EN 12953-9:2007

SLOVENSKI STANDARD
01-september-2007
Mnogovodni kotli - 9. del: Zahteve za omejilne naprave kotla in opremo
Shell boilers - Part 9: Requirements for limiting devices of the boiler and accessories
Großwasserraumkessel - Teil 9: Anforderungen an Begrenzungseinrichtungen an Kessel
und Zubehör
Chaudieres a tubes de fumée - Partie 9: Exigences pour les dispositifs de limitation de la
chaudiere et de ses accessoires
Ta slovenski standard je istoveten z: EN 12953-9:2007
ICS:
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.

EUROPEAN STANDARD
EN 12953-9
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2007
ICS 27.060.30
English Version
Shell boilers - Part 9: Requirements for limiting devices of the
boiler and accessories
Chaudières à tubes de fumée - Partie 9: Exigences pour Großwasserraumkessel - Teil 9: Anforderungen an
les dispositifs de limitation de la chaudière et de ses Begrenzungseinrichtungen an Kessel und Zubehör
accessoires
This European Standard was approved by CEN on 26 May 2007.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12953-9:2007: E
worldwide for CEN national Members.

Contents Page
Foreword. 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Requirements for limiter . 9
4.1 General. 9
4.2 Materials and design . 9
4.3 Electrical equipment. 10
4.4 Fault assessment. 10
4.5 Marking . 12
5 Special requirements for water level limiters .14
5.1 Components. 14
5.2 Design . 14
5.3 Floating devices. 15
5.4 Level electrode devices . 15
5.5 Examination of functional capability . 16
5.6 Fault detection . 19
6 Special requirements for pressure limiters .19
6.1 Components. 19
6.2 Additional fault assessment requirements .19
6.3 Design . 19
6.4 Electrical equipment. 20
6.5 Examination of functional capability . 20
6.6 Fault detection . 22
7 Special requirements for temperature limiters. 22
7.1 Components. 22
7.2 Design . 22
7.3 Electrical equipment. 24
7.4 Examination of functional capability . 24
8 Special requirements for flow limiters. 25
8.1 Components. 25
8.2 Design . 25
8.3 Electrical equipment. 25
8.4 Examination of functional capability . 25
Annex A (informative) Limiting device. 26
Annex B (informative) Example of an examination plan . 27
Annex C (informative) Marking of limiters . 29
Annex D (normative) Immunity against electrical and electromagnetic influences —
Requirements and testing. 32
D.1 General. 32
D.2 Immunity against mains voltage variations .32
D.3 Immunity against short-time voltage interruptions and reductions. 32
D.4 Immunity against mains frequency changes. 33
D.5 Immunity against electrostatic discharge (ESD). 33
D.6 Immunity against fast transient disturbance variables (burst). 33
D.7 Immunity against surges . 34
D.8 Immunity against high-frequency electromagnetic fields. 34
D.9 Immunity against conducted disturbances induced by high frequency fields. 35
D.10 Immunity against power frequency magnetic fields. 35
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 97/23/EC. 36
Bibliography. 37

Foreword
This document (EN 12953-9:2007) 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 January 2008 and conflicting national standards shall be withdrawn at
the latest by January 2008.
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 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 the involvement of an inspection body independent of the manufacturer.
Although these Parts may be obtained separately, it should be recognised 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.
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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and United Kingdom.
Introduction
The types of limiters which shall be fitted to boilers are specified in EN 12953-6 and the design of the safety
systems are specified in EN 50156-1.
A limiter (or limiting device) is one element of a shell boiler safety system. It comprises a sensor and
monitoring elements to achieve the desired level of reliability.
In order to provide the necessary safety function, for example, to cut off the heat supply to the boiler in the
event of a low water fault, the limiter is connected to other elements in the safety system such as actuators
and safety logic circuits.
1 Scope
This European Standard specifies requirements for limiters (or limiting devices) which are incorporated into
safety systems for shell boilers as defined in EN 12953-1.
A limiter (or limiting device) can be either:
 a safety accessory as defined in the Pressure Equipment Directive, Article 1, clause 2.1.3, and needs to
include the safety logic and final actuator, or
 one element of a safety system, for example, a self-monitoring water level sensor used as part of a safety
accessory as defined in the Pressure Equipment Directive, Article 1, clause 2.1.3. The overall boiler
protection function needs to be provided in association with additional safety logic (where appropriate)
and a final actuator.
The design requirements and examination of functional capability for the limiters are covered in this European
Standard.
For an explanation of the extent of the limiter (or limiting device) see Figure A.1.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 298:2003,
...