SIST EN 12952-8:2022
(Main)Water-tube boilers and auxiliary installations - Part 8: Requirements for firing systems for liquid and gaseous fuels for the boiler
Water-tube boilers and auxiliary installations - Part 8: Requirements for firing systems for liquid and gaseous fuels for the boiler
This Part of this European Standard specifies requirements, for liquid and gaseous fuel firing systems of steam boilers and hot water generators as defined in EN 12952-1.
These requirements also apply to firing systems of chemical recovery boilers (black liquor boilers) with the additions and amendments specified in Annex A of this standard.
These requirements also apply to gas turbines in combination with fired/unfired heat recovery steam generators with the additions and amendments specified in Annex B of this standard.
NOTE 1 This standard is not applicable to coil type boilers (flash boilers/small boilers) that use burners in accordance with EN 12953 7 apply for single burner installations.
NOTE 2 This standard is not applicable to the storage of liquid fuels and to transfer stations of long-distance gas pipelines.
Wasserrohrkessel und Anlagenkomponenten - Teil 8: Anforderungen an Feuerungsanlagen für flüssige und gasförmige Brennstoffe für den Kessel
1.1 Feuerungsanlagen
Dieses Dokument legt Anforderungen an Feuerungsanlagen für flüssige und gasförmige Brennstoffe von Dampf- und Heißwassererzeugungsanlagen nach EN 12952 1:2015 fest.
Diese Anforderungen gelten für Feuerungsanlagen von Laugenrückgewinnungskesseln (Schwarzlaugen-kesseln) mit den in Anhang A aufgeführten Zusätzen und Ergänzungen.
Diese Anforderungen gelten auch für Gasturbinen in Kombination mit befeuerten/unbefeuerten Wärmerückgewinnungsdampferzeugern, mit den in Anhang B festgelegten Zusätzen und Ergänzungen.
ANMERKUNG 1 Dieses Dokument gilt nicht für Spiralrohrkessel (Schnellverdampfer/kleine Kessel), für die Öl- und Gasfeuerungsanlagen nach EN 12953 7 für Anlagen mit Einzelbrenner verwendet werden.
ANMERKUNG 2 Dieses Dokument gilt nicht für die Lagerung flüssiger Brennstoffe und für Übergabestationen für Ferngas.
1.2 Brennstoffe
Die in diesem Dokument festgelegten Anforderungen gelten für flüssige und gasförmige Brennstoffe nach diesem Dokument. Für nicht normgerechte handelsübliche flüssige oder gasförmige Brennstoffe können zusätzliche oder alternative Sicherheitsmaßnahmen notwendig werden. Für Schwarzlauge sind diese Sicherheitsmaßnahmen in Anhang A aufgeführt.
Chaudières à tubes d'eau et installations auxiliaires - Partie 8 : Exigences pour les équipements de chauffe pour combustibles gazeux et liquides de la chaudière
1.1 Équipements de chauffe
Le présent document spécifie les prescriptions relatives aux équipements de chauffe pour combustibles liquides et gazeux pour les chaudières à vapeur et les générateurs d'eau surchauffée définis dans l’EN 12952 1:2015.
Ces exigences s’appliquent aussi aux équipements de chauffe des chaudières de récupération chimique (chaudières à liqueur noire) avec les compléments et les amendements spécifiés dans l’Annexe A.
Ces prescriptions s'appliquent également aux turbines à gaz combinées à des générateurs de vapeur à récupération de chaleur avec ou sans combustion, avec les ajouts et modifications précisés à l'Annexe B.
NOTE 1 Ce document ne s‘applique pas aux chaudières à serpentins (chaudières à vaporisation instantanée/chaudières à faible volume) utilisant des brûleurs conformément à l’EN 12953 7 pour les installations à brûleur unique.
NOTE 2 Ce document ne s‘applique pas au stockage de combustibles liquides et aux postes de livraison équipés de tuyauteries de transport de très grande longueur.
1.2 Combustibles
Le présent document spécifie les exigences qui concernent l’utilisation de combustibles liquides et gazeux tels que définis dans ce document. Les combustibles s'écartant des types normalisés disponibles dans le commerce peuvent nécessiter des mesures de sécurité supplémentaires ou alternatives. Pour la liqueur noire, ces mesures de sécurité sont données en Annexe A.
Vodocevni kotli in pomožne napeljave - 8. del: Zahteve za gorilnike kotlov na tekoča in plinasta goriva
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 12952-8:2022
01-december-2022
Nadomešča:
SIST EN 12952-8:2002
Vodocevni kotli in pomožne napeljave - 8. del: Zahteve za gorilnike kotlov na
tekoča in plinasta goriva
Water-tube boilers and auxiliary installations - Part 8: Requirements for firing systems for
liquid and gaseous fuels for the boiler
Wasserrohrkessel und Anlagenkomponenten - Teil 8: Anforderungen an
Feuerungsanlagen für flüssige und gasförmige Brennstoffe für den Kessel
Chaudières à tubes d'eau et installations auxiliaires - Partie 8 : Exigences pour les
équipements de chauffe pour combustibles gazeux et liquides de la chaudière
Ta slovenski standard je istoveten z: EN 12952-8:2022
ICS:
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
SIST EN 12952-8:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN 12952-8:2022
---------------------- Page: 2 ----------------------
SIST EN 12952-8:2022
EN 12952-8
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2022
EUROPÄISCHE NORM
ICS 27.040 Supersedes EN 12952-8:2002
English Version
Water-tube boilers and auxiliary installations - Part 8:
Requirements for firing systems for liquid and gaseous
fuels for the boiler
Chaudières à tubes d'eau et installations auxiliaires - Wasserrohrkessel und Anlagenkomponenten - Teil 8:
Partie 8 : Exigences pour les équipements de chauffe Anforderungen an Feuerungsanlagen für flüssige und
pour combustibles gazeux et liquides de la chaudière gasförmige Brennstoffe für den Kessel
This European Standard was approved by CEN on 15 August 2022.
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, Türkiye 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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12952-8:2022 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
Contents Page
European foreword . 4
1 Scope . 6
1.1 Firing systems . 6
1.2 Fuels . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Fuel supply . 11
4.1 General. 11
4.2 Fuel transfer and preparation . 11
4.3 Fuel lines . 12
4.4 Safety shut-off devices (Safety trip valves) . 13
5 General. 15
5.1 Air supply . 15
5.2 Air/fuel ratio . 16
5.3 Flue gas discharge . 16
6 Firing system . 17
6.1 Burners . 17
6.2 Flue gas recirculation . 18
6.3 Control and monitoring . 18
6.4 Electrical equipment. 19
6.5 Safety precautions . 19
6.6 Common stack for several firing systems . 20
7 Operating manual . 20
8 Particular requirements for firing systems burning gaseous fuels with high relative
density . 20
8.1 Main firing systems . 20
8.2 Ignition burner systems . 21
Annex A (normative) Chemical recovery boiler (black liquor boiler) . 22
A.1 General. 22
A.2 Additional requirements for the firing system for black liquor in the chemical
recovery boiler . 22
A.3 Special requirements for oil- or gas firing for chemical recovery boilers . 23
Annex B (normative) Gas turbines in combination with heat recovery steam generators . 25
B.1 General. 25
B.2 Additional requirements for gas turbines in combination with heat recovery steam
generators . 25
Annex C (informative) Operational requirements for permanent supervised firing systems
for liquid and gaseous fuels . 27
C.1 General. 27
2
---------------------- Page: 4 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
C.2 Operation . 27
C.3 Fuel preparation . 27
C.4 Safety shutoff devices . 27
C.5 Air/fuel ratio . 27
C.6 Modification of firing, burner or air/fuel ratio setting . 27
C.7 Control and monitoring . 28
C.8 Emergency operation . 28
C.9 Operating and maintenance instructions . 28
C.10 Firing systems burning gaseous fuels with high relative density . 28
Annex D (informative) Significant technical changes between this document and the
previous edition . 30
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2014/68/EU aimed to be covered . 31
Bibliography . 33
3
---------------------- Page: 5 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
European foreword
This document (EN 12952-8:2022) 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 April 2023, and conflicting national standards shall be
withdrawn at the latest by April 2023.
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 12952-8:2002.
The technical modifications in comparison with the previous edition are listed in Annex D.
The 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.
4
---------------------- Page: 6 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
• 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.
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, Türkiye and the United
Kingdom.
5
---------------------- Page: 7 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
1 Scope
1.1 Firing systems
This document specifies requirements for liquid and gaseous fuel firing systems of steam boilers and hot
water generators as defined in EN 12952-1:2015.
These requirements also apply to firing systems of chemical recovery boilers (black liquor boilers) with
the additions and amendments specified in Annex A.
These requirements also apply to gas turbines in combination with fired/unfired heat recovery steam
generators with the additions and amendments specified in Annex B.
NOTE 1 This document is not applicable to coil type boilers (flash boilers/small boilers) that use burners in
accordance with EN 12953-7 for single burner installations.
NOTE 2 This document is not applicable to the storage of liquid fuels and to transfer stations of long-distance
gas pipelines.
1.2 Fuels
This document specifies requirements which cover the use of liquid and gaseous fuels as defined in this
document. Fuels deviating from standardized commercially available types can require additional or
alternative safety measures. For black liquor these safety measures are given in Annex A.
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 161:2011+A3:2013, Automatic shut-off valves for gas burners and gas appliances
1
EN 751-3:1996, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases
and hot water – Part 3: Unsintered PTFE tapes
EN 12952-18:2012, Water-tube boilers and auxiliary installations - Part 18: Operating instructions
EN 12952-5:2021, Water-tube boilers and auxiliary installations - Part 5: Workmanship and construction
of pressure parts of the boiler
EN 13480-2:2017, Metallic industrial piping - Part 2: Materials
EN 16678:2015, Safety and control devices for gas burners and gas burning appliances - Automatic shut-
off valves for operating pressure of above 500 kPa up to and including 6 300 kPa
EN ISO 228-1:2003, Pipe threads where pressure-tight joints are not made on the threads - Part 1:
Dimensions, tolerances and designation (ISO 228-1:2000)
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)
1
As impacted by EN 751-3:1996/AC:1997.
6
---------------------- Page: 8 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
EN ISO 23553-1:2022, Safety and control devices for oil burners and oil-burning appliances - Particular
requirements - Part 1: Automatic and semi-automatic valves (ISO 23553-1:2022)
ISO 7-1:1994, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions,
tolerances and designation
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
black liquor
spent liquor from the pulp cook
3.2
black liquor gun
device for the introduction of the black liquor as a spray of droplets into the furnace
Note 1 to entry: The black liquor gun is not a burner.
3.3
high volume low concentration odorous gas
mixtures of air and a low concentration of odorous gases collected from the pulp mill processes, where
the concentration of the combustible odorous gas is always kept below the lower explosion limit
3.4
burner
device (including main or igniter burners) for the introduction of fuel and air into a combustion chamber
of a steam generator at required velocities, turbulence and local fuel concentration to establish and
maintain proper ignition and stable combustion of the fuel
Note 1 to entry: Burners are differentiated by their mode of operation.
3.4.1
chemical recovery boiler start-up burner
oil- or gasfired burner mainly intended for the initiation of the black liquor combustion process
Note 1 to entry: The chemical recovery boiler start-up burners are located in and integrated with a combustion air
register, like the primary or the secondary air register of the furnace. Thus, they have no individual air supply and
no individual combustion air control.
3.4.2
multi-fuel burner
burner in which more than one fuel is burned either simultaneously or alternately
3.4.3
pilot burner
burner which maintains a proper permanent ignition source for one or a group of other non-monitored
burners
7
---------------------- Page: 9 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
3.5
burner group
burners operated in unison and controlled jointly, one of which can be a master burner
3.6
burner management system
system that 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 manages controlled shutdown and lockout
3.7
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 monitoring devices
Note 1 to entry: A flue gas recirculation system can be an integral part of the firing system.
3.8
firing system heat input
heat input into the combustion chamber according to the mass flow of the fuel supplied multiplied by the
net calorific value
3.9
flame monitor
device which detects the presence or absence or break-away of the flame and transmits a signal to the
control device, and generally consists of a sensing device (with amplifier if necessary) and switching
equipment
3.10
flue gas recirculation
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
3.11
implosion
unintentional instantaneous negative pressure build-up caused, for example, by an explosion in a
confined space, by rapid closing of dampers, or by rapid reduction in temperature (flame out)
3.12
limiters
transducer, which, 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
3.13
lock-out
isolation of energy supply which requires a manual intervention to reinstate
3.14
master fuel trip
extinction of all burners and igniters in the combustion chamber
8
---------------------- Page: 10 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
3.15
maximum heat input of the firing system
heat input including the reserve required for load control at which the boiler can be safely operated
3.16
maximum firing rate of the burners
firing rate at which the burner may be operated
3.17
monitor
limit transducer which senses the reaching of a fixed limit value and initiates an alarm and/or a cut out
Note 1 to entry: The output signal is only cancelled if the cause of the alarm has been removed and the value has
returned to within its fixed limits.
3.18
multi-fuel firing system
firing system where, in a common combustion chamber, more than one fuel can be burnt simultaneously
or alternately by separate or multi-fuel burners
3.19
purge of burner guns
carried out after shutdown of a burner to ensure the removal of residual fuel by the introduction of steam
or pressurized air into the fuel lines downstream of the shut-off devices
3.20
purging of the flue gas passes
forced flow of air through the combustion chamber, flue gas passes, and associated ducts which
effectively removes any gaseous combustibles and replace them with air
3.21
quick-acting shut-off device
safety trip valve which closes within 1 s according to EN 161:2011+A3:2013, EN 16678:2015 or
EN ISO 23553-1:2022, as appropriate
3.22
relative density
ratio of the density of the gas to the density of dry air under equal conditions of pressure and temperature
3.23
liquid fuel
fuel including light fuel oils, and heavy fuel oils which need preheating for proper atomisation
Note 1 to entry: For improvement of atomisation, emulsions of heavy fuel oil with water may be used with
appropriate precautions
3.24
gaseous fuel
standardized quality differentiated mainly by their relative density
9
---------------------- Page: 11 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
3.24.1
light gas
with relative density below 1,3 e.g. natural gas, coke-oven gas, blast-furnace gas
Note 1 to entry: Natural gas in accordance with ISO 6976 [4].
3.24.2
heavy gas
with relative density exceeding 1,3 e.g. liquefied petroleum gases, the main components of which are
propane and butane
3.25
restart
operation where fuel supply shut-off is initiated within 1 s at the latest after extinction of the flame during
operation, and a directly following attempt of re-ignition is automatically made in compliance with the
start-up sequence
Note 1 to entry: This operation ends with the operating condition being reached or, if the flame is not ignited after
expiration of the ignition safety time, with the lock-out.
3.26
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 vortex chamber into the combustion chamber, but flows backwards into the storage
tank or to the suction side of the pump via a separate return line
Note 1 to entry: Output is adjusted by a control device in the return line.
3.27
safety shut-off device
safety trip valve
valve which automatically and totally cuts off the fuel supply
3.28
safety time
time taken from the occurrence of an unsafe operating condition (for example, flame interrupt during
normal operation) to the point at which the actuating element is initiated
Note 1 to entry: The reaction time of the actuating element is to be considered separately.
[SOURCE: EN 50156-1:2015 [9], 3.43]
3.28.1
ignition time
when starting-up the burner, the period of time between the first fuel entering the combustion chamber
and the first indication of the flame by the flame monitor
3.28.2
ignition safety time
when starting-up the burner, the period of time between the first fuel entering the combustion chamber
and the de-energizing of the quick-acting shut-off device if the flame monitor does not indicate a flame
10
---------------------- Page: 12 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
3.28.3
main burner safety time
when there is an ignition safety time applicable to an igniter burner only, the period of time between the
first fuel of the main burner entering the combustion chamber and the de energizing of the quick acting
shut-off device of the main burner if the flame monitor does not indicate a flame
3.28.4
extinction safety time
during operation of the burner, the period of time between the extinction of the flame and the de-
energizing of the quick-acting shut-off device
3.29
transfer station
one or more lines each including a pressure control valve and a quick-acting shut-off device for the
protection of the downstream supply lines and the connected appliances against overpressure
Note 1 to entry: The transfer station may comprise heating and filtering equipment for the gas supply, measuring
equipment for flow and calorific value and noise abatement devices.
4 Fuel supply
4.1 General
For multifuel firing systems using separate or combined burners these requirements shall apply to the
oil and/or gas firing part involved.
Where several fuels are burnt simultaneously, improved safety measures can be necessary, especially in
respect to limitation of heat input into the firing system and proper air supply to the individual fuels.
4.2 Fuel transfer and preparation
4.2.1 The fuel supply line shall be equipped with a reliable shut-off device which shall be positioned in
a safe location. It shall reliably cut off the fuel supply to the boiler room or the boiler area and shall be
operable by remote control or by an emergency switch (see 6.4.2).
4.2.2 Some liquid fuels, such as heavy fuel oil, require preheating to achieve the viscosity required for
proper atomisation. Where national oil quality standards are in existence, these shall be observed.
Any heat source other than open flames, that can be cut off immediately if required, and the rating of
which can be automatically controlled, shall be used for oil preheating.
In the unpressurized condition the fuel oil temperature shall not attain the fuel oil flash point.
To attain the temperature for the required atomisation viscosity, pressure type preheaters shall be used.
The maximum temperature shall be at least 5 °C below the boiling temperature of water in the oil at the
connected pressure.
Each fuel oil preheating system shall be automatically temperature controlled. A temperature indicator
shall be fitted downstream of the preheating system. Oil temperatures below the temperature prescribed
upstream of each burner or burner group shall shut off the burner or burner group.
Oil temperatures above the temperature prescribed upstream of the burners shall shut off the heat supply
of the preheater or other suitable measures shall be taken.
For pressurized preheaters, the requirements for pressure vessels shall be applied. Functioning of the
necessary overpressure protection shall be ensured by suitable temperature control. Any escaping oil
shall be safely discharged.
11
---------------------- Page: 13 ----------------------
SIST EN 12952-8:2022
EN 12952-8:2022 (E)
Where steam heating coils for oil preheating are installed and the condensate is returned to the boiler,
the heating coils shall be safely dimensioned and tested to ensure that no oil can escape into the
condensate. A means of checking the condensate for oil content shall be provided. When steam lines are
connected to fuel oil lines for purging purposes or for steam assisted atomisation, the line shall be
protected against back flow from the higher pressured fluid.
4.2.3 For gaseous fuels, a pressure controller shall be provided in the supply line assuring continuous
flow pressure to each firing system unless this task is performed by the transfer station. The pressure
controller shall reliably prevent the firing system from overpressurization when the control function has
failed.
NOTE Requirements on pressure controller can be found in EN 676:2020 [3].
4.3 Fuel lines
4.3.1 Fuel lines, including gaskets and valves shall be designed and laid out to withstand the
mechanical, chemical and thermal loads to which they are exposed in service. Only fire resistant piping
material shall be permitted.
4.3.2 The fuel lines shall be tight and properly fixed. In systems subjected to vibrations
...
SLOVENSKI STANDARD
oSIST prEN 12952-8:2020
01-marec-2020
Vodocevni kotli in pomožne napeljave - 8. del: Zahteve za gorilnike kotlov na
tekoča in plinasta goriva
Water-tube boilers and auxiliary installations - Part 8: Requirements for firing systems for
liquid and gaseous fuels for the boiler
Wasserrohrkessel und Anlagenkomponenten - Teil 8: Anforderungen an
Feuerungsanlagen für flüssige und gasförmige Brennstoffe für den Kessel
Chaudières à tubes d'eau et installations auxiliaires - Partie 8 : Exigences pour les
équipements de chauffe pour combustibles gazeux et liquides de la chaudière
Ta slovenski standard je istoveten z: prEN 12952-8
ICS:
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
oSIST prEN 12952-8:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN 12952-8:2020
---------------------- Page: 2 ----------------------
oSIST prEN 12952-8:2020
DRAFT
EUROPEAN STANDARD
prEN 12952-8
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2020
ICS 27.040 Will supersede EN 12952-8:2002
English Version
Water-tube boilers and auxiliary installations - Part 8:
Requirements for firing systems for liquid and gaseous
fuels for the boiler
Chaudières à tubes d'eau et installations auxiliaires - Wasserrohrkessel und Anlagenkomponenten - Teil 8:
Partie 8 : Exigences pour les équipements de chauffe Anforderungen an Feuerungsanlagen für flüssige und
pour combustibles gazeux et liquides de la chaudière gasförmige Brennstoffe für den Kessel
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, Turkey 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12952-8:2020 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
Contents Page
European foreword . 4
1 Scope . 6
1.1 Firing systems . 6
1.2 Fuels . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Fuel supply . 11
4.1 General. 11
4.2 Fuel transfer and preparation . 11
4.3 Fuel lines . 12
4.4 Safety shut-off devices (Safety trip valves) . 13
5 General. 15
5.1 Air supply . 15
5.2 Air/fuel ratio . 16
5.3 Flue gas discharge . 16
6 Firing system . 16
6.1 Burners . 16
6.2 Flue gas recirculation . 17
6.3 Control and monitoring . 18
6.4 Electrical equipment. 19
6.5 Safety precautions . 19
6.6 Common stack for several firing systems . 20
7 Operating manual . 20
8 Particular requirements for firing systems burning gaseous fuels with high relative
density . 20
8.1 Main firing systems . 20
8.1.1 Supply of gases . 20
8.1.2 Safety shut-off device . 20
8.2 Ignition burner systems . 21
Annex A (normative) Chemical recovery boiler (black liquor boiler) . 22
A.1 General. 22
A.2 Additional requirements for the firing system for black liquor in the chemical
recovery boiler . 22
A.3 Special requirements for oil- or gas firing for chemical recovery boilers . 23
A.3.1 General. 23
A.3.2 Special requirements for start-up burners . 23
A.3.3 Special requirements for the firing of odorous gases . 24
Annex B (normative) Gas turbines in combination with heat recovery steam generators . 25
2
---------------------- Page: 4 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
B.1 General . 25
B.2 Additional requirements for gas turbines in combination with heat recovery steam
generators . 25
B.2.1 Safety shut-off devices . 25
B.2.2 Electrical equipment . 25
B.2.3 Bypass operation of the heat recovery boiler . 25
B.2.4 Switching from gas turbine operation to fresh air operation at secondary firing . 25
Annex C (informative) Operational requirements for permanent supervised firing systems
for liquid and gaseous fuels . 27
C.1 General . 27
C.2 Operation . 27
C.3 Fuel preparation . 27
C.4 Safety shutoff devices . 27
C.5 Air/fuel ratio . 27
C.6 Modification of firing, burner or air/fuel ratio setting . 27
C.7 Control and monitoring . 28
C.8 Emergency operation . 28
C.9 Operating and maintenance instructions . 28
C.10 Firing systems burning gaseous fuels with high relative density . 28
Annex D (informative) Significant technical changes between this document and the
previous edition . 30
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2014/68/EU aimed to be covered . 31
Bibliography . 32
3
---------------------- Page: 5 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
European foreword
This document (prEN 12952-8:2020) 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 will supersede EN 12952-8:2002.
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.
Although these parts may 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 Part 4 and Part 15 are not applicable during the design, construction and installation stages.
4
---------------------- Page: 6 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
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.
5
---------------------- Page: 7 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
1 Scope
1.1 Firing systems
This document specifies requirements, for liquid and gaseous fuel firing systems of steam boilers and
hot water generators as defined in EN 12952-1:2015.
These requirements also apply to firing systems of chemical recovery boilers (black liquor boilers) with
the additions and amendments specified in Annex A of this document.
These requirements also apply to gas turbines in combination with fired/unfired heat recovery steam
generators with the additions and amendments specified in Annex B of this document.
NOTE 1 This standard is not applicable to coil type boilers (flash boilers/small boilers) that use burners in
accordance with EN 12953-7 apply for single burner installations.
NOTE 2 This standard is not applicable to the storage of liquid fuels and to transfer stations of long-distance
gas pipelines.
1.2 Fuels
This document specifies requirements, which cover the use of liquid and gaseous fuels as defined in this
standard. Fuels deviating from standardized commercially available types may require additional or
alternative safety measures. For black liquor these safety measures are given in Annex A.
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 161:2011+A3:2013, Automatic shut-off valves for gas burners and gas appliances
EN 751 (series), Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family
gases and hot water
EN 16678:2015, Safety and control devices for gas burners and gas burning appliances - Automatic shut-
off valves for operating pressure of above 500 kPa up to and including 6 300 kPa
EN ISO 23553-1:2014, Safety and control devices for oil burners and oil-burning appliances - Particular
requirements - Part 1: Automatic and semi-automatic valves (ISO 23553-1:2014)
1
prEN 12952-5:2020, Water-tube boilers and auxiliary installations — Part 5: Workmanship and
construction of pressure parts of the boiler
EN 13480-2:2017, Metallic industrial piping - Part 2: Materials
EN 50156-1:2015, Electrical equipment for furnaces and ancillary equipment - Part 1: Requirements for
application design and installation
EN ISO 3677:2016, Filler metal for soldering and brazing - Designation (ISO 3677:2016)
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)
1
Under preparation
6
---------------------- Page: 8 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
ISO 7-1:1994, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions,
tolerances and designation
EN ISO 228-1:2003, Pipe threads where pressure-tight joints are not made on the threads —
Part 1: Dimensions, tolerances and designation (ISO 228-1:2000)
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
black liquor
spent liquor from the pulp cook
3.2
black liquor gun
device for the introduction of the black liquor as a spray of droplets into the furnace
Note 1 to entry: The black liquor gun is not a burner.
3.3
high volume low concentration odorous gas
mixtures of air and a low concentration of odorous gases collected from the pulp mill processes, where
the concentration of the combustible odorous gas is always kept below the lower explosion limit
3.4
burners
devices (including main or igniter burners) for the introduction of fuel and air into a combustion
chamber of a steam generator at required velocities, turbulence and local fuel concentration to establish
and maintain proper ignition and stable combustion of the fuel
Note 1 to entry: Burners are differentiated by their mode of operation.
3.4.1
chemical recovery boiler start up burner
oil- or gasfired burner mainly intended for the initiation of the black liquor combustion process
Note 1 to entry: The chemical recovery boiler start up burners are located in and integrated with a combustion air
register, like the primary or the secondary air register of the furnace. Thus they have no individual air supply and
no individual combustion air control.
3.4.2
multi-fuel burners
burners in which more than one fuel is burned either simultaneously or alternately
3.4.3
pilot burner
burner which maintains a proper permanent ignition source for one or a group of other non-monitored
burners
7
---------------------- Page: 9 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
3.5
burner group
burners operated in unison and controlled jointly. One of the burners can be a master burner
3.6
burner management system
system that 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 manages controlled shutdown and lockout
3.7
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 monitoring devices
Note 1 to entry: A flue gas recirculation system can be an integral part of the firing system.
3.8
firing system heat input
heat input into the combustion chamber according to the mass flow of the fuel supplied multiplied by
the net calorific value
3.9
flame monitor
device which detects the presence or absence or break-away of the flame and transmits a signal to the
control device, and generally consists of a sensing device (with amplifier if necessary) and switching
equipment
3.10
flue gas recirculation
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
3.11
implosion
unintentional instantaneous negative pressure build-up caused, for example, by an explosion in a
confined space, by rapid closing of dampers, or by rapid reduction in temperature (flame out)
3.12
limiters
transducer, which, 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
3.13
lock-out
isolation of energy supply which requires a manual intervention to reinstate
3.14
master fuel trip
extinction of all burners and igniters in the combustion chamber
8
---------------------- Page: 10 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
3.15
maximum heat input of the firing system
heat input including the reserve required for load control at which the boiler can be safely operated
3.16
maximum firing rate of the burners
firing rate at which the burner may be operated
3.17
monitor
limit transducer, which senses the reaching of a fixed limit value and initiates an alarm and/or a cut out
Note 1 to entry: The output signal is only cancelled if the cause of the alarm has been removed and the value has
returned to within its fixed limits.
3.18
multi-fuel firing system
firing system where, in a common combustion chamber, more than one fuel can be burnt
simultaneously or alternately by separate or multi-fuel burners
3.19
purge of burner guns
carried out after shutdown of a burner to ensure the removal of residual fuel by the introduction of
steam or pressurized air into the fuel lines downstream of the shut-off devices
3.20
purging of the flue gas passes
forced flow of air through the combustion chamber, flue gas passes, and associated ducts which
effectively removes any gaseous combustibles and replace them with air
3.21
quick-acting shut-off device
safety trip valve which closes within 1 s according to EN 161:2011+A3:2013 or EN 264
3.22
relative density
ratio of the density of the gas to the density of dry air under equal conditions of pressure and
temperature
3.23
liquid fuels
fuels include light fuel oils, and heavy fuel oils which need preheating for proper atomisation. For
improvement of atomisation, emulsions of heavy fuel oil with water may be used with appropriate
precautions
3.24
gaseous fuels
standardized quality differentiated mainly by their relative density
3.24.1
light gases
with relative density below 1,3 e.g. natural gas, coke-oven gas, blast-furnace gas
Note 1 to entry: Natural gas in accordance with ISO 6976.
9
---------------------- Page: 11 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
3.24.2
heavy gases
with relative densities exceeding 1,3 e.g. liquefied petroleum gases, the main components of which are
propane and butane
3.25
restart
operation where fuel supply shut-off is initiated within 1 s at the latest after extinction of the flame
during operation, and a directly following attempt of re-ignition is automatically made in compliance
with the start-up sequence
Note 1 to entry: This operation ends with the operating condition being reached or, if the flame is not ignited after
expiration of the ignition safety time, with the lock-out.
3.26
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 vortex chamber into the combustion chamber, but flows backwards into the storage
tank or to the suction side of the pump via a separate return line
Note 1 to entry: Output is adjusted by a control device in the return line.
3.27
safety shut-off device
safety trip valve
valve which automatically and totally cuts off the fuel supply
3.28
safety time
time taken from the occurrence of an unsafe operating condition (for example, flame interrupt during
normal operation) to the point at which the actuating element is initiated
Note 1 to entry: The reaction time of the actuating element is to be considered separately.
[SOURCE: EN 50156-1:2015, 3.43]
3.28.1
ignition time
when starting-up the burner, the period of time between the first fuel entering the combustion chamber
and the first indication of the flame by the flame monitor
3.28.2
ignition safety time
when starting-up the burner, the period of time between the first fuel entering the combustion chamber
and the de-energizing of the quick-acting shut-off device if the flame monitor does not indicate a flame
3.28.3
main burner safety time
when there is an ignition safety time applicable to an igniter burner only the period of time between the
first fuel of the main burner entering the combustion chamber and the de energizing of the quick acting
shut-off device of the main burner if the flame monitor does not indicate a flame
10
---------------------- Page: 12 ----------------------
oSIST prEN 12952-8:2020
prEN 12952-8:2020 (E)
3.28.4
extinction safety time
during operation of the burner the period of time between the extinction of the flame and the de-
energizing of the quick-acting shut-off device
3.29
transfer station
one or more lines each including a pressure control valve and a quick-acting shut-off device for the
protection of the downstream supply lines and the connected appliances against overpressure
Note 1 to entry: The transfer station may comprise of heating and filtering equipment for the gas supply,
measuring equipment for flow and calorific value and noise abatement devices.
4 Fuel supply
4.1 General
For multifuel firing systems using separate or combined burners these requirements shall apply to the
oil and/or gas firing part involved.
Where several fuels are burnt simultaneously, improved safety measures can be necessary, especially in
respect to limitation of heat input into the firing system and proper air supply to the individual fuels.
4.2 Fuel transfer and preparation
4.2.1 The fuel supply line shall be equipped with a reliable quick-acting safety shut-off device which
shall be positioned in a safe location. It shall reliably cut off the fuel supply to the boiler room or the
boiler area and shall be operable by remote control or by an emergency switch (see 6.4.2).
4.2.2 Some liquid fuels, such as heavy fuel oil, require preheating to achieve the viscosity required for
proper atomisation. Where national oil quality standards are in existence, these shall be observed.
Any heat source other than open flames, that can be cut off immediately if required, and the rating of
which can be automatically controlled, shall be used for oil preheating.
In the unpressurized condition the fuel oil temperature shall not attain the fuel oil flash point.
To attain the temperature for the required atomisation viscosity, pressure type preheaters shall be
used. The maximum temperature shall be at least 5 °C below the boiling temperature of water in the oil
at the connected pressure.
Each fuel oil preheating system shall be automatically temperature controlled. A temperature indicator
shall be fitted downstream of the preheating system. Oil temperatures below the temperature
prescribed upstream of each burner or burner group shall shut off the burner or burner group.
Oil temperatures above the temperature prescribed upstream of the burners shall shut off the heat
supply of the preheater or other suitable measures shall be taken.
For pressurized preheaters, the requirements for pressure vessels shall be applied. Functioning of the
necessary overpressure protection shall be ensured by suitable temperature control. Any escaping oil
shall be safely discharged.
Where steam heating coils for oil preheating are installed and the condensate is returned to the boiler,
the heating coils shall be safely dimensioned and tested to ensure tha
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.