SIST EN 60079-10:2003
(Main)Electrical apparatus for explosive gas atmospheres - Part 10: Classification of hazardous areas (IEC 60079-10:2002)
Electrical apparatus for explosive gas atmospheres - Part 10: Classification of hazardous areas (IEC 60079-10:2002)
Is concerned with the classification of hazardous areas where flammable gas or vapour risks may arise, in order to permit the proper selection and installation of apparatus for use in such hazardous areas.
Elektrische Betriebsmittel für gasexplosionsgefährdete Bereiche - Teil 10: Einteilung der explosionsgefährdeten Bereiche (IEC 60079-10:2002)
Matériel électrique pour atmosphères explosives gazeuses - Partie 10: Classement des emplacements dangereux (CEI 60079-10:2002)
Est relative au classement des régions dangereuses dans lesquelles des risques dus à des gaz, ou vapeurs, inflammables peuvent apparaître, afin de permettre le choix et l'installation corrects du matériel à utiliser dans de telles régions dangereuses.
Električne naprave za eksplozivne plinske atmosfere - 10. del: Razdelitev eksplozijsko ogroženih prostorov (IEC 60079-10:2002)
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Electrical apparatus for explosive gas atmospheres - Part 10: Classification of hazardous areas]GHOLWHYMatériel électrique pour atmosphères explosives gazeuses - Partie 10: Classement des emplacements dangereuxElektrische Betriebsmittel für gasexplosionsgefährdete Bereiche - Teil 10: Einteilung der explosionsgefährdeten Bereiche29.260.20Electrical apparatus for explosive atmospheresICS:SIST EN 60079-10:2003en,fr,deTa slovenski standard je istoveten z:EN 60079-10:200301-november-2003SIST EN 60079-10:2003SLOVENSKI
STANDARDSIST EN 60079-10:19971DGRPHãþD
EUROPEAN STANDARD
EN 60079-10 NORME EUROPÉENNE EUROPÄISCHE NORM
April 2003 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
© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60079-10:2003 E
ICS 29.260.20 Supersedes EN 60079-10:1996
English version
Electrical apparatus for explosive gas atmospheres Part 10: Classification of hazardous areas (IEC 60079-10:2002)
Matériel électrique pour atmosphères explosives gazeuses Partie 10: Classement des emplacements dangereux (CEI 60079-10:2002)
Elektrische Betriebsmittel für gasexplosionsgefährdete Bereiche Teil 10: Einteilung der explosionsgefährdeten Bereiche (IEC 60079-10:2002)
This European Standard was approved by CENELEC on 2002-12-01. 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, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.
EN 60079-10:2003 - 2 - Foreword The text of the International Standard IEC 60079-10:2002, prepared by SC 31J, Classification of hazardous areas and installation requirements, of IEC TC 31, Electrical apparatus for explosive atmospheres, was submitted to the Unique Acceptance Procedure and was approved by CENELEC as EN 60079-10 on 2002-12-01 without any modification. This European Standard supersedes EN 60079-10:1996. The following dates were fixed: – latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement
(dop) 2003-12-01 – latest date by which the national standards conflicting
with the EN have to be withdrawn
(dow) 2005-12-01
Annexes designated "normative" are part of the body of the standard. Annexes designated "informative" are given for information only. In this standard, Annex ZA is normative and Annexes A, B and C are informative. Annex ZA has been added by CENELEC. __________ Endorsement notice The text of the International Standard IEC 60079-10:2002 was approved by CENELEC as a European Standard without any modification. __________
- 3 - EN 60079-10:2003 Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications 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). NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60050-426 1990 International Electrotechnical Vocabulary (IEV) Chapter 426: Electrical apparatus for explosive atmospheres
- - IEC 60079-4 1975 Electrical apparatus for explosive gas atmospheres Part 4: Method of test for ignition temperature
- - IEC 60079-4A 1970 Part 4: Method of test for ignition temperature – First supplement
- - IEC 60079-20 1996 Part 20: Data for flammable gases and vapours, relating to the use of electrical apparatus
- -
IEC 60079-10Edition 4.0 2002-06INTERNATIONAL STANDARD NORME INTERNATIONALEElectrical apparatus for explosive gas atmospheres – Part 10: Classification of hazardous areas
Matériel électrique pour atmosphères explosives gazeuses – Partie 10: Classement des emplacements dangereux
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE XAICS 29.260.20 PRICE CODECODE PRIXISBN 2-8318-6379-1
60079-10 IEC:2002 – 3 –CONTENTSFOREWORD.3INTRODUCTION.41 General .51.1 Scope.51.2 Normative references .62 Definitions and terms.63 Safety and area classification.103.1 Safety principles.103.2 Area classification objectives.104 Area classification procedure.114.1 General.114.2 Sources of release .124.3 Type of zone .124.4 Extent of zone .134.4.1 Release rate of gas or vapour.134.4.2 Lower explosive limit (LEL).144.4.3 Ventilation .144.4.4 Relative density of the gas or vapour when it is released.144.4.5 Other parameters to be considered.154.4.6 Illustrative examples.155 Ventilation .165.1 General.165.2 Main types of ventilation.165.3 Degree of ventilation .165.4 Availability of ventilation.166 Documentation .176.1 General.176.2 Drawings, data sheets and tables.17Annex A (informative)
Examples of sources of release.18Annex B (informative)
Ventilation.20Annex C (informative)
Examples of hazardous area classification.36Figure C.1 − Preferred symbols for hazardous area zones.57Figure C.2 – Schematic approach to the classification of hazardous areas.58– 2 –60079-10 © IEC:2002
60079-10 IEC:2002 – 5 –INTERNATIONAL ELECTROTECHNICAL COMMISSION____________ELECTRICAL APPARATUS FOR EXPLOSIVE GAS ATMOSPHERES –Part 10: Classification of hazardous areasFOREWORD1)The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprisingall national electrotechnical committees (IEC National Committees). The object of the IEC is to promoteinternational co-operation on all questions concerning standardization in the electrical and electronic fields. Tothis end and in addition to other activities, the IEC publishes International Standards. Their preparation isentrusted to technical committees; any IEC National Committee interested in the subject dealt with mayparticipate in this preparatory work. International, governmental and non-governmental organizations liaisingwith the IEC also participate in this preparation. The IEC collaborates closely with the InternationalOrganization for Standardization (ISO) in accordance with conditions determined by agreement between thetwo organizations.2)The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, aninternational consensus of opinion on the relevant subjects since each technical committee has representationfrom all interested National Committees.3)The documents produced have the form of recommendations for international use and are published in the formof standards, technical specifications, technical reports or guides and they are accepted by the NationalCommittees in that sense.4)
In order to promote international unification, IEC National Committees undertake to apply IEC InternationalStandards transparently to the maximum extent possible in their national and regional standards. Anydivergence between the IEC Standard and the corresponding national or regional standard shall be clearlyindicated in the latter.5)
The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for anyequipment declared to be in conformity with one of its standards.6)
Attention is drawn to the possibility that some of the elements of this International Standard may be the subjectof patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.International Standard IEC 60079-10 has been prepared by subcommittee 31J: Classificationof hazardous areas and installation requirements, of IEC technical committee 31: Electricalapparatus for explosive atmospheres.This fourth edition cancels and replaces the third edition published in 1995, and constitutes atechnical revision.The text of this standard is based on the following documents:FDISReport on voting31J/82/FDIS31J/84/RVDFull information on the voting for the approval of this standard can be found in the report onvoting indicated in the above table.This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.Annexes A, B and C are for information only.The committee has decided that the contents of this publication will remain unchangeduntil 2007. At this date, the publication will be•reconfirmed;•withdrawn;•replaced by a revised edition, or•amended.– 3 –60079-10 © IEC:2002
60079-10 IEC:2002 – 7 –INTRODUCTIONIn areas where dangerous quantities and concentrations of flammable gas or vapour mayarise, protective measures are to be applied in order to reduce the risk of explosions. Thispart of IEC 60079 sets out the essential criteria against which the risk of ignition can beassessed, and gives guidance on the design and control parameters which can be used inorder to reduce such a risk.This standard can be used as a basis for the proper selection and installation of apparatus foruse in a hazardous area.60079-10 © IEC:2002– 4 –
60079-10 IEC:2002 – 9 –ELECTRICAL APPARATUS FOR EXPLOSIVE GAS ATMOSPHERES –Part 10: Classification of hazardous areas1 General1.1 ScopeThis part of IEC 60079 is concerned with the classification of hazardous areas whereflammable gas or vapour risks may arise, in order to permit the proper selection andinstallation of apparatus for use in such hazardous areas.It is intended to be applied where there may be a risk of ignition due to the presence offlammable gas or vapour, mixed with air under normal atmospheric conditions (see note 2),but it does not apply toa)mines susceptible to firedamp;b)the processing and manufacture of explosives;c)areas where a risk may arise due to the presence of ignitable dusts or fibres;d)catastrophic failures which are beyond the concept of abnormality dealt with in thisstandard (see note 3);e)rooms used for medical purposes;f)areas where the presence of flammable mist may give rise to an unpredictable risk andwhich require special consideration (see note 5);g)domestic premises.This standard does not take into account the effects of consequential damage.Definitions and explanations of terms are given together with the main principles andprocedures relating to hazardous area classification.For detailed recommendations regarding the extent of the hazardous areas in specificindustries or applications, reference may be made to the codes relating to those industries orapplications.NOTE 1
For the purpose of this standard, an area is a three-dimensional region or space.NOTE 2
Atmospheric conditions include variations 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 explosion properties of theflammable materials.NOTE 3
Catastrophic failure in this context is applied, for example, to the rupture of a process vessel or pipelineand events that are not predictable.NOTE 4
In any process plant, irrespective of size, there may be numerous sources of ignition apart from thoseassociated with electrical apparatus. Appropriate precautions will be necessary to ensure safety in this context.This standard may be used with judgement for other ignition sources.NOTE 5
Mists may form or be present at the same time as flammable vapours. This may affect the way flammablematerial disperses and the extent of any hazardous areas. The strict application of area classification for gasesand vapours may not be appropriate because the flammability characteristics of mists are not always predictable.Whilst it can be difficult to decide upon the type and extent of zones, the criteria applicable to gases and vapourswill, in most cases, give a safe result. However, special consideration should always be given to the danger ofignition of flammable mists.– 5 –60079-10 © IEC:2002
60079-10 IEC:2002 – 11 –1.2 Normative referencesThe following referenced documents are indispensable for the application of this document.For dated references, only the edition cited applies. For undated references, the latest editionof the referenced document (including any amendments) applies.IEC 60050(426):1990, International Electrotechnical Vocabulary (IEV) – Chapter 426:Electrical apparatus for explosive atmospheresIEC 60079-4:1975, Electrical apparatus for explosive gas atmospheres – Part 4: Method oftest for ignition temperatureIEC 60079-4A:1970, First supplement to IEC 60079-4 (1966), Electrical apparatus forexplosive gas atmospheres – Part 4: Method of test for ignition temperatureIEC 60079-20:1996, Electrical apparatus for explosive gas atmospheres – Part 20: Data forflammable gases and vapours, relating to the use of electrical apparatus2 Definitions and termsFor the purpose of this part of IEC 60079, the following definitions and terms apply.NOTE
Where a definition appears in this clause and in IEC 60050(426), the definition given in this clause isapplicable.2.1explosive atmospheremixture with air, under atmospheric conditions, of flammable substances in the form of gas,vapour, mist or dust, in which after ignition, combustion spreads throughout the unconsumedmixture[IEV 426-02-02, modified]2.2explosive gas atmospheremixture with air, under atmospheric conditions, of flammable substances in the form of gas orvapour in which, after ignition, combustion spreads throughout the unconsumed mixture[IEV 426-02-03, modified]NOTE
Although a mixture which has a concentration above the upper explosive limit (UEL) is not an explosivegas atmosphere, it can readily become so and, in certain cases for area classification purposes, it is advisable toconsider it as an explosive gas atmosphere.2.3hazardous areaarea in which an explosive gas atmosphere is present, or may be expected to be present, inquantities such as to require special precautions for the construction, installation and use ofapparatus[IEV 426-03-01, modified]2.4non-hazardous areaarea in which an explosive gas atmosphere is not expected to be present in quantities suchas to require special precautions for the construction, installation and use of apparatus[IEV 426-03-02, modified]60079-10 © IEC:2002– 6 –
60079-10 IEC:2002 – 13 –2.5zoneshazardous areas are classified into zones based upon the frequency of the occurrence andduration of an explosive gas atmosphere, as follows:2.5.1zone 0place in which an explosive atmosphere consisting of a mixture with air of flammablesubstances in the form of gas, vapour or mist is present continuously or for long periods orfrequently[IEV 426-03-03, modified]2.5.2zone 1place in which an explosive atmosphere consisting of a mixture with air of flammablesubstances in the form of gas, vapour or mist is likely to occur in normal operationoccasionally[IEV 426-03-04, modified]2.5.3zone 2place in which an explosive atmosphere consisting of a mixture with air of flammablesubstances in the form of gas, vapour or mist is not likely to occur in normal operation but, if itdoes occur, will persist for a short period only[IEV 426-03-05, modified]NOTE 1
In this definition, the word "persist" means the total time for which the flammable atmosphere will exist.This will normally comprise the total of the duration of the release, plus the time taken for the flammableatmosphere to disperse after the release has stopped. (The term "persistence time" as used in annex B refersspecifically to only one part of the total time for which the flammable atmosphere will exist.)NOTE 2
Indications of the frequency of the occurrence and duration may be taken from codes relating to specificindustries or applications.2.6source of releasepoint or location from which a flammable gas, vapour, or liquid may be released into theatmosphere in such a way that an explosive gas atmosphere could be formed[IEV 426-03-06, modified]2.7grades of releasethere are three basic grades of release, as listed below in order of decreasing frequency andlikelihood of the explosive gas atmosphere being present:a) continuous grade;b) primary grade;c) secondary grade.A source of release may give rise to any one of these grades of release, or to a combinationof more than one2.7.1continuous grade of releaserelease which is continuous or is expected to occur frequently or for long periods– 7 –60079-10 © IEC:2002
60079-10 IEC:2002 – 15 –2.7.2primary grade of releaserelease which can be expected to occur periodically or occasionally during normal operation2.7.3secondary grade of releaserelease which is not expected to occur in normal operation and, if it does occur, is likely to doso only infrequently and for short periods2.8release ratequantity of flammable gas or vapour emitted per unit time from the source of release2.9normal operationsituation when the equipment is operating within its design parametersNOTE 1
Minor releases of flammable material may be part of normal operation. For example, releases from sealswhich rely on wetting by the fluid which is being pumped are considered to be minor releases.NOTE 2
Failures (such as the breakdown of pump seals, flange gaskets or spillages caused by accidents) whichinvolve urgent repair or shut-down are not considered to be part of normal operation nor are they considered to becatastrophic.NOTE 3
Normal operation includes start-up and shut-down conditions.2.10ventilationmovement of air and its replacement with fresh air due to the effects of wind, temperaturegradients, or artificial means (for example, fans or extractors)2.11explosive limitsNOTE
The terms "explosive limit" and "flammable limit" are equivalent. IEC 60079-20 and IEC 61779-1 use theterm "flammable limit" whilst all the other standards use the more widely accepted term "explosive limit".2.11.1lower explosive limit (LEL)concentration of flammable gas or vapour in air, below which the gas atmosphere is notexplosive[IEV 426-02-09, modified]2.11.2upper explosive limit (UEL)concentration of flammable gas or vapour in air, above which the gas atmosphere is notexplosive[IEV 426-02-10, modified]2.12relative density of a gas or a vapourdensity of a gas or a vapour relative to the density of air at the same pressure and at thesame temperature (air is equal to 1,0)60079-10 © IEC:2002– 8 –
60079-10 IEC:2002 – 17 –2.13flammable material (flammable substance)material which is flammable of itself, or is capable of producing a flammable gas, vapour ormist2.14flammable liquidliquid capable of producing a flammable vapour under any foreseeable operating conditions2.15flammable gas or vapourgas or vapour which, when mixed with air in certain proportions, will form an explosive gasatmosphere2.16flammable mistdroplets of flammable liquid, dispersed in air so as to form an explosive atmosphere2.17flashpointlowest liquid temperature at which, under certain standardized conditions, a liquid gives offvapours in a quantity such as to be capable of forming an ignitable vapour/air mixture[IEV 426-02-14]2.18boiling pointtemperature of a liquid boiling at an ambient pressure of 101,3 kPa (1 013 mbar)NOTE
The initial boiling point that should be used for liquid mixtures is to indicate the lowest value of the boilingpoint for the range of liquids present, as determined in a standard laboratory distillation without fractionation.2.19vapour pressurepressure exerted when a solid or liquid is in equilibrium with its own vapour. It is a function ofthe substance and of the temperature2.20ignition temperature of an explosive gas atmospherelowest temperature of a heated surface at which, under specified conditions, the ignition of aflammable substance in the form of a gas or vapour mixture with air will occur[IEV 426-02-01, modified]NOTE
IEC 60079-4 and IEC 60079-4A standardize a method for the determination of this temperature.2.21extent of zonedistance in any direction from the source of release to the point where the gas/air mixture hasbeen diluted by air to a value below the lower explosive limit2.22liquefied flammable gasflammable material which is stored or handled as a liquid and which at ambient temperatureand atmospheric pressure is a flammable gas– 9 –60079-10 © IEC:2002
60079-10 IEC:2002 – 19 –3 Safety and area classification3.1 Safety principlesInstallations in which flammable materials are handled or stored should be designed, operatedand maintained so that any releases of flammable material, and consequently the extent ofhazardous areas, are kept to a minimum, whether in normal operation or otherwise, withregard to frequency, duration and quantity.It is important to examine those parts of process equipment and systems from which releaseof flammable material may arise and to consider modifying the design to minimize thelikelihood and frequency of such releases and the quantity and rate of release of material.These fundamental considerations should be examined at an early stage of the designdevelopment of any process plant and should also receive prime attention in carrying out thearea classification study.In the case of maintenance activities other than those of normal operation, the extent of thezone may be affected but it is expected that this would be dealt with by a permit-to-worksystem.In a situation in which there may be an explosive gas atmosphere, the following steps shouldbe taken:a)eliminate the likelihood of an explosive gas atmosphere occurring around the source ofignition, orb)eliminate the source of ignition.Where this is not possible, protective measures, process equipment, systems and proceduresshould be selected and prepared so the likelihood of the coincidence of a) and b) is so smallas to be acceptable. Such measures may be used singly, if they are recognized as beinghighly reliable, or in combination to achieve an equivalent level of safety.3.2 Area classification objectivesArea classification is a method of analysing and classifying the environment where explosivegas atmospheres may occur so as to facilitate the proper selection and installation of appa-ratus to be used safely in that environment, taking into account gas groups and temperatureclasses.In most practical situations where flammable materials are used, it is difficult to ensure that anexplosive gas atmosphere will never occur. It may also be difficult to ensure that apparatuswill never give rise to a source of ignition. Therefore, in situations where an explosive gasatmosphere has a high likelihood of occurring, reliance is placed on using apparatus whichhas a low likelihood of creating a source of ignition. Conversely, where the likelihood of anexplosive gas atmosphere occurring is reduced, apparatus constructed to a less rigorousstandard may be used.It is rarely possible by a simple examination of a plant or plant design to decide which parts ofthe plant can be equated to the three zonal definitions (zones 0, 1 and 2). A more detailedapproach is therefore necessary and this involves the analysis of the basic possibility of anexplosive gas atmosphere occurring.60079-10 © IEC:2002– 10 –
60079-10 IEC:2002 – 21 –The first step is to assess the likelihood of this, in accordance with the definitions of zone 0,zone 1 and zone 2. Once the likely frequency and duration of release (and hence the grade ofrelease), the release rate, concentration, velocity, ventilation and other factors which affectthe type and/or extent of the zone have been determined, there is then a firm basis on whichto determine the likely presence of an explosive gas atmosphere in the surrounding areas.This approach therefore requires detailed consideration to be given to each item of processequipment which contains a flammable material, and which could therefore be a source ofrelease.In particular, zone 0 or zone 1 areas should be minimized in number and extent by design orsuitable operating procedures. In other words, plants and installations should be mainlyzone 2 or non-hazardous. Where release of flammable material is unavoidable, processequipment items should be limited to those which give secondary grade releases or, failingthis (that is where primary or continuous grade releases are unavoidable), the releases shouldbe of very limited quantity and rate. In carrying out area classification, these principles shouldreceive prime consideration. Where necessary, the design, operation and location of processequipment should ensure that, even when it is operating abnormally, the amount of flammablematerial released into the atmosphere is minimized, so as to reduce the extent of thehazardous area.Once a plant has been classified and all necessary records made, it is important that nomodification to equipment or operating procedures is made without discussion with thoseresponsible for the area classification. Unauthorized action may invalidate the areaclassification. It is necessary to ensure that all equipment affecting the area classificationwhich has been subjected to maintenance is carefully checked during and after re-assemblyto ensure that the integrity of the original design, as it affects safety, has been maintainedbefore it is returned to service.4 Area classification procedure4.1 GeneralThe area classification should be carried out by those who have knowledge of the propertiesof flammable materials, the process and the equipment, in consultation, as appropriate, withsafety, electrical, mechanical and other engineering personnel.The following subclauses give guidance on the procedure for classifying areas in which theremay be an explosive gas atmosphere and on the extent of zones 0, 1 and 2. An example of aschematic approach to the classification of hazardous areas is given in figure C.1.The area classification should be carried out when the initial process and instrumentation linediagrams and initial layout plans are available and confirmed before plant start-up. Reviewsshould be carried out during the life of the plant.– 11 –60079-10 © IEC:2002
60079-10 IEC:2002 – 23 –4.2 Sources of releaseThe basic elemen
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