oSIST prEN 12809:2011

Residential independent boilers fired by solid fuel - Nominal heat output up to 50 kw - Requirements and test methods

This European Standard specifies requirements relating to the design, manufacture, construction, performance (efficiency and emission), safety, instructions and marking together with associated test methods and test fuels for type testing residential independent boilers fired by solid fuel.
This standard is applicable to hand and automatically fired appliances having nominal heat outputs up to 50 kW, the primary function of which is to provide hot water for central heating and/or domestic use, and which are designed for use only with open vented systems at a working pressure not exceeding 2 bar. In addition to their primary function of providing hot water these appliances also provide space heating to the place of installation. These appliances may burn either solid mineral fuels, peat briquettes or natural or manufactured wood logs or be multi-fuel in accordance with the appliance manufacturer’s instructions.
This standard is not applicable to independent boilers for hot water only production and having heat outputs of less than 5 kW.
This standard is also not applicable to the design and construction of automatic stoking devices.

Heizkessel für feste Brenstoffe - Nennwärmeleistung bis 50 kW - Anforderungen und Prüfungen

Diese Norm gilt für hand- und automatisch beschickte Feuerstätten bis zu einer Nennwärmeleistung von 50 kW, deren Hauptfunktion die Erwärmung von Heiz- und/oder Brauchwasser ist und die ausschließlich für den Einbau in offene Systeme mit einem Arbeitsdruck von höchstens 2 bar verwendet werden. Außer ihrer Hauptfunktion der Erwärmung von Heiz- und Brauchwasser ist die Feuerstätte auch für die Beheizung des Aufstellungsraumes vorgesehen.
Diese Europäische Norm beschreibt Anforderungen an Auslegung, Herstellung, Ausführung, Sicherheit und Leistungsvermögen (Wirkungsgrad und Emission für häuslichen Heizkessel für feste Brennstoffe (hier im folgenden "Feuerstätte(n)" genannt und deren Anleitungen. Weiterhin enthält diese Norm Festlegungen für die Konformitätsbewertung, das heißt Typprüfung (ITT) und werkseigene Produktionskontrolle (FCP) und die Kennzeichnung der Feuerstätten.
Diese Feuerstätten können entweder feste mineralische Brennstoffe, Torfbriketts, Holzbriketts, Scheitholz oder mehrere dieser Brennstoffe nach Anleitung des Feuerstättenherstellers verfeuern.
Diese Norm gilt nicht für Heizkessel, die nur Heiz- und Brauchwasser erwärmen und solche mit einer Nennwärmeleistung von weniger als 5 kW.
Diese Norm gilt nicht für die Auslegung und Ausführung von automatischen Fördersystemen.

Chaudières domestiques à combustible solide destinées à implantées dans le volume habitable - Puissance calorifique nominale inférieure ou égale à 50 kW - Exigences et méthodes d’essai

La présente norme européenne s’applique aux chaudières domestiques destinées à être implantées
dans le volume habitable à alimentation manuelle et automatique à puissances calorifiques nominales
jusqu’à 50 kW, dont la fonction principale est de fournir de l’eau chaude à des fins de chauffage
central et / ou pour usage domestique. Elles ne sont conçues que pour être utilisées avec des
systèmes à expansion ouverts à une pression de service ne dépassant pas 2 bars. Outre leur
fonction principale de fournir de l’eau chaude, ces appareils fournissent également de la chaleur dans
l'espace où ils sont installés.
La présente Norme européenne spécifie les exigences relatives aux instructions de conception,
fabrication, construction, sécurité, performance (rendement et émission) des chaudières domestiques
à combustible solide destinées à être implantées dans le volume habitable (ci-après désigné par les
«appareils» et fournit les instructions les concernant. En outre, elle fournit également des dispositions
concernant l'évaluation de la conformité (à savoir l’essai de type initial (ITT) et du contrôle de la
production en usine et le marquage de ces produits.
Ces appareils peuvent fonctionner avec des combustibles minéraux solides, des briquettes de tourbe,
des bûches de bois naturelles ou manufacturées ; ils peuvent également fonctionner avec plusieurs
combustibles conformément aux instructions du fabricant de l'appareil.
La présente Norme ne s’applique pas aux bouilleurs indépendants uniquement destinés à la
production d’eau chaude à puissances calorifiques inférieures à 5 kW.
La présente norme ne s’applique également pas à la conception et à la construction des dispositifs à
chargement automatique.

Grelni kotli na trdna goriva - Imenska grelna moč do 50 kW - Zahteve in preskusne metode

General Information

• Status: Not Published
• Public Enquiry End Date: 29-Jun-2011
• ICS: 91.140.10 - Central heating systems
• ICS: 97.100.30 - Solid fuel heaters
• Technical Committee: OGS - Heating for buildings
• Current Stage: 98 - Abandoned project (Adopted Project)
• Start Date: 07-Oct-2013
• Due Date: 12-Oct-2013
• Completion Date: 07-Oct-2013
• Directive: 305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Directive: 89/106/EEC - Construction products
• Mandate: M/129 - Mandate to CEN/CENELEC concerning the execution of standardization work for harmonized standards on space heating appliances
• Ref Project: prEN 12809 - Residential independent boilers fired by solid fuel - Nominal heat output up to 50 kw - Requirements and test methods

Relations

• Revised: SIST EN 12809:2003 - Residential independent boilers fired by solid fuel - Nominal heat output up to 50 kW - Requirements and test methods
• Effective Date: 08-Jun-2022
• Revised: SIST EN 12809:2003 - Residential independent boilers fired by solid fuel - Nominal heat output up to 50 kW - Requirements and test methods
• Effective Date: 04-Jul-2009

Overview

prEN 12809 - "Residential independent boilers fired by solid fuel - Nominal heat output up to 50 kW - Requirements and test methods" is a CEN draft European Standard that specifies design, construction, safety, performance and testing requirements for residential independent boilers burning solid fuels. It applies to hand‑ and automatically‑fired appliances with nominal heat outputs up to 50 kW whose primary function is to provide hot water for central heating and/or domestic use (and which also provide space heating), designed for open vented systems at working pressures ≤ 2 bar. Applicable fuels include solid mineral fuels, peat briquettes and natural or manufactured wood logs; multi‑fuel operation is permitted per manufacturer instructions.

This standard is not applicable to independent boilers for hot‑water‑only production below 5 kW, nor to the design of automatic stoking devices.

Key topics and technical requirements

• Design, materials and construction: requirements for steel and cast‑iron boilers, waterways, flueways, ashpan/ashpit, bottomgrate and sealing.
• Safety: temperature limits, strength and leak‑tightness of boiler shell, fan cut‑out devices, electrical safety and operating tools.
• Performance: test methods and requirements for efficiency, emissions, flue gas temperature, nominal heat output, refuelling interval, flue draught, slow combustion and recovery.
• Testing and test fuels: normative Annexes provide test methods and specifications for test fuels and recommended fuels for repeatable type testing (ITT).
• Conformity assessment: procedures for initial type testing (ITT), factory production control (FPC) and marking to support CE/national compliance and traceability.
• Instructions and marking: mandatory installation and user operating instructions, product markings and information for safe use and maintenance.
• Relationship to EU legislation: informative Annex ZA addresses links to the Construction Products Directive.

Applications

• Ensures consistent safety, performance and emissions across residential solid fuel boiler products sold in Europe.
• Provides standardized test methods that manufacturers and independent laboratories use for type testing, performance claims and certification.
• Guides product documentation (installation/user manuals), factory quality control and CE marking processes.

Who uses this standard

• Manufacturers of residential solid fuel boilers (design, R&D, compliance teams)
• Test laboratories and certification bodies performing ITT and emissions testing
• Regulatory authorities and market surveillance bodies verifying compliance
• Installers and HVAC specifiers referencing safe installation and performance requirements

Related standards

• Referenced normative standards on materials, pipe threads and test methods (e.g., ISO and EN standards listed in prEN 12809) and CEN/TS 15883 for emission test methods.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2011
*UHOQLNRWOLQDWUGQDJRULYD,PHQVNDJUHOQDPRþGRN:=DKWHYHLQSUHVNXVQH
PHWRGH
Residential independent boilers fired by solid fuel - Nominal heat output up to 50 kw -
Requirements and test methods
Heizkessel für feste Brenstoffe - Nennwärmeleistung bis 50 kW - Anforderungen und
Prüfungen
Chaudières domestiques à combustible solide destinées à implantées dans le volume
habitable - Puissance calorifique nominale inférieure ou égale à 50 kW - Exigences et
méthodes d’essai
Ta slovenski standard je istoveten z: prEN 12809
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
97.100.30 Grelniki na trdo gorivo Solid fuel heaters
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2011
ICS 91.140.10 Will supersede EN 12809:2001
English Version
Residential independent boilers fired by solid fuel - Nominal heat
output up to 50 kw - Requirements and test methods
Chaudières domestiques à combustible solide destinées à Heizkessel für feste Brenstoffe - Nennwärmeleistung bis 50
implantées dans le volume habitable - Puissance kW - Anforderungen und Prüfungen
calorifique nominale inférieure ou égale à 50 kW -
Exigences et méthodes d'essai
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 295.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12809:2011: E
worldwide for CEN national Members.

Contents Page
Foreword . 4
1 Scope. 5
2 Normative references . 5
3 Terms and definitions . 6
4 Materials, design and construction . 11
4.1 Production documentation . 11
4.2 General construction requirements . 12
4.3 Boilers constructed of steel . 13
4.4 Boilers constructed of cast iron . 15
4.5 Boiler shell tappings . 16
4.6 Draining of boiler shell . 17
4.7 Boiler waterways . 17
4.8 Combustion air supply . 18
4.9 Ash-pit door and firedoor . 18
4.10 Bottomgrate . 18
4.11 Ashpan and ash removal. 19
4.12 Control of flue gas . 19
4.13 Flue draught test point . 19
4.14 Fan cut-out safety device . 19
4.15 Flue spigot or socket . 19
4.16 Front firebars and/or deepening plate . 20
4.17 Flueways . 20
4.18 Provision for cleaning boiler heating surfaces, and flue connector . 20
5 Safety requirements . 20
5.1 Temperature in integral fuel storage container . 20
5.2 Temperature of adjacent combustible materials . 20
5.3 Strength and leaktightness of boiler shell . 20
5.4 Operating tools . 21
5.5 Fan cut-out safety device . 21
5.6 Electrical safety . 21
6 Performance requirements . 21
6.1 Refuelling interval at nominal heat output . 21
6.2 Efficiency . 22
6.3 Flue gas temperature . 22
6.4 Nominal heat output . 22
6.5 Flue draught . 23
6.6 Slow combustion and recovery . 24
6.7 Emissions . 24
7 Appliance instructions . 25
7.1 General . 25
7.2 Installation instructions. 25
7.3 User operating instructions . 26
8 Evaluation of conformity . 27
8.1 General . 27
8.2 Initial type testing . 27
8.3 Factory production control (FPC) . 31
9 Marking . 33
Annex A (normative) Test methods . 36
Annex B (normative) Test fuels and recommended fuels . 65
Annex ZA (informative) Clauses of this European Standard addressing the provisions of
the EU Construction Products Directive . 70
Bibliography . 82

Foreword
This document (prEN 12809:2011) has been prepared by Technical Committee CEN/TC 295
“Residential solid fuel burning appliances”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12809:2001.
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.
This document is a revision of the published standard EN 12809:2001 following comments received at
its 5 year review.
1 Scope
This European Standard is applicable to hand and automatically fired residential independent boilers
having nominal heat outputs up to 50 kW, the primary function of which is to provide hot water for
central heating and/or domestic use, and which are designed for use only with open vented systems
at a working pressure not exceeding 2 bar. In addition to their primary function of providing hot water
these appliances also provide space heating to the place of installation.
This European Standard specifies requirements relating to the design, manufacture, construction,
safety and performance (efficiency and emission) of residential independent boilers fired by solid fuel
(hereafter referred to as “appliance(s)”) and provides instructions for them. Furthermore, it also gives
provisions for evaluation of conformity (i.e. initial type testing (ITT) and factory production
control (FPC) and marking of these products.
These appliances may burn either solid mineral fuels, peat briquettes or natural or manufactured
wood logs or be multi-fuel in accordance with the appliance manufacturer’s instructions.
This standard is not applicable to independent boilers for hot water only production and having heat
outputs of less than 5 kW.
This standard is also not applicable to the design and construction of automatic stoking devices.
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 applies (including amendments).
EN 1561:1997, Founding — Grey cast irons
EN 1563:1997, Founding — Spheroidal graphite cast irons
EN 10025:1993, Hot rolled products of non-alloy structural steels — Technical delivery conditions
EN 10027-2:1992, Designation systems for steels — Part 2: Numerical system
EN 10028-2:1992, Flat products made of steels for pressure purposes — Part 2: Non-alloy and
alloysteels with specified elevated temperature properties
EN 10029:1991, Hot rolled steel plates 3 mm thick or above — Tolerances on dimensions, shape and
mass
EN 10088-2:1995, Stainless steels — Part 2: Technical delivery conditions for sheet/plate and strip for
general purposes
EN 10111:1998, Continuously hot–rolled low carbon steel sheet and strip for cold forming —
Technical delivery conditions
EN 10120:1996, Steel sheet and strip for welded gas cylinders
EN 60335-2-102, Household and similar electrical appliances — Safety — Particular requirements for
gas, oil and solid-fuel burning appliances having electrical connections
ISO 7-1:2000, Pipe threads where pressure-tight joints are made on the threads —
Part 1: Dimensions, tolerances and designation
ISO 7-2:2000, Pipe threads where pressure-tight joints are made on the threads — Part 2: Verification
by means of limit gauges
ISO 228-1:1994, Pipe threads where pressure-tight joints are not made on the threads —
Part 1: Dimensions, tolerances and designation
ISO 228-2:1987, Pipe threads where pressure-tight joints are not made on the threads —
Part 2: Verification by means of limit gauges
ISO 331:1983, Coal — Determination of moisture in the analysis sample — Direct gravimetric method
ISO 334:1992, Solid mineral fuels — Determination of total sulfur — Eschka method
ISO 351:1996, Solid mineral fuels — Determination of total sulfur — High temperature combustion
method
ISO 501:1981, Coal — Determination of the crucible swelling number
ISO 562:1998, Hard coal and coke — Determination of volatile matter
ISO 609:1996, Solid mineral fuels — Determination of carbon and hydrogen — High temperature
combustion method
ISO 687:1974, Coke — Determination of moisture in the analysis sample
ISO 1171:1997, Solid mineral fuels — Determination of ash content
ISO 1928:1995, Solid mineral fuels — Determination of gross calorific value by the bomb calorimetric
method, and calculation of net calorific value
CEN/TS 15883:2009, Residential solid fuel burning appliances — Emission test methods
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
air inlet control
manual or automatic device to control the quantity of air supplied for combustion
3.2
ashpan
removable receptacle shaped to receive the residue falling from the firebed
3.3
ashpit
enclosed chamber designed to receive the residue or the ashpan
3.4
basic firebed
quantity of glowing embers which ensures ignition of the test fuel to be charged
NOTE The basic firebed may be specified by the manufacturer.
3.5
boiler
vessel in which water is heated, intended for fitting in or forming an integral part of a solid fuel
appliance
3.6
boiler waterways
space within a boiler which contains water
3.7
bottomgrate
part of the appliance at the base of the firebox which supports the fire-bed through which the residue
falls into the ashpan or ashpit and through which combustion air and/or combustion gases may be
drawn
3.8
burning rate
reduction in the mass of fuel per unit of time
3.9
charging door
door which covers the refuelling opening
3.10
combustion air
air supplied to the firebox, which is entirely or partially used to burn the fuel
3.11
combustion air selector
device for adjusting the primary and/or secondary air according to the type of fuel burned
3.12
combustion control device
mechanism for setting the primary and/or secondary air in accordance with the burning rate required
3.13
combustion gases
compounds in gaseous form produced inside an appliance when fuel is burned
3.14
damper
mechanism to change the resistance to flow of the combustion gases
3.15
de-ashing
process of clearing a fuelbed and discharging residue into the collecting receptacle
3.16
de-ashing mechanism
device to agitate or disturb the ash to facilitate its removal from the firebed
NOTE It may also be used to change the bottomgrate operating position on some appliances.
3.17
direct water system
hot water system in which stored domestic hot water is heated directly by hot water circulating from
the boiler
3.18
draught regulator
inlet device for admission air downstream of the firebed, enabling the flue draught to be controlled
3.19
efficiency
ratio of total heat output to total heat input during the test period expressed as a percentage
3.20
firebed; fuelbed
fuel contained in the firebox
3.21
firebox; combustion chamber
that part of the appliance in which fuel is burned
3.22
firebox opening
aperture in the firebox through which the appliance may be fuelled
3.23
firedoor
door through which the fire may be viewed and which may be opened to allow refuelling of the firebed
3.24
flue draught
differential between the static air pressure in the place of installation and the static pressure at the flue
gas measurement point
3.25
flue gases
gaseous compounds leaving the appliance flue spigot and entering the flue gas connector
3.26
flue gas adaptor
fitting which allows for variations in size and shape of the flue components
3.27
flue gas connector
duct through which flue gases are conveyed from the appliance into the chimney flue
3.28
flue gas mass flow
mass of flue gas drawn off from the appliance per unit of time
3.29
flue gas temperature
temperature of the flue gas at the specified point in the measurement section
3.30
flue spigot; flue socket
integral part of the appliance for connecting the flue gas connector thus permitting the deliberate
escape of products of combustion into the chimney flue
3.31
flueway
that part of the appliance designed to convey combustion gases from the firebox to the flue spigot
3.32
front firebars; deepening plate
grating or plate fitted at the front of the firebox opening to prevent spillage of fuel and ash or to
change the firebox capacity, or both
3.33
fuel hopper
fuel store integral with the appliance from which fuel is fed to the firebox
3.34
fuel regulator
device for controlling the size of the firebed
3.35
heat input
quantity of energy, which the fuel provides to the appliance
3.36
heat output
quantity of useful heat released by the appliance
3.37
indirect water system
hot water system in which stored domestic hot water is heated by a primary heater through which hot
water from the boiler is circulated without mixing of the primary (heating) water and the stored
domestic hot water
3.38
maximum water operating pressure
limiting water pressure up to which the boiler of an appliance can be safely operated
3.39
nominal heat output
total heat output of the appliance quoted by the manufacturer and achieved under defined test
conditions when burning the specified test fuel
3.40
operating tool
device supplied with the appliance for handling movable, adjustable and/or hot components
3.41
primary air
combustion air, which passes through the fuel bed
NOTE Primary air does not necessarily have separate inlets neither does it necessarily pass through a
bottomgrate
3.42
recovery capability
ability of the fire to re-ignite existing or newly charged fuel after a defined burning period without
external assistance
3.43
recommended fuel
fuel of commercial quality listed in the appliance manufacturer's instructions, and shown to achieve
the claimed performance when tested in accordance with this European Standard
3.44
refuelling interval
period of time for which the combustion may be maintained in the appliance with a single load of fuel,
without intervention by the user
3.45
residue
ashes, including combustibles, which collect in the ashpit
3.46
secondary air
air supplied for the purpose of completing the combustion of gases leaving the fuel bed
3.47
slow-combustion capability
ability of an appliance to continue operating at a low burning rate for a specified minimum period
without any input of fuel and without any interference with the combustion process, in such a manner
that the firebed can be recovered at the end of this period
3.48
slow combustion heat output
heat output achieved during the test period under slow combustion conditions
3.49
solid fuel
natural or manufactured solid mineral fuels, natural or manufactured wood logs and peat briquettes
3.50
solid mineral fuel
coal, lignite, coke and fuels derived from these
3.51
space-heating output
heat output provided by convection and radiation to the room
3.52
start-up device
mechanism to divert the path of the heating gases and/or change the combustion air opening cross
section during the ignition period
3.53
steady-state condition
stage at which values to be measured in successive equal periods of time do not exhibit significant
change
3.54
integral fuel storage container
enclosed area forming part of the appliance, but not connected directly to the fuel charging area, in
which fuel is stored prior to it being physically transferred by the user to the fuel charging position
3.55
test fuel
fuel of commercial quality being characteristic of its type to be used for testing appliances
3.56
thermostat
temperature sensitive device which automatically changes the combustion air inlet cross-sectional
area
3.57
total heat output
rate of useful heat released by the appliance
3.58
type test pressure
pressure to which all waterways of the test appliance are subjected
3.59
water-heating output
heat output to water averaged during the test period
3.60
working surfaces
all surfaces of an appliance designed to transmit heat to the surrounding atmosphere
NOTE All external surfaces of a heating boiler including the flue gas connector in accordance with this
standard are classified as working surfaces because they are designed to transmit heat to the room in which the
appliance is installed.
4 Materials, design and construction
4.1 Production documentation
The type of appliance submitted for testing shall be stated and the appliance shall be tested using the
standard appropriate to that claim.
The parameters and characteristics considered in making the decisions in relation to either the family
or range of appliances to be submitted for initial type testing (see 8.2.1) shall be recorded. Where
changes are made to an appliance in the design, the raw material, the supplier of the components, or
in the production process, which would significantly alter the performance characteristics of the
appliance, especially in respect of one or more of the list of characteristics detailed in Table 9 and
Table 10, (see 8.2.2) these shall be recorded. A copy of the parameters and characteristics
considered in making the decisions shall be included in the production documentation for each
appliance.
To identify the appliance, the manufacturer shall have available documents and/or scaled assembly
drawings showing the basic design and construction of the appliance. The documentation and/or the
drawings shall include at least the following information:
 the specification of the materials used in the construction of the appliance;
 the manufacturer’s declared nominal heat output in kW using fuels recommended by the
manufacturer together with the declared minimum refueling intervals for these fuels;
 the welding process used in the manufacture of the boiler shell;
NOTE The symbol for the type of weld used is sufficient.
 the permissible maximum operating water temperature in °C;
 the permissible maximum water operating pressure in bar;
 the type test pressure in bar;
 the water heating output in kW.
4.2 General construction requirements
4.2.1 Design, manufacture and assembly
The shape and dimensions of the components and equipment and the method of design and
manufacture, and if assembled on site the method of assembly and installation, shall ensure that
when operated in accordance with the appropriate test(s) and exposed to the associated mechanical,
chemical and thermal stresses, the appliance shall operate reliably and safely such that during normal
operation, no combustion gases posing a hazard can escape into the room in which the appliance is
installed nor can embers fall out.
Component parts such as covers, operating controls, safety devices and electrical accessories shall
be arranged in such a way that their surface temperatures, under the test conditions described
in A.4.7, do not exceed those specified either by the manufacturer or in the relevant component part
standard.
NOTE 1 Because the entire heat dissipating surfaces of the appliance including the flue spigot/socket and the
flue gas connector are working surfaces, there is no requirement for limiting the surface temperature of the
appliance.
The appliance shall meet the requirements detailed in 4.3 to 4.18 as appropriate to the material of
construction and intended usage.
The appliance shall be capable of operating safely at a permissible maximum water operating
pressure as declared by the manufacturer of up to but not exceeding 2 bar and shall meet the
requirements of the type pressure test described in 5.3.
Provision shall be made for parts which act as a seal to be located securely by means of bolts,
gaskets or welding; to prevent the ingress or leakage of air, water or combustion products. Adjacent
surfaces between metal components in the firebox or flueways shall be gastight.
Where a seal is made with fire-cement, the cement shall be supported by adjacent metal surfaces.
Component parts, which require periodic replacement and/or removal, shall be either designed or
identified so as to ensure correct fitting.
No part of the appliance shall comprise of or contain asbestos. Hard solder containing cadmium in its
formulation shall not be used.
Where thermal insulation is used, it shall be made of non-combustible material and shall not be a
known hazard to health in its applied position.
NOTE 2 The thermal insulation should withstand normal thermal and mechanical stresses.
4.2.2 Durability
The durability aspects of the appliance shall be deemed to be satisfied if it is shown to meet the
constructional requirements specified in 4.3 to 4.18, the safety requirements specified in Clause 5 and
the performance requirements specified in Clause 6 of this standard.
NOTE The long practice with these products shows that such an approach for dealing with durability is
sufficient.
4.3 Boilers constructed of steel
4.3.1 Parts subject to water pressure
One or more of the steel materials complying at least with the specifications given in Table 1 shall be
used for the manufacture of those parts of the appliance subject to water pressure.
4.3.2 Nominal minimum wall thicknesses
The nominal minimum wall thickness of non-alloyed steel sheets and tubes subject to water pressure
(other than immersion coils or safety heat exchangers) shall be in accordance with Table 2.
The tolerances on the nominal minimum wall thicknesses for non-alloyed steels given in Table 2 shall
be as specified in EN 10029:1991.

Table 1 — Steel material types
1)
References Material type Material numbers
EN10111:1998 DD 11 1.0332
DD12 1.0398
DD13 1.0335
DD14 1.0389
EN 10025 :2004 S235JR 1.0037
S235JRG2 1.0038
S235J0 1.0114
S235J2G3 1.0116
S275JR 1.0044
S275J0 1.0143
S275J2G3 1.0144
S355JR 1.0045
S355J0 1.0553
S355J2G3 1.0570
S355K2G3 1.0595
EN 10028-2 :2004 P195TR1 1.0107
P235GH 1.0345
P285QH 1.0478
P265GH 1.0425
P355NL1 1.0566
P295GH 1.0481
P355QH1 1.0571
P355GH 1.0473
16Mo3 1.5415
15NiCuMoNb5 1.6368
13CrMo4-5 1.7335
10CrMo9-10 1.7380
11CrMo9-10 1.7383
EN 10120 :2008 P245NB 1.0111
P265NB 1.0423
P310NB 1.0437
P355NB 1.0557
EN 10088-2 :2006 X5CrNi18-10 1.4301
X5CrNi17-12-2 1.4401
X2CrNiM017-13-2 1.4404
X6CrNiTi18-10 1.4541
X6CrNiNb18-10 1.4550
X2 CrMnNiN 22-5-2 1.4162
X2 CrNiN 23-4 1.4362
X2 CrNiMoN 22-5-3 1.4462
X1 NiCrMoCuN 25-20-7 1.4529
X1 NiCrMoCu 25-20-5 1.4539
X6CrNiMoTi17-12-2 1.4571
X6CrNiMoNb17-12-2 1.4580
X3CrNiMo17-3-3 1.4436
1) In accordance with EN 10027-2:1992
NOTE Materials and wall thicknesses other than those specified may only be used on production of
appropriate evidence as regards at least their equivalent corrosion resistance, heat resistance and
strength to non-alloy steel at the material thicknesses specified in 4.3.2 for the particular
application/usage.
Table 2 — Steel - Nominal minimum wall thickness
Stainless and
Non-alloy steels for
Non-alloy corrosion
Application appliances burning wood
steels protected
only
steels
mm mm mm
Walls of both the boiler shell and the 5 2 3
combustion chamber which are in
contact with either burning fuel or
products of combustion and/or water
Walls of convection heating surfaces 4 2 3
outside combustion chamber (except
circular tubes)
Circular tubes used in convection part 3,2 1,5 3,2
of heat exchanger
Water cooled grate tubes 4 3 3
Surfaces other than those above which 3 2 3
are not in contact with either burning
fuel or products of combustion and/or
water
NOTE 1 The nominal minimum wall thicknesses apply to pressure loaded sheets and tubes, being part of the
boiler construction.
NOTE 2 The nominal minimum wall thicknesses listed for a particular application/usage have been specified
taking into consideration the following parameters:
- the permissible maximum water operating pressure (as stated by the manufacturer);
- the material properties;
- the heat transfer location.
4.4 Boilers constructed of cast iron
4.4.1 Parts subject to water pressure
The minimum mechanical properties of cast irons used for parts subject to water pressure shall be in
accordance with the values listed in Table 3.
Table 3 — Minimum mechanical requirements for cast irons
1)
Grey cast iron
- Tensile strength R > 150 N/mm
m
- Brinell hardness 160 HB to 220 HB
2)
Spheroidal graphite cast iron
- Tensile strength R
> 400 N/mm
m
- Elongation 18 % A
1) In accordance with EN 1561:1997.
2) In accordance with EN 1563:1997.
4.4.2 Minimum wall thicknesses
The wall thicknesses shall be not less than the minimum thickness listed in Table 4.
Table 4 — Cast iron - Minimum wall thicknesses
Nominal heat output Grey cast iron Spheroidal graphite
cast iron
Minimum wall thicknesses
kW mm
< 30 3,5 3,0
≥ 30 < 50 4,0 3,5
4.5 Boiler shell tappings
The threads of boiler shell tappings, for flow and return pipes, shall be not less than the minimum
thread size designation given in Table 5.
Where tapered threads are used, they shall be in accordance with the requirements of ISO 7-1:1994
and ISO 7-2:2000. Where parallel threads are used, they shall be in accordance with ISO 228-1:2000
and ISO 228-2:1987. The design and position of flow tappings shall be such that air will not be
retained within the boiler shell.
Table 5 — Minimum thread size designation of flow and return tappings
Gravity circulation Pumped circulation
Nominal heat output thread size thread size
1) 1)
designation designation
kW
1 ½
≤ 22
1¼ 1
> 22 ≤ 35
≥ 35 < 50 1½ 1
1)
Designation in accordance with ISO 7 –1:1994 and ISO 7-2:2000 or
ISO 228 –1:2000 and ISO 228-2:1987.

The minimum depth of tapping or length of thread shall be not less than the minimum values given
in Table 6.
Table 6 — Minimum depth of tapping or length of thread
1)
Thread size designation Minimum depth of tapping
or length of thread
mm
½ to 1¼ 16
1½ 19
Designation in accordance with ISO 7-1:1994 and ISO 7-2:2000
or ISO 228-1:2000 and ISO 228-2:1987.

If the appliance is supplied with reducing bushes in horizontal flow tappings, these shall be eccentric
and fixed so that the reduced outlet is uppermost.
4.6 Draining of boiler shell
Where a drain socket is provided in the boiler shell, it shall have a minimum thread size designation
of ½ and shall be accordance with either ISO 7-1:1994 and ISO 7-2:2000 if tapered threads are used
or ISO 228-1:2000 and ISO 228-2:1987 if parallel threads are used.
4.7 Boiler waterways
4.7.1 Venting of the water sections
The boiler shell and its component waterways shall be designed in such a way that their respective
water sections are well vented. To minimize the build up of sediment, designed sharp or wedge-
shaped waterways with a taper towards the bottom shall be avoided.
The design of the boiler shell shall ensure a free flow of water through all parts such that under
normal operation in accordance with the manufacturer’s instructions, no undue boiling noises shall
occur.
4.7.2 Boilers used with direct water systems
The minimum internal dimension of waterways in boilers designed for direct water systems shall be
not less than 25 mm.
4.7.3 Boilers used with indirect water systems
The minimum internal dimension of waterways throughout the main body of the appliance shall be not
less than 20 mm, except where waterways have to be reduced locally to facilitate manufacture or are
in areas not in direct contact with burning fuel; in these cases the width of the waterways shall be not
less than 15 mm.
4.7.4 Water tightness
Holes, for screws and similar components, which are used for the attachment or removal of parts,
shall not open into waterways or spaces through which water flows.
NOTE This does not apply to pockets for measuring, control and safety equipment.
4.8 Combustion air supply
4.8.1 General
The supply of combustion air shall either be by natural draught or by fan assistance.
NOTE A manually adjustable air by-pass capable of being completely closed is advisable for natural draught
boilers fitted with thermostatic air control.
4.8.2 Primary air inlet control
The appliance shall be fitted with a thermostatically controlled primary air inlet control actuated by
water temperature. The design shall be such that during normal operation of the appliance, neither
ash nor unburned fuel can prevent the movement or closure of the air inlet control.
The ‘cold’ setting of the primary air inlet control shall be clearly marked and the method of adjustment
shall be described in the user instructions.
The thermostat shall have a variable temperature range and be of the immersion or dry pocket type.
The pocket shall be positioned so that the thermostat senses the temperature of the flow water from
the appliance.
4.8.3 Secondary air inlet control
Where a secondary air inlet control is provided the position of air entry shall be so designed that the
passage of air is not restricted when the firebox is filled to the manufacturer’s recommended capacity.
4.9 Ash-pit door and firedoor
Any ash-pit door and firedoor shall be designed to prevent accidental opening and to facilitate positive
closure.
NOTE Doors used for closing the ash-pit and combustion chamber should be designed to ensure a positive
seal is made around the openings when the doors are closed.
4.10 Bottomgrate
The bottomgrate, excluding those with water cooled firebars, shall be capable of being removed and
shall be so designed or marked as to ensure correct assembly. A de-ashing mechanism shall be fitted
where fuels other than wood are burned. The bottomgrate shall not become dislodged during the de-
ashing process.
NOTE 1 The preferred design should allow de-ashing to be carried out with the ash-pit door closed. The de-
ashing operation should be possible without undue effort.
NOTE 2 If it is necessary to remove the ash-pit door to de-ash the fire, the appliance should be designed such
that there is no undue spillage of ash during the de-ashing operation.
4.11 Ashpan and ash removal
A means of removing ash residue from the appliance shall be provided. Where an ashpan is provided
it shall be capable of containing the combustion ash residue from two full charges of fuel whilst
retaining sufficient space above to allow adequate flow of primary combustion air through the
bottomgrate or fire bed. If the ashpan resides in the appliance it shall locate in the ashpit in such a
way that it allows the free passage of primary combustion air and in such a position that it does not
obstruct any primary air inlet control.
NOTE An ash-pan should be designed and constructed to ensure that:
a) it effectively collects the residue material from beneath the bottomgrate;
b) it can be easily and safely withdrawn, carried and emptied when hot, using the tool(s) provided,
without undue spillage of residue material.
4.12 Control of flue gas
If a flue damper is fitted, it shall be of a type which does not block the flue totally. The damper shall be
easy to operate and incorporate an aperture within the blade which, in a continuous area, occupies at
least 20 cm or 3 % of the cross-sectional area of the blade if this is greater.
The position of the damper shall be recognizable to the user from the setting of the device.
A flue damper shall not be fitted to an appliance with a forced draught fan but shall be permissible for
appliances with an induced draught fan.
If a draught regulator is fitted the minimum cross sectional area requirement shall not be applicable
but the device shall be easily accessible for cleaning.
4.13 Flue draught test point
A test tapping for the measurement of the flue draught shall be provided either in the boiler flueway or
in the flue gas connector.
If a draught regulator is incorporated, the test measurement point shall be taken before the draught
regulator.
4.14 Fan cut-out safety device
If the appliance is fitted with a forced draught fan to provide combustion air, then a cut-out safety
device shall be provided to switch off the fan in the event of a flue blockage (see 5.5).
4.15 Flue spigot or socket
The flue spigot or socket shall be designed to enable a gas tight connection to be made between the
flue gas connector and the appliance. Where the flue gas connector fits over an outlet spigot, the
overlap shall be a minimum of 40 mm. Where the flue gas connector fits into a socket, the insertion
depth shall be a minimum of 25 mm.
NOTE It is recommended that provision is made for sealing the flue gas connector into the socket with glass
fibre rope and heat resistant sealing compound.
The flue spigot or socket is a fixed and indispensable part of the appliance as tested and sold and
shall not be extended for type test purposes. It is not part of the test rig and shall not be confused with
the flue gas connector. However if an extended flue spigot, socket or fluepipe is part of the appliance
design it shall be included for the type test provided that it is included as part of the appliance
whenever the appliance is marketed and sold.
4.16 Front firebars and/or deepening plate
If the appliance is fitted with removable front firebars and/or deepening plate, they shall be designed
such that they can neither be incorrectly fitted nor accidentally dislodged.
NOTE The front firebars/deepening plate should be designed to retain the fuel or ash during operation of the
appliance particularly during refuelling or de-ashing of the appliance.
4.17 Flueways
It shall be possible to clean the flueways of the appliance completely using commercially available
tools or brushes, unless special cleaning tools or brushes are provided by the appliance manufacturer.
The size of the flueway in its minimum dimension shall be not less than 30 mm except that it shall be
permissible to reduce it to not less than 15 mm for appliances designed only to burn fuels other than
bituminous coals and peat briquettes and where an access door(s) is provided for cleaning the
flueway.
4.18 Provision for cleaning boiler heating surfaces, and flue connector
All boiler-heating surfaces shall be accessible from the flue gas side for inspection and cleaning.
Means shall also be provided for cleaning the appliance outlet and flue connector. Advice on how this
cleaning shall be carried out shall be given in the appliance operating instructions.
5 Safety requirements
5.1 Temperature in integral fuel storage container
When tested during the performance test at nominal heat output in accordance with A.4.7, the
maximum temperature measured in any integral fuel storage container, if provided, shall not exceed
the ambient temperature by more than 65 K.
5.2 Temperature of adjacent combustible materials
When tested during the performance test at nominal heat output in accordance with A.4.7, and when
the appliance is installed in accordance with the clearance distances specified in the manufacturer’s
installation instructions, the temperature of the trihedron test hearth and walls or any other structure
surrounding the appliance e.g. ceiling comprising combustible material shall not exceed the ambient
temperature by more than 65 K.
5.3 Strength and leaktightness of boiler shell
The boiler shell and its water carrying components shall
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