EN 12952-10:2021

SLOVENSKI STANDARD
01-februar-2022
Nadomešča:
SIST EN 12952-10:2003
Vodocevni kotli in pomožne napeljave - 10. del: Zahteve za opremo in varnostne
naprave za preprečevanje prekoračitve tlaka
Water-tube boilers and auxiliary installations - Part 10: Requirements for safety devices
against excessive pressure
Wasserrohrkessel und Anlagenkomponenten - Teil 10: Anforderungen an
Sicherheitseinrichtungen gegen Überdruck
Chaudières à tubes d’eau et installations auxiliaires - Partie 10 : Exigences pour la
protection vis-à-vis des excés de pression
Ta slovenski standard je istoveten z: EN 12952-10:2021
ICS:
13.240 Varstvo pred previsokim Protection against excessive
tlakom pressure
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 12952-10
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2021
EUROPÄISCHE NORM
ICS 23.060.40; 27.040 Supersedes EN 12952-10:2002
English Version
Water-tube boilers and auxiliary installations - Part 10:
Requirements for safety devices against excessive
pressure
Chaudières à tubes d'eau et installations auxiliaires - Wasserrohrkessel und Anlagenkomponenten - Teil 10:
Partie 10 : Exigences pour la protection vis-à-vis des Anforderungen an Sicherheitseinrichtungen gegen
excés de pression Überdruck
This European Standard was approved by CEN on 1 November 2021.

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, Republic of North Macedonia, 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12952-10:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Symbols and abbreviations . 6
5 Requirements . 7
5.1 Steam boiler . 7
5.2 Hot water generator . 10
5.3 Safety shut-off valves . 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

European foreword
This document (EN 12952-10:2021) 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 2022, and conflicting national standards shall be
withdrawn at the latest by June 2022.
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 12952-10:2002.
EN 12952 series, 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;
• 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;
• 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;
• CR 12952 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 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 the document to be satisfactorily fulfilled.
NOTE A “Boiler Helpdesk” has been established in CEN/TC 269 which may be contacted for any questions
regarding the application of EN 12952 series and EN 12953 series, see the following website: http://www.boiler-
helpdesk.din.de
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s) / Regulation(s).
For relationship with EU Directive(s) / Regulation(s), see informative Annex ZA, which is an integral part
of this document.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
1 Scope
This document specifies the requirements for safety devices against excessive pressure in water-tube
boilers as defined in EN 12952-1:2015.
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 ISO 4126-1:2013, Safety devices for protection against excessive pressure - Part 1: Safety valves
(ISO 4126-1:2013)
EN ISO 4126-4:2013, Safety devices for protection against excessive pressure - Part 4: Pilot-operated safety
valves (ISO 4126-4:2013)
EN ISO 4126-5:2013, Safety devices for protection against excessive pressure - Part 5: Controlled safety
pressure relief systems (CSPRS) (ISO 4126-5:2013)
EN 764-7:2002, Pressure equipment - Part 7: Safety systems for unfired pressure equipment
EN 12952-1:2015, Water-tube boilers and auxiliary installations - Part 1: General
EN 13480-3:2017, Metallic industrial piping - Part 3: Design and calculation
ISO 4126-9:2008, Safety devices for protection against excessive pressure — Part 9: Application and
installation of safety devices excluding stand-alone bursting disc safety devices
3 Terms and definitions
For the purposes of this document the terms and definitions given in EN 12952-1:2015, EN ISO 4126-
1:2013, EN ISO 4126-4:2013 and EN ISO 4126-5:2013 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at http://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/

Document impacted by EN ISO 4126-1:2013/A1:2016 and EN ISO 4126-1:2013/A2:2019.
Document impacted by EN ISO 4126-5:2013/A1:2016.
Document impacted by EN 764-7:2002/AC:2006.
4 Symbols and abbreviations
For the purposes of this document, the symbols given in EN 12952-1:2015, Table 1 shall apply.
Throughout this document, additional terminology and symbols have been included where necessary to
meet the requirements of the specific text concerned (see Table 1 and Figure 1).
Table 1 — Symbols and units
Symbol Explanation Unit
D inlet pipe internal diameter mm
E
d0 smallest flow diameter (minimum free bore) mm
L developed length of inlet pipe mm
E
Key
DE inlet pipe internal diameter, in mm
d0 smallest flow diameter (minimum free bore), in mm
L developed length of inlet pipe, in mm
E
Figure 1 — Safety valves
5 Requirements
5.1 Steam boiler
5.1.1 Each steam boiler and each isolatable heated compartment (e.g. reheater, superheater,
economizer) shall be provided with at least one suitable safety device which shall ensure against
excessive pressure. The total certified discharge capacity of all safety devices mounted on the boiler shall
be at least equal to the maximum continuous rating (MCR) of the boiler. Pressure relieving devices shall
be installed in accordance with relevant parts of EN 764-7:2002. The suitability of the safety device shall
be demonstrated by a hot test on the assembled boiler.
The number and type of safety devices to be installed shall be specified by the manufacturer and shall
meet the requirements of this clause.
At least one of the following safety devices shall be considered suitable:
a) safety valves in accordance with EN ISO 4126-1:2013 or;
b) pilot-operated safety valve (POSV) in accordance with EN ISO 4126-4:2013, consisting of a main
valve, controlled by signals from 3 pilot valves;
c) controlled safety pressure relief system (CSPRS) in accordance with EN ISO 4126-5:2013, consisting
of a main valve, controlled by 3 redundant control paths.
In the case of safety devices in accordance with b) and c) the following shall apply:
• The safety device shall be capable of operating when the signal from only one pressure sensing line
is available.
• The size and position of the pressure sensing lines shall ensure that the risk of loss of function is
reduced to a minimum.
NOTE 1 The common size of sensing line is 15 mm internal diameter.
• The mechanical and electrical parts of the pilot and control unit which are used to actuate the main
valves shall still be functionally fit even in the case of an assumed individual defect.
• It shall be possible to prove the reliability of the safety pressure relief device by functional testing on
the plant.
It is permissible to operate more than one main valve from a single control unit.
Safety devices shall have a set pressure not exceeding the maximum allowable pressure (PS) of the
equipment to be protected, except as permitted as follows.
The discharge capacity corresponding to the required relief capacity at maximum continuous rating of
the applicable boiler parts shall be achieved without causing the pressure to be increased by more than
10 % of the maximum allowable pressure. The duration of the pressure increase up to 1,1 PS shall not
exceed 1 h per event.
If the capacity is provided by more than one safety device, only one of the devices needs to be set at a
pressure not exceeding PS. The other device(s) may be set at a pressure not more than 5 % in excess of
PS In these cases, it is necessary to use safety devices with certified overpressure lower than 10 %.
.
NOTE 2 More information can be found in EN 764-7:2002, Annex A.
The pressure at which a safety device is set to operate shall take into account the effect of static head, of
superimposed back pressure and whether this is constant or variable.
5.1.2 The minimum flow diameter of s
...