EN 12622:2001

SLOVENSKI STANDARD
SIST EN 12622:2002
01-januar-2002
Safety of machine tools - Hydraulic press brakes
Safety of machine tools - Hydraulic press brakes
Werkzeugmaschinen - Sicherheit von Werkzeugmaschinen - Hydraulische -
Gesenkbiegepressen
Sécurité des machines-outils - Presses plieuses hydrauliques
Ta slovenski standard je istoveten z: EN 12622:2001
ICS:
25.120.10 Kovaški stroji. Stiskalnice. Forging equipment. Presses.
Škarje Shears
SIST EN 12622:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD
EN 12622
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2001
ICS 25.120.10
English version
Safety of machine tools - Hydraulic press brakes
Sécurité des machines-outils - Presses plieuses Sicherheit von Werkzeugmaschinen - Hydraulische
hydrauliques Gesenkbiegepressen
This European Standard was approved by CEN on 7 March 2001.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12622:2001 E
worldwide for CEN national Members.

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EN 12622:2001
Contents
Foreword. 3
0 Introduction. 3
1 Scope. 3
2 Normative references . 4
3 Definitions and abbreviations. 5
4 List of significant hazards . 9
5 Safety requirements and/or protective measures. 12
6 Verification of the safety requirements and/or protective measures . 28
7 Information for use. 32
Annex A (normative) Calculation of minimum safety distances. 34
Annex B (normative) The response time of the press brake stopping performance . 36
Annex C (informative) Example of redundant and monitored hydraulic control circuits for a
downstroking press brake. 37
Annex D (informative) Conditions for noise measurement of press brakes . 38
Annex E (informative) The connection of the stopping time measurement equipment during press brake
construction. 39
Annex F (informative) Side safeguarding for manually fed press brakes . 40
Annex G (informative) Markings . 41
Annex ZA (informative) Relationship of this document with EC Directives. 42
Bibliography . 43

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EN 12622:2001
Foreword
This European Standard has been prepared by Technical Committee CEN/TC 143 "Machine tools - Safety",
the secretariat of which is held by SNV.
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 October 2001, and conflicting national standards shall be withdrawn at
the latest by October 2001.
This European Standard has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association, and supports essential requirements of EC Directive(s).
For relationship with EC Directive(s), see informative Annex ZA, which is an integral part of this standard.
Annexes A and B to this standard are normative, whereas annexes C to G and ZA are informative.
This standard also contains a “Bibliography”.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland and the United Kingdom.
0 Introduction
0.1
This standard is applicable to hydraulic press brakes as defined in 3.1.9.
0.2
This standard has been prepared to be a harmonized standard to provide one means of conforming
with the essential safety requirements of the Machinery Directive 98/37/EEC and associated EFTA
Regulations. It is a type C standard as described in EN 292–1:1991.
0.3 The extent to which hazards are covered is indicated in the scope of this standard.
0.4 Complementary guidance is given in the type A and type B standards to which reference is made in
the text (see clause 2). The figures are intended to be examples only and not to give the only interpretation of
the text.
1 Scope
1.1 This standard specifies technical safety requirements and protective measures to be adopted by
persons undertaking the design (as defined in 3.11 of EN 292-1:1991), manufacture and supply of hydraulic
press brakes which are intended for cold working of metal or material partly of metal.
1.2
This standard also covers hydraulic press brakes, whose primary intended use is the cold working of
metal, which are to be used in the same way to work other sheet materials such as cardboard or plastic.
1.3 The requirements in this standard take account of intended use, as defined in 3.12 of EN 292-1:1991.
This standard presumes access to the press brake from all directions, deals with the hazards described in
clause 4, and specifies the safety measures for both the operator and other exposed persons.
1.4
This standard also applies to ancillary devices which are an integral part of the press brake, e.g. back
gauges and adjustable front sheet supports. For the safeguarding of integrated manufacturing systems using
press brakes, see also prEN 1921: 1995.
1.5 This standard does not cover machines whose principal designed purpose is:
a) sheet folding by rotary action;
b) tube and pipe bending by rotary action;
c) roll bending.
1.6 This standard applies to machines built after its date of issue.
NOTE An amendment is under preparation to take into account the use of laser/scanner devices for the
safeguarding of operators on press-brakes.

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EN 12622:2001
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 (including amendments).
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 -
+A1:1995 Part 2: Technical principles and specifications
EN 294:1992 Safety of machinery - Safety distances to prevent danger zones being reached by the
upper limbs
EN 349:1993 Safety of machinery - Minimum gaps to avoid crushing of parts of the human body
EN 418:1992 Safety of machinery - Emergency stop equipment, functional aspects - Principles for
design
EN 563:1994 Safety of machinery - Temperatures of touchable surfaces - Ergonomics data to
establish temperature limit values for hot surfaces
EN 574:1996 Safety of machinery - Two-hand control devices - Functional aspects, Principles for
design
EN 614-1:1995 Safety of machinery - Ergonomic design principles - Part 1: Terminology and general
principles
EN 894-2:1997 Safety of machinery - Ergonomics requirements for the design of displays and control
actuators -
Part 2: Displays
EN 894-3:2000 Safety of machinery - Ergonomics requirements for the design of displays and control
actuators -
Part 3: Control actuators
EN 953:1997 Safety of machinery – Guards - General requirements for the design and construction
of fixed and movable guards
EN 954-1:1996 Safety of machinery - Safety related parts of control systems -
Part 1: General principles for design
EN 982:1996 Safety of machinery - Safety requirements for fluid power systems and their
components - Hydraulics
EN 983:1996 Safety of machinery - Safety requirements for fluid power systems and their
components - Pneumatics
EN 999:1998 Safety of machinery – The positioning of protective equipment in respect of approach
speeds of parts of the human body
prEN 1005-2:1998 Safety of machinery - Human physical performance -
Part 2: Manual handling of machinery and components parts of machinery
EN 1050:1996 Safety of machinery - Principles for risk assessment
EN 1088:1995 Safety of machinery - Interlocking devices associated with guards - Principles for
design and selection
EN 1837:1999 Safety of machinery - Integral lighting of machines
prEN 1921:1995 Industrial automation systems - Safety of integrated manufacturing systems - Basic
requirements (ISO 11161:1994 modified)
EN ISO 3746:1995 Acoustics - Determination of sound power levels of noise sources using sound
pressure - Survey method using an enveloping measurement surface over a reflecting
plane (ISO 3746.2:1995)

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EN 12622:2001
EN ISO 4871:1996 Acoustics – Declaration and verification of noise emission values of machinery and
equipement
EN ISO 11202:1995 Acoustics - Noise emitted by machinery and equipment - Measurement of emission
sound pressure levels at the work station and at other specified positions - Survey
method in situ (ISO 11202:1995)
EN ISO 11688-1:1998 Acoustics - Recommended practice for the design of low-noise machinery and
equipment -
Part 1: Planning (ISO/TR 11688:1995).
EN ISO 14122:2001 Safety of machinery - Permanent means of access to
machines and industrial plants
Part 1: Choice of a fixed means of access between two levels
Part 2: Working platforms and gangways
Part 3: Stairways, stepladders and guard-rails
prEN ISO 14122:1999 Safety of machinery - Permanent means of access to machines and industrial plants
Part 4: Fixed ladders
EN 60204-1:1997 Safety of machinery - Electrical equipment of machines -
Part 1: General requirements (IEC 60204-1:1997)
EN 60529:1991 Degrees of protection provided by enclosures (IP code) (IEC 60529:1989)
EN 60825–1: 1994 Safety of laser products –
Part 1: Equipment classification, requirements and user's guide (IEC 60825:1993)
EN 61310-2:1995 Safety of machinery - Indication, marking and actuation -
Part 2: Requirements for marking (IEC 61310-2:1995)
EN 61496-1:1997 Safety of machinery – Electro-sensitive protective equipment -
Part 1: General requirements and tests (IEC 61496–1:1997)
prEN 61496-2:1997 Safety of machinery – Electro-sensitive protective equipment -
Part 2: Particular requirements for equipment using active opto-electronic devices
3 Definitions and abbreviations
3.1 Terms and definitions
For the purposes of this standard, the following definitions apply. Further definitions are provided in relevant
type A and type B standards and in annex A of EN 292-2:1991/A1:1995.
3.1.1
beam
main reciprocating press brake member which normally holds the punch on a downstroking press brake, and
which normally holds the die on an upstroking press brake
3.1.2
blanking
feature available for ESPEs using AOPDs in the form of light curtains in which some parts of the sensing field
can be deactivated
3.1.3
cycle – automatic
operating mode where the operating cycle is repeated continuously or intermittently, all functions achieved
without manual intervention after initiation
3.1.4
cycle – operating
movement completed by the moving part of the tools from the cycle start position (normally the top dead
centre) to the bottom dead centre and back to the cycle stop position (normally the top dead centre). The
operating cycle includes all operations carried out during this movement.

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EN 12622:2001
3.1.5
cycle – single
operating mode where each operating cycle of the moving part of the tools has to be positively actuated by the
operator
3.1.6
dead centres
points at which the punch on a downstroking press brake is
– either nearest/closest to the die, known as the bottom dead centre (BDC),
– or furthest from the die, known as the top dead centre (TDC).
On an upstroking press brake, the centres are reversed.
3.1.7
early opening interlocking guard
guard associated with an interlocking device which, if opened when any hazardous movement in the tools area
has ceased, does not interrupt the operating cycle
3.1.8
guard locking device
mechanical device to maintain an interlocking guard gate in the closed and locked position until the risk of
injury from the hazardous machine functions has passed
3.1.9
hydraulic press brake
machine designed or intended to transmit energy to the moving part of the tools by hydraulic means principally
for the purpose of bending between narrow forming tools along straight lines (see figure 1)
3.1.10
limited movement control device; inching 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. [3.23.8 of EN 292-1 1991]
3.1.11
monitoring
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
3.1.12
muting
temporary automatic suspension of a safety function(s) by safety related parts of the control system [3.7 of EN
954-1:1996]
3.1.13
overall system stopping performance; overall response time
time occurring from actuating the protective device to the cessation of hazardous motion, or to the machine
assuming a safe condition

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EN 12622:2001
3.1.14
position switch
switch which is operated by a moving part of the machine when this part reaches or leaves a predetermined
position
3.1.15
redundancy
application of more than one device or system, or part of a device or a system, with the objective of ensuring
that, in the event of one failing to perform its function, another is available to perform that function [3.44 of EN
60204-1:1998]
3.1.16
restraint valve
device which protects against a gravity fall of the beam
3.1.17
single stroke function
feature used to limit the motion of the moving part of the tools to one operating cycle even if the stroke
initiating means (e.g. a pedal) is held in the operating position
3.1.18
tools
term for the combination of punch and die
3.1.19
tools – closed
tools designed and constructed to be inherently safe
3.1.20
up–stroking press brake
press brake in which the lower tool moves upwards during the closing stroke (reciprocal to a down–stroking
press, see figure 1)

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EN 12622:2001
Key Figure 1 - Example of a downstroking hydraulic press brake
1 : Press cylinder 6 :Backstop 11: Side Safeguard
2 :Control panel 7 :Hydraulic System 12 : Light Curtain
3 : Electircal Switch Gear Cabinet 8 :Beam 13 : Frame
4 :Foot pedal 9 :Tools
5 :Workpiece Support 10 : Bed
3.2 Abbreviations
3.2.1
M
Monitoring (see 3.1.11)
3.2.2
R
Redundancy (see 3.1.15)
3.2.3
S
Single system
3.2.4
BDC
Bottom dead centre (see 3.1.6)
3.2.5
TDC
Top dead centre (see 3.1.6)
3.2.6
PES
Programmable electronic systems

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EN 12622:2001
3.2.7
PPS
Programmable pneumatic systems
3.2.8
AOPD
Active opto-electronic protective devices
3.2.9
ESPE
Electro-sensitive protective equipment
3.2.10
THCD
Two-hand control device
4 List of significant hazards
4.1 The list of hazards contained in table 1 is the result of a hazard identification, their associated danger
zones and reference to protective measures for hydraulic press brakes covered by the scope of this standard.
The safety requirements and/or protective measures and information for use contained in clauses 5 and 7 are
based on a risk assessment and deal with the identified hazards by either eliminating them or reducing the
effects of the risks they generate.
4.2
The risk assessment assumes foreseeable access from all directions, as well as unexpected and
unintended strokes or gravity falls. Risks to both the operators and other persons who can have access to the
danger zones are identified, taking into account hazards which can occur under various conditions of intended
use (e.g. commissioning, tool setting, production, maintenance, repair, decommissioning, dismantling – see
also 3.11 of EN 292–1:1991) during the life of the machine. The assessment includes an analysis of the effect
of failure in the control system.
4.3
The user of this standard (i.e. the designer, manufacturer, supplier) shall check that the list of
significant hazards in table 1 is complete for the machine under consideration. If the user determines that
there are additional hazards then he shall analyse and evalute the risks associated with these hazards in
accordance with EN 1050:1996 with particular attention to the intended use of the machine (e.g.
commissioning, tool setting, production, maintenance, repair, decommissioning, dismantling – see also 3.11 of
EN 292–1: 1991), and its reasonably foreseeable misuse.

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EN 12622:2001
Table 1 - Significant hazards, danger zones, protective measures
Relevant Relevant Protective
No. Hazards Danger zone clauses in clauses in measures:
EN 292- EN 292–1: relevant
2:1991/ 1991 clauses in
A1:1995 this standard
1.0 Mechanical hazards Tools and associated area: 1.3 4.2 5.1, 5.3 to 5.5
generated by: - between tools,
(except 1.3.6)
- machine parts or - between the moving and the
workpieces fixed parts of the press
brake,
- moving workpieces
accumulation of energy - between deflecting 1.5.3, 1.6.1, 4.2 5.8.3
inside machinery caused, for workpieces and other parts, 1.6.3
example, by:
- moving gauges,
- elastic elements (springs)
- moving sheet supports
- liquids and gases under
- guards
pressure
1.1 Crushing hazard Outside tools area: 1.3 (except 4.2.1 5.3 to 5.6,
1.3.6)
- from hazardous situation of 7.1.2 i) to l)
falling objects
1.2 Shearing hazard 1.4 (except
1.3 Cutting or severing hazard 1.4.2.3)
1.4 Entanglement hazard 1.5.14
1.5 Drawing-in or trapping hazard
1.6 Impact hazard Moving parts of electrical, 1.3 4.2.1 5.6
hydraulic and pneumatic
equipment
Motor and drive machinery
Mechanical handling device
1.9 High pressure fluid injection Hydraulic systems 1.3.2 4.2.1 5.2.2.4, 5.8.3
or ejection hazard
2.0
Electrical hazards due to:
2.1 Contact of persons with live Electrical equipment 1.5.1, 1.6.3 4.3 5.8.1
parts (direct contact)
(continued)

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EN 12622:2001
Table 1 (continued)
Relevant Relevant Protective
No. Hazards Danger zone clauses in clauses in measures:
EN 292- EN 292–1: relevant
2:1991/ 1991 clauses in
A1:1995 this standard
2.2 Contact of persons with parts Electrical equipment 1.5.1 5.8.1
which have become live
under faulty conditions
(indirect contact)
3.0 Thermal hazards
3.1 Thermal hazards resulting in Parts of the hydraulic system 1.5.5, 1.5.6, 4.4 5.8.2
burns and scalds, by a 1.5.7
possible contact of persons
4.0 Noise hazards
4.1 Hazards generated by noise Any area at the press brake 1.5.8 4.5 5.8.5
resulting in hearing losses where there is a risk to hearing
(deafness)
6.0 Hazards generated by radiation
6.5 Lasers Any area at the press brake 1.5.12 4.7 5.8.6
where there is a risk due to laser
beams
8.0 Hazards generated by neglecting ergonomic principles in machinery design, as e.g. from:
8.1 Unhealthy postures or 1.1.2d, 1.1.5, 4.9 5.8.8
The working position and any
excessive effort 1.6.2, 1.6.4
area for controls, setting,
maintenance and handling
8.2 Inadequate consideration of 1.1.2 d, 2.2
hand–arm foot–leg anatomy
8.4 Inadequate local lighting 1.1.4 5.8.8.3, 7.2.2 d
8.6 Human error, human 1.1.2 d, 1.2.2, 4.9 5.4.5.1, 5.4.5.4,
behaviour 1.2.5, 1.2.8, 5.4.5.5, 5.4.3,
1.5.4, 1.7 5.4.6
8.7 Inadequate design, location 1.2.2 5.4.5, 5.8.8.2
or identification of manual
controls
8.8 Inadequate design or location 1.7.1 5.8.8.2
of visual display units
10 Unexpected start–up, unexpected overrun/ overspeed
10.1 Failure/disorder of the control Tools and associated area: 1.2.7, 1.6.3 5.2 to 5.5
system
- between tools,
10.2 Restoration of the energy - between the moving and the 1.2.6 5.4.1.1
supply after an interruption fixed parts of the press brake,
- moving workpieces
10.3External influences on- between deflecting work- 1.2.1, 1.5.11 5.4.1
electrical equipment pieces and other parts,
10.5 Errors in the software - moving gauges, 1.2.1 5.4.2, 5.3.12.1f)
10.6 Errors made by the operator - moving sheet supports 1.1.2 d, 1.2.2, 4.9 5.3, 7.2.2
(due to mismatch of 1.2.5, 1.2.8,
- guards
machinery with human 1.5.4, 1.7
characteristics and abilities,
see 8.6 of table 1)
13 Failure of the power supply 1.2.6 5.4.1.1
Failure of the control circuit
14 1.2.1, 1.2.3, 5.2 to 5.5
1.2.4, 1.2.5,
1.2.7, 1.6.3
(continued)

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Table 1 (concluded)
Relevant Relevant Protective
No. Hazards Danger zone clauses in clauses in measures:
EN 292- EN 292–1: relevant
2:1991/ 1991 clauses in
A1:1995 this standard
15 Errors of fitting tools 1.5.4 4.9 5.3.24
16 Break–up during operation Mechanical, electrical, hydraulic 1.3.2 4.2.2 5.2.2.4,
and pneumatic equipment 5.2.2.7,5.2.2.8,
5.2.2.9, 5.4.4
17 Falling or ejected objects Machine components 1.3.3 5.3.24, 5.3.24.1
or fluids
Workpieces and tools
18 Loss of stability/ Floor area around the press 1.3.1 5.8.4, 7.2.2 d)
overturning of machinery brake
19 Slip, trip and fall of persons All access and/or work at heights 1.5.15 4.2.3 5.7
(related to machinery)
Floor area around the press
brake
5 Safety requirements and/or protective measures
5.1 Introduction
The hydraulic press brakes covered by this standard range in size from small high speed machines with a
single operator producing small workpieces to large relatively slow speed machines with several operators and
large complex workpieces.
The methods or measures to be implemented to eliminate the significant hazards (see table 1) or reduce their
associated risks are detailed in this clause in the following manner:
– basic design considerations for major press brake components or systems (see 5.2);
– safeguarding against mechanical hazards in the tools and associated areas under different modes of
production (see 5.3 and tables 2 and 3);
– protection against hazards due to control system or control component failures (see 5.4);
– safeguarding against hazards which can occur during tool setting, trial strokes, maintenance and
lubrication (see 5.5);
– safeguarding against other hazards (see 5.6 to 5.8).
In addition, the machine shall be designed according to the principles of EN 292 for hazards relevant but not
significant which are not dealt with by this standard.
5.2 Basic design considerations
5.2.1 Prevention of unintended gravity fall of the beam during production (downstroking press
brakes)
5.2.1.1 Where there is a risk of injury (force exceeding 150 Newtons), measures shall be provided to prevent
an unintended gravity fall of the beam in the production mode with manual or automatic feed or removal (see
tables 2 and 3). Such a fall can be due to failure of the hydraulic system, mechanical failure or a failure of the
electrical control system. The risk shall be prevented by either:
– a mechanical restraint device;
– a hydraulic restraint device (see 5.2.1.2);
– a combination of a single valve hydraulic restraint device and a mechanical restraint device.
The restraint device(s) shall operate automatically and shall be effective whenever the tool (i.e. punch) is
stopped and operator access to the tools area is possible.
5.2.1.2 Where mechanical restraint is not used and the risk of injury from a gravity fall exists, the hydraulic
restraint devices shall consist either of:
a) two separate hold–up or return cylinders each with a hydraulic restraint device capable of independently
holding the beam, or

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EN 12622:2001
b) two hydraulic restraint valves fitted to the cylinder outlet using flanged, flared or welded pipework,
capable of holding the beam. Compression fittings and glued rings shall not be permitted (see 5.2.2.7
and figure C.1).
c) the piping between the cylinder and the first restraint valve shall be seamless.
5.2.1.3
On a press brake designed solely for:
– automatic operation;
– use with fixed enclosing guards;
– use with a hold-to-run control device used in conjunction with slow closing speed (see 5.3.15);
a single valve hydraulic restraint device or a mechanical restraint device, shall be provided as a minimum.
5.2.1.4
There shall be a system for automatically checking that the restraint system as defined in 5.2.1.1 is
functioning correctly and no press brake stroke shall be possible after any of the systems has failed (see figure
C.1 and 5.4.1.3).
NOTE:
See also 5.4.1.2 and 5.4.1.3 on the control system requirements to prevent unintended strokes.
5.2.2 Hydraulic and subsidiary pneumatic systems - Common features
5.2.2.1 The requirements in EN 982 and EN 983 shall be taken into consideration in designing hydraulic and
pneumatic systems, which shall comply with the particular requirements in 5.2.2 and 5.2.3.
5.2.2.2 Filters and pressure regulators shall be provided.
5.2.2.3 The design shall ensure that the working pressure is maintained within the permitted range.
5.2.2.4 Pressurized transparent bowls (e.g. glass, plastic) shall be protected to prevent injury from flying
particles, without affecting visibility.
5.2.2.5 All piping, pipe fittings, passages, surge or storage tanks and cored or drilled holes, shall be free from
burrs or foreign matter which can cause damage to or failure of the system (see 5.3.4.2.3 of EN 982:1996 and
5.3.4.2.3 of EN 983:1996).
5.2.2.6 Each run of piping shall, where practicable, be continuous from one piece of apparatus to another.
Precautions shall be taken (e.g. avoidance of straight rigid piping between connection joints) to prevent
damage by thermal expansion. Rigid piping shall be supported at frequent intervals to avoid damage from
movement. Kinking of flexible piping shall be avoided.
5.2.2.7 Where a drop in pressure can lead to unexpected hazardous motion of the beam, flexible piping shall
not be used; piping and pipe connections shall be chosen to prevent such a loss of pressure. Such pipe
connections shall not be made with compression fittings, glued rings or similar devices. They shall be made by
means of positive connecting joints, or by the welding of two fitted surfaces. See also 5.2.1.2.
5.2.2.8 Operating valves shall not depend on connected piping for support.
5.2.2.9 Control valves and other control components (e.g. regulators, pressure gauges) shall be mounted in
positions which provide accessibility and protection against damage.
5.2.2.10 Where valves are manually or mechanically (as distinct from electrically) operated, the arrangements
for restoring the valves shall be positive (i.e. when the actuator of the valve is released, the
...