Shell boilers - Part 4: Workmanship and construction of pressure parts of the boiler

This European Standard specifies requirements for the workmanship and construction of shell boilers as defined in EN 12953-1.
NOTE 1   For other components such as water tube walls, see the EN 12952 series.
NOTE 2   For economizers and superheaters, see EN 12953-4 or EN 12952-5.

Großwasserraumkessel - Teil 4: Verarbeitung und Bauausführung für drucktragende Kesselteile

Diese Europäische Norm legt Anforderungen für die Verarbeitung und Bauausführung von in EN 12953 1 definierten Großwasserraumkesseln fest.
ANMERKUNG 1   Für andere Bauteile wie Wasserrohrwände, siehe Normenreihe EN 12952.
ANMERKUNG 2   Für Vorwärmer und Überhitzer, siehe EN 12953 4 oder EN 12952 5.

Chaudières à tubes de fumée - Partie 4 : Fabrication et construction des parties sous pression des chaudières

La présente Norme européenne spécifie les exigences de fabrication et de construction des chaudières à tubes de fumée telles que définies dans l’EN 12953-1.
NOTE 1   Pour les autres composants, tels que les parois à tubes d’eau, voir la série des EN 12952.
NOTE 2   Pour les économiseurs et les surchauffeurs, voir l'EN 12953-4 ou l'EN 12952-5.

Mnogovodni kotli - 4. del: Izdelava in izvedba tlačno obremenjenih delov kotla

Ta del tega evropskega standarda velja za mnogovodne kotle, kot je opredeljeno v standardu prEN 12953-1. Ta del standarda določa pravila za izdelavo in konstrukcijo mnogovodnih kotlov.

General Information

Status
Published
Publication Date
27-Mar-2018
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
20-Nov-2017

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SLOVENSKI STANDARD
SIST EN 12953-4:2018
01-maj-2018
1DGRPHãþD
SIST EN 12953-4:2002
0QRJRYRGQLNRWOLGHO,]GHODYDLQL]YHGEDWODþQRREUHPHQMHQLKGHORYNRWOD

Shell boilers - Part 4: Workmanship and construction of pressure parts of the boiler

Großwasserraumkessel - Teil 4: Verarbeitung und Bauausführung für drucktragende
Kesselteile

Chaudières à tubes de fumée - Partie 4 : Fabrication et construction des parties sous

pression des chaudières
Ta slovenski standard je istoveten z: EN 12953-4:2018
ICS:
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
SIST EN 12953-4:2018 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 12953-4:2018
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SIST EN 12953-4:2018
EN 12953-4
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2018
EUROPÄISCHE NORM
ICS 27.060.30 Supersedes EN 12953-4:2002
English Version
Shell boilers - Part 4: Workmanship and construction of
pressure parts of the boiler

Chaudières à tubes de fumée - Partie 4 : Fabrication et Großwasserraumkessel - Teil 4: Verarbeitung und

construction des parties sous pression des chaudières Bauausführung für drucktragende Kesselteile

This European Standard was approved by CEN on 6 December 2017.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12953-4:2018 E

worldwide for CEN national Members.
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SIST EN 12953-4:2018
EN 12953-4:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 6

3 Terms and definitions ................................................................................................................................... 7

4 Symbols ............................................................................................................................................................... 7

5 General requirements ................................................................................................................................... 7

5.1 General ................................................................................................................................................................ 7

5.2 Traceability ....................................................................................................................................................... 8

5.2.1 General ................................................................................................................................................................ 8

5.2.2 Material ............................................................................................................................................................... 8

5.2.3 Welding ............................................................................................................................................................... 8

5.2.4 Inspection (NDT) ............................................................................................................................................. 8

5.3 Cylindrical shells ............................................................................................................................................. 9

5.4 Tell-tale holes ................................................................................................................................................ 11

5.5 End plates and tube plates ........................................................................................................................ 11

5.6 Plain tubes and stay tubes ........................................................................................................................ 11

5.7 Manhole frames and openings ................................................................................................................ 12

5.7.1 Jointing flanges ............................................................................................................................................. 12

5.7.2 Openings for access and inspection ....................................................................................................... 12

5.8 Connections for accessories ..................................................................................................................... 13

5.8.1 Accessories ..................................................................................................................................................... 13

5.8.2 Set-in flange and set-on flange ................................................................................................................ 13

5.8.3 Flanges on nozzles ....................................................................................................................................... 13

5.8.4 Bolting .............................................................................................................................................................. 14

5.9 Cylindrical furnaces .................................................................................................................................... 14

5.10 Water-cooled reversal chamber ............................................................................................................. 16

5.11 Stays .................................................................................................................................................................. 16

5.11.1 Bar stays .......................................................................................................................................................... 16

5.11.2 Girder stays .................................................................................................................................................... 17

5.11.3 Tube stays ....................................................................................................................................................... 17

5.11.4 Non-perpendicular bar stays or tube stays ........................................................................................ 17

5.12 Design of welded joints .............................................................................................................................. 17

5.12.1 Weld deposition ............................................................................................................................................ 17

5.12.2 Weld crosses .................................................................................................................................................. 17

5.12.3 Types of welds ............................................................................................................................................... 18

5.12.4 Weld preparations ....................................................................................................................................... 19

5.12.5 Welding plates of unequal thickness .................................................................................................... 19

5.13 Openings in or adjacent to welds ........................................................................................................... 19

5.14 Fabrication ..................................................................................................................................................... 19

5.14.1 General ............................................................................................................................................................. 19

5.14.2 Welding ............................................................................................................................................................ 19

5.14.3 Cutting, fitting and alignment .................................................................................................................. 20

5.14.4 Longitudinal seams ..................................................................................................................................... 21

5.14.5 Circumferential seams ............................................................................................................................... 21

5.14.6 Surface condition before welding .......................................................................................................... 21

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SIST EN 12953-4:2018
EN 12953-4:2018 (E)

5.14.7 Middle line alignments ............................................................................................................................... 21

5.14.8 Surface alignment tolerances ................................................................................................................... 22

5.14.9 Miscellaneous welding requirements ................................................................................................... 23

5.14.10 Repair of weld defects ........................................................................................................................ 24

5.15 Post-weld heat treatment (PWHT) and other heat treatments ................................................... 24

5.15.1 General ............................................................................................................................................................. 24

5.15.2 Material thickness ........................................................................................................................................ 24

Annex A (normative) Typical welds for shell boilers ..................................................................................... 27

Annex B (informative) Gaskets for closing systems of access and inspection openings .................... 32

Annex C (informative) Significant technical changes between this European Standard and

the previous edition .................................................................................................................................... 33

Annex ZA (informative) Relationship between this European Standard and the Essential

Requirements of EU Directive 2014/68/EU aimed to be covered .............................................. 34

Bibliography ................................................................................................................................................................. 35

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SIST EN 12953-4:2018
EN 12953-4:2018 (E)
European foreword

This document (EN 12953-4:2018) 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 2018, and conflicting national standards

shall be withdrawn at the latest by September 2018.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN 12953-4:2002.

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.

The informative Annex C lists the significant technical changes between this European Standard and the

previous edition.
EN 12953, 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 boilers;

— 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;

— Part 14: Guideline for involvement of an inspection body independent of the manufacturer [CR 12953-

14].
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SIST EN 12953-4:2018
EN 12953-4:2018 (E)

Although these parts can be obtained separately, 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 standard to be satisfactorily fulfilled.

NOTE A “Boiler Helpdesk” has been established in CEN/TC 269 which can be contacted for any questions

regarding the application of the 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, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
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SIST EN 12953-4:2018
EN 12953-4:2018 (E)
1 Scope

This European Standard specifies requirements for the workmanship and construction of shell boilers

as defined in EN 12953-1.
NOTE 1 For other components such as water tube walls, see the EN 12952 series.
NOTE 2 For economizers and superheaters, see EN 12953-4 or EN 12952-5.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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+A1:2013, Flanges and their joints — Circular flanges for pipes, valves, fittings and

accessories, PN designated — Part 1: Steel flanges

EN 1092-2:1997, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN

designated — Part 2: Cast iron flanges

EN 1515-4:2009, Flanges and their joints — Bolting — Part 4: Selection of bolting for equipment subject

to the Pressure Equipment Directive 97/23/EC

EN 1759-1:2004, Flanges and their joint — Circular flanges for pipes, valves, fittings and accessories, Class

designated — Part 1: Steel flanges, NPS 1/2 to 24

EN 10216-2:2013, Seamless steel tubes for pressure purposes — Technical delivery conditions — Part 2:

Non-alloy and alloy steel tubes with specified elevated temperature properties

EN 10217-2:2002, Welded steel tubes for pressure purposes — Technical delivery conditions — Part 2:

Electric welded non-alloy and alloy steel tubes with specified elevated temperature properties

EN 10217-5:2002, Welded steel tubes for pressure purposes — Technical delivery conditions — Part 5:

Submerged arc welded non-alloy and alloy steel tubes with specified elevated temperature properties

EN 12953-1:2012, Shell boilers — Part 1: General

EN 12953-2:2012, Shell boilers — Part 2: Materials for pressure parts of boilers and accessories

EN 12953-3:2016, Shell boilers — Part 3: Design and calculation for pressure parts

EN 12953-5:2002, Shell boilers — Part 5: Inspection during construction, documentation and marking of

pressure parts of the boiler

EN ISO 2553:2013, Welding and allied processes — Symbolic representation on drawings — Welded joints

(ISO 2553:2013)

EN ISO 9606-1:2017, Qualification testing of welders — Fusion welding — Part 1: Steels (ISO 9606-1:2012

including Cor 1:2012 and Cor 2:2013)

EN ISO 14731:2006, Welding coordination — Tasks and responsibilities (ISO 14731:2006)

EN ISO 14732:2013, Welding personnel — Qualification testing of welding operators and weld setters for

mechanized and automatic welding of metallic materials (ISO 14732:2013)
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SIST EN 12953-4:2018
EN 12953-4:2018 (E)

EN ISO 15609-1:2004, Specification and qualification of welding procedures for metallic materials —

Welding procedure specification — Part 1: Arc welding (ISO 15609-1:2004)

EN ISO 15614-1:2017, Specification and qualification of welding procedures for metallic materials —

Welding procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys

(ISO 15614-1:2017)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 12953-1 and the following

apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
seam
generic term for welded joints, welded seams or welds
4 Symbols

For the purposes of this document, the symbols given in EN 12953-1:2012, Table 1 apply.

5 General requirements
5.1 General

5.1.1 The rules in this part are applicable to all aspects of fabrication, including welding, of boilers

and boiler parts, and shall be used in conjunction with the specific requirements applicable to the

grades of materials used.

5.1.2 All welding activities shall be in accordance with the requirements of this standard.

5.1.3 For category II, III and IV boilers, all welders or welding operators and welding procedures shall

be approved (see 5.14.2). For category I boilers, approval shall not be mandatory.

5.1.4 The manufacturer of a boiler, built in accordance with the requirements of this European

Standard, shall be responsible for the welding done by his workmen or subcontracted by him. The

manufacturer shall designate a competent welding supervisor in accordance with EN ISO 14731.

No production work should be undertaken on category II, III and IV boilers according to the Pressure

Equipment Directive PED 2014/68/EU until both the welding procedures and the welders or welding

operators have been approved.

5.1.5 Materials and welding consumables shall fulfil the requirements of EN 12953-2:2012.

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SIST EN 12953-4:2018
EN 12953-4:2018 (E)
5.2 Traceability
5.2.1 General

The manufacturer shall demonstrate during the whole manufacturing process that identification and

traceability shall be achieved for at least:
— pressure part materials;
— welding;
— inspection (NDT).

This traceability shall be achieved through either marking of the part or by a documentation system.

5.2.2 Material
5.2.2.1 Pressure bearing parts

When laying out and cutting material the manufacturer shall take into consideration the location of the

transferred identification markings to ensure that they are clearly visible when the pressure part is

completed.

In case the original identification markings are unavoidably cut out or the material is divided into two

or more pieces the markings shall be accurately transferred by the manufacturer's nominated

personnel prior to cutting.

The actual material marking shall be by methods which are not harmful to the material in subsequent

use/operation.

The transfer of markings shall take place before partitioning of the product and after verification of the

marks present with the corresponding certification.

The manufacturer shall verify traceability of the material markings with the material certificates.

5.2.2.2 Non pressure bearing parts

For non-pressure-bearing parts welded to a pressure part of the shell boiler, the material shall be

compatible with the pressure part material, corresponding to a specification which can be identified,

and shall have a maximum carbon content in the ladle analysis of 0,24 %.
5.2.2.3 Welding consumables

The manufacturer shall ensure that the correct welding consumables according to the relevant welding

procedure specification (WPS) are used.
5.2.3 Welding

The welds made by each welder shall be marked with a stamp showing the welder’s identity or some

other appropriate record shall be made. If hand stamping is employed; only low-stress shall be used.

5.2.4 Inspection (NDT)

An as built sketch or equivalent shall be produced by the manufacturer in order to record the locations

where the NDT has been performed.

On welds which have undergone RT or UT the “zero datum point” shall be indicated.

The location of any repairs shall be also clearly indicated on the reports.
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SIST EN 12953-4:2018
EN 12953-4:2018 (E)
5.3 Cylindrical shells

5.3.1 Each ring shall be formed from not more than two plates, bent to cylindrical form to the extreme

ends of the plate. The bending shall be performed entirely by machine, and local heating or hammering

shall not be used.

5.3.2 The shell of completed boilers shall be in accordance with the following requirements.

a) Straightness

Unless otherwise shown on the drawing, the maximum deviation of the shell from a straight line shall

not exceed 0,3 % both of the total cylindrical length and of any 5 m length. Measurements shall be made

to the surface of the parent plate and not to a weld, fitting, or other raised part.

b) Irregularities in profile
1) Gradual local departures from circularity

Irregularities in profile (checked by a 20° gauge) shall not exceed 2 % of the gauge length.

This maximum value may be increased by 25 % if the length of the irregularities does not exceed

one quarter of the length of the shell part between two circumferential seams, with a maximum of

1 m. Greater irregularities require proof by calculation or strain gauge measurement that the

stresses are permissible.
2) Peaking at welded seams

If an irregularity in profile occurs at the welded seam and is associated with “flats” adjacent to the

weld, the irregularity in profile or “peaking” shall not exceed the values given in Table 1.

Table 1 — Maximum permitted peaking for dynamic and cyclic loads
Dimensions in millimetres
Wall thickness
Maximum permitted peaking
e < 3 1,5
3 ≤ e ≤ 6 2,5
6 ≤ e ≤ 9 3,0
9 ≤ e the lesser of e/3, or 10 mm

A conservative method of measurement (covering peaking and ovality) shall be by means of a 20°

profile gauge or template.

The use of such a profile gauge shall be in accordance with Figure 1. Two readings shall be taken, P and

P , on each side of the seam at any particular location, the peaking is taken as being equivalent to

0,25 (P +P ), or P .
1 2 3
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SIST EN 12953-4:2018
EN 12953-4:2018 (E)
a) 20° profile gauge
b) Reading 1
c) Reading 2
d) Negative peaking (flat)
Key
a cut out in gauge to clear weld reinforcement
Figure 1 — Profile gauge and its method of use
c) Out of roundness

Out of roundness u shall be calculated in accordance with the following Formula (1):

2 d− d
u × 100 in % (1)
dd+
where
is the maximum mean diameter of the shell;
is the minimum mean diameter of the shell.

The out of roundness u shall be ≤ 1,5 % for the concerned parts of the shell boiler except for corrugated

furnace.
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SIST EN 12953-4:2018
EN 12953-4:2018 (E)

Measurements shall be made to the surface of the parent plate and not to the weld, fitting or other

raised part.

As example, shell sections should be measured for departure from circularity either when laid flat on

their sides or when set up on end. If the shell sections are checked when laid flat, each measurement for

diameter shall be repeated after turning the shell through 90° about its longitudinal axis. The two

measurements for each diameter shall be averaged to give the out-of-roundness.
Any local departure from circularity shall be gradual.
d) Cold rolling

Cold rolling of a welded shell to rectify a small departure from circularity shall be permitted, provided

that non-destructive testing in accordance with EN 12953-5 is carried out after the departure from

circularity has been remedied.
5.4 Tell-tale holes

Reinforcing plates and saddles of nozzles attached to the outside of a boiler shall be provided with at

least one tell-tale hole. These tell-tale holes may be left open or may be plugged when the boiler is in

service. If the holes are plugged, the plugging material used shall not be capable of sustaining pressure

between the reinforcing plate and the boiler wall.
5.5 End plates and tube plates

If practicable, flat or dished ends shall be made in one piece except that, where the diameter is so large

as to make this impracticable, flat ends may be made from two plates butt welded together

(see Figure A1 in Table A.1). The weld shall be located preferably between two rows of bar stays or, if

there is only one row of bar stays, between this row and the top row of stay tubes.

Dished end plates and flanging of flat end plates shall be produced either by pressing or spinning. The

cylindrical skirt shall have a good surface condition and shall be free from local irregularities.

Cold forming of flat flanged end plates, tube plates and dished ends shall be permitted in accordance

with an agreed approved procedure, including normalizing, if required.

Hot forming of plates that have been dished or flanged at non-uniform temperatures, or that have been

locally heated, shall be normalized after forming unless the manufacturer can demonstrate that the

safety of the component is not affected.

Where hemispherical shell end plates are pressed from one plate, they shall be pressed to form by

machine in progressive stages, and shall be normalized on completion.

Normalizing can be omitted for hot formed ends, when the forming process is completed at

temperatures within the normalizing range.
5.6 Plain tubes and stay tubes

5.6.1 Tubes shall be expanded or welded into the tube plate, or secured by a combination of both

methods.

5.6.2 If the tubes are fully expanded only, the process shall be carried out with roller expanders, and

the expanded portion of the tube shall be parallel throughout the full thickness of the plate.

5.6.3 In addition to expanded tubes, flared tubes, bell-mouthed tubes or beaded tubes shall be

permitted.

5.6.4 Connections of smoke tube to tube sheet shall fulfil the requirements of EN 12953-3:2016, 12.4.

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SIST EN 12953-4:2018
EN 12953-4:2018 (E)
5.7 Manhole frames and openings
5.7.1 Jointing flanges

The jointing flanges of openings and covers shall be machined on the face and edges and on the bearing

surface of the bolt heads and nuts.
5.7.2 Openings for access and inspection
The closing system consists of the following elements:
— gasket;
— metallic closure parts with straight or conical welding rings;
— plain or dished cover;
— studs, nuts, washers and cross-bars.

Recommendations for gaskets that are used for access and inspection openings are indicated in

Annex B.

The inboard cover is braced by studs, nuts and cross-bars and additionally acts self-sealing under

internal pressure. In general, the joint surfaces shall be machined.
a) b) c) d)
Figure 2 — Typical types of closing systems for access and inspection openings
Openings for access an
...

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