SIST EN 14986:2024
(Main)Design of fans working in potentially explosive atmospheres
Design of fans working in potentially explosive atmospheres
1.1 This document specifies the constructional requirements for fans constructed to Group II G (of explosion groups IIA, IIB and hydrogen) categories 1, 2 and 3, and Group II D categories 2 and 3, intended for use in explosive atmospheres.
NOTE 1 Operation conditions for the different categories of fans used in this document are defined in Clause 4.
1.3 This document specifies requirements for design, construction, testing and marking of complete fan units intended for use in potentially explosive atmospheres in air containing gas, vapour, mist and/or dusts. Such atmospheres can exist inside (the conveyed atmosphere (flammable or not)), outside, or inside and outside of the fan.
This document covers mechanical equipment, in particular fans. The “type of protection” as specified in EN ISO 80079 37:2016 is constructional safety.
1.4 This document is applicable to fans working in ambient atmospheres and with normal atmospheric conditions at the inlet, having
— absolute pressures ranging from 0,8 bar to 1,1 bar,
— and temperatures ranging from −20 °C to +60 °C,
— and maximum volume fraction of 21 % oxygen content,
— and an aerodynamic energy increase of less than 25 kJ/kg.
NOTE 1 25 kJ/kg is equivalent to 30 kPa at inlet density of 1,2 kg/m3.
This document can also be helpful for the design, construction, testing and marking of fans intended for use in atmospheres outside the validity range stated above or in cases where other material pairings need to be used. In this case, the ignition risk assessment, ignition protection provided, additional testing (if necessary), manufacturer's marking, technical documentation and instructions to the user, clearly demonstrate and indicate the equipment's suitability for the conditions the fan can encounter.
NOTE 2 Temperatures below −20 °C can be considered. Material suitability can require specific evaluation for these temperatures. With lower temperature the explosion pressure increases, which leads to increased test pressures (see A.3) and can require specific testing. Although the standard atmospheric conditions in EN ISO 80079 36:2016 give a temperature range for the atmosphere of −20 °C to +60 °C the normal ambient temperature range for the equipment is −20 °C to +40 °C unless otherwise specified and marked.
1.5 This document does not apply to:
— group I fans (fans for mining);
— explosion group IIC (other than hydrogen);
— category 1D fans;
— cooling fans or impellers on rotating electrical machines;
— cooling fans or impellers on internal combustion engines, vehicles or electric motors.
NOTE 3 Measures for category 1D fans are given in EN 1127 1:2019.
NOTE 4 Measures for explosion group IIC (other than hydrogen) are given in EN 1127 1:2019.
NOTE 5 Measures for explosion group I are given in EN ISO/IEC 80079 38:2016 and EN 1127 2:2014.
Konstruktion von Ventilatoren für den Einsatz in explosionsgefährdeten Bereichen
1.1 Dieses Dokument legt die baulichen Anforderungen an Ventilatoren der Gruppe II G (der Explosionsgruppen IIA, IIB und Wasserstoff) Kategorien 1, 2 und 3 und Gruppe II D Kategorien 2 und 3 für die Verwendung in explosionsfähigen Atmosphären fest.
ANMERKUNG Betriebsbedingungen für die verschiedenen Kategorien von Ventilatoren, die von diesem Dokument erfasst werden, sind in Abschnitt 4 definiert.
1.3 Dieses Dokument legt Anforderungen an Konstruktion, Bau, Prüfung und Kennzeichnung kompletter Ventilatoreinheiten fest, die für den Einsatz in explosionsgefährdeten Bereichen, die durch Gase, Dämpfe, Nebel und/oder Staub entstehen, bestimmt sind. Solche Atmosphären können innerhalb (durch das geförderte Fluid [entflammbar oder nicht]), außerhalb oder innerhalb und außerhalb des Ventilators existieren.
Dieses Dokument behandelt mechanische Geräte, insbesondere Ventilatoren. Die wie in EN ISO 80079 37:2016 festgelegte „Zündschutzart“ ist konstruktive Sicherheit.
1.4 Dieses Dokument ist anwendbar auf Ventilatoren, die in Umgebungsluft und unter üblichen atmosphärischen Bedingungen an der Saugseite betrieben werden, für die gilt
- absolute Drücke von 0,8 bar bis 1,1 bar;
- und Temperaturen von −20 °C bis +60 °C;
- und ein höchstmöglicher Volumenanteil des Sauerstoffgehalts von 21 %;
- und ein aerodynamischer Energieanstieg von weniger als 25 kJ/kg.
ANMERKUNG 1 25 kJ/kg entsprechen 30 kPa bei einer Eintrittsdichte von 1,2 kg/m3.
Dieses Dokument kann auch hilfreich sein für Konstruktion, Bau, Prüfung und Kennzeichnung von Ventilatoren, die für den Einsatz in Atmosphären bestimmt sind, die nicht in den Gültigkeitsbereich dieser Norm fallen, oder in Fällen, in denen andere Werkstoffpaarungen verwendet werden müssen. In diesem Fall müssen die Zündgefahrenbewertung, der vorgesehene Zündschutz, zusätzliche Prüfungen (falls erforderlich), die Herstellerkennzeichnung, die technische Dokumentation und Anweisungen an den Betreiber die Bedingungen, denen der Ventilator ausgesetzt sein kann, angeben und die Eignung des Geräts nachweisen.
ANMERKUNG 2 Temperaturen unter −20 °C können in Erwägung gezogen werden. Die Eignung von Werkstoffen kann die spezifische Bewertung dieser Temperaturen erfordern. Bei geringeren Temperaturen steigt der Explosionsdruck, was zu erhöhten Prüfdrücken (siehe Abschnitt A.3) führt und spezifisches Prüfen erfordern kann. Obwohl die atmosphärischen Standardbedingungen in EN ISO 80079 36:2016 einen Temperaturbereich für die Atmosphäre von −20 °C bis +60 °C definieren, liegt der gewöhnliche Umgebungstemperaturbereich für die Geräte zwischen −20 °C und +40 °C, sofern nicht anders festgelegt und gekennzeichnet.
1.5 Dieses Dokument ist nicht anwendbar für:
- Ventilatoren der Gruppe I (Ventilatoren für den Bergbau);
- Explosionsgruppe IIC (außer Wasserstoff);
- Ventilatoren der Kategorie 1D;
- Kühlgebläse oder Flügelräder für drehende elektrische Maschinen;
- Kühlgebläse oder Flügelräder für Verbrennungsmotoren, Fahrzeuge oder Elektromotoren.
ANMERKUNG 1 Maßnahmen für Ventilatoren der Kategorie 1D sind in EN 1127 1:2019 angegeben.
ANMERKUNG 2 Maßnahmen für Explosionsgruppe IIC (außer Wasserstoff) sind in EN 1127 1:2019 angegeben.
ANMERKUNG 3 Maßnahmen für die Explosionsgruppe I sind in EN ISO/IEC 80079 38:2016 und EN 1127 2:2014 angegeben.
Conception des ventilateurs pour les atmosphères explosibles
1.1 Le présent document spécifie les exigences de construction pour les ventilateurs fabriqués selon le Groupe II G (des groupes d’explosion IIA, IIB et hydrogène) des catégories 1, 2 et 3, et selon le Groupe II D catégories 2 et 3, destinés à être utilisés en atmosphères explosibles.
NOTE Les conditions de fonctionnement des différentes catégories de ventilateurs utilisées dans le présent document sont définies à l’Article 4.
1.3 Le présent document définit les exigences relatives à la conception, à la construction, aux essais et au marquage de ventilateurs complets destinés à être utilisés en atmosphères explosibles dans l’air chargé de gaz, de vapeurs, de brouillards et/ou de poussières. Ces atmosphères peuvent exister à l’intérieur (de l’atmosphère transportée (inflammable ou non)), à l’extérieur, ou à l’intérieur et à l’extérieur du ventilateur.
Le présent document couvre les équipements mécaniques, en particulier, les ventilateurs. Le « type de protection » tel que spécifié dans l’EN ISO 80079-37:2016 relève de la sécurité de construction.
1.4 Le présent document est applicable aux ventilateurs fonctionnant en atmosphères ambiantes et dans des conditions atmosphériques normales au niveau de l’aspiration avec :
- des pressions absolues de 0,8 bar à 1,1 bar,
- des températures de −20 °C à +60 °C,
- une teneur maximale en oxygène de 21 %,
- une augmentation d’énergie aérodynamique inférieure à 25 kJ/kg.
NOTE 1 25 kJ/kg sont équivalents à 30 kPa pour une masse volumique à l’aspiration de 1,2 kg/m3.
Le présent document peut également s’avérer utile pour la conception, la construction, les essais et le marquage des ventilateurs destinés à être utilisés dans des atmosphères n’entrant pas dans la plage de validité indiquée ci-dessus ou dans des cas où le recours à d’autres couples de matériaux s’avère nécessaire. Dans ce cas, il convient que l’évaluation du risque d’inflammation, la protection prévue à cet effet, les essais supplémentaires (si nécessaire), le marquage du fabricant, la documentation technique et les instructions destinées à l’utilisateur démontrent et indiquent clairement que l’appareil est adapté aux conditions que le ventilateur peut rencontrer.
NOTE 2 Les températures inférieures à -20°C peuvent être envisagées. L'adéquation des matériaux peut nécessiter une évaluation spécifique pour ces températures. Avec une température plus basse, la pression d'explosion augmente, ce qui entraîne une augmentation des pressions d'essai (voir Annexe A.3) et peut nécessiter des essais spécifiques. Bien que les conditions atmosphériques standard de l’EN ISO 80079-36:2016 donnent une plage de température pour l'atmosphère de -20 °C à +60 °C, la plage de température ambiante normale pour l'équipement est de -20 °C à +40 °C, sauf indication contraire et marquage.
1.5 Le présent document ne s’applique pas aux :
- ventilateurs du groupe 1 (ventilateurs pour les mines) ;
- ventilateurs du groupe d’explosion IIC (autre que l’hydrogène)
- ventilateurs de catégorie 1D ;
- ventilateurs de refroidissement ou roues montées sur des machines électriques tournantes ;
- ventilateurs de refroidissement ou roues montées sur des moteurs fixes à combustion interne, des véhicules ou des moteurs électriques.
NOTE 1 Les mesures relatives aux ventilateurs de catégorie 1D sont données dans l’EN 1127-1:2019.
NOTE 2 Les mesures relatives au groupe d’explosion IIC (autre que l’hydrogène) sont données dans l’EN 1127-1:2019.
NOTE 3 Les mesures pour le groupe d'explosion I sont indiquées dans les normes EN ISO/IEC 80079 38:2016 et EN 1127-2:2014.
Načrtovanje ventilatorjev za delovanje v potencialno eksplozivnih atmosferah
1.1 Ta dokument določa konstrukcijske zahteve za ventilatorje, izdelane za skupino II G (v okviru eksplozijskih skupin II A, II B in vodika) kategorij 1, 2 in 3 ter skupino II D kategorij 2 in 3, ki so namenjeni za uporabo v eksplozivnih atmosferah.
OPOMBA 1: Pogoji delovanja za različne kategorije ventilatorjev, ki se uporabljajo v tem dokumentu, so določeni v točki 4.
OPOMBA 2: Zahteve za ventilatorje kategorije 1 D v tem dokumentu ne zadostujejo za zagotovitev varnosti. Poleg tega so potrebni ukrepi protieksplozijske zaščite iz standarda EN 1127 1:2019, da se prepreči vžig v primeru redkih okvar.
OPOMBA 3: Tehnične zahteve za eksplozijsko skupino IIC (razen vodika) v tem dokumentu niso podane. V primeru takih atmosfer so lahko potrebni dodatni ukrepi protieksplozijske zaščite, kot je določeno v standardu EN 1127-1:2019.
1.2 Ta dokument se ne uporablja za ventilatorje skupine I (ventilatorji za uporabo v rudarstvu), hladilne ventilatorje ali rotorje pri rotacijskih električnih strojih in hladilne ventilatorje ali rotorje pri motorjih, vozilih ali električnih motorjih z notranjim izgorevanjem.
OPOMBA 1: Zahteve za ventilatorje skupine I so podane v standardu EN ISO/IEC 80079-38:2016.
OPOMBA 2: Zahteve za električne dele so zajete s sklici na standarde za električno opremo.
1.3 Ta dokument določa zahteve za načrtovanje, izdelavo, preskušanje in označevanje zaključenih ventilatorskih enot, namenjenih za uporabo v potencialno eksplozivnih atmosferah plinov, hlapov, meglic in/ali prahu v zraku. Take atmosfere lahko obstajajo znotraj (prenesena atmosfera (vnetljiva ali ne)), zunaj ali znotraj in zunaj ventilatorja.
OPOMBA: Ta dokument zajema mehansko opremo, zlasti ventilatorje. »Koncept zaščite« iz standarda EN ISO 80079-37:2016 je konstrukcijska varnost. Zahteve za označevanje so podane v standardu EN ISO 80079-37:2016.
1.4 Ta dokument se uporablja za ventilatorje, ki delujejo v okoljskih atmosferah in v običajnih vhodnih pogojih
– z vrednostmi absolutnega tlaka od 0,8 bara do 1,1 bara,
– s temperaturami od −20 °C do +60 °C,
– z največjim prostorninskim deležem vsebnosti kisika 21 % in
– pri porastu aerodinamične energije manj kot 25 kJ/kg.
OPOMBA 1: 25 kJ/kg je enako 30 kPa pri vhodni gostoti 1,2 kg/m3.
Ta dokument je lahko uporaben tudi pri načrtovanju, izdelavi, preskušanju in označevanju ventilatorjev za uporabo v atmosferah z vrednostmi zunaj zgoraj navedenega validativnega obsega ali v primerih potrebne uporabe drugih vezav materialov. V tem primeru mora biti ustreznost opreme za potencialne pogoje delovanja ventilatorja jasno izražena in prikazana z oceno tveganja za vžig, razpoložljivo zaščito pred vžigom, dodatnim preskušanjem (če je potrebno), označbami proizvajalca, tehnično dokumentacijo in navodili za uporabnika.
OPOMBA 2: Obravnavati je mogoče temperature, nižje od −20 °C, vendar je pri teh temperaturah morda potrebno posebej ovrednotiti ustreznost materiala. Z nižjo temperaturo se poveča tlak pri eksploziji, kar povzroči večje vrednosti preskusnega tlaka (glej točko A.3) in lahko zahteva posebne preskuse. Čeprav je za običajne atmosferske pogoje iz standarda EN ISO 80079-36:2016 podan temperaturni razpon atmosfere od –20 °C do +60 °C, je običajen razpon sobne temperature opreme od –20 °C do +40 °C, razen če je določeno ali označeno drugače.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2024
Načrtovanje ventilatorjev za delovanje v potencialno eksplozivnih atmosferah
Design of fans working in potentially explosive atmospheres
Konstruktion von Ventilatoren für den Einsatz in explosionsgefährdeten Bereichen
Conception des ventilateurs pour les atmosphères explosibles
Ta slovenski standard je istoveten z: EN 14986:2024
ICS:
23.120 Zračniki. Vetrniki. Klimatske Ventilators. Fans. Air-
naprave conditioners
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 14986
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2024
EUROPÄISCHE NORM
ICS 23.120 Supersedes EN 14986:2017
English Version
Design of fans working in potentially explosive
atmospheres
Conception des ventilateurs pour les atmosphères Konstruktion von Ventilatoren für den Einsatz in
explosibles explosionsgefährdeten Bereichen
This European Standard was approved by CEN on 16 March 2024.
This European Standard was corrected and reissued by the CEN-CENELEC Management Centre on 8 May 2024.
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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N
EUROPÄISCHES KOMITEE FÜR NORMUN G
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14986:2024 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 7
3 Terms and definitions . 7
4 Requirements for all fans . 8
4.1 Ignition hazard assessment . 8
4.1.1 General. 8
4.1.2 Normal operating conditions. 8
4.1.3 Expected malfunction . 8
4.1.4 Rare malfunction . 9
4.2 Assignment of categories . 9
4.2.1 General. 9
4.2.2 Influence of external parts on internal hazards and vice-versa . 9
4.2.3 Leakage . 9
4.3 Temperatures. 10
4.3.1 General. 10
4.3.2 Maximum surface temperature . 10
4.3.3 Temperature of the conveyed atmosphere (flammable or not) . 10
4.4 Mechanical design criteria . 11
4.4.1 General. 11
4.4.2 Clearance between rotating elements and the fan casing . 11
4.5 Casing . 12
4.5.1 General. 12
4.5.2 Gas tightness . 12
4.6 Impellers . 12
4.7 Materials for rotating and stationary parts of fans . 13
4.7.1 General. 13
4.7.2 Permissible material pairings . 13
4.8 Linings and tip extensions . 19
4.9 Vibration . 20
4.10 Earthing conducting parts . 21
4.11 Electrostatic charges. 21
4.12 Electrical equipment. 21
4.13 Prevention of deposits inside the fan . 21
4.14 Shaft seals . 21
4.15 Bearings. 22
4.16 Power transmission systems . 22
4.17 Clutches and couplings . 22
4.18 Brakes and braking systems . 22
4.19 Impeller-shaft attachment . 22
4.20 Corrosion of fan components . 26
4.21 Fire resistance . 26
4.22 Protection against foreign particles. 26
5 Additional requirements for category 2. 26
5.1 General . 26
5.2 Impeller-shaft attachment . 26
5.3 Vibration . 26
5.4 Material pairings. 27
6 Category 1G fans for specific use with a gaseous explosive atmosphere as a conveyed
atmosphere (flammable or not) . 27
6.1 General requirements . 27
6.2 Flame arresters . 27
6.2.1 General . 27
6.2.2 Stabilized burning . 27
6.3 Casings . 27
6.3.1 General . 27
6.3.2 Gas tightness . 28
7 Information for use . 28
7.1 General . 28
7.2 Accompanying documentation . 28
7.3 Markings . 30
Annex A (normative) Additional requirements for category 1G fans. 31
A.1 General . 31
A.2 Flame transmission test . 31
A.3 Pressure test . 32
Annex B (informative) Classification of requirements for the different categories . 34
Annex C (informative) Checklist for verification of the safety requirements and/or
protective measures . 38
C.1 General . 38
C.2 All categories . 38
C.3 Category 2 – Gas and dust . 39
C.4 Category 1 – Gas . 39
Annex D (informative) Examples of types of fans showing ignition minimizing features . 40
Annex E (normative) List of significant hazards . 48
Annex F (informative) Significant changes between this document and EN 14986:2017 . 53
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2014/34/EU aimed to be covered . 55
Bibliography . 59
European foreword
This document (EN 14986:2024) has been prepared by Technical Committee CEN/TC 305 “Potentially
explosive atmospheres — Explosion prevention and protection”, 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 October 2024, and conflicting national standards shall
be withdrawn at the latest by October 2024.
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 supersedes EN 14986:2017.
The significant changes with respect to EN 14986:2017 are listed in Annex F.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Introduction
This document is a type C standard as stated in EN ISO 12100:2010.
The machinery concerned and the extent to which hazards, hazardous situations and events are
covered and indicated in the scope of this document.
When provisions of this type C standard are different from those which are stated in type A or B
standards, the provisions of this type C standard take precedence over the provisions of the other
standards, for machines that have been designed and built according to the provisions of this type C
standard.
1 Scope
1.1 This document specifies the constructional requirements for fans constructed to Group II G (of
explosion groups IIA, IIB and hydrogen) categories 1, 2 and 3, and Group II D categories 2 and 3,
intended for use in explosive atmospheres.
NOTE Operation conditions for the different categories of fans used in this document are defined in Clause 4.
1.3 This document specifies requirements for design, construction, testing and marking of complete
fan units intended for use in potentially explosive atmospheres in air containing gas, vapour, mist
and/or dusts. Such atmospheres can exist inside (the conveyed atmosphere (flammable or not)),
outside, or inside and outside of the fan.
This document covers mechanical equipment, in particular fans. The “type of protection” as specified in
EN ISO 80079-37:2016 is constructional safety.
1.4 This document is applicable to fans working in ambient atmospheres and with normal
atmospheric conditions at the inlet, having
— absolute pressures ranging from 0,8 bar to 1,1 bar,
— and temperatures ranging from −20 °C to +60 °C,
— and maximum volume fraction of 21 % oxygen content,
— and an aerodynamic energy increase of less than 25 kJ/kg.
NOTE 1 25 kJ/kg is equivalent to 30 kPa at inlet density of 1,2 kg/m .
This document can also be helpful for the design, construction, testing and marking of fans intended for
use in atmospheres outside the validity range stated above or in cases where other material pairings
need to be used. In this case, the ignition risk assessment, ignition protection provided, additional
testing (if necessary), manufacturer's marking, technical documentation and instructions to the user,
clearly demonstrate and indicate the equipment's suitability for the conditions the fan can encounter.
NOTE 2 Temperatures below −20 °C can be considered. Material suitability can require specific evaluation for
these temperatures. With lower temperature the explosion pressure increases, which leads to increased test
pressures (see A.3) and can require specific testing. Although the standard atmospheric conditions in
EN ISO 80079-36:2016 give a temperature range for the atmosphere of −20 °C to +60 °C the normal ambient
temperature range for the equipment is −20 °C to +40 °C unless otherwise specified and marked.
1.5 This document does not apply to:
— group I fans (fans for mining);
— explosion group IIC (other than hydrogen);
— category 1D fans;
— cooling fans or impellers on rotating electrical machines;
— cooling fans or impellers on internal combustion engines, vehicles or electric motors.
NOTE 1 Measures for category 1D fans are given in EN 1127-1:2019.
NOTE 2 Measures for explosion group IIC (other than hydrogen) are given in EN 1127-1:2019.
NOTE 3 Measures for explosion group I are given in EN ISO/IEC 80079-38:2016 and EN 1127-2:2014.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 1127-1:2019, Explosive atmospheres — Explosion prevention and protection — Part 1: Basic concepts
and methodology
EN 60079-14:2014, Explosive atmospheres — Part 14: Electrical installations design, selection and
erection (IEC 60079-14:2013)
EN IEC 60079-0:2018, Explosive atmospheres — Part 0: Equipment — General requirements
(IEC 60079-0:2017)
EN ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk
reduction (ISO 12100:2010)
EN ISO 13349-1:2022, Fans — Vocabulary and definitions of categories — Part 1: Vocabulary
(ISO 13349-1:2022)
EN ISO 16852:2016, Flame arresters — Performance requirements, test methods and limits for use (ISO
16852:2016)
EN ISO 80079-36:2016, Explosive atmospheres — Part 36: Non-electrical equipment for explosive
atmospheres — Basic method and requirements (ISO 80079-36:2016)
EN ISO 80079-37:2016, Explosive atmospheres — Part 37: Non-electrical equipment for explosive
atmospheres — Non-electrical type of protection constructional safety ''c'', control of ignition sources ''b'',
liquid immersion ''k'' (ISO 80079-37:2016)
CLC/TR 60079-32-1:2018, Explosive atmospheres — Part 32-1: Electrostatic hazards, guidance
ISO 14694:2003, Industrial fans — Specifications for balance quality and vibration levels
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1127-1:2019,
EN ISO 80079-36:2016 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
externally mounted flame arrester
flame arrester consisting of a flame arrester housing and flame arrester elements mounted as a
separate equipment on the fan
3.2
integrated flame arrester
flame arrester consisting of a flame arrester housing and flame arrester elements where the flame
arrester housing is part of the fan housing
3.3
contact diameter
dimension of a rotating part at the point where it can hit a stationary part
4 Requirements for all fans
4.1 Ignition hazard assessment
4.1.1 General
An ignition hazard assessment according to EN ISO 80079-36:2016 shall be carried out. A list of main
hazards identified is given in Annex E. These include hazards inside and outside the fan. Additional
hazards may need to be considered.
For the purposes of fans designed and made according to this document the following operational
conditions shall be used as a basis for the ignition hazard assessment and for the assignment of a fan to
a particular category.
Release of flammable material shall be considered in the ignition hazard assessment for the outside of
the fan, see 4.2.3.
4.1.2 Normal operating conditions
Normal operating conditions shall be considered to occur in situations where the fan performs its
intended use within its design parameters. This includes conditions during start up and shut down (see
also EN ISO 12100:2010).
For the purposes of fans designed and made according to this document, failures (such as a breakdown
of seals, flange gaskets or releases of substances caused by accidents) which involve repair or shut-
down are not considered to be part of normal operation.
4.1.3 Expected malfunction
An expected malfunction shall be considered to be a failure or fault in a fan which normally occurs in
practice. In addition, an expected malfunction shall be considered to occur when a fan or its
components do not perform their intended functions.
For the purposes of fans designed and made according to this document this can happen for a variety of
reasons, including:
a) variation in the properties or dimensions of the fan assembly (e.g. warping of the casing);
b) disturbance to or failure of the power supply or other services;
c) unnoticed long time operation with defective bearing and leading to contact between impeller and
housing;
d) running for an extended period with high vibrations.
4.1.4 Rare malfunction
A rare malfunction is a type of malfunction which is known to happen but only in rare instances. Two
independent expected malfunctions which, separately, would not create an effective ignition source but
which, in combination, do create an effective ignition source, are regarded as a single rare malfunction.
4.2 Assignment of categories
4.2.1 General
A fan may have a different category for the inside and outside or none at one side. Fans which may be
used both to convey an explosive gas, vapour, mist or dust atmosphere and/or are located in an
explosive gas, vapour, mist or dust atmosphere are assigned categories internally and externally
depending on the likelihood of them acting as an effective ignition source.
Category 3 fans shall not create an effective ignition source in normal operation, see 4.1.2.
Category 2 fans shall meet category 3 fans requirements, and in addition not create an effective ignition
source with expected malfunctions, see 4.1.3. Category 1 fans shall meet category 2 fans requirements,
and in addition not create an effective ignition source with rare malfunctions, see 4.1.4.
4.2.2 Influence of external parts on internal hazards and vice-versa
For all external parts used for fans with an internal category, the effects of external faults on the interior
shall be considered in the ignition hazard assessments.
NOTE 1 An example is fans that use an external drive to support the impeller. Errors in the bearing of the drive
can lead to ignition sources in the interior of the fan housing.
The effects of internal faults on the exterior shall be considered in ignition hazard assessments for fans
with an external category.
NOTE 2 An example is an unbalanced impeller that results in overheating of an external bearing.
External parts which are in contact with the atmosphere inside the fan, and can create a potential
ignition source, shall have the same equipment category as is required for the interior of the fan. If the
equipment category is achieved by the use of additional instrumentation e.g. a temperature monitoring,
then the overall system shall be evaluated as part of the conformity assessment.
NOTE 3 For a configuration shown in Figures D.4 and D.5 or Figure D.6 the motor can be considered external to
the fan casing. For configuration shown in Figure D.7 with a flange mounted motor the motor can be considered as
an internal part which can create a potential ignition source and is in contact with the atmosphere inside the fan.
4.2.3 Leakage
The manufacturer shall consider leak aspects in the ignition hazard assessment.
Fans, especially their shaft seals and flexible connections at the inlet and outlet, are possibly not
absolutely gas tight, and connected ducts are possibly not leak proof. The hazardous atmosphere can
leak either from the inside of the fan into the adjacent environment, or from a hazardous environment
around a fan, and into the fan casing through a leakage path e.g. a shaft seal when this is below
atmospheric pressure.
NOTE 1 A leak is possible in either direction, depending on for example the installation configuration or/and
on whether the fan is operating.
The ignition hazard assessment shall evaluate leaks under all operating conditions that are specified in
the instructions for use as required in Clause 7.
NOTE 2 Example situations include a fan which is category 1G or 2G outside and 3G or non-hazardous inside,
which on start-up can contain flammable material due to leaks into the fan housing; and fans which normally
convey gas above the UFL (Upper Flammability Limit), where in-leaks of air can result in the mixture becoming
flammable.
NOTE 3 In normal operation, leakage of flammable material into the fan (gas or dust) is not a hazard as this
would be immediately dissipated by air/gas flow within the fan. Leakage of dust from inside the fan to the
external surroundings would not be sufficient to require the outside of the fan to be additionally rated for dust.
The manufacturer shall give information about possible leakage rates relevant for the actual application
in the information for use. Where the leakage rates are not known, the manufacturer shall construct the
fan so that there is no more than one category difference between the inside and the outside.
Where the fan has an open inlet and/or outlet (installation modes A, B, C according to
EN ISO 13349-1:2022) the inside and the outside of the fan shall have the same category.
4.3 Temperatures
4.3.1 General
Both the temperature of potentially hot surfaces and the temperature of the conveyed atmosphere
(flammable or not) and/or of the atmosphere surrounding the fan shall be considered.
4.3.2 Maximum surface temperature
The maximum surface temperature of the fan characterizes the hottest part of the equipment that can
come in contact with the explosive atmosphere or the maximum temperature of the conveyed
atmosphere (flammable or not) which can act as an ignition source.
The maximum surface temperatures of both the inside and outside parts of the fan that can come in
contact with the explosive atmosphere shall be determined in accordance with EN ISO 80079-36:2016.
In addition to that, the maximum surface temperature marked for the inside of the fan shall be the
greater of either:
— the maximum surface temperature determined in accordance with EN ISO 80079-36:2016
including the appropriate safety margins for the different categories; or
— the maximum temperature of the conveyed atmosphere (flammable or not) at the outlet with a
safety margin of 20 % (with temperatures measured in °C).
These temperatures are determined considering the highest inlet temperature specified in 4.3.3.
NOTE This safety margin of 20 % has been chosen because of the enhanced ignition risk at higher gas
temperatures.
The maximum surface temperature of the equipment is used – after the application of the above safety
margins – for marking of the equipment with a defined temperature, a temperature class of the
equipment or an appropriate explosive atmosphere.
EXAMPLE A fan with the following parameters: The maximum surface temperature of the inside, measured
according to EN ISO 80079-36:2016 with the appropriate safety margin is 90 °C, the temperature of the conveyed
atmosphere (flammable or not) measured at the outlet is 80 °C for an inlet temperature of 60 °C. With a 20 %
safety margin the maximum outlet temperature is 96 °C. Therefore, the maximum temperature marked for the
inside of the fan is 96 °C.
4.3.3 Temperature of the conveyed atmosphere (flammable or not)
While it is only the ambient and the inlet temperature which is generally known by the user, it is the
normally higher outlet temperature which determines the suitability of the fan for the intended use.
As well as temperature increases during normal service, extraordinary temperature increases shall be
considered.
The fan manufacturer shall ensure that the appropriate temperature limits are maintained between
−10 % or +20 % of nominal gas flow, and at maximum and minimum expected densities. The
manufacturer may specify a wider operating range where the temperature limits are maintained.
Generally maximum temperature rise will occur at minimum flow and maximum density. For variable
speed fans the calculation shall be carried out at maximum fan speed and/or the speed which gives
maximum fluid outlet temperature. For fans with motor mounted in conveyed atmosphere (flammable
or not) consideration shall be given to the heating effect from the motor. The manufacturer's
instructions shall include the minimum and maximum air flow rates which are required to maintain the
temperature rating.
The manufacturer shall measure or calculate the maximum gas temperature for an inlet gas
temperature of 60 °C within the gas flow limits or −10 % to +20 % of nominal gas flow.
Where the maximum inlet temperature is below 60 °C, the above calculation shall be made with this
lower maximum temperature and the manufacturer shall mark the fan appropriately.
Electric motors and other temperature sensitive elements shall receive special attention as they
generally are designed for a maximum ambient temperature of 40 °C.
4.4 Mechanical design criteria
4.4.1 General
Fans for operation in potentially explosive atmospheres shall be of rigid design. This requirement is
considered as fulfilled for casings, supporting structures, guards, protective devices and other external
parts if the deformation resulting from an impact test at the most vulnerable point is so small that the
moving parts do not come into contact with the casing. The test shall be carried out in accordance with
EN ISO 80079-36:2016.
NOTE Foreseeable causes of reducing the clearances between the casing and the moving parts include
distortion of the casing caused by connection to ductwork with no flexible joints, or by damage to the casing
during installation. Reduction of clearance is also possible if the fan is installed, and the inlet is blanked off
subjecting fan case and ducting to a negative pressure equal to maximum produced by the fan at its maximum
speed
All impellers, bearings, pulleys, cooling disks etc. shall be securely fixed in position.
This requirement shall not apply to the bearings incorporated within electric motors which shall be
subject to the requirements specified in EN IEC 60079-0:2018.
The manufacturer shall specify the maximum forces and torques in each direction that may be imposed
on the casing from connecting ductwork.
The fan shall be capable of withstanding the lowest inlet pressure that can be generated by the fan itself
when the inlet is closed, without causing contact between the casing and the moving parts.
4.4.2 Clearance between rotating elements and the fan casing
The clearance between rotating elements and the fan casing is the most important safety feature of
ignition minimizing fans. The minimum clearances between rotating parts such as the impeller and
fixed parts e.g. the fan casing shall be at least 0,5 % of the relevant contact diameters (diameter of a
rotating part at the point where it can contact a stationary part) of the finished component, but shall not
be less than 2 mm in the axial or radial directions nor need be more than 13 mm. The design and
construction shall ensure that the clearances are maintained under all conditions covered by the
intended use. Non-contact seals and seal housings shall comply with these criteria. For other seals
see 4.14. The manufacturer's instructions shall include where necessary the appropriate maintenance
instructions to maintain the clearance.
NOTE 1 Minimum clearance is defined as taking into account all possible tolerances due to manufacture and
fitting.
NOTE 2 The clearance can change with rotation, temperature, and due to vibrations and belt drive tension.
NOTE 3 See Annex D for examples on position of critical clearances.
4.5 Casing
4.5.1 General
The fan casing shall be of a substantially rigid design, to satisfy the mechanical design requirements
specified in 4.4.
Inspection doors and other openings are permitted, but shall be designed to have a similar level of leak
tightness as the rest of the casing.
4.5.2 Gas tightness
The manufacturer shall consider the possibility of leakage in the selection of components and
equipment.
Gas leakage can come from the shaft seal, or joints in the casing. The manufacturer shall provide
information about maintenance requirements for the seals as the shaft seal leakage rate may increase
over time.
4.6 Impellers
Impellers shall be of a rigid design. An impeller design that enables a primary stress calculation based
on 2/3 of the yield stress shall be deemed to satisfy the requirements for a rigid design without testing.
Impeller designs validated by testing shall be able to withstand a test run at a minimum of X times the
maximum operational rotating speed for at least 60 s without causing an ignition risk, i.e. the impeller
shall not contact the casing. The factor X shall be as follows:
X = 1,15
where the run test is carried out at the maximum operating temperature or
X = 1,15 x √(Rp20/RpT)
Where the run test is carried out at 20 °C and where
RpT is the yield strength at maximum operating temperature or the creep rupture strength at
maximum operating temperature whatever is smaller;
Rp20 is the yield strength at 20 °C.
The above factors are based on a type test principle for series production of identical units. If individual
testing of all fan units is employed, a factor of 1,1 shall be used rather than 1,15 in the above
calculations.
An impeller either overspeed tested or shown by design to meet the above will satisfy the requirement
of not creating an ignition source in expected malfunction d in 4.1.3.
4.7 Materials for rotating and stationary parts of fans
4.7.1 General
In view of possible friction, due to malfunctions or even rare malfunction, potential areas of contact
between the rotating elements and fixed components shall be manufactured from materials in which
the risk of ignition through friction and friction-impact sparks, hot spots or hot surfaces is minimized.
Consideration should be given to the fact that layers of combustible or non-combustible materials may
cause increased ignition risks. See Annex C.
Where the gap between fixed and moving parts can be checked, as part of routine maintenance, on a fan
once it is installed and any ducting fitted to inlet and outlet, the manufacturer shall include in the
instructions for use how this should be done, and the acceptable minimum gap. Recommendations for
the frequency of checking this gap shall also be included.
For category 3 fans there are no requirements for material pairings as specified in 4.7.2 if one of the
following requirements is fulfilled:
a) Motor power does not exceed 5,5 kW and relative rubbing speed < 40 m/sec;
or
b) the conditions for verifying the critical gap as described above can be met during service.
All alloys except aluminium alloys (sheet or cast) shall not contain more than a mass fraction of
15 % aluminium and shall have a homogenous structure. Paints and coatings shall not contain more
than a mass fraction of 10 % aluminium.
When selecting materials, hydrogen embrittlement hazards should be taken into account.
NOTE A method for the determination of the susceptibility to hydrogen embrittlement/cracking is provided
in EN ISO 17642-1, EN ISO 17642-2 and EN ISO 17642-3.
4.7.2 Permissible material pairings
One of the material pairings given in Table 1 for gas explosion groups IIA and IIB and dust applications
or in Table 2 for hydrogen for the different categories shall be used in the construction of ignition
protected fans.
The pairings shown are for the stationary rubbing part and the rotating rubbing part. Either
material (1) or material (2) may be chosen for the rotation part subject to satisfactory mechanical
stress performance over the design life of the fan.
For category 1G fans this document requires additional protective measures, thus rotating and
stationary parts of fans acceptable for category 2 fans are also suitable for category 1G.
NOTE Many of the material pairings given in Table 1 can cause ignition of potentially explosive atmospheres
if there is a high degree of friction for a long enough time. These pairings have been chosen as a represent a
gradation of the ignition risk for different applications. The other constructional measures detailed in this
document are essential to ensure the appropriate level of safety of the fan.
Table 1 — Permissible material pairings for gas explosion groups IIA and IIB and dust
applications
Item Material (1) Material (2) Requirements Footnotes
a f g
1 Leaded brass Carbon or — Paint containing
CuZn39Pb or stainless steel aluminium shall not be
naval brass or nickel base used because of the risk of
CuZn39Sn or or cast iron thermite sparks
tin bronze (EN 1127-1:2019).
2 Copper Carbon or — Nickel-based alloys shall
stainless steel contain a minimum mass
fraction 60 % nickel.
or nickel-
based alloy or Nickel-based alloys and
cast iron nickel-based steel alloys
shall contain a maximum
mass fraction of 4 % in
total of magnesium,
titanium and zirconium.
All alloys shall have a
homogeneous structure.
— Even if these alloys are
non-sparking, they can
easily form hot spots due
to friction and low heat
conductivity.
11 CuNi10Fe1.6Mn Any steel alloy — This pairing can
(CW352H) or nickel- cause ignition of
based alloy explosive
atmospheres when
rubbing occurs. This
shall be included in
the technical
documentation
provided to the user.
— In category 1G- or
category 2 fans these
pairings shall be
limited to fans
having a motor
power not exceeding
11 kW and a relative
rubbing speed
between stationary
and rotating parts
not exceeding
40 m/s, provided the
clearances at all
possible points of
contact specified
in 4.4.2 are ensured
by design or checks
during service.
Where greater motor
powers or relative
rubbing speeds
occur, additional
Item Material (1) Material (2) Requirements Footnotes
measures are
required to control
the clearance (e.g.
vibration control, see
5.3).
7 Nickel-based Nickel-based — Nickel-based alloys — These pairings can cause
alloy alloy shall contain a ignition of explosive
minimum mass atmospheres when
fraction 60 % nickel. rubbing occurs. This shall
Nickel-based alloys be included in the
and nickel-based technical documentation
steel alloys shall provided to the user.
contain a maximum
— In category 1G or 2 fans
mass fraction of 4 %
these pairings shall be
in total of
limited to fans having a
magnesium, titanium
motor power not
and zirconium. All
exceeding 5,5 kW and a
alloys shall have a
relative rubbing speed
homogeneous
between stationary and
structure.
rotating parts
— Even if these alloys is < 40 m/sec, provided
are non-sparking, the clearances as specified
they can easily form in 4.4.2 are ensured by
hot spots due to design or in service.
friction and low heat Where greater motor
conductivity. powers or relative rubbing
speeds occurs, additional
8 Stainless steel Stainless steel
measures are required to
control the clearance (e.g.
9 Any other steel Any other — Paint containing
vibration control, see 5.3).
alloy or cast steel alloy or aluminium shall not
iron cast iron be used because of
— In this material pairing
the risk of thermite
austenitic steel shall have
sparks
a mass fraction of at least
(EN 1127-1:2019).
16,5 % chrome (see [2],
[3]), to minimize the
g
10 An
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...