IEC_60364-4-482-1982_scan.pdf

5COMMISSION ELECTROTECHNIQUE INTERNATIONALENORME DE LA CEIINTERNATIONAL ELECTROTECHNICAL COMMISSIONIEC STANDARDPublication 364-4-482Premiere edition-First edition1982Installations electriques des batimentsQuatrieme partie:Protection pour assurer la securiteChapitre 48:Cholx des mesures de protection en fonction des influences externesSection 482-Protection contre lincendieElectrical installations of buildingsPart 4:Protection for safetyChapter 48:Choice of protective measures as a function of external influencesSection 482-Protection against fireCCE1 1982Droits de reproduction reserves-Copyright-all rights reservedAucune partie de cette publication ne peut tre reproduite ni utilise sous No part of this publication may be reproduced or utlized in anyquelque forme que ce soit et par aucun procede,lectronique ou mca-form or by any means,electronic or mechanical,including photocopyingnique,y compris la photocopie et les microfims,sans Iaccord crit de lediteur.and microfilm,without pernision in writing from the publisher.Bureau Central de la Commission Electrotechnique Internationale3,rue de VarembeGeneve,Suisse能16-IEcVoL 12,364-4-482IEC1982一3INTERNATIONAL ELECTROTECHNICAL COMMISSIONELECTRICAL INSTALLATIONS OF BUILDINGSPart 4:Protection for safetyChapter 48:Choice of protective measures as a functionof external influencesSection 482-Protection against fireFOREWORD1)The formal decisions or agreements of the IECon technical matters,prepared by Technical Committees on which all theNational Committees having a special interest therein are represented,express,as nearly as possible,an internationalconsensus of opinion on the subjects dealt with.2)They have the form of recommendations for international use and they are accepted by the National Committees in thatsense.3)In order to promote international unification,the IECexpresses the wish that all National Committees should adopt thetext of the I E C recommendation for their national rules in so far as national conditions will permit.Any divergencebetween the IE C recommendation and the corresponding national rules should,as far as possible,be clearly indicated inthe latter.PREFACEThis standard has been prepared by IEC Technical Committee No.64:Electrical Installations ofBuildings.A draft of this standard was discussed at the meeting held in Pretoria in 1980.As a result of thismeeting,a draft,Document 64(Central Office)112,was submitted to the National Committees forapproval under the Six MonthsRule in March 1981.The National Committees of the following countries voted explicitly in favour of publication:AustraliaJapanAustriaNetherlandsCanadaPolandDenmarkSwitzerlandEgyptUnited States of AmericaFranceOther IEC publications quoted in this standard:Publications Nos.332-1:Tests on Electric Cables under Fire Conditions,Part 1:Test on a Single Vertical InsulatedWire or Cable.364-3:Electrical Installations of Buildings,Part 3:Assessment of General Characteristics.364-4-41:Part 4:Protection for Safety,Chapter 41:Protection against Electric Shock.364-4-482IEC19825-ELECTRICAL INSTALLATIONS OF BUILDINGSPart 4:Protection for safetyChapter 48:Choice of protective measures as a functionof external influencesSection 482-Protection against fire482.PROTECTION AGAINST FIRE482.0 GeneralThe requirements of this section shall be observed in addition to those of Chapter 42 forinstallations in locations where the following conditions of external influences exist.482.1 Conditions of evacuation in an emergency(Influences BD2:Low density occupation,difficult conditions of evacuationBD3:High density occupation,easy conditions of evacuationBD4:High density occupation,difficult conditions of evacuationaccording to Clause 322.4.)Note.-Conditions BD may be regulated by authorities responsible for building construction,public gatherings,fireprevention.482.1.1 In conditions BD2,BD3 and BD4,wiring systems shall preferably not encroach on escaperoutes,but if such encroachment is unavoidable,the wiring shall be provided with sheaths orenclosures which will not contribute to or propagate a fire or attain a temperature high enoughto ignite adjacent material,during the time authorized by regulations for building elements ofthe escape route or for 2 h in the absence of such regulation.Note.-Corresponding test conditions are under consideration.Wiring systems encroaching on escape routes shall not be within arms reach or shall beprovided with protection against mechanical damage likely to occur during an evacuation.Anywiring systems in escape routes shall be as short as practicable.482.1.2 In conditions BD3 and BD4,switchgear and controlgear devices,except certain devices tofacilitate evacuation,shall be accessible only to authorized persons.If they are placed inpassages,they shall be enclosed in cabinets or boxes constructed of non-combustible or notreadily combustible material.Note.-Definitions fornon-combustibleand not readily combustibleare under consideration.482.1.3 In conditions BD3 and BD4 and in escape routes,the use of electrical equipmentcontaining flammable liquids is prohibited.Note.-Individual auxiliary capacitors incorporated in apparatus are not subject to this requirement.This exceptionprincipally concerns discharge lamps and capacitors of motor starters.364-4-482IEC19827482.2 Nature of processed or stored materialsCondition BE2:Fire risk(according to Clause 322.5).Notes 1.-Quantities of flammable materials,surface or volume of the locations may be regulated by nationalauthorities.2.-For explosion risks,see IEC Report XXX:Electrical Installations in Explosive Gas Atmospheres(other than Mines)(in preparation).482.2.1Electrical equipment shall be restricted to that necessary to the use of these locations,exceptwiring systems according to Sub-clause 482.2.6.482.2.2 Where it is expected that dust sufficient to cause a fire hazard could accumulate onenclosures of electrical equipment,measures shall be taken to prevent the enclosures fromattaining excessive temperatures.482.2.3 Electrical equipment shall be so selected and erected that its normal temperature rise andforeseeable temperature rise during a fault cannot cause a fire.These arrangements may be effected by the construction of equipment or its conditions ofinstallation.Special measures are not necessary where the temperature of surfaces is unlikely to causecombustion of nearby substances.482.2.4 Switchgear for protection,control and isolation shall be placed outside locations presentingBE2 conditions,unless it is in an enclosure providing a degree of protection appropriate forsuch a location but at least IP4X.482.2.5 Where wiring is not embedded in non-combustible material,precautions shall be taken toensure that the wiring cannot propagate flame.In particular,conductors and cables shall satisfy the test for flame retardance defined byIE C Publication 332-1:Tests on Electric Cables under Fire Conditions,Part 1:Test on aSingle Vertical Insulated Wire or Cable.482.2.6 Wiring systems which traverse these locations but are not necessary to the use of theselocations shall satisfy the following conditions:-the wiring systems are made in accordance with the rules of Sub-clause 482.2.5;they have no connection along the route inside these locations,unless these connections areplaced in a fire-resistant enclosure;they are protected against overcurrent in accordance with the rules of Sub-clause 482.2.11.482.2.7 In forced-air heating installations,the air intake shall be outside locations,where presenceof combustible dust exists.The temperature of the outgoing air shall not be such as to cause fire in the location.482.2.8 Motors,other than light-duty servomotors,which are automatically or remotely controlledor which are not continuously supervised,shall be protected against excessive temperature riseby temperature responsive devices.364-4-482IEC19829482.2.9 Luminaires shall be appropriate for such a location and be provided with enclosuresproviding a degree of protection of at least IP4X.Lamps and elements of lighting apparatus shall be adequately protected in places wheremechanical damage is anticipated,for example,by sufficiently robust plastic covers,grilles orrobust glass covers.These protective devices shall not be fixed on lampholders unless this isforeseen by construction.482.2.10 Where it is necessary to limit the consequences of fault currents in wiring systems from thepoint of view of fire risks,the circuit shall either be:-protected by a residual-current protective device,the rated operating residual current ofwhich does not exceed 0.5 A,ormonitored by a continuous insulation monitoring device which initiates an alarm on theoccurrence of an insulation fault.A bare monitoring conductor which may be a protective conductor,may be incorporated inthe wiring system of the corresponding circuit,unless the wiring system comprises a metallicenclosure connected to the protective conductor.482.2.11 Circuits supplying or traversing BE2 locations shall be protected against overload andagainst short circuits by protective devices located in advance of these locations.482.2.12 Notwithstanding Sub-clause 411.1.3.7,in circuits at safety extra-low voltage,live partsshall be:-either contained in enclosures affording the degree of protection IP2X,or provided with insulation capable of withstanding a test voltage of 500 V for 1 min.regardless of the nominal voltage of the circuit.482.2.13 PEN conductors are not allowed in BE2 locations,except for circuits traversing suchlocations.482.3 Combustible constructional materialsCondition CA2(according to Clause 323.1).482.3.1 Precautions shall be taken to ensure that electrical equipment cannot provoke the ignitionof walls,floors and ceilings.482.4 Fire propagating structuresCondition CB2(according to Clause 323.2).482.4.1 In structures of which the shape and dimensions facilitate the spread of fire,precautionsshall be taken to ensure that the electrical installation cannot propagate a fire(e.g.chimneyeffect).Note.-Fire detectors may be provided which ensure the implementation of measures for preventing propagation offire,for example,the closing of fire-proof shutters in ducts,troughs or trunkings.