Shell boilers - Part 1: General

This European Standard applies to shell boilers with volumes in excess of 2 litres for the generation of steam and/or hot water at an allowable pressure greater than 0,5 bar and with a temperature in excess of 110 °C.
The purpose of this European Standard is to ensure that the hazards associated with the operation of shell boilers are reduced to a minimum and that adequate protection is provided to contain the hazards that still prevail when the shell boiler is put into service.
This protection will be achieved by the proper application of the design, manufacturing, testing and inspection methods and techniques incorporated in the various parts of this European Standard. Where appropriate, adequate warning of residual hazards and the potential for misuse are given in the training and operating instructions and local to the equipment concerned (see EN 12953-7 and EN 12953-8).

Großwasserraumkessel - Teil 1: Allgemeines

1.1 Allgemeines
Diese Europäische Norm gilt für Großwasserraumkessel mit einem Inhalt von mehr als 2 Litern zur Erzeugung
von Dampf und/oder Heißwasser bei einem zulässigen Druck von mehr als 0,5 bar und bei einer Temperatur
über 110 °C.
Diese Europäische Norm hat sicherzustellen, dass die Gefahren, die mit dem Betrieb von Großwasserraumkesseln
verbunden sind, auf ein Minimum verringert werden und dass ein ausreichender Schutz geboten
wird, um den bei Inbetriebsetzung des Großwasserraumkessels noch vorhandenen Gefahren zu begegnen.
Dieser Schutz ist zu erreichen, indem die in den einzelnen Teilen dieser Europäischen Norm festgelegten
Verfahren und Techniken bei Auslegung, Herstellung Prüfung und Inspektion exakt angewendet werden.
Wenn zutreffend, werden geeignete Warnhinweise vor verbleibenden Gefahren und vor einer potenziellen
fehlerhaften Nutzung in den Schulungs- und Betriebsanleitungen und lokal am jeweiligen Druckgerät
angegeben (siehe EN 12953-7 und EN 12953-8).
ANMERKUNG 1 Weitere Anforderungen sowohl an die Betriebsanleitungen in EN 12953-13 sollten ebenso berücksichtigt
werden wie Anforderungen bezüglich der Gefahrenanalyse in CEN/TS 764-6.
Diese Europäische Norm regelt Anforderungen sowohl an direkt befeuerte und elektrisch beheizte
Dampfkessel einschließlich sowohl Niederdruck-Dampfkessel (NDD, siehe 3.7) wie auch Abhitzekessel mit
einem gasseitigen Druck bis 0,5 bar, die zylinderförmig sind, aus C- oder C-Mn-Stählen durch Schweißen
hergestellt werden und deren Auslegungsdruck 40 bar nicht überschreitet. Dampfkessel nach dieser
Europäischen Norm sind für den Gebrauch an Land zur Versorgung mit Dampf oder Heißwasser bestimmt
(typische Beispiele werden in den Bilder 3.1 bis 3.6 gezeigt).
ANMERKUNG 2 Für Dampfkessel, die bei einem höheren als dem angegebenen Druck betrieben werden, gelten die
Vorschriften dieser Norm ebenfalls. (...)

Chaudières à tubes de fumée - Partie 1: Généralités

1.1 Généralités
La présente Norme Européenne s'applique aux chaudières à tubes de fumée ayant un volume supérieur à
2 litres pour la production de vapeur et/ou d'eau surchauffée à une pression de service admissible supérieure
à 0,5 bar et à une température supérieure à 110 °C.
L'objet de la présente Norme européenne est d'assurer que les phénomènes dangereux associés à
l'exploitation des chaudières à tubes de fumée sont réduits à un minimum et qu'une protection appropriée est
fournie pour maîtriser les phénomènes dangereux qui subsistent toujours lorsque la chaudière à tubes de
fumée est mise en service. Cette protection sera assurée par l'application correcte des méthodes et
techniques de conception, de fabrication, d'essai et de contrôle incorporées dans les différentes parties de la
présente Norme européenne. Le cas échéant, des avertissements appropriés vis-à-vis les phénomènes
dangereux résiduels et la mauvaise utilisation sont donnés dans les instructions de formation et de service et
apposés sur l'équipement concerné (voir l'EN 12953-7 et l'EN 12953-8).
NOTE Il convient de tenir compte d'autres exigences relatives aux instructions de service spécifiées dans
l'EN 12953-13 ainsi que d'autres exigences relatives à l'analyse des phénomènes dangereux données dans le
CEN/TS 764-6.
La présente Norme européenne spécifie à la fois les prescriptions pour les chaudières directement soumises à
la flamme et chauffées électriquement y compris les chaudières basse pression (LPB, voir 3.7) ainsi que les
incinérateurs de déchets de conception cylindrique dont la pression côté gaz ne dépasse pas 0,5 bar 1),
construites à partir d'acier au carbone ou au carbone-manganèse par soudage par fusion et ayant une
pression de conception ne dépassant pas 40 bar. (...)

Mnogovodni kotli - 1. del: Splošno

Ta evropski standard se uporablja za mnogovodne kotle s prostornino, večjo od 2 litrov, za proizvodnjo pare in/ali vroče vode pri najvišjem dovoljenem tlaku, višjem od 0,5 bara, in temperaturi, višji od 110 °C. Namen tega evropskega standarda je zagotoviti, da se nevarnosti, povezane z delovanjem mnogovodnih kotlov, čim bolj zmanjšajo in da se zagotovi ustrezna zaščita pred nevarnostmi, ki še vedno obstajajo, ko se kotli dajo v uporabo. Ta zaščita bo dosežena s pravilno uporabo metod in tehnik konstruiranja, proizvodnje, preskušanja in pregledovanja iz različnih delov tega evropskega standarda. Po potrebi so ustrezna opozorila glede ostalih nevarnosti in možnosti zlorabe navedena v navodilih za usposabljanje in uporabo ter na kraju uporabe zadevne opreme (glejte EN 12953-7 in EN 12953-8). Poleg izpolnjevanja zahtev iz tega standarda je odgovornost proizvajalca, da upošteva posebne ukrepe, ki bi lahko bili potrebni, da se pri izdelavi doseže zahtevana stopnja varnosti v skladu z Direktivo EU 97/23/ES (PED). Ta evropski standard določa zahteve za neposredno kurjene in električno segrevane kotle, vključno z nizkotlačnimi kotli (LPB, glejte 3.6), ter za kotle z vračanjem toplote s plinskim tlakom največ 0,5 barov, ki so valjaste oblike in izdelani iz ogljikovega ali ogljikovega/manganskega jekla s fuzijskim varjenjem ter imajo računski tlak največ 40 barov. Kotli, zajeti v tem evropskem standardu, so namenjeni za prostorsko uporabo za zagotavljanje pare ali tople vode (značilni primeri so prikazani na slikah od 1 do 6). Pri nizkotlačnih kotlih (LPB) so sprejemljive manj stroge zahteve v zvezi s konstruiranjem in izračunom. Podrobnosti so določene v ustreznih točkah. Če gre pri posameznem kotlu za kombinacijo mnogovodnega in vodocevnega kotla, se poleg tega evropskega standarda uporablja še skupina standardov za vodocevne kotle EN 12952. Primer takšne kombinacije je prikazan na sliki 3. Ta evropski standard se uporablja za generator, od dovoda napajalne vode ali vode do odvoda pare ali vode in do vseh drugih povezav, vključno z ventili ter pritrdilnimi elementi za paro in vodo. Če se uporabijo varjeni končni deli, tu navedene zahteve začnejo ali prenehajo veljati na zvaru, kjer bi bile nameščene prirobnice, če bi se uporabile.

General Information

Status
Published
Public Enquiry End Date
19-Aug-2010
Publication Date
18-Apr-2012
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
23-Mar-2012
Due Date
28-May-2012
Completion Date
19-Apr-2012

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Mnogovodni kotli - 1. del: SplošnoGroßwasserraumkessel - Teil 1: AllgemeinesChaudières à tubes de fumée - Partie 1: GénéralitésShell boilers - Part 1: General27.060.30Grelniki vode in prenosniki toploteBoilers and heat exchangersICS:Ta slovenski standard je istoveten z:EN 12953-1:2012SIST EN 12953-1:2012en,fr,de01-maj-2012SIST EN 12953-1:2012SLOVENSKI
STANDARDSIST EN 12953-1:20021DGRPHãþD



SIST EN 12953-1:2012



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12953-1
March 2012 ICS 27.060.30 Supersedes EN 12953-1:2002English Version
Shell boilers - Part 1: General
Chaudières à tubes de fumée - Partie 1: Généralités
Großwasserraumkessel - Teil 1: Allgemeines This European Standard was approved by CEN on 7 January 2012.
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, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12953-1:2012: ESIST EN 12953-1:2012



EN 12953-1:2012 (E) 2 Contents Page Foreword . 31Scope . 52Normative references . 63Terms and definitions . 64Interdependency of the Parts of the series . 125Symbols and abbreviations . 126Responsibilities . 17Annex A (informative)
Information to be supplied by the purchaser to the manufacturer . 19Annex B (informative)
Vocabulary for shell boiler . 21Annex C (informative)
Vocabulary on typical components of a shell boiler . 29Annex D (informative)
Significant technical changes between this European Standard and the
previous edition . 33Annex ZA (informative)
Relationship between this
European
Standard and the Essential Requirements of EU Directive 97/23/EC . 34Bibliography . 35 SIST EN 12953-1:2012



EN 12953-1:2012 (E) 3 Foreword This document (EN 12953-1:2012) 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 September 2012, and conflicting national standards shall be withdrawn at the latest by September 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 12953-1:2002. 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(s), see informative Annex ZA, which is an integral part of this document. Annex D provides details of significant technical changes between this European Standard and the previous edition. 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 feedwater and boiler water quality;  Part 11: Acceptance tests;  Part 12: Requirements for grate firing systems for solid fuels for the boiler;  Part 13: Operating instructions;  CR 12953 Part 14: Guideline for involvement of an inspection body independent of the manufacturer. Although these parts may be obtained separately, it should be recognized that the parts are interdependent. As such, the design and manufacture of shell boilers requires the application of more than one part in order for the requirements of the European Standard to be satisfactorily fulfilled. For any questions arising when using these standards the Boiler Helpdesk of CEN/TC 269 may be contacted: http://www.boiler-helpdesk.din.de
SIST EN 12953-1:2012



EN 12953-1:2012 (E) 4 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, Turkey and the United Kingdom.
SIST EN 12953-1:2012



EN 12953-1:2012 (E) 5 1 Scope 1.1 General This European Standard applies to shell boilers with volumes in excess of 2 litres for the generation of steam and/or hot water at a maximum allowable pressure greater than 0,5 bar and with a temperature in excess of
110 °C. The purpose of this European Standard is to ensure that the hazards associated with the operation of shell boilers are reduced to a minimum and that adequate protection is provided to contain the hazards that still prevail when the shell boiler is put into service. This protection will be achieved by the proper application of the design, manufacturing, testing and inspection methods and techniques incorporated in the various parts of this European Standard. Where appropriate, adequate warning of residual hazards and the potential for misuse are given in the training and operating instructions and local to the equipment concerned (see EN 12953-7 and EN 12953-8). It is the manufacturer's responsibility, in addition to complying with the requirements of this standard, to take into consideration special measures which could be necessary in order to achieve by manufacturing the required level of safety in accordance with the EU Directive 97/23/EC (PED). NOTE 1 Further requirements relating to operating instructions in EN 12953-13 and to hazard analysis in
CEN/TS 764-6 should be taken into consideration. This European Standard specifies requirements for both directly fired and electrically heated boilers including Low Pressure Boilers (LPB, see 3.6) as well as for heat recovery boilers with a gas-side pressure not exceeding 0,5 bar of cylindrical design, constructed from carbon or carbon manganese steels by fusion welding and a design pressure not exceeding 40 bar. The boilers covered by this European Standard are intended for land use for providing steam or hot water (typical examples are shown in Figures 1 to 6). For Low Pressure Boilers (LPB) less stringent requirements concerning design and calculation are acceptable. Details are defined in the respective clauses. NOTE 2 For boilers operating at a pressure on the gas-side greater than 0,5 bar the rules of this standard equally apply. However, it is generally considered that additional design analysis, inspection and testing may be necessary. Where a particular boiler is a combination of shell and water-tube design then the water-tube standard series EN 12952 is used in addition to this European Standard. One such example of this combination is shown in Figure 3. This European Standard applies to the generator, from the feed-water or water inlet connection to the steam or water outlet connection and to all other connections, including the valves and steam and water fittings. If welded ends are used, the requirements specified herein begin or end at the weld where flanges, if used, would have been fitted. 1.2 Exclusions This European standard does not apply to the following types of boilers and equipments: a) water-tube boilers; b) non stationary boilers, e.g. locomotive boilers; c) thermal oil boilers; d) boilers where the main pressure housing is made of cast material. e) pumps, gaskets, etc. SIST EN 12953-1:2012



EN 12953-1:2012 (E) 6 f) brickwork setting and insulation, etc. NOTE Stainless steel boilers are covered by EN 14222. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12953-3:2002, Shell boilers — Part 3: Design and calculation for pressure parts EN 12953-10:2003, Shell boilers — Part 10: Requirements for feedwater and boiler water quality EN 12953-13:2012, Shell boilers — Part 13: Operating instructions CR 12953-14:2002, Shell boilers — Part 14: Guideline for involvement of an inspection body independent of the manufacturer 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 purchaser
individual or organization that buys the boiler or part thereof from the manufacturer
3.2
manufacturer individual or organisation that is responsible for the design, fabrication, testing, inspection, installation of pressure equipment and assemblies where relevant
[SOURCE: EN 764-3:2002] Note 1 to entry: The manufacturer can subcontract one or more of the above mentioned tasks under its responsibility (for example, designer, installer, etc.).
3.3 material supplier
individual or organisation, that may or may not be the material manufacturer, who supplies material or parts used in the manufacture of pressure equipment and assemblies [SOURCE: EN 764-3:2002] Note 1 to entry: A material supplier may be a stockist. 3.4
material manufacturer
individual or organisation that produces material in the basic product forms used in the manufacture of pressure equipment
[SOURCE: EN 764-3:2002] SIST EN 12953-1:2012



EN 12953-1:2012 (E) 7 3.5 installer individual or organisation that carries out the assembly of the pressure equipment at the location where it is to be put into service
Note 1 to entry: Depending on the contractual circumstances, the installer may be considered as the manufacturer of the assembly. 3.6
low pressure boilers (LPB)
steam boilers with a maximum saturation temperature of 120 °C (this corresponds to a pressure of 1 bar gauge) or hot water boilers with a maximum outlet temperature of 120 °C and a maximum allowable pressure of 10 bar gauge Note 1 to entry: The manufacturer may have the option of using this harmonised European Standard or alternatively EN 14394 for low pressure boilers which are to be used as hot water heating boilers. 3.7 shell boiler closed vessel containing water in which flames and/or hot gases pass through the inside of tubes located within the shell which forms part of an assembly
Note 1 to entry: This is opposed to water-tube boiler where the water is inside the tubes and flue gas is outside the tubes.
Note 2 to entry: Figures 1 to 6 are typical configurations and examples of shell boilers. Other configurations are also permissible (e.g. vertical shell). Note 3 to entry: Informative Annex C gives translations of some typical components of a shell boiler.
SIST EN 12953-1:2012



EN 12953-1:2012 (E) 8
Key 1) cylindrical shell 2) furnace tube (1st pass): for example plain or corrugated or with bowling hoops 3) front tube plate (or front plate depending on the configuration) 4) rear plate (or rear tube plate depending on the configuration) 5) smoke tube(s) (2nd pass/3rd pass) (maybe with stay tubes or bar stays) 6) wrapper plate (shell of reversal chamber) 7) reversal chamber tube plate 8) wet back rear plate 12) lifting lugs 13) gusset stays 14) branches 15) supports 16) inspection opening
NOTE The main pressure-bearing parts are the parts, which constitute the envelope under pressure, and the parts which are essential for the integrity of the boiler. Figure 1 — Typical components of a shell boiler
SIST EN 12953-1:2012



EN 12953-1:2012 (E) 9
a) two pass boiler b) three pass boiler Key 1) cylindrical shell 2) furnace tube (1st pass): for example plain or corrugated or with bowling hoops 3) front tube plate (or front plate depending on the configuration) 4) rear plate (or rear tube plate depending on the configuration) 5) smoke tube(s) (2nd pass/3rd pass) (maybe with stay tubes or bar stays) 6) wrapper plate (shell of reversal chamber) 7) reversal chamber tube plate 8) wet back rear plate NOTE The effective radiant heating surface comprises the furnace tube and the surface of the reversal chamber, where applicable. Figure 2 — Wet back boiler with internal reversal chamber
a) two pass boiler b) three pass boiler Key 1) cylindrical shell 2) furnace tube (1st pass): for example plain or corrugated or with bowling hoops 3) front tube plate (or front plate depending on the configuration) 4) rear plate (or rear tube plate depending on the configuration) 5) smoke tube(s) (2nd pass/3rd pass) (maybe with stay tubes or bar stays) 9)
header 10)
membrane wall
NOTE The effective radiant heating surface comprises the furnace tube and complete surface of the reversal chamber. Figure 3 — Wet back boiler with external reversal chamber
SIST EN 12953-1:2012



EN 12953-1:2012 (E) 10
a) two pass boiler b) three pass boiler Key 1) cylindrical shell 2) furnace tube (1st pass): for example plain or corrugated or with bowling hoops 3) front tube plate (or front plate depending on the configuration) 4) rear plate (or rear tube plate depending on the configuration) 5) smoke tube(s) (2nd pass/3rd pass) (maybe with stay tubes or bar stays) 6) wrapper plate (shell of reversal chamber)
7)
reversal chamber tube plate
11)
insulation: for example refractory NOTE The effective radiant heating surface comprises the furnace tube wrapper plate and reversal chamber tube plate. Figure 4 — Semi-wet back boiler
a) two pass boiler b) three pass boiler Key 1) cylindrical shell 2) furnace tube (1st pass): for example plain or corrugated or with bowling hoops 3) front tube plate (or front plate depending on the configuration) 4) rear plate (or rear tube plate depending on the configuration) 5) smoke tube(s) (2nd pass/3rd pass) (maybe with stay tubes or bars)
11)
insulation: for example refractory NOTE The effective radiant heating surface comprises the furnace tube and rear tube plate. Figure 5 — Dry back boiler SIST EN 12953-1:2012



EN 12953-1:2012 (E) 11
Key 1) cylindrical shell 2) furnace tube (1st pass): for example plain or corrugated or with bowling hoops 3) front tube plate (or front plate depending on the configuration) 4) rear plate (or rear tube plate depending on the configuration)
5)
smoke tube(s) (2nd pass/3rd pass) (maybe with stay tubes or bars) NOTE The effective radiant heating surface consists of the furnace only. Figure 6 — Reverse flame boiler
3.8 generator assembly with boiler, burner, valves and, if applicable, protective devices Note 1 to entry: For this European Standard, the term “generator” is applicable to shell boilers (see Figure B.2). 3.9 assembly consists, as a minimum a generator, and where applicable, with an economiser and/or a superheater,
inter-connecting piping and instrumentation (protective, control and indicating devices) placed on the market by one manufacturer
Note 1 to entry: See also Figure B.3. 3.10 operating instructions see EN 12953-13
SIST EN 12953-1:2012



EN 12953-1:2012 (E) 12 4 Interdependency of the Parts of the series Parts 2 to 13 of EN 12953, together with Part 1, form a consistent set of specifications which shall be followed for compliance to the Standard. NOTE 1 Parts 10 and 11 of the series are published as supporting European Standards. NOTE 2 Part 14 of the series is published as a CEN Report. It is not a European Standard. 5 Symbols and abbreviations
For the purposes of this European Standard, the general symbols and abbreviations indicated in Table 1 shall apply, however specific symbols and abbreviations can be used for specific requirements in other Parts of the standard. Table 1 — Symbols and abbreviations — (1 of 6) Symbol Description Unit A Effective radiant heating surface (see Figures 1 to 6) m2 Af Cross-sectional area effective as compensation without consideration of allowances mm2 Afb Cross-sectional area of branch effective as compensation mm2 Afp Cross-sectional area of reinforcing pad effective as compensation mm2 Afs Cross-sectional area of main body effective as compensation mm2 Ap Pressure-loaded area without consideration of allowances mm2 Apb Pressure-loaded area relative to branch mm2 Aps Pressure-loaded area relative to main body mm2 At Original cross-sectional area of test piece subjected to a tensile test mm2 a Dimensions indicated in EN 12953-3, Figures 10.1-1, 10.2-2 to 10.2-4 mm ai Inner major axis of compensation plate mm ao Outer major axis of compensating plate mm b Dimensions indicated as examples in EN 12953-3, Figures 10.1-1, 10.2-2 to 10.2-5, 13.1-1 and in EN 12953-3, Annex B mm b1 Minor axis of manhole mm bi Inner minor axis of compensating plate mm bo Outer minor axis of compensating plate mm C Shape factor for unstayed dished heads without openings indicated in EN 12953-3, Figure 9.1-1 — C1 Shape factor for unstayed walls, ends or plates as given in EN 12953-3, 9.2 — SIST EN 12953-1:2012



EN 12953-1:2012 (E) 13 Table 1 — Symbols and abbreviations — (2 of 6) Symbol Description Unit c1 Minus tolerance on the ordered nominal wall thickness mm c2 Allowance for metal wastage mm C4 Constant determined from EN 12953-3, Table 10.2-1 — Db Gasket mean diameter mm DL Bolt circle diameter mm d Diameter of tube hole mm dg Depth of welded-on girder stay mm di Inside diameter mm dib Inside diameter of branch without allowances (defined by dib = dob - 2 * (eb - c1 - c2)) mm dip Diameter of inner periphery of circular pad or compensating plate mm dis Inside diameter of main body (cylindrical shell, spherical shell or dished end) without allowances (defined as an example by dis = dos - 2 * (es - c1 - c2)) mm dm Mean diameter mm do Nominal outside diameter mm dob Nominal outside diameter of branch
mm dop Diameter of outer periphery of circular pad of compensating plate mm dos Nominal outside diameter of main body
mm ds Diameter of stay mm E Modulus of elasticity at design temperature MPa
e Wall thickness mm ecb Calculated wall thickness of branch or nozzle without allowances mm ecf Calculated wall thickness of furnace without allowances mm SIST EN 12953-1:2012



EN 12953-1:2012 (E) 14 Table 1 — Symbols and abbreviations — (3 of 6) Symbol
Description Unit ech Calculated wall thickness of flat end without allowances mm ecp Calculated wall thickness of reinforcing pad mm ecs Calculated wall thickness of the main body (cylindrical or spherical shells or dished ends) without allowances mm ect Calculated wall thickness of straight tube without allowances mm efa Calculated wall thickness of furnace with allowances mm eg Calculated thickness of gusset stay mm eh Ordered thickness of flat end mm eh1 Wall thickness in relief groove mm ep Ordered wall thickness of reinforcing pad mm erb Actual wall thickness of branch or nozzle without allowances mm erf Actual wall thickness of furnaces mm erh Actual wall thickness of flat end without allowances mm erp Actual wall thickness of reinforcing pad without allowances mm ers Actual wall thickness of main body (cylindrical or spherical shell or dished end) without allowances mm ert Actual tube wall thickness without allowances mm es Ordered wall thickness of main body mm esa Required wall thickness of main body with allowances mm et Ordered tube wall thickness mm eta Required wall thickness of straight tube with allowances mm F Calculation overall exchange factor — f Nominal design stress MPa fa Existing mean stress MPa
fa- Existing mean stress between the centres of two openings MPa fb Nominal design stress for branch material MPa fc Combined stress at supports MPa
fp Nominal design stress for reinforcing ring material MPa fs Nominal design stress for main body material MPa G Gas mass flow rate in first pass tubes kg/(m2 ⋅ s) SIST EN 12953-1:2012



EN 12953-1:2012 (E) 15 Table 1 — Symbols and abbreviations — (4 of 6) Symbol Description Unit g, g1 Clear height as shown in EN 12953-3, Figure 14.2-1 mm hc Depth of curvature of dished head (with knuckle, without cylindrical skirt) mm hf Height of manhole frame mm hg Minimum width of gusset stay mm hs Height of cylindrical skirt of dished end mm H Heat input (see EN 12953-3, note 3 of Figure 5.4-1) W I1 Second moment of area of one complete furnace corrugation about its neutral axis excluding corrosion allowance mm4 I2 Second moment of area of stiffeners mm4 K Design strength value MPa
Kt Design strength value at test (gauge) pressure MPa
(KC) Thermal conductivity (W ⋅ mm) / (m2 ⋅ K) L Distance between two effective points of furnace support mm L1 Shortest distance from the edge of the access opening to the centre-line of the stay furthest away from the access opening, or, where is no access opening, half the maximum distance between the centre-lines of the stays mm L2 Distance between the rear plate of the reversal chamber and the boiler back end plate mm Lb Length of boiler between end plates mm Lcor Total length of corrugation mm Li Length of leg of fillet weld around inner periphery of pad or compensating plate mm Lg Length of welded-on girders mm Lh Heated length of furnace mm Lo Length of leg of fillet weld around outer periphery of pad or compensating plate mm Ls Length of shell between end plates mm Lt Mean pitch of adjacent tubes mm lb0 Cylindrical length of the branch from the transition zone up to the weld mm lb1 Measured length of external projection of branch mm lb2 Measured length of internal projection of branch mm SIST EN 12953-1:2012



EN 12953-1:2012 (E) 16 Table 1 — Symbols and abbreviations — (5 of 6) Symbol Description Unit lrb Effective length of branch contributing to reinforcement mm lrbi Effective length of inward projection of set-through branch contributing to reinforcement mm lrp Effective width of reinforcing ring mm lrs Effective length of main body contribution to reinforcement mm ls0 Cylindrical length of the main body from the transition zone up to the weld mm Pcor Pitch of corrugations mm Pg Pitch of welded-on girders mm P- Centre-to-centre distance of adjacent openings, staggered by the angle - referring to centre of wall
mm PS Maximum allowable pressure as defined by the PED MPa, bar a pc Calculation pressure MPa, bar a pd Design pressure MPa, bar a ps Allowable (total gauge) pressure for hot-water generators MPa, bar a pt Test (gauge) pressure MPa, bar a Rm Minimum tensile strength of the grade of material concerned at room temperature MPa
Rp0,2tc Minimum value of 0,2 % proof strength for the grade of steel concerned at temperature tc MPa
rik Inside radius of dishing of dished ends or of knuckle or relief groove of flat ends mm ris Inside corner radius of dished end or spherical shell mm rms Mean radius of shell mm rok Outside radius of knuckle of dished end mm ros Outside corner radius of dished end or spherical shell mm S Safety factor — St Safety factor for test (gauge) pressure — TS Maximum/Minimum allowable temperature °C tc Calculation temperature °C td Design temperature °C tm Maximum metal temperature °C SIST EN 12953-1:2012



EN 12953-1:2012 (E) 17 Table 1 — Symbols and abbreviations — (6 of 6) Symbol Description Unit ts Saturation temperature corresponding to design pressure °C u Departure from circularity % v Weld factor — va Allowable ligament efficiency for branches or openings — vb Ligament efficiency for isolated branches or openings — vm Ligament efficiency for adjacent branches or openings — W Force exerted by the pressure on the end plate in the zone assumed to be supported by the gusset N w Nominal overall depth of corrugation (see EN 12953-3, Figure 13.1-1)
mm h (wc) Measured depth of corrugations (see EN 12953-4, Figure 5.9-1) mm X2 Cross-sectional area of longitudinal section of furnace wall of length equal to one pitch and thickness erf — c2 mm2 x Stress reduction factor — y Factor determined from EN 12953-3, Figure 10.2-4 using the ratio b/a — - Angle of connecting lines between the centres of two openings relative to the axis of the main body degree /5 Elongation after fracture (gauge length ratio = 5) %
Angle of inclination of branch relative to the normal to the circumferential line of the main body degree a In this European Standard units are referenced both in bar and MPa:
1 MPa = 1 N/mm2 = 1 MN/m2 = 10 bar 6 Responsibilities 6.1 Purchaser
The purchaser shall be responsible for specifying the overall output requirements.
Where the boiler is being designed for a specific application, the purchaser shall be responsible for furnishing the manufacturer with the performance requirements and operating conditions of the boiler, together with details of any transient or adverse conditions under which the boiler is required to operate. In addition, any special requirements to facilitate in-service inspection (see also guide for procurement EN 45510-3-2, where applicable). Two options apply for the technical specification:  “Standard” case: the manufacturer proposes a boiler from his standard range of equipment for the purchaser based upon his specific requirements and needs. In this case, the tender shall become the technical specification and then form the contract for supply;  “Bespoke” case: detailed technical specification document produced by the purchaser defining the scope of supply. This document shall be agreed by the manufacturer and then form the contract for supply. NOTE For typical minimum information to be supplied by the purchaser, see Annex A. SIST EN 12953-1:2012



EN 12953-1:2012 (E) 18 6.2 Manufacturer
Manufacturer(s) shall supply and/or install a boiler, a generator or an assembly, where applicable, in accordance with:  applicable legislation related to supply the boiler;  this European Standard;  the contractual document. The manufacturer is also responsible to provide the relevant documentation:  operating instructions (see EN 12953-13);  declaration of conformity. The limitations for the operation conditions of the boiler shall be agreed between manufacturer and purchaser. It is the responsibility of the manufacturer to specify the conditions and limitations necessary for the safe use of the boiler. Duties carried out by Notified Bodies shall not absolve the manufacturer from his responsibility.
Components of the shell boiler are not subjected to individual conformity assessment procedures (no CE mark). However, manufacturers of such components shall demonstrate that they comply with the relevant requirements of EU Directive(s) such that the conformity assessment can take place on the completed equipment. NOTE 1 The completed shell boilers placed on the market as an individual item of equipment (e.g. without safety accessories and other fittings) should be CE marked.
NOTE 2 Materials which are supplied to EN 12953-2 and have not been subjected to any additional work are not regarded as components of the shell boiler. NOTE 3 When the boiler is to be installed in a country outside of EU, National requirements should determine the Responsible Authority.
6.3 Notified Body
Responsibilities of the Notified Body are indicated in CR 12953-14. NOTE See also PED Annex III. 6.4 Owner and/or user In order to maintain the ongoing integri
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