SIST EN 303-1:2017

Heating boilers - Part 1: Heating boilers with forced draught burners - Terminology, general requirements, testing and marking

This European Standard applies to standard boilers and low temperature boilers with forced draught burners with a nominal heat output not exceeding 1 000 kW, which are operated either with negative pressure (natural draught boilers) or with positive pressure (pressurised boiler) in the combustion chamber, in accordance with the boiler manufacturer’s instruction.
This standard specifies the necessary terminology, the requirements on the materials and testing of them, and marking requirements for heating boilers.
Particular requirements for boilers which can be used with open vented systems are contained in EN 303 4.
The requirements of this standard apply to heating boilers which are tested on an authorised test rig.
Boilers in accordance with this standard are designed for the heating of central heating installations in which the heat carrier is water, and the maximum allowable operating temperature of which is restricted to 100 °C. The maximum allowable operating pressure is 8 bar.
For boilers with a built in or attached water heater (storage or continuous flow heater) this standard only applies to the parts of the water heater which are necessarily subject to the operating conditions of the heating boiler (heating part).
This standard does not apply to gas boilers with atmospheric burners, boilers for solid fuels, oil or gas fired condensing boilers and boilers with oil vaporisation burners. For these boilers there are further requirements.

Heizkessel - Teil 1: Heizkessel mit Gebläsebrenner - Begriffe, Allgemeine Anforderungen, Prüfung und Kennzeichnung

Diese Europäische Norm gilt für Kessel von Zentralheizungen (Heizkessel) mit Gebläsebrennern bis zu einer Nennwärmeleistung von 1 000 kW, die nach den Festlegungen des Kesselherstellers entweder mit Unterdruck (Naturzugkessel) oder mit Überdruck (Überdruckkessel) im Brennraum betrieben werden.
Diese Norm legt die notwendigen Begriffe sowie die Anforderungen an Werkstoffe, Prüfungen und Kennzeichnungen für Heizkessel fest.
Für Heizkessel, die in offenen Heizungsanlagen betrieben werden, gilt EN 303-4.
Die Anforderungen dieser Norm gelten für Heizkessel, die auf einem zugelassenen Prüfstand geprüft werden.
Heizkessel in Übereinstimmung mit dieser Norm sind für die Beheizung von zentralen Heizungsanlagen bestimmt, deren Wärmeträger Wasser mit einer maximal zulässigen Betriebstemperatur von 100°C ist. Der maximal zulässige Betriebsdruck ist 8 bar.
Diese Norm gilt nur für die Bauelemente von Heizkesseln und Wassererwärmern (Speicher- oder Durchlaufwassererwärmer), die den Betriebsbedingungen des Heizkessels zwangsläufig unterworfen sind (Heizungsteil).
Die Norm gilt nicht für Gasheizkessel mit atmosphärischen Brennern, Heizkessel für feste Brennstoffe und Heizkessel mit Ölverdampfungsbrennern. Für diese Kessel sind andere Anforderungen zu erfüllen.

Chaudières de chauffage - Partie 1 : Chaudières avec brûleurs à air soufflé - Terminologie, prescriptions générales, essais et marquage

La présente Norme européenne s'applique aux chaudières de chauffage central (chaudières de chauffage) équipées de brûleurs à air soufflé d'une puissance utile nominale inférieure ou égale à 1 000 kW, fonctionnant soit en dépression (chaudières à tirage naturel), soit en pression (chaudières pressurisées) dans la chambre de combustion, selon les indications du fabricant de la chaudière.
La présente norme spécifie la terminologie nécessaire, les exigences relatives aux matériaux et aux essais qui s'y rapportent, ainsi que les exigences de marquage pour les chaudières de chauffage.
Pour les chaudières qui peuvent être utilisées avec un vase d’expansion ouvert, les exigences particulières de construction sont précisées dans l'EN 303-4.
Les exigences de la présente norme s'appliquent aux chaudières de chauffage soumises à essai sur un banc d'essai agréé.
Les chaudières conformes à la présente norme sont conçues pour le chauffage d'installations de chauffage central dont le fluide caloporteur est l'eau et dont la température de fonctionnement maximale autorisée est limitée à 100 °C. La pression de service maximale autorisée est de 8 bar.
Pour les chaudières mixtes et les chauffe-eau (dispositif de chauffage à accumulation ou à production instantanée), la présente norme s'applique uniquement aux éléments qui sont nécessairement soumis aux conditions de fonctionnement de la chaudière de chauffage (partie chauffage).
La présente norme ne s'applique pas aux chaudières à gaz à brûleur atmosphérique, aux chaudières pour combustibles solides, ni aux chaudières à brûleur fioul à caléfaction. Ces chaudières sont soumises à d'autres exigences.

Kotli za gretje - 1. del: Kotli z ventilatorskimi gorilniki - Terminologija, splošne zahteve, preskušanje in označevanje

Ta evropski standard se uporablja za standardne kotle in nizkotemperaturne kotle z ventilatorskimi gorilniki z nazivno izhodno toploto, ki ne presega 1000 kW, ki delujejo bodisi z negativnim tlakom (kotli na naraven vlek) bodisi s pozitivnim tlakom (kotli pod tlakom) v zgorevalni komori, v skladu z navodili proizvajalca kotla. Ta standard določa potrebno terminologijo, zahteve glede materialov in njihovo preskušanje ter zahteve glede označevanja kotlov za gretje. Posebne zahteve za kotle, ki jih je mogoče uporabljati z odprtimi prezračevalnimi sistemi, so v standardu EN 303-4. Zahteve tega standarda veljajo za grelne kotle, ki se preskušajo na pooblaščeni napravi za preskušanje. Kotli za gretje v skladu s tem standardom so namenjeni za gretje v sistemih centralnega ogrevanja, pri čemer toploto prenaša voda. Najvišja dovoljena obratovalna temperatura je 100 °C, najvišji dovoljen obratovalni tlak pa 8 barov.  V zvezi s kotli z vgrajenim ali pritrjenim (termoakumulacijskim ali pretočnim) grelnikom vode se ta standard uporablja le za tiste dele grelnika vode, za katere obvezno veljajo obratovalni pogoji kotla za gretje (grelni del). Ta standard se ne uporablja za plinske kotle z atmosferskimi gorilniki, kotle na trda goriva, kondenzacijske kotle na nafto ali plin in kotle z oljnimi uparjalniki. Za te kotle veljajo še dodatne zahteve.

General Information

• Status: Published
• Public Enquiry End Date: 31-Jul-2016
• Publication Date: 12-Nov-2017
• ICS: 01.040.91 - Construction materials and building (Vocabularies)
• ICS: 27.060.01 - Burners and boilers in general
• ICS: 91.140.10 - Central heating systems
• Technical Committee: PLN - Gas appliances for domestic use
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-Nov-2017
• Due Date: 12-Jan-2018
• Completion Date: 13-Nov-2017
• Directive: 811/2013 - Commission Delegated Regulation (EU) No 811/2013 of 18 February 2013 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to the energy labelling of space heaters, combination heaters, packages of space heater, temperature control and solar device and packages of combination heater, temperature control and solar device
• Directive: 813/2013 - Commission Regulation (EU) No 813/2013 of 2 August 2013 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for space heaters and combination heaters
• Mandate: M/495 - Standardisation mandate to CEN, CENELEC and ETSI under Directive 2009/125/EC relating to harmonised standards in the field of Ecodesign
• Mandate: M/535 - [C(2016)2626) Standardisation request to the European standardisation organisations to draft harmonised European standards pursuant to Article 10(1) of Regulation (EU) No 1025/2012 of the European Parliament and of the Council in support of implementation of Commission Regulation (EU) No 813/2013 of 2 August 2013 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to eco-design requirements for space heaters and combination heaters and Commission Delegated Regulation (EU) No 811/2013 of 18 February 2013 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to the energy labelling of space heaters, combination heaters, packages of space heaters, temperature control and solar device and packages of combination heater, temperature control and solar device
• Ref Project: EN 303-1:2017 - Heating boilers - Part 1: Heating boilers with forced draught burners - Terminology, general requirements, testing and marking

RELATIONS

• Replaces: SIST EN 303-1:1999 - Heating boilers - Part 1: Heating boilers with forced draught burners - Terminology, general requirements, testing and marking
• Effective Date: 01-Dec-2017
• Replaces: SIST EN 15034:2007 - Heating boilers - Condensing heating boilers for fuel oil
• Effective Date: 01-Dec-2017
• Replaces: SIST EN 15034:2007/AC:2008 - Heating boilers - Condensing heating boilers for fuel oil - Corrigendum AC
• Effective Date: 01-Dec-2017
• Replaces: SIST EN 303-1:1999/A1:2004 - Heating boilers - Part 1: Heating boilers with forced draught burners - Terminology, general requirements, testing and marking
• Effective Date: 01-Dec-2017

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN 303-1:2017
01-december-2017
1DGRPHãþD
SIST EN 15034:2007
SIST EN 15034:2007/AC:2008
SIST EN 303-1:1999
SIST EN 303-1:1999/A1:2004

.RWOL]DJUHWMHGHO.RWOL]YHQWLODWRUVNLPLJRULOQLNL7HUPLQRORJLMDVSORãQH

]DKWHYHSUHVNXãDQMHLQR]QDþHYDQMH

Heating boilers - Part 1: Heating boilers with forced draught burners - Terminology,

general requirements, testing and marking
Heizkessel - Teil 1: Heizkessel mit Gebläsebrenner - Begriffe, Allgemeine
Anforderungen, Prüfung und Kennzeichnung
Chaudières de chauffage - Partie 1 : Chaudières avec brûleurs à air soufflé -
Terminologie, prescriptions générales, essais et marquage
Ta slovenski standard je istoveten z: EN 303-1:2017
ICS:
01.040.91 Gradbeni materiali in gradnja Construction materials and
(Slovarji) building (Vocabularies)
27.060.01 Gorilniki in grelniki vode na Burners and boilers in
splošno general
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
SIST EN 303-1:2017 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 303-1:2017
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SIST EN 303-1:2017
EN 303-1
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2017
EUROPÄISCHE NORM
ICS 91.140.10 Supersedes EN 15034:2006, EN 303-1:1999
English Version
Heating boilers - Part 1: Heating boilers with forced
draught burners - Terminology, general requirements,
testing and marking

Chaudières de chauffage - Partie 1 : Chaudières avec Heizkessel - Teil 1: Heizkessel mit Gebläsebrennern -

brûleurs à air soufflé - Terminologie, prescriptions Begriffe, Allgemeine Anforderungen, Prüfung und

générales, essais et marquage Kennzeichnung
This European Standard was approved by CEN on 26 June 2017.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 303-1:2017 E

worldwide for CEN national Members.
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SIST EN 303-1:2017
EN 303-1:2017 (E)
Contents Page

European foreword ....................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions, units and symbols ............................................................................................. 7

3.1 Terms and definitions ................................................................................................................................... 7

3.2 Units and symbols ........................................................................................................................................ 10

3.2.1 Units .................................................................................................................................................................. 10

3.2.2 Symbols ............................................................................................................................................................ 11

4 Requirements ................................................................................................................................................ 11

4.1 Construction requirements ...................................................................................................................... 11

4.1.1 General requirements ................................................................................................................................ 11

4.1.2 Specific requirements ................................................................................................................................. 23

4.2 Operational requirements ........................................................................................................................ 25

4.2.1 General ............................................................................................................................................................. 25

4.2.2 Verification of the nominal condensing output ................................................................................ 25

4.2.3 Formation of condensation ...................................................................................................................... 25

4.2.4 Temperature of combustion products ................................................................................................. 25

4.2.5 Surface temperature ................................................................................................................................... 25

4.2.6 Water side resistance of the boiler ........................................................................................................ 26

4.2.7 Soundness of the boiler .............................................................................................................................. 26

4.2.8 Temperature sensing control type TR and temperature sensing control type STB ............ 26

4.3 Electrical equipment ................................................................................................................................... 26

4.3.1 Electrical safety ............................................................................................................................................. 26

4.3.2 Electromagnetic compatibility ................................................................................................................ 27

5 Tests .................................................................................................................................................................. 27

5.1 General ............................................................................................................................................................. 27

5.2 Boilers of steel or non-ferrous metal .................................................................................................... 27

5.2.1 Tests to be carried out before production .......................................................................................... 27

5.2.2 Factory production control (FPC) for steel boilers .......................................................................... 27

5.3 Boilers of cast iron or non-ferrous metals .......................................................................................... 28

5.3.1 Test to be carried out before production ............................................................................................ 28

5.3.2 Test during production .............................................................................................................................. 28

5.4 Test for gas soundness ............................................................................................................................... 29

5.5 Water side resistance measurement .................................................................................................... 29

5.5.1 General ............................................................................................................................................................. 29

5.5.2 Test rig for the establishment of the water side resistance ......................................................... 29

5.6 Additional tests for low temperatures boilers .................................................................................. 31

5.6.1 Additional tests by using of corrosion resistant coatings ............................................................. 31

5.6.2 Additional tests for oil-fired low temperatures boilers ................................................................. 31

6 Marking ............................................................................................................................................................ 31

6.1 Information on the boiler data plate ..................................................................................................... 31

6.2 Requirements of the data plate ............................................................................................................... 31

7 Technical documentation, scope of supply ......................................................................................... 31

7.1 General ............................................................................................................................................................. 31

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SIST EN 303-1:2017
EN 303-1:2017 (E)

7.2 Technical information (product fiche) and installation instructions ....................................... 31

7.3 Operating instructions ................................................................................................................................ 33

7.4 Label .................................................................................................................................................................. 33

Annex A (informative) Conformity evaluation ................................................................................................ 34

Annex ZA (informative) Relationship between this European Standard and the ecodesign

requirements of Commission Regulation (EU) No [813/2013] aimed to be covered .......... 35

Annex ZB (informative) Relationship between this European Standard and the ecodesign

requirements of Commission Regulation (EU) No [811/2013] aimed to be covered .......... 36

Bibliography ................................................................................................................................................................. 37

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SIST EN 303-1:2017
EN 303-1:2017 (E)
European foreword

This document (EN 303-1:2017) has been prepared by Technical Committee CEN/TC 57 “Central

heating boilers”, the secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by March 2018, and conflicting national standards shall

be withdrawn at the latest by March 2018.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document has been prepared under a mandate M/534 and M/535 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 and Annex ZB, which are integral parts

of this document.
This document supersedes EN 303-1:1999 and EN 15034:2006.
The following essential changes have been made:
a) Construction requirements were adopted from EN 15034;
b) Terminology of EU-Regulations 811/2013 and 813/2013 adopted;
c) the document was completely revised technically;
d) the document was completely revised editorially.

The following structure is intended for the European Standards for heating boilers:

— EN 303-1, Heating boilers — Part 1: Heating boilers with forced draught burners — Terminology,

general requirements, testing and marking

— EN 303-2, Heating boilers — Part 2: Heating boilers with forced draught burners — Special

requirements for boilers with atomizing oil burners

— EN 303-3, Heating boilers — Part 3: Gas fired central heating boilers — Assembly comprising a boiler

body and a forced draught burner

— EN 303-4, Heating boilers — Part 4: Heating boilers with forced draught burners — Special

requirements for boilers with forced draught oil burners with outputs up to 70 kW and a maximum

operating pressure of 3 bar — Terminology, special requirements, testing and marking

— EN 303-5, Heating boilers — Part 5: Heating boilers for solid fuels, hand and automatically fired, with

a nominal heat output of up to 300 kW — Terminology, requirements, testing and marking

— EN 304, Heating boilers — Test code for heating boilers for atomizing oil burners

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
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SIST EN 303-1:2017
EN 303-1:2017 (E)
1 Scope

This European Standard applies to boilers used for central heating (heating boilers) with forced

draught burners with a nominal heat output not exceeding 1 000 kW, which are operated either with

negative pressure (natural draught boilers) or with positive pressure (pressurized boiler) in the

combustion chamber, in accordance with the boiler instructions.

This European Standard specifies the necessary terminology, the requirements on the materials and

testing of them, and marking requirements for heating boilers.

Particular requirements for boilers that can be used with open vented systems are contained in

EN 303-4.

The requirements of this standard apply to heating boilers that are tested on an authorized test rig.

Boilers in accordance with this standard are designed for the heating of central heating installations in

which the heat carrier is water, and the maximum allowable operating temperature of which is

restricted to 100 °C. The maximum allowable operating pressure is 8 bar.

For boilers and water heaters (storage or continuous flow heater) this standard only applies to the

parts which are necessarily subject to the operating conditions of the heating boiler (heating part).

This standard does not apply to gas boilers with atmospheric burners, boilers for solid fuels, boilers

with oil vaporization burners. For these boilers there are further requirements.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

EN 226:1987, Atomizing oil burners - Connecting dimensions between burners and heat generators

EN 303-2:2017, Heating boilers - Part 2: Heating boilers with forced draught burners - Special

requirements for boilers with atomizing oil burners

EN 303-4:1999, Heating boilers - Part 4: Heating boilers with forced draught burners - Special

requirements for boilers with forced draught oil burners with outputs up to 70 kW and a maximum

operating pressure of 3 bar - Terminology, special requirements, testing and marking

EN 304:2017, Heating boilers - Test code for heating boilers for atomizing oil burners

EN 10025-2:2004, Hot rolled products of structural steels - Part 2: Technical delivery conditions for non-

alloy structural steels
EN 10027-2:2015, Designation systems for steels - Part 2: Numerical system

EN 10028-2:2017, Flat products made of steels for pressure purposes - Part 2: Non-alloy and alloy steels

with specified elevated temperature properties

EN 10028-3:2017, Flat products made of steels for pressure purposes - Part 3: Weldable fine grain steels,

normalized

EN 10029:2010, Hot-rolled steel plates 3 mm thick or above - Tolerances on dimensions and shape

EN 10088-2:2014, Stainless steels - Part 2: Technical delivery conditions for sheet/plate and strip of

corrosion resisting steels for general purposes
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SIST EN 303-1:2017
EN 303-1:2017 (E)
EN 10204:2004, Metallic products - Types of inspection documents

EN 13501-1:2007+A1:2009, Fire classification of construction products and building elements - Part 1:

Classification using data from reaction to fire tests

EN 14597:2012, Temperature control devices and temperature limiters for heat generating systems

EN 60335-1:2012, Safety of household and similar electrical appliances — Part 1: General requirements

(IEC 60335-1:2010)

EN 60529:1991, Degrees of protection provided by enclosures (IP Code) (IEC 60529:1989)

EN 60730-1:2011, Automatic electrical controls for household and similar use - Part 1: General

requirements (IEC 60730:2010), modified

EN 60730-2-9:2010, Automatic electrical controls for household and similar use - Part 2-9: Particular

requirements for temperature sensing controls (IEC 60730-2-9:2008), modified

EN 61000-6-2:2005, Electromagnetic compatibility (EMC) - Part 6-2: Generic standards - Immunity for

industrial environments (IEC 61000-6-2:2005)

EN 61000-6-3:2007, Electromagnetic compatibility (EMC) - Part 6-3: Generic standards - Emission

standard for residential, commercial and light-industrial environments (IEC 61000-6-3:2006)

EN 60335-2-102:2016, 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 + A1:2008, modified + A2:2012, modified)

EN ISO 4063:2010, Welding and allied processes - Nomenclature of processes and reference numbers (ISO

4063:2009)
EN ISO 6506 (all parts), Metallic materials - Brinell hardness test

EN ISO 9606-1:2013, Qualification testing of welders - Fusion welding - Part 1: Steels (ISO 9606-1:2012

including Cor 1:2012)

EN ISO 9606-2:2004, Qualification test of welders - Fusion welding - Part 2: Aluminium and aluminium

alloys (ISO 9606-2:2004)

EN ISO/IEC 17025:2005, General requirements for the competence of testing and calibration laboratories

(ISO/IEC 17025:2005)

ISO 7-1:1994, 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 185:2005, Grey cast irons - Classification

ISO 228-1:2000, Pipe threads where pressure-tight joints are not made on the threads — Part 1:

Dimensions, tolerances and designation
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SIST EN 303-1:2017
EN 303-1:2017 (E)

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 857-2:2005, Welding and allied processes — Vocabulary — Part 2: Soldering and brazing processes

and related terms

ISO 2553:2013, Welding and allied processes - Symbolic representation on drawings - Welded joints

ISO 7005-1:2011, Pipe flanges — Part 1: Steel flanges for industrial and general service piping systems

ISO 7005-2:1988, Metallic flanges — Part 2: Cast iron flanges
ISO 7005-3:1988, Metallic flanges — Part 3: Copper alloy and composite flanges
3 Terms and definitions, units and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
operating pressure
maximum allowable pressure at which the boiler is to be normally operated

Note 1 to entry: The operating pressure is less than the test pressure and the type test pressure.

3.1.2
test pressure
pressure to which all boilers and their parts are subjected during production
3.1.3
type test pressure

pressure to which the pre-production heating boiler(s) and associated parts are subjected before start

of mass production in the manufacturing works
3.1.4
operating temperature

maximum allowable temperature at which the boiler can be operated under normal operating

conditions at the maximum setting of the boiler’s water temperature controller
3.1.5
heat output
amount of heat transferred to the heat carrier (water) per unit of time
3.1.6
heat output range

span between the minimal and the maximal heat output over which the boiler meets the requirements

of this standard and over which it can be used, whether it is a range rated or a modulating boiler

3.1.7
nominal heat output
continuous output in accordance with the requirements of this standard

Note 1 to entry: The nominal heat output is equal to the rated heat output P4 according to EU Regulation

813/2013.
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SIST EN 303-1:2017
EN 303-1:2017 (E)
3.1.8
heat input

amount of heat in unit time which is supplied to the furnace of the heating boiler by the fuel based on its

net calorific value
3.1.9
boiler efficiency
ratio of the heat output (P) to the heat input (Q ) supplied by the fuel

Note 1 to entry: η is equal to η4 according to EU Regulation 813/2013, if P is equal to 100 % P full load .

( )

Note 2 to entry: η is equal to η1 according to EU Regulation 813/2013, if P is equal to 0,3 × P .

3.1.10
draught

pressure differential between the static air pressure in the place of installation and the static pressure

of the exhaust gases, as measured in the exhaust gas measuring section, which is required for correct

operation of the boiler at nominal output
3.1.11
flue gas resistance
pressure differential between the combustion chamber and the boiler exit
3.1.12
combustion circuit

comprises all components between air inlet and flue gas outlet of boiler which may include the air

supply device, the burner, the combustion chamber, the heat exchanger and the flue gas evacuation

device
3.1.13
soundness of the boiler
limited leakage of the combustion circuit
3.1.14
flue gas temperature
dfg
temperature measured at the outlet of the boiler
3.1.15
flue gas loss
quantity of heat per unit time lost at the flue gas exit of the boiler
3.1.16
water side resistance

pressure loss across the boiler measured at the flow and return connections of the boiler, with a volume

flow corresponding to the nominal heat output
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SIST EN 303-1:2017
EN 303-1:2017 (E)
3.1.17
condensate
liquid formed from the combustion products during the condensation process
3.1.18
standard boiler
boiler for which the average water temperature can be restricted by design
3.1.19
low temperature boiler

boiler which can work continuously with a water return temperature of 35 ° to 40 °C or lower, possibly

producing condensation in certain circumstances without impairing the boiler’s operation and without

necessity of condensate drainage
Note 1 to entry: No nozzle for condensate drainage intended.
3.1.20
condensing boiler

boiler that, under normal operating conditions and at certain operating water temperatures, partially

condenses the water vapour in the combustion products in order to make use of the latent heat of water

vapour for heating purposes
Note 1 to entry: Always with nozzle for condensate drainage.
3.1.21
electrical power consumption at rated output
max
auxiliary electricalpower consumption at full load, expressed in kW
3.1.22
electrical power consumption at part load
min
auxiliary electrical power consumption at part load, expressed in kW
3.1.23
Electrical power consumption at standby

auxiliary electrical power consumption of a heater in standby mode, expressed in kW

3.1.24
seasonal space heating energy efficiency in active mode
son

weighted average of the useful efficiency at rated heat output and the useful efficiency at 30 % of the

rated heat output, expressed in %
[SOURCE: EU Regulation 813/2013 Annex I, Definition 11]
3.1.25
seasonal space heating energy efficiency

ratio between the space heating demand for a designated heating season, supplied by a heater and the

annual energy consumption required to meet this demand, expressed in %
[SOURCE: EU Regulation 813/2013, §2 (20)]
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EN 303-1:2017 (E)

Note 1 to entry: Weighted average of the useful efficiency at rated heat output and the useful efficiency at 30 %

of the rated heat output, expressed in % corrected with respect to control, the electrical consumption, the standby

heat loss and the pilot consumption if any.
3.1.26
temperature sensing control type TR

thermostat or modulating thermostat used in heat generating systems for controlling the temperature

of liquid or/and gaseous media, which has provisions for setting by the user and which, if equipped

with an electrical output, provides at least type 1B action

Note 1 to entry: See 2.2.4 and 2.2.6 of EN 60730–1:2011 and see 2.2.105 of EN 60730–2-9:2010.

3.1.27
temperature sensing control type STB

safety temperature limiter (thermal cut out, protective control) for heat generating systems which can

only be reset manually or by a tool and which provides at least the actions according to EN 14597

Note 1 to entry: Type 2K action will be considered to be provided if type 2N action is provided.

Note 2 to entry: Actions according to EN 14597: type 2B, type 2K, type 2P and type 2V and optionally any of the

following actions: type 2F and type 2N; the settings of this control are unchangeably fixed or can be fixed with a

tool or a special tool.
3.1.28
nominal condensing output
cond

value of useful output, in kW and corresponding to the operation of the boiler in a 50 °C/30 °C water

temperature regime
[SOURCE: EN 15034:2006, definition 3.2]
3.2 Units and symbols
3.2.1 Units

The unit system applied in this standard is the SI system, cf. ISO 80000-1 and others.

The following units and their multiples are used:
Length m (metre);
mm (millimetre);
Mass kg (kilogram);
Power kW (kilowatt);
Efficiency η (percent);
Other units applied:
Temperature °C (degrees Celsius).
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EN 303-1:2017 (E)
3.2.2 Symbols
Table 1 — Symbols
Symbol Name Unit
P heat output kW
P nominal heat output kW
Q heat input kW
η boiler efficiency %
T exit flue gas temperature °C
dfg
el electrical power consumption at rated output kW
max
el electrical power consumption at part load kW
min
P electrical power consumption at standby kW
η seasonal space heating energy efficiency in %
son
active mode
η seasonal space heating energy efficiency %
P nominal condensing output kW
cond
4 Requirements
4.1 Construction requirements
4.1.1 General requirements
4.1.1.1 Introduction

Boilers shall be fire-resistant and safe to operate. They shall be made of non-combustible materials and

shall be resistant to deformation and shall be such that:
— they can withstand the stresses arising during normal operation;
— the burner and the boiler cannot become heated to create a hazard;

— dangerous accumulations of combustible gases (fuels mixed with air) in the combustion chamber

and in the flues are prevented; and
— gases cannot leak from the boiler in dangerous quantities.
Combustible materials are allowable for:

— components of accessories, e.g. burner covers, if the parts are fitted outside of the boiler;

— internal components of controls and safety equipment;
— operating handles;
— electrical equipment;

— thermal insulation (see 4.1.1.6.9); all materials containing asbestos are forbidden.

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SIST EN 303-1:2017
EN 303-1:2017 (E)

Component parts of covers, operating, control and safety devices and electrical accessories shall be

arranged in such a way that their surface temperatures, under steady-state conditions, do not exceed

those specified either by the technical documentation or in the component part standard.

The materials for the parts subject to pressure shall be in accordance with generally accepted technical

requirements. They shall be suitable for the purpose and treatment intended. The mechanical and

physical properties as well as the chemical composition of the materials shall be guaranteed by the

relevant material producer/supplier.
All parts of the heating boiler likely to come into contact with
...