EN 746-2:2010

Industrial thermoprocessing equipment - Part 2: Safety requirements for combustion and fuel handling systems

This part of EN 746 together with EN 746-1 specifies safety requirements for single and multiple burners that are part of Industrial Thermoprocessing Equipment. (In this standard referred to as IThE).
This document deals with significant hazards, hazardous situations and events relevant to combustion and fuel handling systems that are part of IThE as listed in Clause 4, when used as intended and under the conditions foreseen by the manufacturer.
This European Standard covers:
- fuel pipework downstream of and including the manual isolating valve;
- burner(s), burner system and ignition device;
- safety related control system (protective system).
This European Standard applies to any oxidation with air or other gases containing free oxygen of gaseous, liquid and solid fuels or any combustion of them to release thermal energy.
For thermal or catalytic post combustion and waste incineration, this European Standard applies only to auxiliary burners designed to start-up and/or support the process.
The pressure hazard of the piping and components covered by this standard is within the maximum pressure/size relationship of category I as described in normative Annex D.
This European Standard also gives the necessary requirements for the information for use.
This European Standard does not cover hazards from heating generated by electricity.
This European Standard does not deal with the hazards created by the release of flammable substances from the products processed in the IThE.
NOTE EN 1539, Dryers and ovens, in which flammable substances are released — Safety requirements
This European Standard is not applicable to combustion and fuel handling systems
- of welding and soldering machines;
- up-stream of the IThE manual isolating valve.
This European Standard is not applicable to electricity cabling and power cabling upstream of the IThE control panel/protective system.
Noise can be a significant hazard for combustion and fuel handling systems.

Industrielle Thermoprozessanlagen - Teil 2: Sicherheitsanforderungen an Feuerungen und Brennstoffführungssysteme

Dieser Teil der EN 746 legt zusammen mit EN 746-1 die Sicherheitsanforderungen für Einzelbrenner und
Mehrbrenner-Systeme fest, die Teile einer Industrielle Thermoprozessanlagen sind. (Im Folgenden werden
Industrielle Thermoprozessanlagen als „IThE“ bezeichnet).
Dieses Dokument behandelt die in Abschnitt 4 aufgeführten signifikanten Gefährdungen, Gefährdungssituationen
und Ereignisse für Feuerungen und Brennstoffführungssystemen an IThE, auf der Grundlage das
diese wie vorgesehen und unter den vom Hersteller vorgesehenen Bedingungen eingesetzt werden.
Diese Europäische Norm gilt für:
⎯ Brennstoff-Leitungssystem in Strömungsrichtung beginnend mit dem handbetätigtem Hauptabsperrventil
⎯ Brenner, Brennersystem und Zündeinrichtungen;
⎯ Sicherheitsbezogenes Steuerungssystem (Schutzsystem);
Diese Europäische Norm ist anwendbar für alle Arten von Oxidation oder Verbrennung von gasförmigen,
flüssigen oder festen Brennstoffen mit Luft oder anderen Gasen, die freien Sauerstoff enthalten, die zur
Freisetzung von Wärmeenergie dienen.
Bei thermischen oder katalytischen Nachverbrennungsanlagen und Müllverbrennungen ist diese Europäische
Norm nur anwendbar auf Hilfsbrenner, die zum Anfahren und/oder zur Unterstützung des Prozesses dienen.
Die Druckgefährdung der Rohrleitungen und Komponenten, die in dieser Norm abgedeckt sind, liegt innerhalb
des maximalen Druck-/Größenverhältnisses der Kategorie I, wie im normativen Anhang D beschrieben.
Diese Europäische Norm beinhaltet auch notwendige Anforderungen für die Benutzerinformation.
Diese Europäische Norm behandelt nicht die durch elektrische Beheizung entstehende Gefährdungen.
Diese Europäische Norm behandelt nicht die Gefährdungen, die durch Freisetzung von entzündbaren
Substanzen aus den in der IThE verarbeitenden Produkten entstehen.
ANMERKUNG EN 1539 behandelt Sicherheitsanforderungen an Trockner und Öfen, in denen brennbare Stoffe
freigesetzt werden.

Equipements thermiques industriels - Partie 2: Prescriptions de sécurité concernant la combustion et la manutention des combustibles

La présente partie de l'EN 746, associée à l'EN 746-1, spécifie les prescriptions de sécurité relatives aux
brûleurs simples et multiples faisant partie d'un équipement thermique industriel (désigné par EThI dans la
présente norme).
Le présent document traite des phénomènes, situations et événements dangereux significatifs relatifs aux
systèmes de combustion et de manutention des combustibles faisant partie des EThI, tels qu'énumérés à
l'Article 4, dans le cadre d'une utilisation normale et dans les conditions prévisibles spécifiées par le fabricant.
La présente Norme européenne couvre :
⎯ la tuyauterie de combustible en aval du robinet de barrage à commande manuelle et y compris celui-ci ;
⎯ le(s) brûleur(s), le système de brûleur(s) et le dispositif d'allumage ;
⎯ le système de commande relatif à la sécurité (système de protection).
La présente Norme européenne s'applique à tout phénomène d'oxydation avec l'air ou d'autres gaz contenant
de l'oxygène libre des combustibles gazeux, liquides et solides, ou toute combustion de ceux-ci en vue de
dégager de la chaleur.
En ce qui concerne la post-combustion thermique ou catalytique et l'incinération des déchets, la présente
Norme européenne s'applique uniquement aux brûleurs auxiliaires conçus pour démarrer et/ou soutenir le
procédé.
Le phénomène dangereux engendré par la pression dans la tuyauterie et les composants couverts par la
présente norme correspond à la relation pression maximale/dimensions I telle que décrite dans l'Annexe E
normative.
La présente Norme européenne fournit également les prescriptions nécessaires quant aux informations pour
l'utilisation.
La présente Norme européenne ne couvre pas les phénomènes dangereux liés à la chaleur électrique.
La présente Norme européenne ne traite pas des phénomènes dangereux engendrés par le dégagement de
substances inflammables par les produits traités dans l'EThI.

Industrijska termoprocesna oprema - 2. del: Varnostne zahteve za sisteme zgorevanja in sisteme za ravnanje z gorivom

Ta del EN 746 skupaj z EN 746-1 določa varnostne zahteve za enojne ali večkratne gorilnike, ki so del industrijske termoprocesne opreme (v tem standardu imenovano IThE). Ta dokument obravnava velike nevarnosti, nevarne situacije in primere, ki se tičejo sistemov za zgorevanje in rokovanje goriv, ki so del IThE, kot je navedeno v Klavzuli 4, kadar se uporabljajo, kot je predvideno, in pod pogoji uporabe, ki jih predvidi proizvajalec. Ta evropski standard zajema:
- cevovode za gorivo, ki so v smeri toka, vključno z ročnim izolacijskim ventilom;
- gorilnike, gorilne sisteme in naprave za vžig;
- nadzorni sistem, povezan z varnostjo (zaščitni sistem).
Ta evropski standard velja za vso oksidacijo z zrakom ali drugimi plini, ki vsebujejo prost kisik, pri plinastih, tekočih ali trdnih gorivih ali njihovem izgorevanju za sprostitev toplotne energije. Za toplotno ali katalitično poizgorevanje in zgorevanje odpadkov, ta evropski standard velja samo za pomožne gorilnike, namenjene za zagon in/ali podporo procesu. Nevarnost zaradi pritiska v ceveh in sestavnih delih, zajeta v tem standardu, je znotraj mej maksimalnega razmerja pritisk/velikost, kot je opisano v Dodatku E. Ta evropski standard prav tako podaja potrebne zahteve za informacije o uporabi. Ta evropski standard ne zajema nevarnosti, ki nastanejo zaradi toplote, ki jo generira elektrika. Ta evropski standard se ne ukvarja z nevarnostmi, ki nastanejo zaradi izpusta gorljivih snovi iz proizvodov, izdelanih z IThE. OPOMBA EN 1539, sušilniki in pečice, v katerih so gorljive snovi izpuščene – varnostne zahteve tega evropskega standarda ne veljajo za sisteme za zgorevanje in rokovanje z gorivi; - stroje za varjenje in spajkanje; - IThE ročni izolacijski ventil v smeri proti toku.
Ta evropski standard ne velja za električne kable in električne kable v smeri proti toku IThE nadzorne plošče/zaščitnega sistema. Hrup je lahko velika nevarnost za sisteme za zgorevanje in rokovanje z gorivi. Ni zajet v tem standardu. Ta evropski standard ne velja za sisteme za zgorevanje in rokovanje z gorivi, ki so del IThE, ki so bili proizvedeni pred datumom njegove objave kot EN.

General Information

• Status: Withdrawn
• Publication Date: 11-May-2010
• Withdrawal Date: 22-Sep-2025
• ICS: 25.180.01 - Industrial furnaces in general
• Technical Committee: CEN/TC 186 - Industrial thermoprocessing - Safety
• Drafting Committee: CEN/TC 186/WG 2 - Combustion and fuel handling systems - Safety requirements
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 20-Dec-2023
• Completion Date: 23-Sep-2025
• Directive: 2006/42/EC - Directive 2006/42/EC of the European Parliament and of the Council of 17 May 2006 on machinery, and amending Directive 95/16/EC (recast)
• Directive: 98/37/EC - Machinery
• Mandate: M/079 - Mandate to CEN and CENELEC for standardization in the field of machines
• Mandate: M/396 - Mandate to CEN and Cenelec for standardisation in the field of machinery
• Ref Project: SIST EN 746-2:2010 - Industrial thermoprocessing equipment - Safety requirements for combustion and fuel handling systems

Relations

• Replaces: EN 746-2:1997 - Industrial thermoprocessing equipment - Part 2: Safety requirements for combustion and fuel handling systems
• Effective Date: 22-Dec-2008
• Replaced By: EN ISO 13577-2:2023 - Industrial furnaces and associated processing equipment - Safety - Part 2: Combustion and fuel handling systems (ISO 13577-2:2023)
• Effective Date: 19-Jan-2023
• Revised: prEN 746-2 - Industrial thermoprocessing equipment - Part 2: Safety requirements for combustion and fuel handling systems
• Effective Date: 18-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2010
1DGRPHãþD
SIST EN 746-2:2000
Industrijska termoprocesna oprema - 2. del: Varnostne zahteve za sisteme
zgorevanja in sisteme za ravnanje z gorivom
Industrial thermoprocessing equipment - Safety requirements for combustion and fuel
handling systems
Industrielle Thermoprozessanlagen - Teil 2: Sicherheitsanforderungen an Feuerungen
und Brennstoffführungssysteme
Equipements thermiques industriels - Partie 2: Prescriptions de sécurité concernant la
combustion et la manutention des combustibles
Ta slovenski standard je istoveten z: EN 746-2:2010
ICS:
25.180.01 ,QGXVWULMVNHSHþLQDVSORãQR Industrial furnaces in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 746-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2010
ICS 25.180.01 Supersedes EN 746-2:1997
English Version
Industrial thermoprocessing equipment - Safety requirements for
combustion and fuel handling systems
Equipements thermiques industriels - Partie 2: Industrielle Thermoprozessanlagen - Teil 2:
Prescriptions de sécurité concernant la combustion et la Sicherheitsanforderungen an Feuerungen und
manutention des combustibles Brennstoffführungssysteme
This European Standard was approved by CEN on 11 March 2010.

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, Croatia, 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.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 746-2:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .6
Introduction .7
1 Scope .8
2 Normative references .9
3 Terms and definitions . 11
4 List of hazards . 20
5 Safety requirements, measures and verification means . 21
5.1 General . 21
5.2 Gaseous fuels . 21
5.2.1 Gas pipework . 21
5.2.2 Required safety devices . 24
5.2.3 Combustion air and pre-purging the combustion chamber and flue passages . 30
5.2.4 Supply of pre-mixed fuel gas/air . 32
5.2.5 Burners . 33
5.2.6 Automatic burner control systems . 37
5.3 Liquid fuels . 39
5.3.1 Liquid fuel pipework . 39
5.3.2 Required safety devices . 42
5.3.3 Combustion air and pre-purging the combustion chamber and the flue passages . 45
5.3.4 Liquid fuel atomisation . 47
5.3.5 Burners . 47
5.3.6 Automatic burner control systems . 49
5.4 Solid fuels . 51
5.4.1 Pulverised solid fuel pipework . 51
5.4.2 Graded fuel pipework (applicable to grate burners and fluidised beds) . 52
5.4.3 Required devices (for pulverised fuels and fluidised beds) . 53
5.4.4 Combustion air and pre-purging of the combustion chamber and flue passages . 54
5.4.5 Burners . 54
5.4.6 Automatic burner control systems (pulverised fuel) . 56
5.5 Multiple fuels . 56
5.5.1 General . 56
5.5.2 Fuel circuit . 57
5.5.3 Combustion air supplies . 57
5.5.4 Operation of the safety devices . 57
5.5.5 Air/fuel ratio . 57
5.6 Oxygen or oxygen-enriched combustion air . 57
5.6.1 General . 57
5.6.2 Suitability for oxygen service . 57
5.6.3 Sealing materials for oxygen pipework . 57
5.6.4 Pipework . 58
5.6.5 Pipes velocities . 58
5.6.6 Fittings . 58
5.6.7 Blow off and venting lines . 58
5.6.8 Manual torches . 58
5.6.9 Safety devices against gas backflow. 59
5.6.10 Safety devices against oxygen backflow in mixture with other substances . 59
5.6.11 Material requirements . 59
5.7 Design requirements for electrical and electronic equipment for control system and
protective system . 59
5.7.1 General . 59
5.7.2 Requirements for protective systems . 60
5.7.3 Fault assessment for a hardwired protective system . 64
5.7.4 Electrical power failure . 70
5.7.5 Reset . 70
6 Verification of the safety requirements and/or measures . 72
7 Information for Use . 77
7.1 General . 77
7.2 Marking . 77
7.3 Instruction handbook . 78
7.3.1 General . 78
7.3.2 Description of equipment . 78
7.3.3 Inspection procedures . 79
7.3.4 Commissioning, start-up and operating procedures . 79
7.3.5 Shut-down procedures . 80
7.3.6 Maintenance procedures . 80
7.3.7 Documentation . 80
Annex A (informative) Typical Examples of IThE, Fuels and Burners . 81
A.1 List – Machines concerned, descriptions, functions . 81
A.1.1 List of IThE . 81
A.2 Classification of fuels . 84
A.2.1 Gaseous fuels . 84
A.2.2 Liquid fuels . 84
A.2.3 Solid fuels . 84
A.3 Classification of burners . 85
A.3.1 Gaseous fuels . 85
A.3.2 Liquid fuels . 85
A.3.3 Solid fuels . 85
Annex B (informative) Technical terms . 86
Annex C (informative) Typical examples of piping and components . 101
Annex D (informative) Methods for burner start-up . 111
Annex E (normative) Maximum allowable pressure . 118
Annex ZA (informative) . 123
Bibliography . 124

Figures
Figure 1 — Block diagram of control/protective and heated system . 60
Figure 2 a — Example for requirements of 5.7.2 a . 61
Figure 2 b — Example for requirements of 5.7.2 b . 62
Figure 2 c — Example for requirements of 5.7.2 c . 63
Figure 2 d — Example for requirements of 5.7.2 d . 63
Figure 3 — Fault assessment for the hardwired section of a protective system . 65
Figure 4 — Consideration of fault tolerance time and safety time for IThE . 66
Figure 5 — Examples for wiring of fuel shut-down with hardware diversity of the disconnecting
devices . 67
Figure 6 — Example for wiring of fuel shut-down with diverse functionality of the disconnecting
devices . 68
Figure C.1 — Single burner equipment . 101
Figure C.2a — Multiple burner equipment – Central pipework – Example a two burners system . 102
Figure C.2b — Multiple burner equipment – Central pipework – Example b. 103
Figure C.2c — Multiple burner equipment – Central pipework – Example c . 104
Figure C.3a — Multiple burner equipment – Zone pipework – Example a . 105
Figure C.3b — Multiple burner equipment – Zone pipework – Example b . 106
Figure C.3c — Multiple burner equipment – Zone pipework – Example c . 107
Figure C.4 — Multiple burner equipment (burner pipework). 108
Figure C.5 — Central pipework for low cycling applications . 109
Figure C.6 — Draft breaks . 110
Figure D.1 — Direct main burner ignition at full rate (see Table 3, Column 2, Q ≤ 120 kW) . 111
F max
Figure D.2 — Direct main burner ignition at reduced ratewith slow opening valve (see Table 3,
Column 3, Q ≤ 360 kW) . 111
F max
Figures D.3 and D.4 — Direct main burner ignition at reduced rate with by-pass start gas supply
(see Table 3, Column 4) . 112
Figures D.5 and D.6 — Direct main burner ignition at reduced rate with limited start gas input
(see Table 3, Column 4) . 113
Figures D.7 and D.8 — Main burner ignition with independent pilot burner
(see Table 3, Column 5, Q ≤ 120 kW) . 114
F max
Figures D.9 and D.10 — Main burner ignition with independent pilot burner
(see Table 3, Column 5, Q ≤ 360 kW) . 115
F max
Figures D.11 and D.12 — Main burner ignition with independent pilot burner (see Table 3, Column 5)
................................................................................................................................................................... 116
Figures D.13 and D.14 — Main burner ignition with independent pilot burner (see Table 3, Column 5)
................................................................................................................................................................... 117
Figure E.1 — Piping referred to clause a) group 1 of Annex E . 119
Figure E.2 — Piping referred to clause a) group 2 of Annex E . 120
Figure E.3 — Piping referred to clause b) group 1 of Annex E. 121
Figure E.4 — Piping referred to clause b) group 2 of Annex E. 122

Tables
Table 1 — Maximum safety times for natural draught burners operating in open air . 34
Table 2 — Maximum safety times for natural draught burners operating in combustion chamber . 35
Table 3 — Maximum safety times for forced and induced draught burners . 36
Table 4 — Maximum safety times . 48
Table 5 — Materials requirements . 59
Table 6 — Verification of the safety requirements and/or measures . 72
Table B.1 — English – German – French . 86
Table B.2 — German – English – French . 91
Table B.3 — French – English – German . 96

Foreword
This document (EN 746-2:2010) has been prepared by Technical Committee CEN/TC 186 “Industrial
Thermoprocessing Equipment”, 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 November 2010, and conflicting national standards shall be withdrawn
at the latest by May 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 746-2:1997.
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.
Following a request from CEN/TC 186, CEN has agreed to defer the date of withdrawal of EN 746-2:1997 for
a transitional period of 12 months.
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, Croatia, 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 the United Kingdom.

Introduction
This European Standard is a Type C standard as defined in EN ISO 12100-1.
The machinery concerned and the extent to which hazards, hazardous situations and events are covered, is
indicated in the scope of this document.
When provisions of this type C standard are different from those which are stated in type A or B standards, the
provisions of this type C standard take precedence over the provisions of the other standards, for machines
that have been designed and built according to the provisions of this type C standard.
This Part of EN 746 assumes that the equipment is not creating any potentially explosive atmosphere and is
located in a normally ventilated area.
This European Standard forms one part of a series of safety standards covering Industrial Thermoprocessing
Equipment (IThE). The full list of these standards is given below:
EN 746, Industrial thermoprocessing equipment
Part 1: Common safety requirements for industrial thermoprocessing equipment
Part 2: Safety requirements for combustion and fuel handling systems
Part 3: Safety requirements for the generation and use of atmosphere gases
Part 4: Particular safety requirements for hot dip galvanising thermoprocessing equipment
Part 5: Particular safety requirements for salt bath thermoprocessing equipment
Part 6: Particular safety requirements for material melting, re-melting and liquid phase maintaining
thermoprocessing equipment
Part 7: Particular safety requirements for vacuum thermoprocessing equipment
Part 8: Particular safety requirements for quenching equipment
Compliance with European product standards e.g. EN 267, EN 12952-8, EN 12953-7 or EN 676 is not
sufficient to ensure the minimum safety requirement for industrial thermoprocessing equipment. This part 2 of
EN 746 shall always have priority for IThE.
An IThE generally consists of the following components:
 processing chamber (e.g. steel construction with lining);
 heating system;
 protective system;
 control and instrumentation system/operator-control level.
It is assumed that (IThE) will only be operated and maintained by trained personnel.
1 Scope
This part of EN 746 together with EN 746-1 specifies safety requirements for single and multiple burners that
are part of Industrial Thermoprocessing Equipment. (In this standard referred to as IThE).
This document deals with significant hazards, hazardous situations and events relevant to combustion and
fuel handling systems that are part of IThE as listed in Clause 4, when used as intended and under the
conditions foreseen by the manufacturer.
This European Standard covers:
 fuel pipework downstream of and including the manual isolating valve;
 burner(s), burner system and ignition device;
 safety related control system (protective system).
This European Standard applies to any oxidation with air or other gases containing free oxygen of gaseous,
liquid and solid fuels or any combustion of them to release thermal energy.
For thermal or catalytic post combustion and waste incineration, this European Standard applies only to
auxiliary burners designed to start-up and/or support the process.
The pressure hazard of the piping and components covered by this standard is within the limits of maximum
pressure/size relationship as described in normative Annex E.
This European Standard also gives the necessary requirements for the information for use.
This European Standard does not cover hazards from heating generated by electricity.
This European Standard does not deal with the hazards created by the release of flammable substances from
the products processed in the IThE.
NOTE EN 1539, Dryers and ovens, in which flammable substances are released — Safety requirements
This European Standard is not applicable to combustion and fuel handling systems
 of welding and soldering machines;
 up-stream of the IThE manual isolating valve.
This European Standard is not applicable to electricity cabling and power cabling upstream of the IThE control
panel/protective system.
Noise can be a significant hazard for combustion and fuel handling systems. It is not dealt with in this
standard.
This European Standard is not applicable to combustion and fuel handling systems as part of IThE which is
manufactured before the date of its publication as EN.
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 88-1:2007, Pressure regulators and associated safety devices for gas appliances — Part 1: Pressure
regulators for inlet pressures up to and including 500 mbar
EN 88-2:2007, Pressure regulators and associated safety devices for gas appliances — Part 2: Pressure
regulators for inlet pressures above 500 mbar up to and including 5 bar
EN 125:1991, Flame supervision devices for gas burning appliances — Thermo-electric flame supervision
devices
EN 161:2007, Automatic shut-off valves for gas burners and gas appliances
EN 230:2005, Automatic burner control systems for oil burners
EN 264:1991, Safety shut-off devices for combustion plants using liquid fuels — Safety requirements and
testing
EN 298:2003, Automatic gas burner control systems for gas burners and gas burning appliances with or
without fans
EN 331:1998, Manually operated ball valves and closed bottom taper plug valves for gas installations for
buildings
EN 334:2005, Gas pressure regulators for inlet pressures up to 100 bar
EN 751-1:1996, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases
and hot water — Part 1: Anaerobic jointing compounds
EN 751-2:1996, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases
and hot water — Part 2: Non-hardening jointing compounds
EN 1057:2006, Copper and copper alloys — Seamless, round copper tubes for water and gas in sanitary and
heating applications
EN 1643:2000, Valve proving systems for automatic shut-off valves for gas burners and gas appliances
EN 1854:2006, Pressure sensing devices for gas burners and gas burning appliances
EN 10241:2000, Steel threaded pipe fittings
EN 10242:1995, Threaded pipe fittings in malleable cast iron
EN 12067-1:1998, Gas/air ratio controls for gas burners and gas burning appliances — Part 1: Pneumatic
types
EN 12067-2:2004, Gas/air ratio controls for gas burners and gas burning appliances — Part 2: Electronic
types
EN 12078:1998, Zero governors for gas burners and gas burning appliances
EN 14382:2005, Safety devices for gas pressure regulating stations and installations — Gas safety shut-off
devices for inlet pressure up to 100 bar
EN 60204-1:2006, Safety of machinery — Electrical equipment of machines — Part 1: General requirements
(IEC 60204-1:2005, modified)
EN 60664 -1:2007, Insulation coordination for equipment within low-voltage systems — Part 1: Principles,
requirements and tests (IEC 60664-1:2007)
EN 60947-4-1:2001, Low-voltage switchgear and controlgear — Part 4-1: Contactors and motor-starters;
Electromechanical contactors and motor-starters (IEC 60947-4-1:2000)
EN 61140:2002, Protection against electric shock - Common aspects for installation and equipment (IEC
61140:2001)
EN 61558-1:2005, Safety of power transformers, power supplies, reactors and similar products — Part 1:
General requirements and tests (IEC 61558-1:2005)
EN 61810-1:2008, Electromechanical elementary relays — Part 1: General requirements (IEC 61810-1:2008)
EN 62061:2005, Safety of machinery — Functional safety of safety-related electrical, electronic and
programmable electronic control systems (IEC 62061:2005)
EN ISO 5817:2007, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) — Quality levels for imperfections (ISO 5817:2003, corrected version:2005, including Technical
Corrigendum 1:2006)
EN ISO 8434-1:2007, Metallic tube connections for fluid power and general use — Part 1: 24 degree cone
connectors (ISO 8434-1:2007)
EN ISO 8434-4:2000, Metallic tube connections for fluid power and general use — Part 4: 24° cone
connectors with O-ring weld-on nipples (ISO 8434-4:1995)
EN ISO 12100-1, Safety of machinery — Basic concepts, general principles for design — Part 1: Basic
terminology, methodology (ISO 12100-1:2003)
EN ISO 12100-2, Safety of machinery — Basic concepts, general principles for design — Part 2: Technical
principles and specifications (ISO 12100-2:2003)
EN ISO 13849-1:2008, Safety of machinery — Safety-related parts of control systems — Part 1: General
principles for design (ISO 13849-1:2006)
EN ISO 19879:2005, Metallic tube connections for fluid power and general use — Part 5: Test methods for
hydraulic fluid power connections (ISO 19879:2005)
ISO 7-1:1994, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions,
tolerances and designation
ISO 228-1:2000, Pipe threads where pressure-tight joints are not made on the threads — Part 1: Dimensions,
tolerances and designation
ISO 6976:1995, Natural gas — Calculation of caloric values, density, relative density and Wobbe index from
composition
ISO 7005-1:1992, Metallic flanges —Part 1: Steel flanges
ISO 7005-2:1988, Metallic flanges — Part 2: Cast iron flanges
ISO 7005-3:1988, Metallic flanges — Part 3: Copper alloy and composite flanges
ISO 8434-2:1994, Metallic tube fittings for fluid power and general use — Part 2: 37 degree flared connectors
ISO 8434-3:2005, Metallic tube connections for fluid power and general use — Part 3: O-ring face seal fittings
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE 1 A classification of plant, fuels and burners is given in informative Annex A.
NOTE 2 An alphabetic listing of technical terms in German, French and English, as well as their cross-references
where applicable is given in informative Annex B.
3.1
automatic burner control system
protective system comprising at least a programming unit and all the elements of a flame detector device
NOTE The various functions of an automatic burner control system can be in one or more housings (see also 3.66). It
is a protective system.
3.2
air pressure detector
device for sensing the existence of air pressure
3.3
air/fuel ratio
ratio between the mass flow of combustion air and the mass flow of the fuel
3.4
burner
combustion system under the control of individual automatic shut-off valves
3.5
burner, alternating pilot
pilot burner that is extinguished at the end of the main burner ignition period and is re-ignited immediately
when the main burner is shut down for control purposes
3.6
burners, cross-ignited
group of burners designed and arranged such that, by means of their proximity and relative position, ignition of
all burners can be ensured if one burner is ignited
3.7
burner, forced draught
burner in which the combustion air is supplied by mechanical means, usually of a fan or blower
3.8
burner, grate
solid fuel combustion system where the burning fuel is supported by a metallic grate
3.9
burner, induced draught
burner in which the combustion air is supplied by providing suction in the combustion chamber by mechanical
means, usually a fan
3.10
burner input rate
highest quantity of fuel energy used by a burner in unit time corresponding to the volumetric or mass flow
rates, the calorific value used being the net calorific value
3.11
burner, manual
burner whereby all the operating sequences are performed by an operator
3.12
burner, natural draught
burner in which the combustion air is entrained at atmospheric pressure, by the buoyancy of a chimney or the
fuel velocity
3.13
burner, open firing
burner not requiring an enclosed combustion chamber
EXAMPLE Torches, work station burners, equipment-integrated burners, and other burners firing in the open.
3.14
burner, permanent pilot
pilot burner that is intended to be left on permanently
3.15
burner, pilot
independently controlled burner designed to ignite the main burner
3.16
burner, portable
burner designed to be capable of being transported to fire in different locations
3.17
burner, radiant tube
burner that heats up the IThE indirectly by means of firing into a radiant tube protruding into the IThE process
chamber whereby the combustion remains wholly separated from the IThE process chamber
3.18
burner, work station
burner used at a particular work station and not requiring an enclosed combustion chamber
3.19
by-pass
passage conveying fuel from the upstream side to the downstream side of a pipework component so as to be
independent of the action of the pipework component
3.20
calorific value
quantity of heat produced by the combustion of unit volume or mass of fuel at a constant pressure of
1 013 mbar
NOTE A distinction is made between the gross calorific value (where the water produced by combustion is assumed
to be condensed) and the net calorific value.
3.21
combustion air
ambient air, or mixture of ambient air with other gases such as water vapour, carbon dioxide, . that is used
as oxygen supply for combustion process
3.22
combustion chamber
part of the IThE in which the combustion takes place
3.23
condensate drain
pipe designed to collect and drain condensates from a low point in the gas circuit and to drain it from a low
point
3.24
control system
system which responds to input signals from the process and/or the operator and generates output signals
which cause the process control to operate in the required way
3.25
EMC
immunity of the IThE to Electro Magnetic disturbances
3.26
enriched air
air with an oxygen concentration higher than 23 % (volume) obtained either by the addition of oxygen or the
reduction of nitrogen content
3.27
explosion/pressure relief
device (e.g. a flange) containing a disc which is designed to yield safely to an unsafe increase of internal
pressure
3.28
fault tolerance time
fault tolerance time is the time between the occurrence of an unsafe condition (caused by the process itself or
due to equipment failure) and the point when the process changes into critical operation, which result in an
hazardous event
3.29
filter/strainer, strainer/filter
device that enables foreign elements which could otherwise cause failures in the system, to be collected
3.30
flame response time
FRT
period of time that starts with the loss of sensed flame and ends with the de-energising of the terminals for the
automatic shut-off valve
3.31
flame detector device
device by which the presence of a flame is detected and signalled
NOTE It can consist of a flame sensor, an amplifier and a relay for signal transmission.
3.32
flame sensor
actual flame-sensing element, the output signal value of which is used as the input for flame detector amplifier
3.33
flame trap or flame arrestor
device fitted to the pipe conveying gas or a gas-air mixture and whose intended function is to prevent the
transmission of flame
3.34
flash back
flame propagation from the burner in upstream direction inside the pipework
3.35
fluids
gases, liquids and vapours in pure phase as well as mixtures thereof
NOTE A fluid contains a suspension of solids.
3.36
fluids group 1
fluids defined as explosive, extremely flammable, highly flammable, flammable (where the maximum allowable
temperature is above flashpoint), very toxic, toxic, and/or oxidizing
3.37
fluids group 2
all other fluids not referred to as group 1 fluids
3.38
functional safety
capability of a safety system or other means to reduce risk, to execute the actions required for achieving or
maintaining a safe state for the process and its related equipment
3.39
gas flow detector
device for sensing the presence of an adequate gas flow
3.40
gas pressure detector
device for sensing the presence of gas pressure
3.41
gas pressure regulator
device which maintains the downstream pressure constant to within fixed limits, independent of variations,
within a given range, of the upstream pressure and/or flow rate
3.42
graded fuel
solid fuel in the form of lumps which are classified according to size
3.43
high temperature equipment
IThE operating at a temperature above 750 °C measured at the combustion chamber walls and/or the
processing chamber walls
3.44
ignition
starting up chemical reaction of combustion of a fuel/combustion air mixture by application of a much smaller
energy source
3.45
initial boiling point
temperature of a liquid fuel that is measured at the instant that the first drop of condensate falls from the lower
end of the condenser tube in a boiling point test
3.46
lighting torch
hand-held burner which is used to ignite another burner
3.47
liquefied petroleum gas
LPG
commercial butane or commercial propane or any mixtures there of
3.48
lock-out, non volatile
safety shut-down by the protective system itself, such that a restart can only be accomplished by a manual
reset
3.49
lower flammability limit
LFL
lowest concentration of fuel in air at which the air/fuel mixture is flammable
3.50
low temperature equipment
IThE operating at a temperature measured below 750 °C at any part of the combustion chamber walls and/or
the processing chamber walls
3.51
main flame
flame, other than the ignition flame, on the main burner
3.52
manual reset
action after a lock-out of a safety related device (e.g. automatic burner control) carried out manually by the
supervising operator
3.53
multiple burner equipment
IThE with several burners with a common air and gas pipework firing in a common combustion chamber
3.54
nominal size
DN
numerical designation of size which is common to all components in a pipework other than components
indicated by outside diameter or by thread size
NOTE It is a convenient round number for reference purposes and is only loosely related to manufacturing
dimensions. The nominal size is designated by DN followed by a number.
3.55
operating temperature
temperature, or range of temperatures, at which the IThE is designed to operate
3.56
operator supervision
circumstance by which an operator has continuous control and surveillance of the plant and is located in a
position where he can shut the IThE down in the event of an emergency
3.57
pipework
assembly of piping (e.g. vale(s), orifice(s), . ) by means of which fuel and combustion air convey from the
point(s) of supply to the burner(s)
3.58
piping
components intended for the transport of fluids, when connected together for integration into a pressure
system
NOTE Piping includes in particular a pipe or system of pipes, tubing, fittings, expansion joints, hoses, or other
pressure-bearing components as appropriate. Heat exchangers consisting of pipes for the purpose of cooling or heating
air are considered as piping.
3.59
PLC
Programmable Logic Control
electronic device designed for control of the logical sequence of events
3.60
pre-purge
forced introduction of air or inert gas into the combustion chamber and flue passages, in order to displace any
remaining fuel/air mixture and/or products of combustion, and which takes place between the start signal and
the energising of the ignition device
3.61
pressure
pressure relative to atmospheric pressure, i.e. gauge pressure
NOTE As a consequence vacuum is designated by a negative value.
3.62
pressure accessories
devices with an operational function and having pressure-bearing housings
3.63
pressure equipment
vessels, piping, safety accessories and pressure accessories
NOTE Where applicable, pressure equipment includes elements attached to pressurized parts, such as flanges,
nozzles, couplings, supports, lifting lugs, etc.
3.64
pressure, maximum allowable
PS
maximum pressure for which the equipment is designed, as specified by the manufacturer
NOTE It is defined at a location specified by the manufacturer. This is the location of connection of protective and/or
limiting devices or the top of equipment
...