Water-tube boilers and auxiliary installations - Part 3: Design and calculation for pressure parts of the boiler

This European Standard specifies the requirements for the design and calculation of water-tube boilers as defined in EN 12952-1.
The purpose of this European Standard is to ensure that the hazards associated with water-tube boilers are reduced to a minimum by the proper application of the design according to this part of EN 12952.

Wasserrohrkessel und Anlagenkomponenten - Teil 3: Konstruktion und Berechnung für drucktragende Kesselteile

Diese Europäische Norm legt Anforderungen an die Konstruktion und Berechnung von Wasserrohrkesseln
nach der Definition in EN 12952-1 fest.
Durch die sachgemäße Konstruktion nach diesem Teil der Europäischen Norm EN 12952 wird sichergestellt,
dass die Gefahren, die mit Wasserrohrkesseln einhergehen auf ein Minimum reduziert werden.

Chaudières à tubes d'eau et installations auxiliaires - Partie 3: Conception et calcul des parties sous pression de la chaudière

La présente Norme européenne spécifie les règles de conception et de calcul des chaudières à tubes d'eau
telles que définies dans l'EN 12952-1.
L’objet de la présente Norme européenne est d’assurer que les phénomènes dangereux associés aux
chaudières à tubes d’eau sont réduits au minimum par l’application appropriée des exigences de conception
de la présente partie de l’EN 12952.

Vodocevni kotli in pomožne napeljave - 3. del: Konstruiranje in izračun tlačno obremenjenih delov

Ta evropski standard določa zahteve za konstruiranje in izračun vodocevnih kotlov iz standarda EN 12952-1. Namen tega evropskega standarda je zagotoviti, da se nevarnosti, povezane z vodocevnimi kotli, čim bolj zmanjšajo s pravilnim konstruiranjem v skladu s tem delom standarda EN 12952.

General Information

Status
Withdrawn
Publication Date
20-Dec-2011
Withdrawal Date
01-Nov-2022
Current Stage
9960 - Withdrawal effective - Withdrawal
Completion Date
02-Nov-2022

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Wasserrohrkessel und Anlagenkomponenten - Teil 3: Konstruktion und Berechnung für drucktragende TeileChaudières à tubes d'eau et installations auxiliaires - Partie 3: Conception et calcul des parties sous pressionWater-tube boilers and auxiliary installations - Part 3: Design and calculation for pressure parts27.060.30Grelniki vode in prenosniki toploteBoilers and heat exchangersICS:Ta slovenski standard je istoveten z:EN 12952-3:2011SIST EN 12952-3:2012en,fr,de01-maj-2012SIST EN 12952-3:2012SLOVENSKI

STANDARDSIST EN 12952-3:20021DGRPHãþD
SIST EN 12952-3:2012
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12952-3
December 2011 ICS 27.040 Supersedes EN 12952-3:2001English Version

Water-tube boilers and auxiliary installations - Part 3: Design and calculation for pressure parts of the boiler

Chaudières à tubes d'eau et installations auxiliaires - Partie 3: Conception et calcul des parties sous pression de la chaudière

Wasserrohrkessel und Anlagenkomponenten - Teil 3: Konstruktion und Berechnung für drucktragende KesselteileThis European Standard was approved by CEN on 26 November 2011.

CEN 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 CEN-CENELEC 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 translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,

B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12952-3:2011: ESIST EN 12952-3:2012

EN 12952-3:2011 (E) 2 Contents Page Foreword ..............................................................................................................................................................41Scope ......................................................................................................................................................62Normative references ............................................................................................................................63Terms and definitions ...........................................................................................................................64Symbols and abbreviations ..................................................................................................................75General ....................................................................................................................................................75.1Purpose ...................................................................................................................................................75.2Dimensions of pressure parts ..............................................................................................................75.3Strength of pressure parts ....................................................................................................................85.4Design by analysis.................................................................................................................................85.5Cyclic loading .........................................................................................................................................85.6Other design requirements ...................................................................................................................95.7Design, calculation and test pressures ............................................................................................ 105.8Metal wastage ...................................................................................................................................... 125.9Attachment on pressure parts ........................................................................................................... 136Calculation temperature and nominal design stress ...................................................................... 136.1Calculation temperature ..................................................................................................................... 136.2Maximum through-the-wall temperature difference and maximum flue gas temperature for heated drums and headers ................................................................................................................ 186.3Design stress ...................................................................................................................................... 187Cylindrical shells of drums and headers under internal pressure ................................................ 227.1Shell thickness .................................................................................................................................... 227.2Basic calculation................................................................................................................................. 237.3Combined stress in drum or header shells ...................................................................................... 237.4Boiler drum supports ......................................................................................................................... 277.5Other stresses in cylindrical shells .................................................................................................. 278Openings and branches in cylindrical shells of drums and headers and integral tubes ........... 278.1General ................................................................................................................................................. 278.2Efficiency factor, calculation by way of approximation, and maximum diameter of unreinforced openings ....................................................................................................................... 358.3Design of openings and branches in cylindrical shells (efficiency and reinforcement) ............. 388.4Bolted connections............................................................................................................................. 488.5Screwed and socket welded connections ........................................................................................ 559Headers and plain tubes of rectangular section ............................................................................. 579.1General ................................................................................................................................................. 579.2Symbols and abbreviations ............................................................................................................... 599.3Required wall thickness ..................................................................................................................... 6010Ends and spherical shells .................................................................................................................. 6310.1Symbols and abbreviations ............................................................................................................... 6310.2Spherical shells and dished heads ................................................................................................... 6310.3Unstayed flat ends .............................................................................................................................. 7210.4Flat unstayed closures ....................................................................................................................... 7811Tubes ................................................................................................................................................... 8011.1Symbols and abbreviations ............................................................................................................... 8011.2Thickness of straight boiler tubes .................................................................................................... 8011.3Thickness of tube bends and elbows ............................................................................................... 82SIST EN 12952-3:2012

EN 12952-3:2011 (E) 3 11.4Flexibility of integral tubing systems ................................................................................................ 8411.5Structural attachments to tubes ........................................................................................................ 8411.6Fitting and joining of heated tubes .................................................................................................... 8911.7Joining of unheated tubes .................................................................................................................. 8912Pressure parts of irregular shape ...................................................................................................... 9012.1Hydrostatic test for determining the allowable internal pressure .................................................. 9012.2Numerical methods ............................................................................................................................. 9113Fatigue .................................................................................................................................................. 9213.1General ................................................................................................................................................. 9213.2Symbols and abbreviations ................................................................................................................ 9313.3Exemption rule for fatigue analysis ................................................................................................... 9513.4Stress analysis for fatigue calculation ............................................................................................ 10513.5Example calculations ........................................................................................................................ 114Annex A (normative)

Calculation of tube bends and elbows ..................................................................... 119Annex B (normative)

Fatigue cracking – Design to allow for fluctuating stress ..................................... 129Annex C (informative)

Examples of calculating the effects of fatigue ...................................................... 145Annex D (informative)

Physical properties of steels ................................................................................... 152Annex E (informative)

Significant technical changes between this European Standard and the previous edition ................................................................................................................................. 162Annex ZA (informative)

Clauses of this European Standard addressing essential safety requirements of the Pressure Equipment Directive 97/23/EC ...................................................... 163Bibliography .................................................................................................................................................... 165 SIST EN 12952-3:2012

EN 12952-3:2011 (E) 4 Foreword This document (EN 12952-3:2011) has been prepared by Technical Committee CEN/TC

269 “Shell and water-tube boilers”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2012, and conflicting national standards shall be withdrawn at the latest by June 2012. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12952-3:2001. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). For relationship with EU Directive 97/23/EC, see informative Annex ZA, which is an integral part of this document. Annex E provides details of significant technical changes between this European Standard and the previous edition. The European Standard series EN 12952 concerning water-tube boilers and auxiliary installations 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 of the boiler;  Part 4: In-service boiler life expectancy calculations;  Part 5: Workmanship and construction of pressure parts of the boiler;  Part 6: Inspection during construction, documentation and marking of pressure parts of the boiler;  Part 7: Requirements for equipment for the boiler;  Part 8: Requirements for firing systems for liquid and gaseous fuels for the boiler;  Part 9: Requirements for firing systems for pulverized solid fuels for the boiler;  Part 10: Requirements for safeguards against excessive pressure;  Part 11: Requirements for limiting devices of the boiler and accessories;  Part 12: Requirements for boiler feedwater and boiler water quality;  Part 13: Requirements for flue gas cleaning systems; SIST EN 12952-3:2012

EN 12952-3:2011 (E) 5  Part 14: Requirements for flue gas DENOX-systems using liquified pressurized ammonia and ammonia water solution;  Part 15: Acceptance tests;  Part 16: Requirements for grate and fluidized-bed firing systems for solid fuels for the boiler;  CR 12952 Part 17: Guideline for the involvement of an inspection body independent of the manufacturer. NOTE 1 A Part 18 on operating instructions is currently in preparation. Although these parts may be obtained separately, it should be recognized that the parts are inter-dependent. As such, the design and manufacture of water-tube boilers requires the application of more than one part in order for the requirements of this European Standard to be satisfactorily fulfilled. NOTE 2 Part 4 and Part 15 are not applicable during the design, construction and installation stages. NOTE 3 A "Boiler Helpdesk" has been established in CEN/TC 269 which may be contacted for any questions regarding the application of European Standards series EN 12952 and EN 12953, see the following website: http://www.boiler-helpdesk.din.de

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 12952-3:2012

EN 12952-3:2011 (E) 6 1 Scope This European Standard specifies the requirements for the design and calculation of water-tube boilers as defined in EN 12952-1. The purpose of this European Standard is to ensure that the hazards associated with water-tube boilers are reduced to a minimum by the proper application of the design according to this part of EN 12952. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1092-1:2007, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN designated — Part 1: Steel flanges EN 1759-1:2004, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, Class designated — Part 1: Steel flanges NPS ½ to 24 EN 10028-1:2007+A1:2009, Flat products made of steels for pressure purposes — Part 1: General requirements EN 10164:2004, Steel products with improved deformation properties perpendicular to the surface of the product — Technical delivery conditions EN 10266:2003, Steel tubes, fittings and structural hollow sections — Symbols and definitions of terms for use in product standards EN 12952-1:2001, Water-tube boilers and auxiliary installations — Part 1: General EN 12952-2:2011, Water-tube boilers and auxiliary installations — Part 2: Materials for pressure parts of boilers and accessories EN 12952-5:2011, Water-tube boilers and auxiliary installations — Part 5: Workmanship and construction of pressure parts of the boiler EN 12952-6:2011, Water-tube boilers and auxiliary installations — Part 6: Inspection during construction; documentation and marking of pressure parts of the boiler EN 12952-12:2003, Water-tube boilers and auxiliary installations — Part 12: Requirements for boiler feedwater and boiler water quality EN 12953-3:2002, Shell boilers — Part 3: Design and calculation for pressure parts EN 13445-3:2009, Unfired pressure vessels — Part 3: Design EN 13480-3:2002, Metallic industrial piping — Part 3: Design and calculation 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12952-1:2001 apply. SIST EN 12952-3:2012

EN 12952-3:2011 (E) 7 4 Symbols and abbreviations For the purposes of this document, the symbols given in EN 12952-1:2001, Table 4-1 apply. Throughout this European Standard, additional terminology and symbols have been included where necessary to meet the requirements of the specific text concerned. 5 General 5.1 Purpose Water-tube boiler pressure parts shall be designed in accordance with the requirements of this European Standard. The resulting designs shall be reproduced in the form of approved drawings and specifications to ensure the proper application of the design requirements during the manufacturing and inspection stages. 5.2 Dimensions of pressure parts The wall thickness and other dimensions of pressure parts sufficient to withstand the calculation pressure at calculation temperature for the design lifetime shall be determined in accordance with this European Standard using materials in accordance with EN 12952-2:2011. The design for loadings arising from the following situations shall also be determined in accordance with this European Standard: a) the bending of a drum or header as a beam under self weight and imposed loads; b) local support loads on drums; c) thermally induced forces and moments within or arising from systems of integral tubing; d) local loading of tubes by structural attachments; e) rapid and frequent changes of pressure and temperature. Methods for calculating stresses caused by external loads applied to nozzles and to attachments shall be in accordance with EN 13445-3:2009. NOTE The purpose of this part is to give specific design rules for common forms of loadings to which boiler parts are normally subjected to and general rules on how other loadings are to be considered. It does not give specific design rules for loadings other than those described in a) to e). These design rules are adequate for boilers of established construction, installed and operated in accordance with the manufacturer's instructions. Determination of the dimensions of pressure parts shall be given special consideration not included in this European Standard, when abnormal conditions are present, such as:  abnormally high corrosive products of combustion;  highly pressurized products of combustion;  poor feedwater. Deviations from the requirements of this European Standard by the use of alternative design methods shall be permitted, provided it can be shown that the adoption of such methods does not impair the safety of the component. A record of all deviations shall be recorded in the manufacturer’s dossier. See also

EN 12952-1:2001, Clause 7. SIST EN 12952-3:2012

EN 12952-3:2011 (E) 8 5.3 Strength of pressure parts The strengths of the pressure parts shall be such as to withstand the following loads: a) internal pressure; b) the weight of all pressure parts and their contents, the weight of components suspended from them and any superimposed slag, fuel, ash or dust; c) loads caused by gas pressure differentials over the boiler furnace and flue gas passes; d) loads arising at connections between the boiler system and other parts. If applicable, the pressure parts shall be adequate to withstand wind and earthquake loads. The conditions applicable for such loads shall be determined by the customer. These determinations shall be considered by the manufacturer under his responsibility. 5.4 Design by analysis It shall be permissible to design by analysis provided the safety and functional requirements of the components are not impaired. The results of any stress calculations carried out for loadings not explicitly covered by equations in this Clause 5 shall be determined by using the criteria given in EN 13445-3:2009. 5.5 Cyclic loading Boiler components are deemed to be exposed to cyclic loading if the boiler is designed for more than 500 cold start-ups. Where cylindrical or spherical pressure parts with openings are subject to cyclic loading, the following calculation for the allowable temperature change rate vt shall be carried out: 2msmssmmot5,0eZendpXv−××−=α (5.5-1) where vt allowable rate of temperature change in K/s; po is the maximum operating pressure; dm is the mean diameter of the shell; ems is the minimum wall thickness; ns = 2 for cylindrical shells or ns = 4 for spherical shells; αm = 4 or if there is any doubt that this value is conservative, the exact value αm for cylindrical shells taken from Figure 13.4-5 or αsp for spherical shells, taken from Figure 13.4-7 shall be used; Xζ=ζ550 N/mm2; Z = 2 K mm4/(Ns) for ferritic steels, or Z = 1 K mm4/(Ns) for austenitic and martensitic steels, or )(1thvE.DZ−−=ttspcyl0,5 (5.5-2) SIST EN 12952-3:2012

EN 12952-3:2011 (E) 9 where exact values Dth, t, E, v may be taken from Annex D, cyl/sp from Figures 13.4-6 or 13.4-9 and αt from Figure 13.4-8. If the result of this calculation is smaller than the required temperature transient at start-up, or if it is negative, then 13.4 shall apply. For designs subject to cyclic loading, careful attention shall be paid to the design configuration in order to avoid stress raising features and to ensure good stress distribution. Stamping of materials shall not be done in critical areas. In considering operating conditions, the design shall make adequate allowance for corrosion and fatigue. The level of non-destructive testing adopted shall meet the acceptance criteria for main drum welds in EN 12952-6:2011. 5.6 Other design requirements 5.6.1 General In particular, cognizance shall be taken of the following requirements in EN 12952-5:2011 and

EN 12952-6:2011: a) the design shall be such that manufacturing and welding in accordance with EN 12952-5:2011 and inspection in accordance with EN 12952-6:2011 shall be possible; b) where partial penetration welds are to be used, the depth of the required weld preparation groove shall be specified on the drawing; c) the welds attaching branches, nozzles, stubs and supports to drums and headers shall not involve any combination of austenitic and ferritic steel; d) the requirements covering the attachment of nozzles and branches to drums and headers without strength welding shall be in accordance with EN 12952-5:2011, 9.3; e) the requirements covering tube connections to drums and headers without strength welding shall be in accordance with EN 12952-5:2011, 9.4; f) limits of operation for nodular graphite cast iron valves and fittings; g) where random NDE of welds is permitted by EN 12952-6:2011, it shall be demonstrated that the welding is adequate for the imposed loading when a weld joint factor of 0,85 is applied; h) the special requirements applicable to coil boilers are given in EN 12952-5:2011, Annex D; i) the special requirements applicable to chemical recovery boilers are given in EN 12952-5:2011, Annex E. For major components operating in the creep range, facilities shall be provided for monitoring the creep in relation to operation. 5.6.2 Access The boiler shall be designed to ensure adequate access is provided to facilitate the internal examination of the drums and headers. The examination may be either manual or remote in accordance with the physical size of the components. The requirements and limitations of access and inspection openings shall be in accordance with EN 12952-5:2011, 9.2. SIST EN 12952-3:2012

EN 12952-3:2011 (E) 10 5.6.3 Drainage and venting The boiler shall be provided with adequate means of drainage and venting in order to avoid water hammer and vacuum collapse, and to enable internal inspections to be carried out. 5.7 Design, calculation and test pressures 5.7.1 Design pressure For the purpose of EN 12952-3 the design pressure pd shall be equal to/or greater than the maximum allowable pressure PS. For each compartment of the water-tube boiler, the design pressure shall be at least the highest set pressure of any safety valve mounted on that compartment. NOTE A compartment is any pressurized section of plant which can be isolated by shut-off valves. 5.7.2 Calculation pressure Each compartment may be divided into sections, each with its own calculation pressure pc and calculation temperature tc. The design of each section shall be based on one of the following: a) for parts whose design stress has been derived from tensile strength Rm or minimum yield proof strength Rp0,2 tc the calculation pressure shall be the design pressure increased to the highest pressure possible when the plant is operating at the calculation temperature. Any difference between design pressure and calculation pressure might be caused by hydrostatic pressure and by pressure drop caused by fluid flow. Differences in hydrostatic height less than or equal to 0,05 MPa can be ignored; b) for parts whose design stress has been derived from the creep rupture strength, the calculation pressure shall be the lowest set pressure of any safety valve at the superheater/reheater outlet, as appropriate, increased by the highest pressure difference possible under maximum continuous rating conditions. A check shall be made of the thickness calculated by method b), using the calculation pressure of a) above with a design stress derived from tensile strength Rm or minimum yield/proof strength Rp0,2 tc at the calculation temperature used in b), and the greater thickness used. If the minimum yield strength data at higher temperatures are not available, linear extrapolation may be allowed. 5.7.3 Calculation pressure for pressure differences For parts with a design pressure not less than 1 MPa, which are simultaneously subject to both internal and external pressure, e.g. surface type attemperators in boiler drums, and where the design ensures that both pressures always occur together, the calculation pressure shall be the maximum pressure difference, but not less than 1 MPa. The loading occurring during hydrostatic testing shall be taken into account. 5.7.4 Hydrostatic test 5.7.4.1 General In order to demonstrate the strength and integrity of individual components and of the completely assembled water-tube boiler, and to establish that no major error or defect has occurred, completely assembled water-tube boilers shall be hydrostatically tested to the test pressure specified in 5.7.4.2 and individual components shall be hydrostatically tested in accordance with 5.7.4.2 without any sign of weakness or defect. SIST EN 12952-3:2012

EN 12952-3:2011 (E) 11 The hydrostatic tests shall be carried out on welded components or the completed water-tube boiler after all welding and heat treatment has been completed, but may be carried out prior to the drilling of holes for expanded tubes in the boiler drum. All components which are not reasonably accessible for inspection after assembly into the water-tube boiler shall be individually hydrostatically tested to the test pressure specified in 5.7.4.2 before assembly into the water-tube boiler. 5.7.4.2 Test pressure A boiler assembly comprises of a number of components each having its own specific calculation pressure pc and calculation temperature tc. The test pressure pt for components as defined in 5.7.4.1 shall be determined directly in accordance with 5.7.4.3. As there can be only one hydrostatic test pressure for a boiler assembly or separately isolated compartment as defined in EN 12952-1:2001, 1.2, it shall be necessary to carry out a series of individual calculations on selected components throughout the assembled boiler or isolated compartment, if applicable, in accordance with 5.7.4.3, to determine the individual apparent test pressure for each selected component. The hydrostatic test pressure for the whole assembly shall be the pressure which ensures that none of the components selected shall be subjected under test conditions to a stress greater than that given in 6.3.7.

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