SIST EN 50176:2010

SLOVENSKI STANDARD
oSIST prEN 50176:2007
01-november-2007
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Stationary electrostatic application equipment for ignitable liquid coating material - Safety
requirements
Stationäre Ausrüstung zum elektrostatischen Beschichten mit entzündbaren flüssigen
Beschichtungsstoffen - Sicherheitsanforderungen
Matériel stationaire de projection électrostatique de produit a projeter liquide inflammable
- Exigences de sécurité
Ta slovenski standard je istoveten z: prEN 50176:2007
ICS:
87.100 Oprema za nanašanje Paint coating equipment
premazov
oSIST prEN 50176:2007 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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DRAFT
EUROPEAN STANDARD
prEN 50176

NORME EUROPÉENNE
September 2007
EUROPÄISCHE NORM

ICS 87.100 Will supersede EN 50176:1996


English version


Stationary electrostatic application equipment
for ignitable liquid coating material -
Safety requirements



Matériel stationaire de projection Stationäre Ausrüstung zum
électrostatique de produit à projeter elektrostatischen Beschichten mit
liquide inflammable - entzündbaren flüssigen
Exigences de sécurité Beschichtungsstoffen -
Sicherheitsanforderungen



This draft European Standard is submitted to CENELEC members for CENELEC enquiry.
Deadline for CENELEC: 2007-11-09.

It has been drawn up by CLC/SC 31-8.

If this draft becomes a European Standard, CENELEC 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.

This draft European Standard was established by CENELEC in three official versions (English, French, German).
A version in any other language made by translation under the responsibility of a CENELEC member into its own
language and notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to
change without notice and shall not be referred to as a European Standard.


CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Project: 16944 Ref. No. prEN 50176:2007 E

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Foreword
This draft European Standard was prepared by SC 31-8, Electrostatic painting and finishing
equipment, of Technical Committee CENELEC TC 31, Electrical apparatus for explosive atmospheres.
It is submitted to the CENELEC enquiry.
This European Standard will supersede EN 50176:1996.
This draft European Standard has been prepared under a mandate given to CENELEC by the
European Commission and the European Free Trade Association and covers essential requirements
of EC Directive 94/9/EC. See Annex ZZ.
_____________________

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Contents
0 Introduction.4
0.1 Process .4
0.2 Explosion hazard.4
0.3 Electric hazards.4
1 Scope .5
2 Normative references .5
3 Definitions.6
4 General requirements.9
5 Requirements for the equipment.10
5.1 Electrostatic spraying systems.10
5.2 Requirements for spraying systems of category 3.10
5.3 Special requirements for spraying systems of category 2G.12
5.4 Spraying area .13
5.5 High voltage supply.13
5.6 Electric requirements .14
5.7 Grounding measures.14
6 Testing.14
6.1 Tests of the high voltage cables.14
6.2 Tests of the stationary equipment.14
6.3 Specific test requirements for spraying systems of type B-L, type C-L or type D-L
category 2G.16
7 Information for use .17
7.1 General.17
7.2 Instruction handbook.17
7.3 Marking .18
7.4 Warning sign .20
Annex ZZ (informative) Coverage of Essential Requirements of EC Directives .21
Bibliography .22
Figure
Figure 1 – Test assembly according to 6.3.2.16
Tables
Table 1 – Electrostatic spraying systems for ignitable and hard to ignite liquid coating materials –
Fields of application.10
Table 2 – Requirements for electrostatic spraying systems of category 3 for ignitable and hard to
ignite liquid coating materials .11
Table 3 – Survey of tests.15
Table 4 – Test intervals .18

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0 Introduction
0.1 Process
During the electrostatic coating process the liquid coating material is transported to an electrostatic
spraying device where it is converted to droplets by mechanical forces and by the influence of an
electric field. During this atomising process the droplets are charged by high voltage of some 10 kV
and a spray cloud is generated. The charged droplets are attracted by and applied to the earthed
workpiece.
Droplets, which are not applied to the workpiece (overspray) are removed by a suction device or by
other means.
After the coating process the coated workpieces are introduced into a dryer where the solvent is
evaporated and a dry film of coating material is generated.
0.2 Explosion hazard
An explosion could occur, if
– the concentration of sprayed liquid ignitable coating materials in air is within the explosion limits,
– an ignition source of appropriate energy for this explosive atmosphere is present.
Ignition sources could be, for instance, a hot surface, an open flame, an electric arc or a spark.
An explosion could be prevented, if one – or better both – conditions are avoided. Because it is very
difficult to exclude the possibility of discharges completely, the main focus should be the prevention of
ignitable concentrations.
0.2.1 Mixtures of ignitable coating materials and air could only explode within a given range of
concentration, but not, if the concentration is above or below this range.
NOTE If an explosive cloud of coating materials is trapped in a closed room, an explosion could lead to a fatal increase of
pressure.
0.2.2 Particular attention should be paid to the prevention of electrostatic charges on different
surfaces, which are in the vicinity of the spray cloud. This could apply to workpieces during the coating
process or the reciprocating devices and the mounting parts of the spraying system etc.
0.3 Electric hazards
0.3.1 Electric shock (by direct or indirect contact) could be generated, for instance, by contact with
– live parts, which are not insulated for operational reasons,
– conductive parts, which are not under dangerous voltage during normal operation, but in case of
failure,
– insulated live parts whose insulation is insufficient or has been damaged due to mechanical
influences.
0.3.2 Inadequate grounding could result, for instance, from
– faulty connections to the protective grounding system,
– a too high resistance to ground.
0.3.3 Hazards could occur, for instance, if hazardous malfunctions (e.g. shortcut of electronic
safety circuits, of access guards to dangerous areas or of warning devices) occur due to interferences
of the high voltage equipment and the components of control and safety systems.
0.3.4 Hazardous electrostatic discharges could be generated, for instance, by non-earthed
conductive components or by large insulating surfaces, especially if they are backed with conductive
material.
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1 Scope
1.1 This European Standard specifies the requirements for stationary electrostatic equipment for
ignitable liquid coating materials and for hard to ignite liquid coating materials to be used in explosive
atmospheres generated by their own spray cloud. A distinction is made between spraying systems
corresponding to EN 50050:2001 and spraying systems designed for higher discharge energies and/or
currents.
This European Standard also specifies the design-related requirements for a safe operation of the
stationary equipment including its electrical installation.
1.2 This European Standard considers four types of electrostatic spraying systems; see 5.1 for
more details.
1.3 This European Standard deals with all hazards significant for the electrostatic spraying of
coating materials, which could also contain small quantities of added metal particles, if the work is
carried out under conditions recommended by the manufacturer. In particular, this includes ignition
hazards resulting from the generated explosive atmosphere, and the protection of persons from
electric shocks.
1.4 This stationary equipment is classified as equipment of group II, category 2G or category 3G
for use in potentially explosive areas of zone 1 or 2, respectively.
NOTE For other safety aspects like
– zone classification of the areas in and around spray booths, see EN 12215:2004, 5.7.2.3;
– zone classification of other areas with explosive atmosphere, see EN 60079-10-1;
– selection, installation and application of other electrical and non electrical equipment in areas with explosion hazard, see
EN 60079-14 and EN 12215:2004, 5.7.2.5;
– health protection (for instance, noise), see also EN 12215:2004, 5.5 and EN 14462;
– cleaning of spraying areas, see instruction manual of the spraying equipment;
– fire prevention and protection (for instance fire hazards due to other sources) see also EN 12215:2004, 5.7.1.
Design-related measures for reducing the generation of noise of the stationary equipment for electrostatic coating are given in
EN ISO 11688-1. See also EN 14462.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 1081, Resilient floor coverings – Determination of the electrical resistance
EN 1127-1, Explosive atmospheres – Explosion prevention and protection – Part 1: Basic concepts
and methodology
1)
EN 1149-5 , Protective clothing – Electrostatic properties – Part 5: Performance requirements
EN ISO 12100-1, Safety of machinery – Basic concepts, general principles for design –
Part 1: Basic terminology, methodology (ISO 12100-1)
EN ISO 12100-2, Safety of machinery – Basic concepts, general principles for design –
Part 2: Technical principles (ISO 12100-2)

1)
At draft stage.
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EN 12215:2004, Coating plants – Spray booths for application of organic liquid coating materials –
Safety requirements
EN 13463-1, Non-electrical equipment for potentially explosive atmospheres – Part 1: Basic method
and requirements
EN 13478:2001, Safety of machinery – Fire prevention and protection
EN ISO 20344, Personal protective equipment – Test method for footwear (ISO 20344)
EN 50050:2001, Electrical apparatus for potentially explosive atmospheres – Electrostatic hand-held
spraying equipment
EN 60079-0, Electrical apparatus for explosive gas atmospheres – Part 0: General requirements
(IEC 60079-0)
EN 60204-1, Safety of machinery – Electrical equipment of machines – Part 1: General requirements
(IEC 60204-1)
EN 60529, Degrees of protection provided by enclosures (IP code) (IEC 60529)
EN 61340-4-1, Electrostatics – Part 4-1: Standard test methods for specific applications – Electrical
resistance of floor coverings and installed floors (IEC 61340-4-1)
EN 62061, Safety of machinery – Functional safety of safety-related electrical, electronic and
programmable electronic control systems (IEC 62061)
3 Definitions
For the purposes of this document, the following terms and definitions apply.
3.1
stationary electrostatic application equipment for ignitable liquid coating material
equipment in which the electrostatic spraying equipment is either fixed stationary (e.g. on supports)
and is operated automatically or is guided by reciprocators (e.g. robots).
In general, the equipment comprises the following:
– spray booth,
– spraying area,
– spraying device,
– fixtures for workpieces,
– conveyors,
– grounding system,
– forced ventilation,
– fire prevention and protection equipment
3.2
spraying system
devices for application of liquid coating material by means of electrostatic charge.
In general, the spraying system consists of the following compounds:
– device for the supply of coating material,
– high voltage electrode,
– high voltage supply system,
– spraying device
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3.3
high voltage supply system
system consisting in general of the following compounds:
─ low voltage section with devices for switching on and off the unit and for adjustment, control,
regulation, limitation and monitoring of current and voltage, as well as the required connecting
cables,
─ high voltage generator,
─ high voltage switching device,
─ high voltage cable,
─ high voltage plug-and-socket connector
3.4
spraying area
area, closed or not, in which the coating material is applied to the workpiece by the electrostatic
spraying system
3.5
dangerous discharge
discharge which generates the hazard of ignition of explosive mixtures or of electric shock
3.6
workpiece
article to which the coating material is applied
3.7
ignitable liquid coating materials
sprayed materials, especially varnishes, which could be ignited by an effective ignition source and
which continue to burn after the ignition source has been removed or may react in the form of an
explosion
3.8
hard to ignite liquid coating materials
sprayed materials, especially varnishes, which could be ignited by an effective ignition source with an
energy of 2 J or above and which continue to burn after the ignition source has been removed, or may
react in the form of an explosion
NOTE A formula for the estimation of ignitability on the basis of the composition of the coating material is given in Annex A.
3.9
explosive atmosphere
mixture of air, under atmospheric conditions, and ignitable substances in the form of gas, vapour, mist,
powder or flock, in such proportions that it can be ignited by effective ignition sources, such as
excessive temperature, arcs or sparks (see EN 1127-1)
3.10
lower explosion limit (LEL)
concentration of ignitable gas, vapour, mist, powder or flock in air below which an explosive
atmosphere will not be formed
3.11
average concentration of ignitable coating materials in air
mass of the ignitable coating material applied to the spraying area divided by the volume of air
exchanged during the same period of time
3.12
discharge energy
energy discharged from a conductive part of the installation in form of a spark which could cause both
electric shock to a person and an ignition of an explosive atmosphere
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3.13
antistatic footwear
footwear that has a resistance to earth via its sole, which is low enough to prevent the build-up of
electrostatic charges capable to produce an incendive discharge (see EN ISO 20344)
NOTE A necessary electric insulating resistance to prevent electric shocks is not contradictory to this definition.
3.14
antistatic clothes
clothes that have a resistance to earth, which is low enough to prevent the build-up of electrostatic
charges capable to produce an incendive discharge (see EN 1149-5)
NOTE A necessary electric insulating resistance to prevent electric shocks is not contradictory to this definition.
3.15
antistatic floor
floor that has a resistance to earth, which is low enough to prevent the build-up of electrostatic charges
capable to produce an incendive discharge
3.16
minimum air volume flow
air volume flow of the forced ventilation which shall be ensured in case of worst operational conditions
as described in 5.4.1
3.17
accessories
accessories are all devices, components and other equipment, except for 3.2 of this standard
3.18
constant-voltage operation
closed control circuit system with direct feedback of the actual value of the output high voltage. During
the constant-voltage operation the adjusted output high voltage is maintained constant up to the
capacity of the high voltage part via a control device, independent of the variable operational current
NOTE In general the symbol for this type of operation is U .
k
3.19
voltage-controlled operation
open control circuit system without feedback of the output high voltage. During the voltage-controlled
operation the output high voltage is adjusted generally at a defined operational current. The output high
voltage, however, is not maintained constant by a control device, it varies depending on the operational
current and the on-load behaviour of the high voltage device
NOTE In general the symbol for this type of operation is U .
v
3.20
constant current operation
closed control circuit system with direct feedback of the actual value of the high voltage current to a
control device. In doing so, the operational current is maintained constant, and the output high voltage
varies load-dependently between a minimum and a maximum value defined by the process
NOTE In general the symbol for this type of operation is I .
k
3.21
operational current
current which flows within the high voltage circuit during failure-free operation
NOTE In general the symbol for the operational current is I .
b
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3.22
overcurrent
current occurring during a malfunction, exceeding the operational current of the high voltage circuit and
giving rise to expect that in voltage-controlled and constant voltage operation hazardous discharges or
arcs between high voltage parts and earthed parts of the plant could occur in case the safety distance
drops below the permissible limit
NOTE In general the symbol for overcurrent in the high voltage circuit is I .
ü
3.23
minimum voltage
voltage of the high voltage circuit giving rise to expect that in constant current operation hazardous
discharges or arcs could occur between high voltage parts and earthed parts of the plant, in case the
safety distance drops below the permissible limit
NOTE In general the symbol for minimum voltage in the high voltage circuit is U .
min
3.24
disconnection threshold
limit value for current I or voltage U . In case of any deviation of the actual value from the threshold
ü min
value, disconnection of the high voltage supply is activated
3.25
locally acting fire extinguishing system
device which protects the highly hazardous area between spraying system and workpiece and is
actuated immediately in case of fire. It shall meet the special requirements of electrostatic coating
3.26
skilled person
person who, due to technical training, experience and recent occupational activities, has sufficient
knowledge in the field of electrostatic coating with stationary equipment, is familiar with the relevant
and generally accepted technical rules, and thus is able to check and evaluate the occupationally safe
state of coating plants
3.27
repeated inspection
inspection of the entire electrical equipment, systems and plants to be carried out at regular intervals
4 General requirements
4.1 All equipment and components shall be designed and constructed according to good
engineering practice and comply with the required categories for group II devices to ensure avoidance
of any ignition source.
4.2 All accessories shall be, if possible, outside the areas with explosion hazards.
4.3 All accessories used in areas with explosion hazards shall comply with the requirements of
EN 60079-0 and/or EN 13463-1.
4.4 An appropriate grounding of the different surfaces shall be provided. Special care shall be
taken that sufficient grounding is maintained by the hangers. These hangers shall be designed in such
a way that deposits of coating materials are minimized.
4.5 Stationary equipment shall be designed and constructed to satisfy the intended function as
given by the limitations of the manufacturer safely even in case of varying environmental conditions,
influence of external voltages, exposure to humidity, vibrations, contaminations as well as other
environmental influences. Stationary equipment shall be suitable for the intended mechanical and
thermal demands and shall withstand the effects of present or predictable aggressive materials.
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4.6 Spraying systems of category 2 shall have at least IP-protection IP64 according to EN 60529
and spraying systems of category 3 at least IP-protection IP54 according to EN 60529.
4.7 Safety devices shall function independently of the measuring, control and regulation devices
required for operation. The failure of a safety device shall be detected, if possible, by appropriate
technical measures in an adequate period so that hazardous conditions are not likely to occur.
Fundamentally the fail-safe principle shall be applied.
In case of a failure of safety devices the stationary equipment shall be led to a safe condition as far as
possible.
4.8 If the safety functions of the safety devices of the stationary equipment according to Clause 5
and Table 2 depend on software, particular attention shall be paid to the risks due to program errors.
This requirement is satisfied by observance of the requirements for the safety integrity level 2
according to EN 62061.
5 Requirements for the equipment
5.1 Electrostatic spraying systems
Depending on the maximal discharge energy that can occur, electrostatic spraying systems are
categorised in four types according to Table 1.
Table 1 – Electrostatic spraying systems for ignitable and hard to ignite
liquid coating materials – Fields of application
Types Discharge energy Hazard by Hazard
(“L” for liquid ignitable discharge by
coating during processing electric shock
materials)
Ignitable coating Hard to ignite
material coating material
(see 3.7) (see 3.8)
Type A-L < 0,24 mJ No No No
Type B-L < 350 mJ Yes No No
Type C-L < 2 J Yes No Yes
Type D-L > 2 J Yes Yes Yes
NOTE 1 The discharge energy W can be calculated by the following formula: W = ½ C · U². If resistors, semiconductors or
liquid conductors are present the calculation of W leads to a too high value, Alternatively, the discharge energy can be
determined by experiments.
NOTE 2 Hazards listed in the table are adequately prevented by observing this standard.

5.2 Requirements for spraying systems of category 3
The requirements related to the different types are listed in Table 2.
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Table 2 – Requirements for electrostatic spraying systems of category 3 for ignitable
and hard to ignite liquid coating materials
Subclause Requirements Type A-L Type B-L Type C-L Type D-L
a a
5.2.1 Distance workpiece-spraying system No Yes Yes Yes
a
5.2.2 Disconnection of high voltage No Yes Yes Yes
5.5.2 Protection against contact No No Yes Yes
5.2.3 Personal protection No No Yes Yes
b
5.2.4 Ignition protection/cleaning agent Yes Yes Yes Yes
a a
5.2.5 Locally acting fire extinguishing No Yes Yes Yes
c
equipment
a
Not required if only hard to ignite liquid coating materials are processed (see 3.8).
b
Satisfied by construction.
c
A locally acting fire extinguishing equipment is not required when using category 2G equipment of types B-L, C-L and D-L
only in areas classified as zone 2.

5.2.1 Distance workpiece – spraying system
The distance between the workpieces and the parts of the spraying system under high voltage shall be
so great that an electrical discharge is prevented during normal operation.
5.2.2 Safe disconnection of high voltage
A device shall be installed which prevents the occurrence of discharges between parts under high
voltage and earthed parts in such a way that it disconnects the high voltage, discharges the spraying
system and shuts down the supply of coating materials. In this context, a difference shall be made
between voltage-controlled, constant voltage and constant current operating modes.
For category 3 devices, this requirement is considered to be satisfied if the safe disconnection is
actuated after the first discharge at the latest. However, during normal operation spark discharges shall
not occur.
5.2.2.1 Voltage-controlled and constant voltage operating mode
A device shall be installed, which is to disconnect the high voltage, in case the safety distance between
the parts under high voltage and earthed parts drops below the permissible limit.
For voltage-controlled and constant voltage operating mode this is achieved by disconnection in case
of overcurrent I .
ü
The disconnection threshold shall be defined with consideration of the operational and local conditions.
NOTE 1 In general, an overcurrent I , for operational currents of less than 200 µA up to 200 % or for operational currents of
ü
more that 200 µA up to 50 % is permissible.
NOTE 2 If the disconnection threshold I value is set too high, the safe disconnection of the high voltage in case the safety
ü
distance drops below the permissible limit and the breakthrough distance between parts under high voltage and earthed parts
of the plant is not ensured any more. This should
...