A Comparison Of The ASME And European Standards To Achieve .

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A Comparison of the ASME and EuropeanStandards to achieve safe boiler operationProf Stuart CameronConsultant, Doosan BabcockASME Governor Doosan Babcock Limited 2017. Not to be reproduced whether in whole or in part, by any means electronic or otherwise, without the express written permission ofDoosan Babcock Limited.

AbstractBoiler plant designed and manufactured to the ASME and EN Standards haveequivalent levels of safety but have a different approach in terms of the role ofthe Inspecting Body and the technical requirements.ASME tends to focus on the critical safety requirements which is supportedby the technical specifications of the Manufacturer whereas the EN Standardis more prescriptive.An overview comparison of the two Codes will be presented together with anoutline of the proposals for incorporation of a new Part in the ASME Codewhich will be applicable to ultra- supercritical boiler plant.Page 2 Doosan Babcock Limited 2017

Why Me? – My Code BackgroundASMEMember of :Council on Standards and CertificationBoard on Strategic Initiatives for Standards and Certification (Vice Chair)Section I Committee – Power boilersSection I Sub-Group – Fabrication & ExaminationSection II Sub-Group – International Material SpecificationsCommittee on B&PV Conformity AssessmentBSIChairman of : Pressure Equipment Standards Policy CommitteePast Chairman of: BS1113 Committee and UK representative on European BoilerCommitteeISOMember of ISO TC11 – International Standards for Boilers and Pressure vesselsChairman of TC11 WG11 – Conformity Assessment ProcedureLeader of international group of experts to assist ISO secretariatPage 3 Doosan Babcock Limited 2017

Why is there not an ISO Standard ?In an ideal world there would be a single, comprehensive ISO Standard butthis is not the caseMost countries have their own Health & Safety LegislationMain Standards used worldwide tend to be developed by USA (ASME) andEurope (CEN)Other national standards tend to be a derivative of theseCEN completed the development of new EN Standards to comply with thePressure Equipment Directive which took over 10 years.To create an ISO Standard would be a lengthy process mainly due to thedifficulties of achieving the necessary level of compromise among themember countriesThe main reasons for this are the differing approaches historically taken byregulatory authorities, and differences in the underlying design andconstruction philosophies in the various national and regional productstandards.Page 4 Doosan Babcock Limited 2017

Boiler StandardsFor boiler plant we currently have two main StandardsASME Section Ia well established Standard that has been developed overmany yearsEN12952a relatively new European Standard which in the main is anintegration of the best parts of British and German StandardsHow do they compare?Page 5 Doosan Babcock Limited 2017

CE marking has been a feature of EC legislationsince 1987.It indicates a declaration by the Manufacturer thatthe product or system complies with the essentialrequirements of the Directive(s) relevant to thatproduct or system.Member States are required to presumecompliance and therefore the product or systemcan be placed on the market without initialchallenge by the national administrations.Page 6 Doosan Babcock Limited 2017

‘S’ marking has been a feature of US legislationsince 1915.It indicates a declaration by the Manufacturer thatthe product or system complies with the essentialrequirements of the ASME I relevant to thatproduct or system.Regulators are required to presume complianceand therefore the product or system can be‘erected’ on the market without initial challengeby the national administrations.Page 7 Doosan Babcock Limited 2017

ASME BoilerCommittee 1911ASME BPV-I2011Page 8 Doosan Babcock Limited 2017

Committee StructureBoard on PressureTechnologyCodes & StandardsCommitteeSub-GroupSC IPower BoilersGeneralRequirements& PipingSC IIMaterialsMaterialsSC VNDEDesignSC VIIIPressure VesselsPostConstructionFabrication &ExaminationPage 9 Doosan Babcock Limited 2017

Committee StructureBoard on PressureTechnologyCodes & StandardsSC-DDesignDesignAnalysisSafety thopeningsBolted FlangejointsPage 10 Doosan Babcock Limited 2017

Reference StandardsSection IPower BoilersSection IIINuclearSection VIIIPressure VesselsSection IIMaterialsSection VNon-destructiveExaminationSection IXWeldingB31.1PipingPage 11 Doosan Babcock Limited 2017

ASME Section I – Power BoilersContentsPreamblePG – General requirementsPW – Boilers fabricated by weldingPR – Boilers fabricated by Riveting (use 1971 Code)PB – Boilers fabricated by BrazingPWT – watertube boilersPFT – firetube boilersPFH – Optional requirements for feedwater heatersPMB – Miniature boilersPEB – Electric boilersPVG – Organic fluid vapourisersAppendicesInterpretationsCode CasesPage 12

ASME Section I – Power BoilersContentsPreamblePG – General requirementsPW – Boilers fabricated by weldingPR – Boilers fabricated by Riveting (use 1971 Code)PB – Boilers fabricated by BrazingPWT – watertube boilersPFT – firetube boilersPFH – Optional requirements for feedwater heatersPMB – Miniature boilersPEB – Electric boilersPVG – Organic fluid vapourisersAppendicesInterpretationsCode CasesPage 13

ASME Section I PreambleThe Code does not contain rules to cover all details ofdesign and construction. Where complete details are notgiven, it is intended that the manufacturer, subject toacceptance of the Authorised Inspector, shall providedetails of design and construction which will be as safeas otherwise provided by the rules of the Code.In the US this tends to result in most boilers being builtto ASME plus additional requirements of the mainmanufacturers but when the Code is used outwith theUS then the same level of additional requirements maynot necessarily be recognised.Page 14 Doosan Babcock Limited 2017

EN12952 compared to ASME Section I EN12952 was developed to comply with the PressureEquipment Directive (PED) It is more prescriptive and specific than ASME Section Iand in general represents current European workingpractice Being a relatively new Code EN12952 (10 years old) itis very logical and structured ASME Section I has developed over a long period oftime with numerous additions and deletions Involvement by the Notified Body is defined in the PEDand is based on the level of risk of the componentPage 15 Doosan Babcock Limited 2017

ASME and EN12952 – Steady State ConditionsClient additionalrequirementsTotal SpecificationManufacturer’sin- house additionalrequirementsEN12952Client additionalrequirementsManufacturer’sin- house additionalrequirementsASME IPage 16 Doosan Babcock Limited 2017

ASME and EN12952 – High Temperature Cyclic LoadingClient additionalrequirementsClient additionalrequirementsTotal SpecificationManufacturer’sin- house additionalrequirementsManufacturer’sin- house additionalrequirementsShould some oftheserequirements bein Section I?EN12952ASME IPage 17 Doosan Babcock Limited 2017

Example of Additional Requirements Non-destructive examinationASME Section IThe main method of non-destructive examination is still radiographyalthough ultrasonic recently allowedAll longitudinal and circumferential welds above a specified nominaldiameter or thickness are mandatoryThere is no requirement to carry out NDE on welds below these sizes e.g.tube butt welds, or on branch connections or on load carrying attachmentsEuropean Boiler StandardAcceptance criteria for surface imperfections for MT or PT examinationIn general UT is preferred to RT10% RT on tube butt welds to include sample of each welder’s work100% UT on branch connections with thk 1 ½” (10% for less than this)100% MT or PT on load carrying attachmentsSome of these are often incorporated in theManufacturer’s Specification Doosan Babcock Limited 2017Page 18

ASME and EN12952Client additionalrequirementsClient additionalrequirementsTotal SpecificationManufacturer’sin- house additionalrequirementsManufacturer’sin- house additionalrequirementsMonitoredby NotifiedBodyMonitored byManufacturer’sInspector whocan concessEN12952ASME IMonitoredbyAuthorizedInspectorPage 19 Doosan Babcock Limited 2017

ASME and EN12952Client additionalrequirementsClient additionalrequirementsTotal SpecificationManufacturer’sin- house additionalrequirementsManufacturer’sin- house additionalrequirementsThese are additionalcosts which if werein Code would applyto all manufacturersEN12952ASME IPage 20 Doosan Babcock Limited 2017

Contents of EN12952The European boiler standard EN 12952 is in 16 partsFirst 6 parts are mainly equivalent to contents of ASME I1 – General2 – Materials3 – Design4 – In-service boiler life expectancy calculations5 – Workmanship and Construction6 – Inspection, documentation and markingPage 21 Doosan Babcock Limited 2017

EN12952 – 5 Annex F – Competency of Boiler ManufacturersIt is the responsibility of the boiler purchaser to place the order for boilerplant with a competent boiler manufacturer to ensure adequate quality isobtained when the boiler is put in operation in accordance with themanufacturers instructions.Annex F is an informative Annex identifying criteria whereby ajudgement can be made as to the competency of a boiler manufacturer’sorganisation and controls.The principles of ISO 9001 have been used a a basis but is specific toboiler plant and the guidelines include criteria covering design,materials, fabrication, erection, commissioning, examination andinspection.A Competency Declaration Form is completed by the ManufacturerPage 22 Doosan Babcock Limited 2017

EN12952 – 5 Annex F – Competency of Boiler ManufacturersIt is the responsibility of the boiler purchaser to place the order for boilerplant with a competent boiler manufacturer to ensure adequate quality isobtained when the boiler is put in operation in accordance with themanufacturers instructions.Annex F is an informative Annex identifying criteria whereby ajudgement can be made as to the competency of a boiler manufacturer’sorganisation and controls.The principles of ISO 9001 have been used a a basis but is specific toboiler plant and the guidelines include criteria covering design,materials, fabrication, erection, commissioning, examination andinspection.A Competency Declaration Form is completed by the ManufacturerPage 23 Doosan Babcock Limited 2017

Level of Involvement of Inspection BodyFull QA plusLevel of InvolvementDesign examinationNotified BodyFull QAUnexpected visitsAuthorizedInspectorQA of productionSurveillance visitsNo involvementIIIIIILow pressure and smallvolume with safe contentsIVRisk CategoryHigh pressure and large volumewith ‘dangerous’ contents Doosan Babcock Limited 2017Page 24

EN12952 – 3 : Design & Calculation of Pressure PartsGeneral rules for calculating thickness of shells, heads, etcPLUSExemption rules for fatigue analysisStress analysis for fatigue analysisCalculation of stresses in tube bendsFatigue cracking – design to allow fluctuating stressExamples for calculating the effects of fatiguePage 25 Doosan Babcock Limited 2017

General production requirements for weldingThe welding on site of widely differing materials e.g. austenitic to ferriticmaterials should be avoided whenever possible.It is recognized that there may be difficulty in complying strictly with therequirements for the root gap. Minor modifications imposed by practicalconsiderations shall be permitted, providing the manufacturer canensure that the safety of the boiler is not impaired.Temporary attachments to pressure parts should be kept to a minimumand should be removed prior to first pressurization.Particular attention shall be paid to the quality of tack welds and wherenecessary the ends of these shall be dressed to facilitate proper fusion ifthey are to be incorporated into the root run. Any cracked tack weldsshall be completely removed.Again most of these are often incorporated in Manufacturer’s SpecificationPage 26 Doosan Babcock Limited 2017

Membrane welding tolerances – typical sketches Doosan Babcock Limited 2017Page 27

NDE of Header WeldsType of WeldSurfaceVolumetricCircumferential Welds100%100%100%100%15mm thk 25mm (full pen) 100%10%All other welds, incl. seal welds10%-Load carrying100%-Non-load carrying10%-End plate welds100%Pressure connection weldsThk 25mm (full pen)Attachment welds100% (UT) Doosan Babcock Limited 2017Page 28

EN12952 – Part 4 :In-service boiler life expectancy calculationsUnique to international boiler CodesInformative Annexes of calculation of creep and fatigue damage basedon German methodologyThe calculations are not required to be carried out by the manufactureras part of his responsibilities within EN12952The calculations may be carried out using transposed design equationsusing the measured wall thickness .The results may be used as a guideline for the decision to inspect acomponent for fatigue cracks or to inspect for creep pores by the replicamethod or any other suitable method.Page 29 Doosan Babcock Limited 2017

Standards for ultra super-critical boiler plantEN12952 meets the requirements for new plantoperating in cyclic mode but doesn’t cover creep fatigueinteraction at the design stageASME are developing a new Part’ to ASME Section I tocover a similar scope to EN12952.Page 30 Doosan Babcock Limited 2017

Evaluation of Needs of a new Part for ASME Section I’In general Section I was originally developed for industrial boilers through tosub-critical boilers operating at relatively low temperatures and pressuresunder steady state conditions.Current and future boilers operate at higher temperatures and pressures undercyclic loading require a more detailed assessment and examination to:allow Design By Analysis with associated other requirementsdevelop a sensible approach to creep-fatigue interactiondefine the extent of NDE and corresponding accep

The European boiler standard EN 12952 is in 16 parts First 6 parts are mainly equivalent to contents of ASME I 1 – General 2 – Materials 3 – Design 4 – In-service boiler life expectancy calculations 5 – Workmanship and Construction 6 – Inspection, documentation and marking.