kSIST FprEN 12952-1:2026
(Main)Water-tube boilers and auxiliary installations - Part 1: General
- Abstract
This document is applicable to water-tube boilers and boiler assemblies with volumes in excess of two litres for the generation of steam and/or hot water at a maximum allowable pressure PS greater than 0,5 bar and with a temperature in excess of 110 °C as well as auxiliary installations (other plant equipment).
The requirements of this document take account of pressure-related hazards, which apply to water tube boilers, including failure of pressure-retaining components due to overheating.
This document does not apply to the following types of boiler plant:
a) boilers other than stationary boilers;
b) shell type boilers;
c) electrical boilers;
d) nuclear primary circuits, the failure of which can cause an emission of radioactivity.
- Status
- Not Published
- Public Enquiry End Date
- 01-Aug-2024
- Technical Committee
- TLP - Pressure vessels
- Current Stage
- 5020 - Formal vote (FV) (Adopted Project)
- Start Date
- 22-Jul-2026
- Due Date
- 09-Sep-2026
- Completion Date
- 11-Aug-2026
kSIST FprEN 12952-1:2026 is the general part of the EN 12952 series for water-tube boilers and auxiliary installations, published by SIST as an identical adoption of the draft European standard. It sets out the general safety-oriented framework for stationary water-tube boilers and boiler assemblies used to generate steam and/or hot water, and it is written for manufacturers, purchasers, designers and responsible authorities.
What does kSIST FprEN 12952-1:2026 specify?
kSIST FprEN 12952-1:2026 specifies the general requirements for water-tube boilers and boiler assemblies with volumes above two litres, a maximum allowable pressure (PS) greater than 0,5 bar, and a temperature above 110 °C. It also covers auxiliary installations and defines how the parts of the EN 12952 series fit together.
The scope is focused on pressure-related hazards, including overheating that can lead to failure of pressure-retaining parts. The document excludes boilers other than stationary boilers, shell type boilers, electrical boilers, and nuclear primary circuits whose failure could emit radioactivity.
The document is organized into:
- Clause 1 - Scope
- Clause 2 - Normative references
- Clause 3 - Terms and definitions
- Clause 4 - Interdependency of the parts of the series
- Clause 5 - Symbols and abbreviations
- Clause 6 - Equipment and components of water tube boiler
- Clause 7 - Responsibilities
- Clause 8 - Design/type appraisal of pressure parts
- Annex A - Significant technical changes between this document and the previous edition
- Annex ZA - Relationship with Directive 2014/68/EU
| Annex | What it covers |
|---|---|
| Annex A | Significant technical changes compared with the previous edition |
| Annex ZA | Relationship between this European Standard and Directive 2014/68/EU |
What are the key requirements of kSIST FprEN 12952-1:2026?
kSIST FprEN 12952-1:2026 is a framework document: it sets the safety, responsibility and system-boundary rules that the later parts of EN 12952 build on. In practice, it tells users what equipment is in scope, who is responsible for what, and how design and conformity work for pressure parts.
Scope and safety approach
Clause 1 ties the document to essential safety requirements and says the aim is reached through proper design, manufacturing, testing and inspection, plus protective measures and information on residual hazards. For users, this means safety is handled by both technical design and by documenting the remaining risks.
How the boiler assembly is defined
Clause 6.1 defines the boiler assembly that is subject to global conformity assessment. It includes the boiler as a pressure equipment entity from the feedwater inlet, including the inlet valve, to the steam and/or hot water outlet, including the outlet valve or first downstream weld or flange. This matters because it fixes the assessment boundary for the main pressure system.
What can be part of the assembly
Clause 6.1 also allows certain items to be integrated at the manufacturer’s discretion, such as isolatable superheaters, reheaters, economizers, firing systems, fuel preparation and feedwater systems, and pressure expansion vessels and tanks for hot water plants. That helps manufacturers decide which equipment is treated as part of the boiler assembly and which is handled separately.
Other plant equipment
Clause 6.2 lists supporting plant equipment such as structural steelwork, insulation or brickwork, casing, air supply equipment, flue-gas handling equipment and air pollution reducing equipment. In practice, this tells the reader what belongs to the wider boiler plant even if it is not part of the pressure boundary.
Responsibilities of purchaser and manufacturer
Clause 7.1 requires the purchaser to specify normal working conditions, transient and adverse operating conditions, and any special requirements for in-service inspection. Clause 7.2 requires qualified personnel and qualified offices, workshops and sites, with qualification shown by a competency declaration. This is important because design and procurement need clear operating data and evidence of capability.
Case-by-case design/type appraisal
Clause 8 says pressure parts are appraised case by case according to the design and manufacturing details involved. Where manufacturing changes or concessions are needed, they are allowed only if safety and required function are not impaired, and they must be recorded in the technical documentation and the manufacturer’s data dossier.
What terms does kSIST FprEN 12952-1:2026 define?
kSIST FprEN 12952-1:2026 defines the main parties involved in the design, supply and independent oversight of boiler work. These terms matter because they assign responsibility across the supply chain.
- Purchaser - the individual or organization that buys the boiler or part of it.
- Manufacturer - the party responsible for design, fabrication, testing, relevant installation and compliance, even when subcontractors do the work.
- Designer - the party that designs the boiler plant on behalf of the manufacturer, including shape, dimensions, thicknesses, materials and construction methods.
- Material supplier - a supplier of material or prefabricated parts used in pressure components, other than a material manufacturer.
- Material manufacturer - the producer of material in the basic product form used to make pressure equipment.
- Responsible authority (RA) - an independent competent organization such as a notified body, recognized third-party organization or user inspectorate.
Who uses kSIST FprEN 12952-1:2026?
kSIST FprEN 12952-1:2026 is used by boiler manufacturers, designers, purchasers, inspection bodies and responsible authorities working with water-tube boiler plant. It is also relevant to teams handling procurement, qualification, construction, inspection and conformity assessment of pressure parts.
What changed in kSIST FprEN 12952-1:2026 from the previous edition?
kSIST FprEN 12952-1:2026 supersedes EN 12952-1:2015. The stated changes include alignment with the latest versions of the other EN 12952 parts and with the latest version 6.0 of the guidelines related to Directive 2014/68/EU, updated normative references, addition of symbol W in the symbols table, a revised scope for the boiler assembly, a revised Annex ZA, and a revised bibliography.
Which standards are used with kSIST FprEN 12952-1:2026?
kSIST FprEN 12952-1:2026 cites EN 764-1:2016, EN 12952-5:2021 and EN 12952-6:2021 as normative references. EN 764-1 provides the general pressure equipment vocabulary, EN 12952-5 supports workmanship and construction of pressure parts, and EN 12952-6 supports inspection during construction, documentation and marking.
The foreword also places this part within the EN 12952 series and notes the interdependence of the parts. That means users normally need more than this general part when they design, build or inspect a boiler.
What does the kSIST FprEN 12952-1:2026 document contain?
kSIST FprEN 12952-1:2026 contains a very large table of symbols and abbreviations for design calculations, including dimensions, pressures, stresses, efficiencies and temperatures. It also contains the boiler-assembly boundary definition, the responsibilities of purchaser and manufacturer, and the case-by-case rules for design/type appraisal of pressure parts.
Annex A summarizes the significant technical changes from the previous edition, while Annex ZA maps selected clauses to the essential requirements of Directive 2014/68/EU. For users, that means the document is not only a general description - it also supports calculation, conformity assessment and documentation work.
Relations
- Effective Date
- 28-Jan-2026
- Effective Date
- 01-Jul-2024
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Frequently Asked Questions
kSIST FprEN 12952-1:2026 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Water-tube boilers and auxiliary installations - Part 1: General". This standard covers: This document is applicable to water-tube boilers and boiler assemblies with volumes in excess of two litres for the generation of steam and/or hot water at a maximum allowable pressure PS greater than 0,5 bar and with a temperature in excess of 110 °C as well as auxiliary installations (other plant equipment). The requirements of this document take account of pressure-related hazards, which apply to water tube boilers, including failure of pressure-retaining components due to overheating. This document does not apply to the following types of boiler plant: a) boilers other than stationary boilers; b) shell type boilers; c) electrical boilers; d) nuclear primary circuits, the failure of which can cause an emission of radioactivity.
This document is applicable to water-tube boilers and boiler assemblies with volumes in excess of two litres for the generation of steam and/or hot water at a maximum allowable pressure PS greater than 0,5 bar and with a temperature in excess of 110 °C as well as auxiliary installations (other plant equipment). The requirements of this document take account of pressure-related hazards, which apply to water tube boilers, including failure of pressure-retaining components due to overheating. This document does not apply to the following types of boiler plant: a) boilers other than stationary boilers; b) shell type boilers; c) electrical boilers; d) nuclear primary circuits, the failure of which can cause an emission of radioactivity.
kSIST FprEN 12952-1:2026 is classified under the following ICS (International Classification for Standards) categories: 27.040 - Gas and steam turbines. Steam engines; 27.060.30 - Boilers and heat exchangers. The ICS classification helps identify the subject area and facilitates finding related standards.
kSIST FprEN 12952-1:2026 has the following relationships with other standards: It is inter standard links to SIST-TP CEN/TR 12952-17:2024, SIST EN 12952-1:2016. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
kSIST FprEN 12952-1:2026 is associated with the following European legislation: EU Directives/Regulations: 2014/68/EU; Standardization Mandates: M/071, M/601. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
kSIST FprEN 12952-1:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 12952-1:2024
01-julij-2024
Vodocevni kotli in pomožne napeljave - 1. del: Splošno
Water-tube boilers and auxiliary installations - Part 1: General
Wasserrohrkessel und Anlagenkomponenten - Teil 1: Allgemeines
Chaudières à tubes d'eau et installations auxiliaires - Partie 1: Généralités
Ta slovenski standard je istoveten z: prEN 12952-1
ICS:
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
oSIST prEN 12952-1:2024 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 12952-1:2024
oSIST prEN 12952-1:2024
DRAFT
EUROPEAN STANDARD
prEN 12952-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2024
ICS Will supersede EN 12952-1:2015
English Version
Water-tube boilers and auxiliary installations - Part 1:
General
Chaudières à tubes d'eau et installations auxiliaires - Wasserrohrkessel und Anlagenkomponenten - Teil 1:
Partie 1: Généralités Allgemeines
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 269.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12952-1:2024 E
worldwide for CEN national Members.
oSIST prEN 12952-1:2024
prEN 12952-1:2024 (E)
Contents Page
European foreword . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Interdependency of the parts of the series . 7
5 Symbols and abbreviations . 7
6 Equipment and components of water tube boiler . 11
6.1 Boiler assembly . 11
6.2 Other plant equipment . 12
7 Responsibilities . 12
7.1 Purchaser . 12
7.2 Manufacturer . 12
7.2.1 Qualification . 12
7.2.2 Demonstration of qualification . 12
8 Design/type appraisal of pressure parts . 12
Annex A (informative) Significant technical changes between this document and the
previous edition . 13
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2014/68/EU aimed to be covered . 14
oSIST prEN 12952-1:2024
prEN 12952-1:2024 (E)
European foreword
This document (prEN 12952-1:2024) has been prepared by Technical Committee CEN/TC 269 “Shell and
water-tube boilers”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document supersedes EN 12952-1:2015.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For relationship with EU legislation(s), see informative Annex ZA which is an integral part of this
document.
The informative Annex A lists the significant technical changes between this document and the previous
edition.
EN 12952, 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 14: Requirements for flue gas DENOX-systems using liquefied 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;
oSIST prEN 12952-1:2024
prEN 12952-1:2024 (E)
— CEN/TR 12952 Part 17 Part 17: Guideline for the involvement of an inspection body independent of
the manufacturer;
— Part 18: Operating instructions.
Although these parts can be obtained separately, it is 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 the document 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
oSIST prEN 12952-1:2024
prEN 12952-1:2024 (E)
1 Scope
This document applies to water-tube boilers and boiler assemblies with volumes in excess of two litres
for the generation of steam and/or hot water at a maximum allowable pressure PS greater than 0,5 bar
and with a temperature in excess of 110 °C as well as auxiliary installations (other plant equipment).
The purpose of this document is to ensure that the necessary essential safety requirements according to
Annex I of the Pressure Equipment Directive are fulfilled in order to guarantee the safety of water tube
boilers.
This aim will be achieved by:
— the proper application of the design, manufacturing, testing and inspection methods and techniques,
— the provision of protective measures against hazards, which cannot be eliminated, and
— the provision of information on residual hazards and other measures to reduce risk,
which are incorporated in the various parts of this document.
The requirements of this document take account of pressure-related hazards, which apply to water tube
boilers, including failure of pressure-retaining components due to overheating.
This standard recognizes that it is not possible to cover all the combinations of situations that might arise.
This document does not apply to the following types of boiler plant:
a) boilers other than stationary boilers;
b) shell type boilers;
c) electrical boilers;
d) nuclear primary circuits, the failure of which can cause an emission of radioactivity.
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 764-1:2016, Pressure equipment — Part 1: Vocabulary
EN 12952-5:2021, Water-tube boilers and auxiliary installations - Part 5: Workmanship and construction
of pressure parts of the boiler
EN 12952-6:2021, Water-tube boilers and auxiliary installations - Part 6: Inspection during construction,
documentation and marking of pressure parts of the boiler
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 764-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
ISO Online browsing platform: available at https://www.iso.org/obp/
IEC Electropedia: available at https://www.electropedia.org/
oSIST prEN 12952-1:2024
prEN 12952-1:2024 (E)
3.1
purchaser
individual or organization that buys the boiler or a part thereof
3.2
manufacturer
individual or organization responsible for the design, fabrication, testing, installation where relevant, and
compliance with the requirements of the relevant product standard, whether executed by him or a
subcontractor
Note 1 to entry: The manufacturer can subcontract one or more of the abovementioned tasks under their
responsibility.
[SOURCE: EN 764-1:2016, 3.5.5, modified – Note 1 complete and Note 2 deleted.]
3.3
designer
individual or organization that, on behalf of the manufacturer, carries out the design of the boiler plant
Note 1 to entry: The designer determines the shape, dimensions and thicknesses of the boiler plant components,
selects the materials and details the methods of construction and testing.
3.4
material supplier
individual or organization, not being a material manufacturer, that supplies material or prefabricated
parts to be used in the construction of pressure components
[SOURCE: EN 764-1:2016, 3.5.7]
3.5
material manufacturer
individual or organization that produces material in the basic product form used in the manufacture of
pressure equipment
[SOURCE: EN 764-1:2016, 3.5.6]
3.6
responsible authority
competent organizations which are independent of the manufacturer
Note 1 to entry: This standard identifies responsible authorities. Such organizations may be notified bodies,
recognized third-party organizations or user inspectorates. For the purpose of this standard, these organizations
have been collectively termed responsible authorities (RA).
Note 2 to entry: The definition of a notified body and the criteria controlling its operation are given in Article 24 of
the Pressure Equipment Directive 2014/68/EU.
Note 3 to entry: The definition of a recognized third-party organization and the criteria controlling its operation are
given in Article 24 of the Pressure Equipment Directive 2014/68/EU.
Note 4 to entry: The definition of a user inspectorate and the criteria controlling its operation are given in Article 25
of the Pressure Equipment Directive 2014/68/EU.
Note 5 to entry: The responsibility of the manufacturer is described in 3.2.
oSIST prEN 12952-1:2024
prEN 12952-1:2024 (E)
4 Interdependency of the parts of the series
EN 12952-1 to EN 12952-18 form a consistent set of specifications to be followed.
NOTE 1 Parts 4, 12, 13 and 15 of the series are published as supporting European Standards.
NOTE 2 Part 17 of the series is published as a CEN Report. It is not a European Standard.
5 Symbols and abbreviations
For the purposes of this document, the general symbols and abbreviations given in Table 1 shall apply.
Table 1 — Symbols
Symbol Description Unit
A area mm
Af effective cross-sectional area without allowances mm
A effective cross-sectional area of branch mm
fb
A effective cross-sectional area of reinforcing pad mm
fp
Afs effective cross-sectional area of main body mm
Ap pressurized area without allowances mm
A pressurized area referred to branch mm
pb
A pressurized area referred to main body mm
ps
As shell cross-sectional area referred to main body mm
C shape factor —
C1 shape factor for unstayed ends or plates —
c allowance to consider the minus tolerance of wall thickness mm
C shape factor for rectangular and elliptical plates —
c2 allowance for metal wastage mm
C3 shape factor for flat plates with openings —
d diameter of tube hole (if applicable in the condition after metal wastage) mm
d diameter of counter boring for expanded tubes mm
di inside diameter mm
dib inside diameter of branch without allowances mm
d inside diameter of main body (cylindrical shell, sph
...