SIST EN 15270:2008

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Pellet burners for small heating boilers - Definitions, requirements, testing, markingSUHVNXãDQMHR]QDþHYDQMHBruleurs a granulés pour petites chaudieres de chauffage - Définitions, exigences, essais, marquagePellet Brenner für kleine Heizkessel - Definitionen, Anforderungen, Prüfung, KennzeichnungTa slovenski standard je istoveten z:EN 15270:2007SIST EN 15270:2008en97.100.30ICS:SLOVENSKI
STANDARDSIST EN 15270:200801-marec-2008

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15270December 2007ICS 97.100.30 English VersionPellet burners for small heating boilers - Definitions,requirements, testing, markingBrûleurs à granulés pour petites chaudières de chauffage -Définitions, exigences, essais, marquagePelletbrenner für kleine Heizkessel - Definitionen,Anforderungen, Prüfung, KennzeichnungThis European Standard was approved by CEN on 3 November 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial 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 STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15270:2007: E

Vocabulary.29 Annex B (informative)
Fireproof non-metallic materials for pellet burners.32 Annex C (normative)
Requirements for electronic burner start up functions and pellet-air ratio controls.34 Annex D (informative)
Example of risk assessment to prevent back burning.36 Annex E (informative)
Example of risk assessment and the allocation of safety level for control functions using electronic devices for pellet burners.38 Annex F (informative)
Long term stability test (optional).40 Annex G (informative)
Measurement methods for some physical parameters.41 Annex H (normative)
Determination of organic gaseous compounds content.44 Annex I (informative)
Conformity evaluation.46 Bibliography.49

3.6 conveyor system, auger, feed screw
mechanical arrangement, normally incorporating a feed screw, used for transporting the pellets from the fuel hopper to the burner head 3.7 fuel hopper fuel store from which fuel is fed to the pellet burner 3.8 storage with external fuel hopper external fuel store from which fuel is fed to the pellet burner and which is separate from the pellet burner. It can be located either inside or outside the room where the pellet burner is located 3.9 storage with integral fuel hopper integral fuel store container from which fuel is fed to the pellet burner and which is integral with the pellet burner 3.10 burner head
part of a pellet burner where the pellets are burned 3.11 back burning situation in which the flames from the burning pellets in the burner head propagate and ignite the pellets in the conveyor system 3.12 temperature limiter safety level B device that causes the safe shutdown and lockout of the fuel supply and/or the combustion air supply respectively if the limiter value exceeds a pre-set limit. According to EN 14597 it is a device of Type “TB”

safety device that allows small droplets of water to be released onto the pellets in the conveyor system if back burning occurs 3.15 drop chute sloping channel, through which the pellets fall from a conveyor system into a burner head or into moving equipment 3.16 cell feeder device that intermittently interrupts the fuel stream thus only allowing a small amount of pellets at a time to be supplied to the burner, thereby preventing the flue gases from reaching the hopper 3.17 fire damper mobile closure within a duct which is designed to prevent the passage of fire 3.18 combustion air supply air required by the pellet burner to ensure the safe and efficient combustion of pellets and supplied into the combustion chamber, which is entirely or partially used to burn the pellets in the burner head 3.19 ash discharge arrangement for removing the ash from the burner head or the combustion chamber which may be automatically controlled 3.20 non volatile lockout shutdown condition such that a restart can be accomplished only by a manual reset and by no other means 3.21 volatile lockout shutdown condition such that a restart can be accomplished by restoration of the electrical supply after its loss or by manual reset 3.22 heat input, in kW, amount of heat as a function of time released by the burner at a given throughput
3.23 maximum heat input, in kW, maximum heat input, at continuous burning, as specified by the manufacturer
3.24 minimum heat input, in kW, minimum heat input, at continuous burning, as specified by the manufacturer
3.25 excess air ratio ratio between the effectively introduced quantity of air and the theoretically required quantity of air

Ash content in the test fuel at dry bases mass fraction in %
Bd Mass of test fuel referred to the test duration kg/h at dry bases Bw Mass of test fuel referred to the test duration kg/h at firing CC Carbon content of the test fuel mass fraction in %
CCO
Carbon monoxide content of the dry flue gases volume fraction in %
CCO2 Carbon dioxide content of the dry flue gases volume fraction in %
COGC
Calculated content of organic gaseous compounds mg/m³ dry flue gas at 10 % O2 Cr
Carbon content of residues referred to quantity of test fuel mass fraction in %
CTHC,m
Measured total hydrocarbon content expressed in mg/m³ methane equivalents in wet flue gas mg/m³ methane CTHC,p
Measured total hydrocarbon content expressed in mg/m³ propane equivalents in wet flue gas mg/m³ propane Gd
Actual specific dry flue gas volume
m³/kg fuel Gw
Actual specific wet flue gas volume m³/kg fuel

Hydrogen content mass fraction in % s mr Total residue in boiler after test kg O2, m Measured oxygen content in dry flue gas % as mean value OGC Organic gaseous compound
Qib Heat input kW R Total residue referred to the mass of test fuel mass fraction in %
t
Test duration h THC Total hydrocarbon content mg/m³ Tamb Ambient temperature °C Treturn Return temperature °C Tflow Flow temperature °C CW
Moisture content
mass fraction in %
λ Excess air ratio
4 Classification and groupings for pellet burners 4.1
Classification For the purpose of this standard pellet burners are classified in accordance with the following: Methods of control and grouped as detailed in 4.2; Means of ignition and grouped as detailed in 4.3; External or integral fuel hopper; Combustion chamber; Monobloc or other type of burner. 4.2 Methods of control of pellet burner Methods of control are grouped as follows: a. On-off control; b. Modulating control; c. Multi-stage control. 4.3 Means of ignition Means of ignition are grouped as follows: a. Manual ignition; b. Automatic electric ignition;

The connection shall be designed to withstand a possible gas explosion inside the boiler.

Components requiring regular maintenance shall be arranged or designed so that they are easily detachable. Furthermore, they shall be designed or marked in such a way that if the manufacturer’s instructions are followed they cannot be replaced incorrectly. Any parts subject to wear shall be accessible for replacement.
Sensors for the safety systems must be accessible for inspection and cleaning. The manufacturer shall give information on how to clean the feed screw, especially when a water sprinkler system has been actuated. 5.1.1.5 Handling of ashes The burner shall be so designed that ashes can easily be removed. When this necessitates removing the burner, it shall be easy to perform. If the burner is fitted with an automatic ash discharge system, this shall be in the form of an enclosed system or discharge the ashes into a water container.
If it is a necessity to use a special tool to remove the ashes from the burner, this shall be provided by the manufacturer. 5.1.2 Equipment 5.1.2.1 Motors and fans Motors and fans shall be so protected by suitable guards, shields or screens of adequate size, strength and durability that they are not liable to be touched accidentally. The degree of protection shall be at least IP 20, according to EN 60529. Removal of such guards, shields or screens shall only be possible with the use of tools. Mechanical drives (belt, chain drives etc), when used, shall be so designed or positioned as to afford protection to the operator. The correct tension is important. This can be achieved either by automatic means or manually. In the latter case access shall only be possible by the use of tools.

Any integral fuel hopper shall incorporate a device that interrupts the supply of fuel, if the lid is open. The device shall fulfil the requirements according to H.27 of EN 60730-2-5:2002. 5.1.2.5 Cell feeder or a fire damper For burners with a cell feeder or a fire damper, the leakage through the device shall not exceed 1 m³/h at 5 Pa positive pressure. 5.1.2.6 Water sprinkler system If the burner is equipped with a water sprinkler system, the water container shall have a level switch or a pressure switch and a volume of at least 5 l. 5.1.3 Interface to boiler The manufacturer shall provide sufficient information to ensure that the burner matches the boiler to which it is intended to be installed. The requirements for the boiler to which the burner can be attached shall be described in the technical documentation and shall specify at least the following items: a. combustion chamber: minimum dimensions for volume, length, width, height (the direction of the flame and the position of the burner head shall be considered here). Those minimum dimensions shall be used in the testing boiler; b. dimension of opening in the boiler required to fit the burner;

5.2.1 General Potential hazards caused by the burner or the operation of the burner with consideration of the behaviour of the boiler shall be avoided by either constructional means or by the use of safety devices. Safety shall be maintained in the event of possible failures in the safety device itself. The manufacturer shall undertake a risk assessment covering all potential hazards of the burner and the measures how to avoid or control them including allocation of safety levels. The safety levels are defined as follows: 1. safety level A: Control functions which are not intended to be relied upon for the safety of the application. A functional safety assessment is not required; 2. safety level B: Control functions which are intended to prevent an unsafe state of the appliance. Failure of the control function will not lead directly to a hazardous situation. A single fault assessment of the control including software class B according to EN 60730-1 is required; 3. safety level C: Control functions which are intended to prevent special hazards such as explosion or whose failure could directly cause a hazard in the appliance. A second fault assessment of the control including software Class C according to EN 60730-2-5 is required. This risk assessment shall cover at least the following: a. elements given in 5.2.2 to 5.2.11; b. burner functions start-up, purge, ignition, flame supervision, flue gas flow, control of heat demand, pellet-air ratio control. In the risk assessment one of the above mentioned safety levels shall be allocated to any identified hazard. An example of risk analysis for back burning is given in Annex D and an example of the risk analysis with allocation of the appropriate safety levels for control functions using electronic devices is given in Annex E. The actuation of any safety system shall at least result in cutting off the fuel feed. 5.2.2 Safety against back burning Back burning in any state of operation differing from normal operation shall be prevented either by constructional means or by use of safety devices or any other means that gives an equal level of safety.

The test at overload mode according to 6.6.1.3 can be omitted if a safety device, safety level C according to 5.2.1 prevents an overload mode. The boiler shall be equipped with a safety device that stops the fuel supply in the event that there is either insufficient or no combustion in the burner head. The test for interruption of fuel supply according to 6.6.1.3 can be omitted if a safety device, safety level B or C according to 5.2.1 is used. In the ignition phase a safety device shall stop the fuel supply after a safety time which shall be declared by the manufacturer of the burner start up function, if there is no or insufficient combustion. At the end of the safety time there shall be no critical amount of fuel in the burner head, if the ignition of the fuel fails. A failure in the safety device to detect insufficient combustion shall not lead to a dangerous situation. 5.2.4 Voltage variation
In the case of variation in the electrical power supply between 85 % and 110 % of the nominal value, there shall be no deterioration, which prohibits the normal use of the burner. A decrease of the electrical power supply to below 85 % of the nominal value shall not lead to a dangerous situation. Automatic restart of the burner after a power failure is permitted only if by self checking of the burner control system first has verified that all the safety systems are in operation. Loss of power supply or decrease of power supply to the burner shall not cause back burning or smoke passing out through the pellet burner.

C. The temperatures of the adjusting, control and safety devices shall not exceed the value stated by the manufacturer of the device and their operation shall remain satisfactory under the conditions specified in 6.6.1.5. The surface temperatures of knobs and levers, intended to be manipulated, shall not exceed the ambient temperature by more than: a) 35 K for metals; b) 45 K for porcelain or equivalent materials; c) 60 K for plastics or equivalent materials. 5.2.6 Leakage of combustion products Under normal conditions there shall be no significant leakage of combustion products into the surroundings. The tightness shall be ensured also after maintenance of the burner. Any pressurized parts containing combustion products shall be sealed in a sufficiently durable way to maintain its tightness (at least from one maintenance period to the next). 5.2.7 Resistance to over-heating Under the conditions specified in 6.6.1.7 the components of the burner shall not suffer any deterioration other than the normal alterations due to combustion. 5.2.8 Lock-out and re-start Where operation of a protective device or a safety shut-down of a safety device appears a non-volatile lock-out shall occur. Automatic restart after operation of any of the burner's safety systems shall only be permitted after a manual reset. 5.2.9 Safety against overheating the boiler water
The burner shall include a function which stops the operation of the burner if the temperature of the water in the boiler to which it may be fitted exceeds the allowable value for the heating boiler. 5.2.10 Safety against loss of combustion air supply The loss of combustion air supply shall not result in a CO content measured in the boiler that exceeds 5 %. 5.2.11 Safety against variation of combustion chamber pressure Variation of combustion chamber pressure shall not result in a dangerous situation. 5.2.12 Electric safety
5.2.12.1 Electrical safety of devices Those controls which are in accordance with the electrical requirements of EN 60730-1 are considered fulfilling the electrical requirements of this standard, therefore the requirements of 5.2.12.2 do not apply.

NOTE National regulations have to be taken into consideration. 5.3.2 Proportion of unburned fuel in the residue The proportion of combustible material in the residue shall not exceed 50 % by weight of the residue when tested according to 6.6.3. 5.3.3 Excess air ratio The mean value of the excess air ratio λ during the tests shall not exceed the following: at nominal heat input: λ ≤ 2,0. 5.3.4 Electrical consumption The electrical power consumption at start, at stand-by and at normal operation shall be determined according to prEN 15456 and the maximum value at stand-by shall be given on the data plate. 5.3.5 Start and ignition The burner shall ignite when the control system calls for ignition.

- No slag formation shall occur that significantly degrades the combustion characteristics during the test.
- Emissions of CO and OGC shall meet the requirements in Table 2. NOTE A suitable optional test method is described in Annex F. 5.3.7 Noise The noise emission from the pellet burner when operating at maximum heat input shall be determined in accordance with 6.6.7 and the mean measured value noted in the product description and on the data plate. 6 Testing 6.1 General The tests shall include the construction and operating characteristics of the burner. Functional requirements and especially performance requirements shall be tested in a test boiler rig according to 6.2 under consideration of the parameter of the interface. The test boiler rig which is set to simulate the type or types of boiler to which the manufacturer claims it can be fitted. For the parameter of the interface the values according to 6.2 shall be used unless the manufacturer has stated otherwise. 6.2 Test boiler rig Unless otherwise stated by the manufacturer, the burner shall be mounted in the test boiler rig detailed in Figure 1 in accordance with the installation instructions for the burner. The test boiler rig arrangement shall enable all load conditions within the specified output range of the burner while maintaining the water temperatures as specified in 6.6.2.2. In the test boiler rig detailed in Figure 1 the boiler wall and the moveable rear wall shall be water cooled. The door and the backside of the boiler are not water cooled. There shall be a slot between the wall and the surrounding boiler wall of 15 mm for the flue gas to pass. If the manufacturer states that this burner is only intended for a specific boiler, then the burner shall be tested on that boiler.

a) Side view, section
b) Front view
c) Top view
d) Three dimensional view Key H Height of combustion chamber 1 Movable door for adjusting the
burner in the vertical position B
Width of combustion chamber 2 Movable and water cooled rear
wall C
Adjustable length of combustion chamber
Minimum distance between burner head and upper wall of combustion chamber as stated by manufacturer. Dimensions in mm Boiler size B C H small 300 200 to 650 500 large 600 200 to 950 500 Figure 1 — Test boiler rig

CO2 –concentration G.1 ± 0,4 % volume CO2 CO concentration G.2 ± 5 % of limit value O2 –concentration
G.3 ± 0,4 % volume O2 THC concentration
G.4 ± 7 % of the measuring range Dust content in mg/m3
G.5 < 5 % of the limit of the emission class Flue gas temperature G.6 ± 5 K Ambient temperature (same as combustion air temperature) G.7 ± 2 K Water flow- and return temperatures G.8 — Water temperatures (in the radiator circuit, flow and return) G.9 — Surface temperature G.10 ± 2 K Pressure in the boiler combustion chamber G.11 ± 5 % of measured value Electrical energy supplied 6.6.5 ± 0,1 % of measured value Length of combustion chamber
± 3 % Calculated parameters Clause Maximum tolerances CO concentration G.10 ± 5 % of the limit of the emission class Heat input G.12 ± 3 % of measured value OGC concentration Annex H ± 5 % of the limit of the emission class
6.4 Test fuel The tests shall be carried out with wood pellets. The test wood pellets shall be of class “chemically untreated wood excluding bark” in accordance with CEN/TS 14961 and the deformation temperature of the ashes shall not be less than 1 400 ºC measured according to CEN/TS 15404. The moisture content and the calorific value of the test fuel used shall be determined. If the manufacturer states that the burner is intended for use with larger pellet diameters or pellets with other characteristics the test shall be performed with these pellet qualities and as described in 6.6.2.1 a) and b). 6.5 Examination 6.5.1 General The burner shall be checked to ensure its conformity with the relevant construction document provided, prior to its installation on the test rig. 6.5.2 Design examination The burner including fuel hopper, if existing, shall be visually examined to check that the requirements for materials, design, mounting, accessibility for maintenance and use, as well as handling of ashes are met.

d. Check also that the burner has a device that interrupts the fuel supply if the lid is open in accordance with 5.1.2.4. e. In case of a burner with a cell feeder or a fire damper, test the leakage of the device with a positive pressure of 5 Pa to ensure that the requirements of 5.1.2.5 are met. Other safety related burner controls shall be examined according to the relevant standard including the specified deviations mentioned in 5.2.1. 6.5.4 Check interface to boiler Checks shall be made, that all the relevant aspects of the interface to the boiler are described in the technical documentation and that the requirements of 5.1.3 are met. 6.6 Test cases 6.6.1 Safety tests 6.6.1.1 General The safety test procedure involves testing the burner for the following possible faults of the burner as detailed in Table 4.

Table 4 — Test to be performed during the safety test Functional fault Test to be performed clause Feed rate too high Feed screw set to operate continuously at maximum speed 6.6.1.3 Feed rate too low Feed screw motor disconnected 6.6.1.2 Loss of air supply Air fan disconnected by wire Air intake covered 6.6.1.9 Loss of power All power disconnected including pumps 6.6.1.4 Combustion chamber pressure Draught increased to 50 Pa at stand-by until stable condition 6.6.1.10 Open hopper lid Hopper left open at normal draught until stable condition 6.6.1.2 Empty hopper Full load operation until empty hopper 6.6.1.6 Burner detaching Check for existence of switch or need for tools to detach burner 6.5.3 No ignition Test for safe ignition for burners with basic fire bed after 16 hours of stand-by 6.6.6
6.6.1.2 Test of safety against back-burning The following checks shall also be carried out: a. Check the number and types of safety systems to protect against back burning.
b. Check that at least one of the safety systems works regardless of the state of the power supply (see 6.6.1.4 and 6.6.1.8). c. Check also, that at least one of the safety systems is still available after the supply of fuel to the burner head has been stopped. d. If the burner is fitted with a water spray, measure the volume of the water container and check that it includes a level switch or pressure switch.
e. Check the drop distance of any drop chute is according to clause 5.2.2 to stop the propagation of back burning.
f. For a safety system with emergency discharge of the fuel into the boiler, check that it is supplied with an emergency power supply (e.g. battery back up). g. If the burner is fitted with an integral fuel hopper, measure the temperature in the hopper, when performing the test at maximum heat input, at minimum heat input and at the start and ignition test. The temperature shall be measured as close to the fuel feed screw as possible. h. In case of an integral fuel hopper, check that no dangerous situation (e.g. smoking, back burning) arises from opening the lid under normal circumstances or from leaving the lid open. It is acceptable to discharge fuel slowly through the feed screw to avoid back burning if this is done automatically. The safety of the burner shall also be checked with the fuel feed screw disconnected to simulate failure of the drive while operating at full load.
The requirements specified in 5.2.2 shall be satisfied.

The functionality of the safety device for the shut-down of the fuel line shall occur by prevention of the ignition after release of fuel if no or insufficient combustion in the burner head happens.
The test for blocked fuel line shall be achieved by insertion of a metallic object into the feed screw. The requirements specified in 5.2.3 shall be satisfied. 6.6.1.4 Voltage variation Test the pellet burner at maximum heat input and with an electrical supply at 100 % of the rated voltage. Interrupt the electrical supply to the burner and check that no back-burning occurs or that no smoke passes out through the pellet burner.
After the test, carried out at maximum heat input, a test shall be performed at 85 % of the rated voltage with the exception of three-phase a. c. motors, if any. A check shall be made that all safety functions are in operation after the electrical power supply has been decreased.
The requirements specified in 5.2.4 shall be satisfied. 6.6.1.5 Measurement of surface temperatures of accessible parts When performing the test at maximum heat input 6.6.2.2
the surface temperatures of parts of the burner that can be touched after reaching steady state conditions shall be measured. The requirements specified in 5.2.5 shall be satisfied. 6.6.1.6 Measurement of leakage of combustion products When performing the test specified in 6.6.2.2 a check shall be performed to determine that no combustion products are leaking from the burner to the surroundings. To simulate a leaking lid gasket, check that no smoke emerges from the hopper when the lid is open and the burner is operating at maximum heat output. Also check that the hopper is not filled with smoke after running out of fuel under normal conditions. The requirements specified in 5.2.6 shall be satisfied. 6.6.1.7 Check of resistance to over-heating After completion of the tests specified in 6.6.2.2, it shall be ascertained, at room t
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