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BRITISH STANDARDBS EN 12953-6:2002Shell boilers Part 6:Requirements for equipment for the boilerThe European Standard EN 12953-6:2002 has the status of a British StandardICS 27.060.30;27.100NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWLicensed Copy:Institute Of Technology Tallaght,Institute of Technology,Tue May 15 11:08:41 GMT+00:00 2007,Uncontrolled Copy,(c)BSIBS EN 12953-6:2002This British Standard,having been prepared under the direction of the Engineering Sector Policy and Strategy Committee,was published under the authority of the Standards Policy and Strategy Committee on 14 June 2002 BSI 14 June 2002ISBN 0 580 39848 XNational forewordThis British Standard is the official English language version of EN 12953-6:2002.It partially supersedes BS 2790:1992 which will be withdrawn on publication of BS EN 12953 Parts 1,2,3,4,5,6,8 and 9.When the reference to this European Standard has been published in the Official Journal of the European Communities(OJ),compliance with it will confer a presumption of conformity with the essential requirements covered by the standard in respect of the Pressure Equipment Directive.The UK participation in its preparation was entrusted to Technical Committee PVE/16,Shell boilers,which has the responsibility to:A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled“International Standards Correspondence Index”,or by using the“Search”facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract.Users of this publication are responsible for their correct application.Compliance with a British Standard does not of itself confer immunity from legal obligations.aid enquirers to understand the text;present to the responsible international/European committee any enquiries on the interpretation,or proposals for change,and keep the UK interests informed;monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover,an inside front cover,the EN title page,pages 2 to 32,an inside back cover and a back cover.The BSI copyright date displayed in this document indicates when thedocument was last issued.Amendments issued since publicationAmd.No.DateCommentsLicensed Copy:Institute Of Technology Tallaght,Institute of Technology,Tue May 15 11:08:41 GMT+00:00 2007,Uncontrolled Copy,(c)BSIEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12953-6May 2002ICS 27.060.30;27.100English versionShell boilers-Part 6:Requirements for equipment for the boilerChaudires tubes de fume-Partie 6:Exigences pourlquipement de la chaudireGrowasserraumkessel-Teil 6:Anforderungen an dieAusrstung fr den KesselThis European Standard was approved by CEN on 15 May 2002.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration.Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions(English,French,German).A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria,Belgium,Czech Republic,Denmark,Finland,France,Germany,Greece,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Spain,Sweden,Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre:rue de Stassart,36 B-1050 Brussels 2002 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref.No.EN 12953-6:2002 ELicensed Copy:Institute Of Technology Tallaght,Institute of Technology,Tue May 15 11:08:41 GMT+00:00 2007,Uncontrolled Copy,(c)BSIEN 12953-6:2002(E)2ContentspageForeword.31Scope.42Normative references.43Definitions.44General requirements for steam and hot water generators.54.1Safeguards against excessive pressure.54.2Materials for valves,fittings,flanges and bolting.54.3Limiting devices and safety circuits.54.4Temperature measurement of the furnace wall.54.5Boiler heat supply.54.6Flue-gas heated economizers.65Special requirements for steam boilers.65.1Water level indication.65.2Steam pressure and temperature indication.75.3Drain and blowdown devices.85.4Valves for connections.85.5Feed water supply.95.6Feed water control.95.7Limiting devices.95.8Heat supply.95.9Electrically-heated boilers.96Special requirements for hot water generators.106.1Hot water generating systems(for example see annex A).106.2Expansion and feed lines for open vented systems.106.3Water supply.116.4Circulating pumps.116.5Drain devices.116.6Water level indication.126.7Water supply control.126.8Limiting devices.126.9Vent valves.136.10Steam pressure and temperature indication.136.11Pressure controller.136.12Discharge from safety valves.136.13Heat supply.146.14Electrically heated hot water generators.146.15Parallel mode of operation of hot water generators.146.16Safety equipment for hot water generators.147Small shell boilers.177.1Steam boilers.177.2Hot water generators.17Annex A(informative)Design examples for hot water generating systems.18Annex B(normative)Dimensioning of Expansion Space.28Annex C(informative)Operational aspects.31Annex ZA(informative)Clauses of this European Standard addressing essential requirements or otherprovisions of EU Directives.32Licensed Copy:Institute Of Technology Tallaght,Institute of Technology,Tue May 15 11:08:41 GMT+00:00 2007,Uncontrolled Copy,(c)BSIEN 12953-6:2002(E)3ForewordThis document(EN 12953-6:2002)has been prepared by Technical Committee CEN/TC 269 Shell and water-tubeboilers,the secretariat of which is held by DIN.This European Standard has been prepared under a mandate given to CEN by the European Commission and theEuropean Free Trade Association,and supports essential requirements of EU Directive(s).For relationship with EU Directive(s),see informative Annex ZA,which is an integral part of this standard.This European Standard shall be given the status of a national standard,either by publication of an identical text orby endorsement,at the latest by November 2002,and conflicting national standards shall be withdrawn at the latestby November 2002.The European Standard EN 12953 concerning shell boilers consists of the following Parts:?Part 1:General.?Part 2:Materials for pressure parts of boilers and accessories.?Part 3:Design and calculation for pressure parts.?Part 4:Workmanship and construction of pressure parts of the boiler.?Part 5:Inspection during construction,documentation and marking of pressure parts of the boiler.?Part 6:Requirements for equipment for the boiler.?Part 7:Requirements for firing systems for liquid and gaseous fuels for the boiler.?Part 8:Requirements for safeguards against excessive pressure.?Part 9:Requirements for limiting devices of the boiler and accessories.?Part 10:Requirements for boiler feedwater and boiler water quality.?Part 11:Acceptance tests.?Part 12:Requirements for firing systems for solid fuels for the boiler.?Part 13:Operating instructions.CR 12953-14:Guidelines for the involvement of an inspection body independent of the manufacturer.Although these Parts can be obtained separately,it should be recognized that the Parts are inter-dependent.Assuch,the design and manufacture of shell boilers requires the application of more than one Part in order for therequirements of the standard to be satisfactorily fulfilled.Annex A is normative and Annexes B and C are informative.According to the CEN/CENELEC Internal Regulations,the national standards organizations of the followingcountries are bound to implement this European Standard:Austria,Belgium,Czech Republic,Denmark,Finland,France,Germany,Greece,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Spain,Sweden,Switzerland and the United Kingdom.Licensed Copy:Institute Of Technology Tallaght,Institute of Technology,Tue May 15 11:08:41 GMT+00:00 2007,Uncontrolled Copy,(c)BSIEN 12953-6:2002(E)41 ScopeThis Part of this European Standard specifies requirements for safety related equipment for shell boilers as definedin EN 12953-1,irrespective of the degree of supervisions.2 Normative referencesThis European Standard incorporates by dated or undated reference,provisions from other publications.Thesenormative references are cited at the appropriate places in the text,and the publications are listed hereafter.Fordated references,subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision.For undated references the latest edition of thepublication referred to applies(including amendments).EN 12953-1,Shell boilers-Part 1:General.EN 12953-2,Shell boilers-Part 2:Materials for pressure parts of boilers and accessories.EN 12953-3:2002,Shell boilers-Part 3:Design and calculation for pressure parts.EN 12953-8:2001,Shell boilers-Part 8:Requirements for safeguards against excessive pressure.prEN 12953-9,Shell boilers-Part 9:Requirements for limiting devices and safety circuits of the boiler andaccessories.prEN 50156-1,Electrical equipment for furnaces and ancillary equipment-Part 1:Requirements for applicationdesign and installation.3 Terms and definitionsFor the purposes of this Part of this European Standard,the terms and definitions given in EN 12953-1 apply inaddition to the following.3.1controlsdevices used for maintaining the variable to be controlled(e.g.water level,pressure,temperature)at a specificvalue(set point)3.2limitersdevice that,on reaching a fixed value(e.g.pressure,temperature,flow,water level)is used to interrupt and lock-out the energy supply and lock-out requires manual unlocking before restart3.3independentability to function as required without dependence upon other equipment3.4lock-outisolation of energy supply which requires a manual intervention to reinstate3.5functional checktesting of the safety device to ensure it performs its intended function3.6electrically heated boilersboilers in which water is heated by an electric current flowing between electrodes or by immersion heatersLicensed Copy:Institute Of Technology Tallaght,Institute of Technology,Tue May 15 11:08:41 GMT+00:00 2007,Uncontrolled Copy,(c)BSIEN 12953-6:2002(E)53.7expansion vessels and tankscontainers to compensate for temperature dependent volume changes of the water?expansion vessels are pressurised?expansion tanks are not pressurised3.8allowable heat output of a hot water generatormaximum heat output(water mass flow times the difference between outlet and inlet enthalpy)that can be gener-ated during continuous operation and at which hot water generators can be operated3.9allowable flow temperaturehighest temperature,measured at the outlet branch at which the hot water generator can be operated(see 6.8.2.3)3.10maximum continuous rating(MCR)maximum continuous steam output that can be generated during continuous operation taking the specified steamcondition into consideration4 General requirements for steam boilers and hot water generators4.1 Safeguards against excessive pressureEach steam boiler and hot water generator,except open vented hot water generators,shall be equipped withsafeguards against excessive pressure in accordance with EN 12953-8.4.2 Materials for valves,fittings,flanges and boltingThe conditions and requirements to select the material shall be in accordance with EN 12953-2.4.3 Limiting devices and safety circuits4.3.1All limiters and their installation shall be designed in accordance with prEN 12953-9.The electrical safetycircuits shall be in accordance with prEN 50156-1:1999,Table 1 and Annex B.4.3.2Functional checking of all limiters shall be possible at any time during operation e.g.by simulation whereappropriate.4.3.3If a limiter responds,a signal shall be given to indicate the reasons for boiler/generator malfunction.4.3.4After lock out,it shall only be possible to manually restart the boiler/generator from the boiler house.4.4 Temperature measurement of the furnace wallIf in accordance with EN 12953-3:2002,5.4 it is established that temperature measurement of the furnace wall isnecessary,the temperature signal shall be transmitted to a temperature limiter.The limiting temperature shall bedetermined by the manufacturer.4.5 Heat supply4.5.1The heat supply shall be automatically controlled in relation to heat demand and the combustion processshall be completed within the furnace.In the event of shutdown,residual heat shall not cause unacceptable metaltemperatures(e.g.by evaporation of the water).Licensed Copy:Institute Of Technology Tallaght,Institute of Technology,Tue May 15 11:08:41 GMT+00:00 2007,Uncontrolled Copy,(c)BSIEN 12953-6:2002(E)64.5.2The design of the heat supply system and the boiler/generator shall ensure that no excessive evaporationof the water inside the boiler/generator occurs due to the heat accumulation in the combustion chamber and in theboiler/generator passes upon cut off of the heat supply.NOTEThis requirement is deemed to have been met for oil and gas firing systems:?if it is proved that,after switching off the heat supply system from full load steady state condition,the flue gas temperatureat the highest point of the heated surface(HHS)falls to a value below 400?C before the water level has sunk from thelowest water level(LWL)to 50 mm above the highest point of the heated surface(HHS),or?if adequate feed water is ensured(see 5.5).4.5.3Automatic start-up of the boiler/generator and the system shall be permitted provided that equipment isinstalled to ensure that start-up is conducted safely.Automatic restarting after normal shut-down shall not be con-sidered as a start-up.4.6 Flue-gas heated economizersEconomizers shall be fitted with a temperature indicating device on the water outlet,and each economizer that canbe isolated,shall be provided with a pressure gauge in addition to the safety pressure relief device(seeEN 12953-8:2001,4.1.4).5 Special requirements for steam boilers5.1 Water level indication5.1.1Each steam boiler,except for low pressure boilers,shall have at least two independent means of indicatingthe water level,one of which shall be a gauge of transparent material directly connected to the boiler shell.Theother device may be a remote water level indicator or alternate device.For low pressure boilers only one direct water level indicator shall be required.5.1.2The gauge(s)of transparent materia