EN 676:2003+A2:2008

SLOVENSKI STANDARD
01-november-2008
6DPRGHMQLSOLQVNLYHQWLODWRUVNLJRULOQLNLYNOMXþQR]GRSROQLORP$
Automatic forced draught burners for gaseous fuels
Automatische Brenner mit Gebläse für gasförmige Brennstoffe
Brûleurs automatiques à air soufflé pour combustibles gazeux
Ta slovenski standard je istoveten z: EN 676:2003+A2:2008
ICS:
27.060.20 Plinski gorilniki Gas fuel burners
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 676:2003+A2
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2008
ICS 27.060.20 Supersedes EN 676:2003
English Version
Automatic forced draught burners for gaseous fuels
Brûleurs automatiques à air soufflé pour combustibles Automatische Brenner mit Gebläse für gasförmige
gazeux Brennstoffe
This European Standard was approved by CEN on 3 April 2003 and includes Amendment 1 approved by CEN on 1 April 2008 and
Amendment 2 approved by CEN on 1 April 2008.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 676:2003+A2:2008: E
worldwide for CEN national Members.

Contents
Foreword.4
1 Scope .6
2 Normative references .6
3 Terms and definitions .9
3.1 General terms and definitions.9
3.2 Specific terms and definitions.10
4 !Constructional and operational requirements – safety requirements and/or protective
measures".16
4.1 Conversion to different gases .16
4.2 Construction.16
4.3 Equipment .18
4.4 Functional and operational requirements.24
4.5 !Machine safety requirements and/or protective measures .31
5 Test methods.32
5.1 General.32
5.2 Functional tests .36
5.3 Operation .37
5.4 Tests to be carried out on the working and test diagrams .38
5.5 Combustion.42
5.6 Start-up .43
5.7 Obtaining the heat input .43
5.8 Electrical safety.44
5.9 !Verification of safety and /or protective measures.44
6 Marking, labelling and packaging .44
6.1 General.44
6.2 Data plate.45
6.3 Other marking .45
6.4 Instructions for installation, adjustment, maintenance and operation.46
6.5 Marking on the packaging .47
Annex A (informative) Determination of the combustion characteristics - carbon monoxide and
nitrogen oxides .60
Annex B (informative) Examples of control box sequencing .62
Annex C (informative) Test gases.63
C.1 General.63
C.2 Conditions for preparation of the test gases.63
C.3 Practical application of the test gases .64
Annex D (informative) Gas connections conditions in common use in the various countries .67
Annex E (informative) Tests .68
E.1 Supplementary testing .68
E.2 Drawing review.68
E.3 Individual test and inspection .68
E.4 Test report .69
Annex F (informative) Use of alternative gas lines and test documentation .70
F.1 Use of alternative gas lines .70
F.2 Test documentation.70
Annex G (informative) Correction of the influence of combustion air temperature and humidity on NO -
x
emissions .71
Annex H (informative) Check of the air proving device.72
Annex I (informative) !Additional recommendations for specific applications".73
I.1 !General .73
I.2 Pre-heating of the combustion air .73
I.3 Continuous working of the air ventilator .73
I.4 Variable excess of combustion air .73
I.5 Burner with start gas flame .73
I.6 Air filtering.74
Annex J (normative) !Machine related hazards – safety requirements and/or protective measures .75
J.1 General.75
J.2 List of significant hazards .75
J.3 Safety requirements and /or protective measures.75
J.4 Verification of machine safety requirements and/or protective measures .78
J.5 Information for use .78
Annex K (normative) #Additional requirements for burners with pressurised parts and burners firing
pressurised bodies as defined in Pressure Equipment Directive (PED) 97/23/EC .79
K.1 General.79
K.2 Design.79
K.3 Materials .79
K.4 Pressurised parts .79
K.5 Gas line components .80
K.6 Gas pressure governor .81
K.7 High gas pressure over load protection device .81
K.8 Automatic safety shut-off valve .81
K.9 Air proving device .81
K.10 Automatic burner control system .81
K.11 Means for draining and venting .81
K.12 General functions requirements .82
K.13 External safety limiter .83
K.14 Design according to EN 50156-1.83
K.15 Consideration: safety life cycle.84
K.16 Tests of pressurised parts.85
K.17 Other marking .86
K.18 Instructions for installation, adjustment, maintenance and operation.86
Annex ZA (informative) A-deviations .87
Annex ZB (informative) Clauses of this European Standard addressing essential requirements or other
provisions of EU Directives.88
Annex ZC (informative) #Relationship between this European Standard and the essential safety
requirements of the Pressure Equipment (PED) Directive 97/23/EC$ .91
Annex ZD (informative) !Relationship between this European Standard and the Essential
Requirements of EU Directive 98/37/EC Machinery Directive" .98
Annex ZE (informative) !Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC Machinery Directive" .99
Bibliography.100

Foreword
This document (EN 676:2003+A2:2008) has been prepared by Technical Committee CEN/TC 131 “Gas burners
using fans”, the secretariat of which is held by DIN.
This document shall be given the status of a national standard, either by publication of an identical text or by
endorsement, at the latest by December 2008 and conflicting national standards shall be withdrawn at the latest by
June 2010.
This document includes Amendment 1, approved by CEN on 2008-04-01 and Amendment 2, approved by CEN on
2008-04-01.
This document supersedes #EN 676:2003$.
The start and finish of text introduced or altered by amendment is indicated in the text by tags ! " and # $.
This document has been prepared under a mandate given to CEN by the European Commission and the European
Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative #Annexes ZB, ZC, ZD and ZE$, which are integral parts
of this document.
!deleted text"
According to edition 1996 the following fundamental changes are given:
 revisions for special applications;
 implementation of NO -classes and forming of arithmetic average values for determining the NO -values;
x x
 implementation of appliance categories for forced draught burners.
#Following a request from CEN/TC 131, CEN has agreed to defer the date of withdrawal of EN 676:2003 for a
transition period of 2 years.$
#Annexes A, B, C, D, E, F, G, H, I, ZA, ZB, ZC, ZD and ZE are informative.$
!Annexes J and K are normative."
This document includes a Bibliography.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.

Introduction
This European Standard is primarily intended for automatic forced draught gas burners having a combustion air
fan, operated with gaseous fuels, and intended to be marketed as a complete assembly.
EN 437 sets out a system of classification of appliances into categories defined according to the gases and
pressures for which they are designed.
Such a system of classification, when applied to forced draught burners, can lead to difficulties in defining the
precise category to which a particular burner should be allocated. For example many burners are designed to
operate on a wide range of fuel gases with little or no modification other than adjustment of air supply.
The technical committee responsible for the standard decided that the following appliance categories for forced
draught burners should apply:
 single categories: I for natural gas and I for liquefied petroleum gas;
2R 3R
 dual category: II for natural and liquefied petroleum gas.
2R /3R
All the burners of this standard marked with these categories are commissioned on site and the measured values
are recorded in a commissioning report.
However it should be noted that the Gas Appliance Directive requires the specification of the type of gas and the
supply pressure used as well as the burner category.
Forced draught gas burners according to this standard are often used in industrial applications. The safety
principles are the same as for forced draught gas burners used for household/commercial applications. Industrial
forced draught gas burners however should operate safely in their industrial environment and the risks involved can
differ from those for household applications. These industrial forced draught gas burners can be characterized by
the ability to withstand industrial environmental influences, like moisture, high temperature, electrical and magnetic
phenomena, vibrations, etc.
Principal requirements for installation and construction of gas burners and industrial thermal processing are
covered by EN 746-family.
Special requirements for forced draught burners for industrial premises will be given as a note with the addition
"Industrial application".
Further information and application limitation for EN 676 forced draught burners which are used for industrial
application are given in informative annex I.
!This document is a type C standard as stated in EN ISO 12100-1 and EN ISO 12100-2.
The machinery concerned and the extent to which hazards, hazardous situations and hazardous events are
covered are 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 standard, for machines that
have been designed and built according to the provisions of this type C standard."
1 Scope
!This European Standard specifies the terminology, the general requirements for the construction and operation
of automatic forced draught gas burners and also the provision of control and safety devices, and the test
procedure for these burners."
This standard is applicable to
 !automatic gas burners with a combustion air fan (hereinafter called "burners") as described in 3.1.2 and
gas line components, intended for use in appliances of different types, and that are operated with gaseous
fuels;"
 total pre-mixed burners and nozzle mixed burners.
The standard is applicable to
 !single burners with a single combustion chamber;"
 single-fuel and dual-fuel burners when operating only on gas;
 !gas function of dual-fuel burners designed to operate simultaneously on gaseous and liquid fuels."
!This European Standard deals with all significant machine hazards, hazardous situations and events relevant to
burners, when they are used as intended and under conditions of misuse which are reasonably foreseeable by the
manufacturer, see Annex J.
This European Standard specifies the requirements to be met by the manufacturer to ensure the safety during
commissioning, start-up, operation, shut-down and maintenance.
This European Standard does not deal with hazards due to specific applications.
This European Standard is not applicable to automatic forced draught gas burners which are manufactured before
the date of its publication as EN."
#This European Standard does not apply to burners specifically designed for use in industrial processes carried
out on industrial premises.
This European Standard deals also with the additional requirements for the burners in the scope with pressurised
parts and /or firing pressurised bodies, see Annex K.$
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 88-1, 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 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 161, Automatic shut-off valves for gas burners and gas appliances
EN 267, Forced draught oil burners — Definitions, requirements, testing, marking
!EN 294, Safety of machinery — Safety distance to prevent danger zones from being reached by the upper
limbs"
EN 298, Automatic gas burner control systems for gas burners and gas burning appliances with or without fans
EN 334, Gas pressure regulators for inlet pressures up to 100 bar
!EN 953, Safety of machinery — Guards - General requirements for the design and construction of fixed and
movable guards
EN 1088:1995, Safety of machinery — Interlocking devices associated with guards — Principles for design and
selection"
EN 1092-1, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN designated
— Part 1: Steel flanges
EN 1092-2, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN designated
— Part 2: Cast iron flanges
!EN 1092-3", Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN
designated — Part 3: Copper alloy flanges
EN 1643, Valve proving systems for automatic shut-off valves for gas burners and gas appliances
EN 1854, Pressure sensing devices for gas burners and gas burning appliances
#EN 10204, Metallic products — Types of inspection documents$
EN 10208-1, Steel pipes for pipelines for combustible fluids — Technical delivery conditions — Part 1: Pipes of
requirement class A
EN 10208-2, Steel pipes for pipelines for combustible fluids — Technical delivery conditions — Part 2: Pipes of
requirement class B
EN 10216-1, Seamless steel tubes for pressure purposes — Technical delivery conditions — Part 1: Non-alloy
steel tubes with specified room temperature properties
EN 10217-1, Welded steel tubes for pressure purposes — Technical delivery conditions — Part 1: Non-alloy steel
tubes with specified room temperature properties
EN 12067-1, Gas/air ratio controls for gas burners and gas burning appliances — Part 1: Pneumatic types
!EN 12067-2", Gas/air ratio controls for gas burners and gas burning appliances — Part 2: Electronic types
!EN 15036-1:2006, Heating boilers — Test regulations for airborne noise emissions from heat generators —
Part 1: Airborne noise emissions from heat generators"
#EN 50156-1:2004, Electrical equipment for furnaces and ancillary equipment — Part 1: Requirements for
application design and installation$
!deleted text"
!EN 60335-2-102:2007, Household and similar electrical appliances — Safety — Part 2-102: Particular
requirements for gas, oil and solid-fuel burning appliances having electrical connections
(IEC 60335-2-102:2004, modified)"
EN 60529, Degrees of protection provided by enclosures (IP code) (IEC 60529:1989)
!deleted text"
!EN 60730-1, Automatic electrical controls for household and similar use — Part 1: General requirements
(IEC 60730-1:1999, modified + A1:2003, modified)
EN 61310-1, Safety of machinery — Indication, marking and actuating — Part 1: Requirements for visual, auditory
and tactile signals (IEC 61310-1:1995 + Corrigendum 1995)"
!EN 10220", Seamless and welded steel tubes — Dimensions and masses per unit length
!EN ISO 228-1", Pipe threads where pressure-tight joints are not made on the threads — Part 1: Dimensions,
tolerances and designation (ISO 228-1:2000)
EN ISO 3166-1, Codes for the representation of names of countries and their subdivisions — Part 1: Country codes
!(ISO 3166-1:2006)"
!EN ISO 4871, Acoustics — Declaration and verification of noise emission values of machinery and equipment
(ISO 4871:1996)"
#EN ISO 9606-2, Qualification test of welders — Fusion welding — Part 2: Aluminium and aluminium alloys
(ISO 9606- 2:2004)
EN ISO 9606-3, Approval testing of welders — Fusion welding — Part 3: Copper and copper alloys (ISO 9606-
3:1999)
EN ISO 9606-4, Approval testing of welders — Fusion welding — Part 4: Nickel and nickel alloys
(ISO 9606-4:1999)
EN ISO 9606-5, Approval testing of welders — Fusion welding — Part 5: Titanium and titanium alloys, zirconium
and zirconium alloys (ISO 9606-5:2000)$
!EN ISO 12100-1, Safety of machinery — Basic concepts, general principles for design — Part 1: Basic
terminology, methodology (ISO 12100-1:2003)
EN ISO 12100-2:2003, Safety of machinery — Basic concepts, general principles for design — Part 2: Technical
principles (ISO 12100-2:2003)
EN ISO 13849-1, Safety of machinery — Safety-related parts of control systems — Part 1: General principles for
design (ISO 13849-1:2006)"
#EN ISO 15609-1, Specification and qualification of welding procedures for metallic materials — Welding
procedure specification — Part 1: Arc welding (ISO 15609-1:2004)
EN ISO 15609-2, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 2: Gas welding (ISO 15609-2:2001)
EN ISO 15609-3, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 3: Electron beam welding (ISO 15609-3:2004)
EN ISO 15609-4, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 4: Laser beam welding (ISO 15609-4:2004)
EN ISO 15609-5, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 5: Resistance welding (ISO 15609-5:2004)
EN ISO 15612, Specification and qualification of welding procedures for metallic materials — Qualification by
adoption of a standard welding procedure (ISO 15612:2004)
EN ISO 15614-7, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 7: Overlay welding (ISO 15614-7:2007)
EN ISO 15614-11, Specification and qualification of welding procedures for metallic materials — Welding
procedure test — Part 11: Electron and laser beam welding (ISO 15614-11:2002)$
ISO 7-1, 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 terms and definitions given in EN ISO 12100-1 and the following
apply."
3.1 General terms and definitions
3.1.1
forced draught burner
burner in which the total air for combustion is supplied by means of a fan
3.1.2
automatic forced draught burner
burner that is fitted with an automatic ignition, flame monitoring and burner control devices. Ignition, flame
monitoring and the on/off switching of the burner occur automatically. The heat input of the burner can be adjusted
during operation either automatically or manually
3.1.3
dual-fuel burner
burner in which both gaseous and liquid fuels can be burnt either simultaneously or in succession
3.1.4
total pre-mixed burner
burner in which part, or all, of the air for complete combustion of the gas is mixed with the gas upstream of the
mixture outlet ports
3.1.5
nozzle mixed burner
burner in which part, or all, of the air required for combustion of the gas is mixed with the gas at, or downstream of,
the air and gas ports
3.1.6
integrated ignition burner
burner with direct main ignition burner at reduced rate with by-pass start gas supply
3.1.7
start gas rate
gas rate ignited by the ignition device during the start-up of the burner
3.1.8
industrial applications
industrial applications means:
 the extraction,
 growth,
 refining,
 processing,
 production,
 manufacture or
 preparation
of materials, plants, livestock, animal products, food or artefacts
3.1.9
combustion chamber
part of the appliance in which the combustion takes place
3.2 Specific terms and definitions
3.2.1 Combustible gases
3.2.1.1
reference conditions
these correspond to 15 °C, 1 013,25 mbar, unless otherwise specified
3.2.1.2
calorific value
quantity of heat produced by the combustion, at a constant pressure equal to 1 013,25 mbar, of unit volume or
mass of gas, the constituents of the combustible mixture being taken at reference conditions and the products of
combustion being brought back to the same conditions
A distinction is made between:
 the gross calorific value: in which the water produced by combustion is assumed to be condensed;
Symbol: H
s
and
 the net calorific value: in which the water produced by combustion is assumed to be in the vapour state.
Symbol: H
i
Units: either
 megajoules per cubic metre (MJ/m³) of dry gas at the reference conditions, or
 megajoules per kilogram (MJ/kg) of dry gas
3.2.1.3
relative density
ratio of the masses of equal volumes of dry gas and dry air at the same conditions of temperature and pressure
Symbol: d
3.2.1.4
Wobbe index
ratio of the calorific value of a gas per unit volume and the square root of its relative density under the same
reference conditions. The Wobbe index is said to be gross or net according to whether the calorific value used is
the gross or net calorific value
Symbols: gross Wobbe index: W
s
net Wobbe index: W
i
Units: either
 megajoules per cubic metre (MJ/m³) of dry gas at the reference conditions, or
 megajoules per kilogram (MJ/kg) of dry gas
3.2.1.5
gas pressure
static pressure of the moving gas, relative to the atmospheric pressure, measured at right angles to the direction of
flow of the gas. It is expressed in millibars (mbar) or in bars (bar)
3.2.1.6
reference gases
test gases on which burners operate under nominal conditions when they are supplied at the corresponding normal
pressure
3.2.1.7
limit gases
test gases representative of the extreme variations in the characteristics of the gases for which burners have been
designed
NOTE The characteristics of the reference and limit gases are given in Table C.1.
3.2.1.8
normal pressure
pressure under which the burners operate in nominal conditions when they are supplied with the corresponding
reference gas
3.2.1.9
limit pressures
pressures representative of the extreme variations in the burner supply conditions
NOTE The test pressures are given in Table 5.
3.2.1.10
supply pressure
pressure measured at the measuring point M1 as specified in Figure 1, at which the nominal conditions are
achieved
3.2.1.11
adjustment pressure
pressure measured at the measuring point M2 as specified in Figure 1, at which the nominal conditions are
achieved
3.2.1.12
burner head pressure
pressure measured at the measuring point M3 as specified in Figure 1, at which the nominal conditions are
achieved
3.2.1.13
pressure in the combustion chamber
pressure or depression, relative to atmospheric pressure, prevailing in the combustion chamber
3.2.2 Operation of the burner
3.2.2.1 gas rate
3.2.2.1.1
volumetric flow rate
volume of gas consumed by the burner in unit time during continuous operation
3 3
Units: cubic metres per hour (m /h), litres per minute (l/min), cubic decimetres per hour (dm /h) or cubic decimetres
per second (dm /s).
Symbol: V
3.2.2.1.2
nominal volumetric flow rate
volumetric flow rate stated by the manufacturer, expressed in cubic metres per hour (m /h)
3.2.2.1.3
maximum flow rate
highest flow rate stated by the manufacturer, expressed in cubic metres per hour (m /h) at reference conditions
3.2.2.1.4
minimum flow rate
lowest flow rate stated by the manufacturer, expressed in cubic metres per hour (m /h) at reference conditions
3.2.2.1.5
mass flow rate
mass of gas consumed by the burner in unit time during continuous operation
Symbol: M
Units: kilograms per hour (kg/h), or grams per hour (g/h)
3.2.2.1.6
nominal mass flow rate
mass flow rate stated by the manufacturer
3.2.2.1.7
heat input
quantity of energy used in unit time corresponding to the volumetric or mass flow rates, the calorific value used
being either the net or gross calorific value
Symbol: Q
F
Unit: kilowatt (kW)
Burners with fixed heat input or single stage burners have a single heat input. Range-rated burners have a
maximum heat input and a minimum heat input declared by the manufacturer.
3.2.2.1.8
maximum heat input
highest value of the heat input declared by the manufacturer
Symbol: Q
F max
3.2.2.1.9
minimum heat input
lowest value of the heat input declared by the manufacturer
Symbol: Q
F min
3.2.2.2 running conditions
3.2.2.2.1
burners for permanent operation
burners that are designed to remain in the running condition for more than 24 h without interruption
3.2.2.2.2
burners for intermittent operation
burners that are designed to remain in the running condition for less than 24 h
3.2.3 Gas line components
3.2.3.1
gas line
part of the burner which is made up of the valves and controls and safety devices in which gas is conveyed
between the inlet connection and the burner head
3.2.3.2
range-rating device
component on the burner intended to be used for adjusting the heat input, within a range of heat inputs stated by
the manufacturer, to suit the actual heat requirements of the installation.
This adjustment can be progressive or in discrete steps
3.2.3.3
automatic shut-off valve
valve which opens when energised and closes automatically when de-energised
3.2.3.4
filter/strainer
device that enables foreign elements, which might otherwise cause failures in the system, to be collected
#3.2.3.5
pressurised parts
piping components and devices having pressure bearing housings with a pressure greater than 0,5 bar and a size
greater or equal to DN 100 mm
NOTE See EU Directive 97/23/EC.
3.2.3.6
means for draining and venting
devices to allow harmless draining and venting of the pressurised fuel supply lines$
3.2.4 Adjusting, control and safety devices
3.2.4.1
pressure governor
device which maintains the downstream pressure constant to within fixed limits independent of variations, within a
given range, of the upstream pressure
3.2.4.2
adjustable pressure governor
pressure governor fitted with a means of adjusting the loading on the diaphragm and thus the downstream
pressure
3.2.4.3
gas pressure protection devices
device which compares the actual value of the pressure with the desired value, gives a signal when the actual
value exceeds or drops below the desired value and initiates the controlled shut-down
3.2.4.4
flame detector device
device by which the presence of a flame is detected and signalled
It can consist of a flame sensor, an amplifier and a relay for signal transmission. These parts, with the possible
exception of the actual flame sensor, can be assembled in a single housing for use in conjunction with a
programming unit
3.2.4.5
automatic burner control system
system which comprises at least a programming unit and all the elements of a flame detector device. The various
functions of an automatic burner control system can be in one or more housings
3.2.4.6
programming unit
unit which reacts to signals from control and safety devices, gives control commands, controls the start-up
sequence, supervises the burner operation and causes controlled shut-down, and if necessary safety shut-down
and non-volatile lock-out. The programming unit follows a predetermined sequence of actions and always operates
in conjunction with a flame detector device
3.2.4.7
safe start check
procedure employing a protection circuit or circuits, to establish whether or not a fault in a safety system or a flame
simulating condition exists prior to start-up
3.2.4.8
controlled shut-down
process by which the power to the gas shut-off valve(s) is removed before any other action takes place, e.g. as a
result of the action of a controlling function
3.2.4.9
safety shut-down
process which is effected immediately following the response of a safety device or the detection of a fault in the
automatic burner control system and which puts the burner out of operation by immediately removing the power to
the gas shut-off valve(s) and the ignition device
NOTE Safety shut-down can also occur as a result of an interruption/decrease of the power supply.
3.2.4.10
non-volatile lock-out
safety shut-down condition of the system, such that a restart can only be accomplished by a manual reset of the
system and by no other means
3.2.4.11
volatile lock-out
safety shut-down condition of the system, such that a restart can only be accomplished by either the manual reset
of the system, or an interruption of the main power and its subsequent restoration
3.2.4.12
start signal
signal, e.g. from a thermostat, which releases the system from its start position and commences the predetermined
programme
3.2.4.13
recycling
process by which, after a safety shut-down, a full start-up sequence is automatically repeated
3.2.4.14
valve proving system
system to check the effective closure of the start gas or main gas safety shut-off valves, and which is capable of
detecting small gas leakage rates
3.2.4.15
ignition device
any means (flame, electrical ignition or other means) used to ignite the gas at the ignition burner or at the main
burner
3.2.4.16
running position of the burner system
position of the system in which the burner is in normal operation under the supervision of the programming unit and its
flame detector device
3.2.4.17
purge
forced introduction of air into the combustion chamber and flue passages, in order to displace any remaining
fuel/air mixture and/or products of combustion
3.2.4.17.1
pre-purge
purge which takes place between the start signal and the energisation of the ignition device
3.2.4.17.2
post-purge
purge which takes place immediately following a controlled shut-down
#3.2.4.18
monitoring devices
devices used for monitoring and controlling the burner when firing pressurised equipment
NOTE For the purpose of this standard they serve for safe use and operation of the burner. They are not safety accessories
for the purpose of the PED.$
3.2.5 Sequencing times
3.2.5.1
pre-purge time
period during which purge takes place at the proven air rate prior to the energisation of the ignition device
3.2.5.2
post-purge time
period between any shut-down and the moment the fan is switched off
3.2.5.3
ignition time
period between the opening of the gas valves and the first indication of the flame by the flame detector device
3.2.5.4
first safety time
period between the pilot gas valve, the start gas valve or main gas valve(s), as applicable, being energised and the
pilot gas valve, start gas valve or main gas valve(s), as applicable, being de-energised if the flame detector device
signals the absence of a flame
NOTE Where there is no second safety time, this is called the safety time.
3.2.5.5
second safety time
where there is a first safety time applicable to either a pilot or start gas flame only, the second safety time is the
period between the main gas valves being energised and the main gas valves being de-energised if the flame
detector device signals the absence of a flame
3.2.5.6
extinction safety time
period that starts with the signal that the flame has been extinguished and ends with the signal to de-energize the
safety shut-off valve of the gas supply
3.2.5.7
total closing time
period that starts with the signal that the flame has been extinguished and ends with the shut-off valves being
closed
3.2.6 Combustion
3.2.6.1
flame stability
capacity of flame to remain on the burner head or in the flame reception zone intended by the design
3.2.6.2
flame lift
total or partial lifting of the base of the flame away from the burner head or the flame holding zone provided by the
design
3.2.6.3
light back
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