SIST EN 61241-10:2005
(Main)Electrical apparatus for use in the presence of combustible dust -- Part 10: Classification of areas where combustible dusts are or may be present
Electrical apparatus for use in the presence of combustible dust -- Part 10: Classification of areas where combustible dusts are or may be present
Deals with the classification of areas where explosive dust/air mixtures and combustible dust layers are present, in order to permit the proper selection of equipment for use in such areas. The principles of the standard can also be followed when combustible fibres or flyings may cause a hazard. To be applied where there can be a risk due to the presence of explosive dust/air mixtures or combustible dust layers under normal atmospheric conditions.
Elektrische Betriebsmittel zur Verwendung in Bereichen mit brennbarem Staub -- Teil 10: Einteilung von staubexplosionsgefährdeten Bereichen
Matériels électriques pour utilisation en présence de poussières combustibles -- Partie 10: Classification des emplacements où des poussières combustibles sont ou peuvent être présentes
Traite de la classification des emplacements où des mélanges poussières/air explosifs et des couches de poussières combustibles sont présents, pour permettre une sélection appropriée du matériel destiné à être utilisé dans de tels emplacements. Les principes de cette norme peuvent également être suivis lorsque des fibres ou particules volatiles et combustibles sont source de danger. Applicable lorsqu'il y a danger dû à la présence de mélanges poussières/air explosifs ou de couches de poussières combustibles dans des conditions atmosphériques normales.
Električne naprave za uporabo v prisotnosti gorljivega prahu - 10. del: Razdelitev prostorov, v katerih je lahko prisoten gorljiv prah (IEC 61241-10:2004)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61241-10:2005
01-april-2005
1DGRPHãþD
SIST EN 50281-3:2003
(OHNWULþQHQDSUDYH]DXSRUDERYSULVRWQRVWLJRUOMLYHJDSUDKXGHO 5D]GHOLWHY
SURVWRURYYNDWHULKMHODKNRSULVRWHQJRUOMLYSUDK ,(&
Electrical apparatus for use in the presence of combustible dust - Part 10: Classification
of areas where combustible dusts are or may be present
Elektrische Betriebsmittel zur Verwendung in Bereichen mit brennbarem Staub - Teil 10:
Einteilung von staubexplosionsgefährdeten Bereichen
Matériels électriques pour utilisation en présence de poussières combustibles - Partie
10: Classification des emplacements où des poussières combustibles sont ou peuvent
être présentes
Ta slovenski standard je istoveten z: EN 61241-10:2004
ICS:
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
SIST EN 61241-10:2005 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 61241-10:2005
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SIST EN 61241-10:2005
EUROPEAN STANDARD EN 61241-10
NORME EUROPÉENNE
EUROPÄISCHE NORM July 2004
ICS 29.260.20 Supersedes EN 50281-3:2002
English version
Electrical apparatus for use in the presence of combustible dust
Part 10: Classification of areas
where combustible dusts are or may be present
(IEC 61241-10:2004)
Matériels électriques pour utilisation Elektrische Betriebsmittel zur Verwendung
en présence de poussières combustibles in Bereichen mit brennbarem Staub
Partie 10: Classification des emplacements Teil 10: Einteilung von
où des poussières combustibles staubexplosionsgefährdeten Bereichen
sont ou peuvent être présentes (IEC 61241-10:2004)
(CEI 61241-10:2004)
This European Standard was approved by CENELEC on 2004-07-01. 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.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC 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 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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.
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
© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61241-10:2004 E
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SIST EN 61241-10:2005
EN 61241-10:2004 - 2 -
Foreword
The text of document 31H/172/FDIS, future edition 1 of IEC 61241-10, prepared by SC 31H,
Apparatus for use in the presence of combustible dust, of IEC TC 31, Electrical apparatus for
explosive atmospheres, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 61241-10 on 2004-07-01.
This European Standard supersedes EN 50281-3:2002.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2005-04-01
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2007-07-01
with the EN have to be withdrawn
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61241-10 was approved by CENELEC as a European
Standard without any modification.
__________
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SIST EN 61241-10:2005
- 3 - EN 61241-10:2004
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1)
IEC 61241-0 - Electrical apparatus for use in the - -
presence of combustible dust
Part 0: General requirements
1)
IEC 61241-14 - Part 14: Selection and installation - -
1)
Undated reference.
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SIST EN 61241-10:2005
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SIST EN 61241-10:2005
NORME CEI
INTERNATIONALE
IEC
61241-10
INTERNATIONAL
Première édition
STANDARD
First edition
2004-06
Matériels électriques pour utilisation
en présence de poussières combustibles –
Partie 10:
Classification des emplacements
où des poussières combustibles sont
ou peuvent être présentes
Electrical apparatus for use in the
presence of combustible dust –
Part 10:
Classification of areas where combustible
dusts are or may be present
IEC 2004 Droits de reproduction réservés Copyright - all rights reserved
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électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
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Pour prix, voir catalogue en vigueur
For price, see current catalogue
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SIST EN 61241-10:2005
61241-10 IEC:2004 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.11
1 Scope.13
2 Normative references .15
3 Terms and definitions .15
4 Area classification for combustible dusts .19
4.1 General .19
4.2 Area classification objectives for explosive dust atmospheres .19
4.3 Area classification procedure for explosive dust atmospheres .21
5 Sources of release for explosive dust atmospheres .21
5.1 General .21
5.2 Identification of sources of release .23
6 Zones for explosive dust atmospheres.25
6.1 General .25
6.2 Zones for dusts .25
6.3 Examples of zones for explosive dust atmospheres.25
6.4 Extent of zones for explosive dust atmospheres .27
7 Dust layer hazard .31
8 Documentation .31
8.1 General .31
8.2 Drawings, data sheets and tables.31
Annex A (informative) Area classification application .35
Annex B (informative) Risk of fire from hot surface ignition of dust layer .43
Annex C (informative) Housekeeping .49
Bibliography.53
Figure 1 – Identification of zones on drawings .33
Figure A.1 – Bag emptying station within a building and without exhaust ventilation .35
Figure A.2 – Bag emptying station with exhaust ventilation .37
Figure A.3 – Cyclone and filter with clean outlet outside building .39
Figure A.4 – Drum tipper within a building without exhaust ventilation.41
Figure B.1 – Risk of fire from hot surface ignition of dust layer .43
Figure B.2 – Reduction in the maximum permissible surface temperature marking on
apparatus for increasing depth of dust layers .45
Table 1 – Designation of zones depending on presence of combustible dust .25
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SIST EN 61241-10:2005
61241-10 IEC:2004 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ELECTRICAL APPARATUS FOR USE IN THE
PRESENCE OF COMBUSTIBLE DUST –
Part 10: Classification of areas where combustible dusts
are or may be present
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61241-10 has been prepared by subcommittee 31H: Apparatus for
use in the presence of combustible dust, of IEC technical committee 31: Electrical apparatus
for explosive atmospheres.
This first edition of IEC 61241-10 cancels and replaces IEC 61241-3, published in 1997, and
constitutes a major technical revision.
The main changes with respect to IEC 61241-3 are listed below:
a) definitions of zones have changed;
b) layers are no longer restricted to zone 20. Consideration of layers as a source of a dust
cloud has been introduced.
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61241-10 IEC:2004 – 7 –
The text of this standard is based on the following documents:
FDIS Report on voting
31H/172/FDIS 31H/177/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 61241 consists of the following parts under the general title Electrical apparatus for use in
the presence of combustible dust:
Part 0: General requirements
Part 1: Protection by enclosures "tD"
Part 2: Type of protection "pD"
Part 10: Classification of areas where combustible dusts are or may be present
1
Part 11: Protection by intrinsic safety "iD"
Part 14: Selection and installation
Part 17: Inspection and maintenance of electrical installations in hazardous areas (other
2
than mines)
Part 18: Protection by encapsulation "mD"
NOTE All references in this standard to the IEC 61241 series follows the proposed re-numbering of the dust
standards agreed by SC31H and TC31. It may be necessary to alter these numbers if the relevant standards are
not yet published.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
———————
1
To be published.
2
In preparation.
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SIST EN 61241-10:2005
61241-10 IEC:2004 – 9 –
Reference table
Anticipated
Existing New number
Subject date of
standard assigned
change
IEC 61241-0 General requirements 2004
IEC 61241-1-1
IEC 61241-1 Protection by enclosure 2004
IEC 61241-1-2 IEC 61241-14 Selection and installation 2004
IEC 61241-2-1 IEC 61241-20-1 Test methods 2005
IEC 61241-2-2 IEC 61241-20-2 Test methods 2005
IEC 61241-2-3 IEC 61241-20-3 Test methods 2005
IEC 61241-3 IEC 61241-10 Classification 2004
IEC 61241-4 IEC 61241-2 Protection by pressurization 2005
IEC 61241-11 Protection by intrinsic safety 2005
IEC 61241-17 Inspection and maintenance 2005
IEC 61241-18 Protection by encapsulation 2004
IEC 61241-19 Repair and overhaul 2006
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61241-10 IEC:2004 – 11 –
INTRODUCTION
Combustible dusts are hazardous because when they are dispersed in air by any means they
form potentially explosive atmospheres. Furthermore, layers of combustible dust may ignite
and act as ignition sources for an explosive atmosphere.
Therefore, equipment placed in an environment where dust clouds can form should be dust
ignition protected and have a surface temperature limitation below the temperature at which a
dust cloud or layer will ignite.
This part of IEC 61241 gives guidance on the identification of areas where hazards from
combustible dust can arise. The purpose is to permit selection of appropriate equipment for
use in such areas. General and special criteria are given, with examples, for the procedure
used to identify areas.
By exercising ingenuity in the layout of equipment, it is frequently possible to locate much of
the equipment in less hazardous or in non-hazardous locations and thus to reduce the amount
of special equipment required.
This standard contains an informative annex giving practical examples for classifying areas
(Annex A).
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61241-10 IEC:2004 – 13 –
ELECTRICAL APPARATUS FOR USE IN THE
PRESENCE OF COMBUSTIBLE DUST –
Part 10: Classification of areas where combustible dusts
are or may be present
1 Scope
This part of IEC 61241 is concerned with the classification of areas where explosive dust/air
mixtures and combustible dust layers are present, in order to permit the proper selection of
equipment for use in such areas.
In this standard, explosive dust atmospheres and combustible dust layers are treated
separately. In Clause 4, area classification for explosive dusts clouds is described, with dust
layers acting as one of the possible sources of release. In Clause 7, the hazard of dust layer
ignition is described.
This standard assumes effective housekeeping based on a system of cleaning for the plant.
The principles of the standard can also be followed when combustible fibres or flyings may
cause a hazard.
This standard is intended to be applied where there can be a risk due to the presence of
explosive dust/air mixtures or combustible dust layers under normal atmospheric conditions.
It does not apply to
– underground mining areas,
– areas where a risk can arise due to the presence of hybrid mixtures,
– dusts of explosives that do not require atmospheric oxygen for combustion, or to
pyrophoric substances;
– catastrophic failures which are beyond the concept of abnormality dealt with in this
standard (see Note 1),
– any risk arising from an emission of flammable or toxic gas from the dust.
This standard does not take into account the effects of consequential damage following a fire
or an explosion.
NOTE 1 Catastrophic failure in this context is applied, for example, to the rupture of a storage silo or a pneumatic
conveyor.
NOTE 2 In any process plant, irrespective of size, there can be numerous sources of ignition apart from those
associated with equipment. Appropriate precautions will be necessary to ensure safety in this context, but these
are outside the scope of this standard.
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61241-10 IEC:2004 – 15 –
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.
IEC 61241-0, Electrical apparatus for use in the presence of combustible dust – Part 0:
General requirements
IEC 61241-14, Electrical apparatus for use in the presence of combustible dust – Part 14:
3
Selection and installation of apparatus
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
area
three-dimensional region or space
3.2
atmospheric conditions
(surrounding conditions)
conditions that include variations in pressure and temperature above and below reference
levels of 101,3 kPa (1 013 mbar) and 20 °C (293 K), provided that the variations have a
negligible effect on the explosive properties of the combustible dust
3.3
hybrid mixture
mixture of flammable substances in different physical states, with air
NOTE An example of a hybrid mixture is a mixture of methane, coal dust and air.
3.4
dust
small solid particles including fibres and flyings in the atmosphere which settle out under their
own weight, but which may remain suspended in air for some time (includes dust and grit as
defined in ISO 4225)
3.5
explosive dust atmosphere
mixture with air, under atmospheric conditions, of flammable substances in the form of dust,
fibres or flyings in which, after ignition, combustion spreads throughout the unconsumed
mixture
[IEV 426-02-04, modified]
3.6
combustible dust
dust, fibres or flyings that can burn or glow in air and could form explosive mixtures with air at
atmospheric pressure and normal temperatures
———————
3
To be published.
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61241-10 IEC:2004 – 17 –
3.7
hazardous area (dust)
area in which combustible dust in cloud form is, or can be expected to be, present in
quantities such as to require special precautions for the construction and use of equipment in
order to prevent ignition of an explosive dust/air mixture
NOTE Hazardous areas are divided into zones based upon the frequency and duration of the occurrence of
explosive dust/air mixtures (see 6.1 and 6.2)
3.8
non-hazardous area (dust)
area in which combustible dust is not present to an extent that will permit the formation of
significant explosive dust/air mixtures
3.9
dust containment
those parts of the process equipment inside which materials are handled, processed,
transported or stored, e.g. to prevent the release of dust to the surrounding atmosphere
3.10
source of dust release
point or location from which combustible dust can be released into the atmosphere
NOTE 1 This can be from a dust containment or a dust layer.
NOTE 2 Sources of release are divided into the following grades depending on the order of decreasing severity:
a) continuous formation of a dust cloud: locations in which a dust cloud may exist continuously, or may be
expected to continue for long periods or for short periods which occur frequently;
b) primary grade of release: a source can be expected to occasionally release combustible dust in normal
operation;
c) secondary grade of release: a source which is not expected to release combustible dust during normal
operation; if it releases, it is likely to do so only infrequently and for short periods only.
3.11
extent of zone
distance in any direction from the edge of a source of release to the point where the hazard
associated with the release is considered to exist no longer
3.12
normal operation
situation when the process equipment is operating within its design parameters
NOTE Minor releases of dust which may form a cloud or layer (e.g. releases from filters) can be part of normal
operation.
3.13
abnormal operation
expected process-linked malfunctions that occur infrequently
3.14
equipment
machines, apparatus, fixed or mobile devices, control components and instrumentation
thereof and detection or prevention systems which, separately or jointly, are intended for the
generation, transfer, storage, measurement, control and conversion of energy or the
processing of material and which are capable of causing an explosion through their own
potential sources of ignition
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61241-10 IEC:2004 – 19 –
4 Area classification for combustible dusts
4.1 General
This standard adopts the concept, similar to that used for flammable gases and vapour, of
using area classification to give an assessment of the risk of fire and/or explosion from dust
clouds.
Hazardous and non-hazardous areas are defined in 3.7 and 3.8, respectively.
Combustible dusts form explosive atmospheres only at concentrations in the explosion range.
Although a cloud with a very high concentration may not be explosive, the danger
nevertheless exists that, should the concentration fall, it may enter the explosion range.
Depending on the circumstances, not every source of release will necessarily produce an
explosive dust/air mixture.
Dusts which are not removed by mechanical extraction ventilation, settle out at a rate
depending on properties, such as particle size, into layers or accumulations. It has to be
taken into account that a dilute or small continuous source of release, in time, is able to
produce a potentially hazardous dust layer.
The hazards presented by combustible dusts are as follows:
– the formation of a dust cloud from any source of release including a layer or accumulation
to form an explosive atmosphere (see Clause 5);
– the formation of dust layers which are not likely to form a dust cloud and which may ignite
due to self-heating or hot surfaces and cause a fire hazard or over-heating of equipment.
The ignited layer may also act as an ignition source for an explosive atmosphere (see
Clause 7).
Explosive dust clouds and combustible dust layers may exist and therefore sources of ignition
should be avoided.
If this cannot be done, then measures should be taken to reduce the likelihood of combustible
dust and/or ignition sources so that the likelihood of coincidence is so small as to be
acceptable. In some cases, it can be necessary to employ some form of explosion protection
such as explosion venting or explosion suppression.
In this standard, explosive dust atmospheres and ignitable dust layers are treated separately.
In this clause, area classification for explosive dust clouds is described, with dust layers
acting as one of the possible sources of release. The hazard of dust layer ignition is
described in Clause 7.
4.2 Area classification objectives for explosive dust atmospheres
In most practical situations where combustible dusts are present, it is difficult to ensure that
an explosive dust/air mixture will never occur. It can also be difficult to ensure that equipment
will never give rise to a source of ignition. Therefore, in situations where an explosive dust/air
mixture has a high likelihood of occurring, reliance is placed on using equipment which is
designed to have an extremely low likelihood of creating a source of ignition.
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Conversely, where the likelihood of an explosive dust/air mixture occurring is lower,
equipment constructed to a less rigorous specification can be used.
4.3 Area classification procedure for explosive dust atmospheres
Area classification is based on an informed input from a number of sources. The decision to
classify an area depends on whether the dust is combustible or not. Dust combustibility can
be confirmed by laboratory tests. An understanding of the material characteristics to be used
in the process is required and these should be obtained from a process specialist. Account
has to be taken of the operating and maintenance regime for the plant, including
housekeeping. Specialist engineering knowledge may also be necessary to provide
information on the nature of releases from particular items of plant. Close co-operation is
necessary from specialists in safety and equipment. The definitions for zones of risk deal only
with the cloud risk.
The procedure for identifying zones of risk is as follows:
a) The first step is to identify the material characteristics; whether it is combustible and, for
the purposes of apparatus selection, particle size, moisture content, cloud and layer,
minimum ignition temperature and electrical resistivity.
b) The second step is to identify where dust containment or sources of dust release can be
present, as given in 5.2. It may be necessary to consult process line diagrams and
drawings of plant layout. This step should include the identification of the possibility of the
formation of dust layers as given in Clause 7.
c) The third step is to determine the likelihood that dust will be released from those sources
and
...
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