IEC_TR_60079-20-1996_scan.pdf

RAPPORTCEITECHNIQUE TYPE 3IECTECHNICAL79-20REPORT TYPE 3Premiere editionFirst edition1996-10Materiel electrique pour atmospheresexplosives gazeusesPartie 20:Donnees pour gaz et vapeurs inflammables,en relation avec lutilisation des materielselectriquesElectrical apparatus for explosivegas atmospheres-Part 20:Data for flammable gases and vapours,relating to the use of electrical apparatusCEI 1996 Droits de reproduction reserves-Copyright-all rights reservedAucune partie de cette publication ne peut tre reproduite niNo part of this publication may be reproduced or utilizedtilise sous quelque forme que ce soit et par aucun procede.in any form or by any means,electonic or mechanical.lectronique ou mcanique.y compris la photocopie ot lesincluding photooopying and microlilm.without permissionmicrofiims,sans Paccord dcrit de ledtourin writing from the publisherBureau central de la Commission Electrotechnique Intemationale 3,rue de Varembe Geneve SuisseCommission Electrotechnique InternationaleCODE PRIXPRICE CODETInternational Electrotechnical CommissionMexayHapoAHan 3neKTPOTexHHecKan HoMHCCHA三Pour prix,voir catalogue en vigueurFor price.see current catalogue步dVoL.q79-201EC:1996-3-CONTENTSPageFOREWORD.ClauseScope2 General.93 Determination of the properties.04 Properties of particular gases and vapours.95 Reference documents.1313Tables1 Flammability data.2 Minimum igniting current.1642Annex A-Bibliography.44579-201EC:1996-5INTERNATIONAL ELECTROTECHNICAL COMMISSIONELECTRICAL APPARATUS FOR EXPLOSIVEGAS ATMOSPHERESPart 20:Data for flammable gases and vapours,relating to the use of electrical apparatusFOREWORD1)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 International Organizationfor Standardization(ISO)in accordance with conditions determined by agreement between the twoorganizations.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 reports or guides and they are accepted by the National Comrittees 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.The main task of IEC technical committees is to prepare International Standards.Inexceptional circumstances,a technical committee may propose the publication of a technicalreport of one of the following types:type 1,when the required support cannot be obtained for the publication of anInternational Standard,despite repeated efforts;type 2,when the subject is still under technical development or where for any otherreason there is the future but no immediate possibility of an agreement on an InternationalStandard;type 3,when a technical committee has collected data of a different kind from thatwhich is normally published as an International Standard,for example state of the art.Technical reports of types 1 and 2 are subject to review within three years of publication todecide whether they can be transformed into International Standards.Technical reports oftype 3 do not necessarily have to be reviewed until the data they provide are considered to beno longer valid or useful.IEC 79-20,which is a technical report of type 3,has been prepared by technical committee 31:Electrical apparatus for explosive atmospheres.79-20IEC:1996-7-The text of this technical report is based is based on the following documents:Committee draftReport on voting31/195/CDV31/211/RVCFull information on the voting for the approval of this technical report can be found in the reporton voting indicated in the above table.This report is a Technical Report of type 3 and is of a purely informative nature.It is not to beregarded as an International Standard.0079-201EC:1996-9ELECTRICAL APPARATUS FOR EXPLOSIVEGAS ATMOSPHERESPart 20:Data for flammable gases and vapours,relating to the use of electrical apparatus1 ScopeThis technical report gives guidance on the selection of appropriate electrical apparatus,protected by flame-proof enclosure or designed to be intrinsically safe,according to the gas orvapour in which it is intended to be used.2 GeneralTables of chemical and engineering properties of substances are provided to assist electricalengineers in their selection of electrical apparatus to be used in hazardous areas.The scope of these data has been selected with particular reference to the use of electricalequipment in hazardous areas,and notice has been taken of standard measurement methodsgiven in IEC 79-1A,IEC 79-3,IEC 79-4 and IEC 79-4A.NOTES1 The data in this report have been taken from a number of references which are given in the bibliography(see annex A).2 Some variations in the data may appear when references are compared,but usually the discrepancy issufficiently small to be of no importance in the selection of electrical apparatus.Users of the data in this report should be aware that all its data are the result of experimentaldeterminations,and as such are influenced by variation in experimental apparatus andprocedures,and in the accuracy of instrumentation.In particular,some of the data have beendetermined at temperatures above ambient temperature,so that the vapour is within theflammable range.Variation in the temperature for the determination would be expected toinfluence the result of the determination;for example:lower flammability limits and maximumexperimental safe gap decrease with increasing temperature and/or pressure;upperflammability limits increase with increasing temperature and/or pressure.Data are subject torevision and,where more recent information is required,the use of a maintained database1)isrecommended.3 Determination of the properties3.1 GeneralThe compounds listed in this technical report are in accordance with IEC 79-12,or have beenthe subject of a determination of maximum experimental safe gap(MESG),or have physicalproperties similar to those of other compounds in that list.1)For information on the availability of maintained databases refer to annex A.