can operate, but the closure and locking of the guard do not by themselves
initiate their operation.
3.22.6 Control guard
Guard associated with an interlocking device (with or without guard locking) (see 3.23.1) so
that :
pera te until the
- the hazardou ,s machine functions “covered” by the guard cannot o
guard i s closed,
- closing the guard initiates operation of the hazardous machine function(s).
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EN 292-1: 199 1 ISO/TR 12100-I : 1992 (E)
3.23 Safety device
Device (other than a guard) which eliminates or reduces risk, alone or associated with a
guard.
3.23. I Interlocking device (interlock)
Mechanical, electrical or other type of device, the purpose of which is to prevent the
operation of machine elements under specified conditions (generally as long as a guard is not
closed).
3.23.2 Enabling (control) device
Additional manually operated control device used in cory’unction with a start control and
which, when continuously actuated, allows a machine to function.
3.23.3 Hold-to-run control device
Control device which initiates and maintains operation of machine elements only as long as
the manual control (actuator) is actuated. The manual control (actuator) returns
automatically to the stop position when released.
3.23.4 Two-hand control device
Hold-to-run control device which requires at least the simultaneous actuation of two manual
controls (actuators) in order to trigger and to maintain operation of the machine or machine
elements, thus affording a measure of protection for the person operating the manual
controls (actuators).
3.23.5 Trip device
Devic e whi ,ch causes a m achin ,e or machine elements to stop ensures an otherwise safe
(or
limit.
condi ti wh &en a person or a of his body goes beyond a safe
on) Part
Trip devices may be :
- mechanically actuated : e.g. trip wires, telescopic probes, pressure sensitive devices,
etc. ,
non-mechanically actuated : e.g. photo-electric devices, devices using capacitive, ultra-
X, etc. means to achieve det ction.
3.23-r: Mechanical restraint device
Device which introduces into a mechanism a mechanical obstacle (wedge, spindle, strut,
scotch, etc.) which, by virtue of its own strength, can prevent any hazardous movement (for
instance, the fall of a ram due to the failure of the normal retaining system).
3.23.7 Limiting device
Device which prevents a machine or machine elements from exceeding a designed limit (e.g.
space limit, pressure limit, etc.).
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ISO/TR 12100-I : 1992 (E) EN 292~I:1991
3.23.8 Limited movement con-1 device
Control device, the actuation of which permits only a limited amount of travel of a machine
element, thus minimizing risk as much as possible ; further movement is precluded until
there is a subsequent and separate actuation of the control.
3.24 Deterringlimpdeing device
Any physical obstacle which, without totally preventing access to a danger zone, reduces the
probability of access to this zone by offering an obstruction to free access.
4 Description of hazards generated by machinery
4.1 General
The purpose of this clause is to identify and to describe (by their nature or by their
consequences) the various hazards which machinery is likely to generate, in order to
facilitate the hazed analysis which is to be carried out, in particular :
- when designing a machine,
- when working out a safety standard relating to a machine,
- when assessing risk,
4.2 Mechanical hazard
Mechanical hazard is a general designation for all physical factors which may give rise to
irljury due to the mechanical action of machine parts, tools, workpieces or of projected solid
or fluid materials.
4.2.1 The elementary forms of mechanical hazard are notably :
- crushing hazard,
- shearing hazard,
- cutting or severing hazard,
- entanglement hazard,
- drawing-in or trapping hazard,
- impact hazard,
- stabbing or puncture hazard,
- friction or abrasion hazard,
- high pressure fluid ejection hazard.
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EN 29%1:1991
ISO/TR 12100-l : 1992 (E)
4.2.2 The mechanical hazard which may be generated by machine parts (or workpieces) is
conditioned, among other factors, by :
- shape : cutting elements, sharp edges, angular parts, even if they are motionless,
- relative location, which crushing, shearing, entanglement,
create etc. zones, when
may
they are moving,
- mass and stability (potential energy of elements which may move under the effect of
gravW,
- mass and velocity (kinetic energy of elements in controlled or uncontrolled motion),
acceleration,
- inadequate mechanical strength, which may generate hazardous breakages or bursts,
- potential energy of elastic elements (springs), or of liquids or gases under pressure or
vacuum.
4.2.3 Because of their mechanical nature, slip, trip and hlling hazards in relationship with
machinery are also included in subclause 4.2.
4.3 Electrical hazard
This hazard may cause injury or death from electric shock, or burn ; these may
...