EN 12953-7:2002

SLOVENSKI STANDARD
01-november-2002
Mnogovodni kotli - 7. del: Zahteve za gorilnike kotlov na tekoča in plinasta goriva
Shell boilers - Part 7 : Requirements for firing systems for liquid and gaseous fuels for
the boilers
Großwasserraumkessel - Teil 7 : Anforderungen an Feuerungsanlagen für flüssige und
gasförmige Brennstoffe für den Kessel
Chaudieres a tubes de fumée - Partie 7 : Exigences pour les équipements de chauffe
pour combustibles gazeux et liquides de la chaudiere
Ta slovenski standard je istoveten z: EN 12953-7:2002
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 12953-7
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2002
ICS 27.060.30; 27.100
English version
Shell boilers - Part 7 : Requirements for firing systems for liquid
and gaseous fuels for the boilers
Chaudières à tubes de fumée - Partie 7 : Exigences pour Großwasserraumkessel - Teil 7 : Anforderungen an
les équipements de chauffe pour combustibles gazeux et Feuerungsanlagen für flüssige und gasförmige Brennstoffe
liquides de la chaudière für den Kessel
This European Standard was approved by CEN on 15 May 2002.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2002 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12953-7:2002 E
worldwide for CEN national Members.

Contents
page
Foreword . 3
1 Scope. 4
2 Normative references. 4
3 Terms and definitions . 4
4 Fuel supply. 6
4.1 Fuel transfer and preparation . 6
4.2 Fuel lines . 6
4.3 Safety shut-off devices (Safety trip valves). 7
5 Air supply, air/fuel ratio . 7
6 Firing system . 8
6.1 Burners. 8
6.2 Inspection openings. 8
6.3 Purging, start-up and shutdown. 8
6.4 Common stack for several firing systems. 8
6.5 Fuels . 8
Annex ZA (informative) Clauses of this European Standard addressing essential requirements or other
provisions of EU Directives. 9
Bibliography. 10
Foreword
This document (EN 12953-7:2002) 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 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 standard.
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 November 2002, and conflicting national standards shall be withdrawn at the latest
by November 2002.
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 boiler feedwater and boiler water quality.

Part 11: Acceptance tests.

Part 12: Requirements for firing systems for solid fuels for the boiler.

Part 13: Operating instructions.
CR 12953-14: Guidelines for the involvement of an inspection body independent of the manufacturer.
Although these Parts can be obtained separately, it should be recognized that the Parts are inter-dependent. 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.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland and the United Kingdom.
1 Scope
This Part of this European Standard specifies requirements for firing systems for oil and gaseous fuels applicable to
shell boilers, as defined in EN 12953-1, irrespective of the degree of supervision. For multifuel firing systems using
separate or combined burners, these requirements apply to the oil and/or gas firing part involved.
This Part of this European Standard specifies the improved safety measures required when several fuels are burnt
simultaneously.
2 Normative references
This European Standard incorporates, by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the
publication referred to applies (including amendments).
EN 267, Forced draught oil burners - Definitions, requirements, testing, marking.
EN 676, Automatic forced draught burners for gaseous fuels.
EN 12953-1,


 General.
3 Terms and definitions
For the purposes of this Part of this European Standard, the following terms and definitions apply.
3.1
liquid fuels
light fuel oils, and heavy fuel oils which need preheating for proper atomisation
3.2
gaseous fuels
standardized quality differentiated mainly by their relative density
3.2.1
light gases
with relative density below 1,3 e.g. natural gas, coke-oven gas, blast-furnace gas
NOTE Natural gas in accordance with ISO 6976.
3.2.2
heavy gases
with relative densities exceeding 1,3 e.g. liquefied petroleum gases, the main components of which are propane
and butane
3.3
burners
devices for the introduction of fuel and air into a combustion chamber at required velocities, turbulence and local
fuel concentration to establish and maintain proper ignition and stable combustion of the fuel
3.4
burner management system
performs a predetermined sequence of actions and always operates in conjunction with a flame monitor that reacts
to signals from control and safety devices, gives control commands, controls the start-up sequence, supervises the
burner operation, and causes controlled shutdown and lockout
3.5
firing system
total equipment required for the combustion of fuels including the installations for the storage, preparation, and
supply of fuels, the combustion air supply, the burner(s), the flue gas discharge, and all related control and moni-
toring devices
NOTE A flue gas re-circulation system can be installed as an integral part of the firing system.
3.6
firing system heat input
heat input into the combustion chamber, including the reserve required for load control at which the boiler can be
safely operated
NOTE The mass flow of the fuel supplied multiplied by the net calorific value.
3.7
flame monitor
device which detects the presence or absence or break-away of the flame and transmits a signal to the control de-
vice, and generally, consists of a sensing device (if necessary with amplifier) and switching equipment
3.8
flue gas re-circulation
return of flue gas from downstream of the flame zone or from the flue gas exit by hydrodynamic pressure difference
or a separate fan into the air register of the burner or directly into the combustion chamber
3.9
limiters
device that, on reaching a fixed value (e.g. pressure, temperature, flow, water level) is used to interrupt and lock-out
the energy supply and requires manual unlocking before restart
3.10
lock-out
isolation of energy supply which requires a manual intervention to reinstate
NOTE See EN 676 for definition of non-volatile lock-out.
3.11
master fuel trip
device for rapid automatic shut-off of all fuel supplies to the boiler area in the event of danger which may act by
automatic, manual or emergency switch initiation even if a possible electrical or mechanical fault occurs
3.12
firing rate of the burner
rate at which the burner may be operated
3.13
multi-fuel burners
burners in which more than one fuel is burned either simultaneously or separately
3.14
purging of the flue gas passes
forced flow of air through the combustion chamber, flue gas passes, and associated ducts which effectively re-
moves any combustible products and replaces them with air
3.16
relative density
ratio of the density of the gas to the density of dry air under equal conditions of pressure and temperature
3.17
return-flow atomizer
oil burners where a portion of the quantity of oil supplied to the burner via the flow line does not flow from a burner
gun into the combustion chamber, but flows backwards into the storage tank or the suction side of the pump via a
separate return line, the output being adjusted by a control device in the return line
4 Fuel supply
4.1 Fuel transfer and p
...