prEN 16447
(Main)Explosion isolation flap valves
Explosion isolation flap valves
This document specifies the general requirements for flap valves used for dust explosion isolation. An explosion isolation flap valve is a protective system, which prevents a dust explosion from propagating via connecting pipes or ducts into other parts of apparatus or plant areas.
NOTE 1 An explosion isolation flap valve is also used as a process equipment (back pressure flap valve), to prevent the exposure of workers to dust cloud at workplaces when the flow is stopped in normal operation or by a process shut down. This function which is not related to explosion isolation is not in the scope of this European Standard.
An explosion isolation flap valve can only stop the propagation of a dust explosion when it propagates against the direction of the normal process flow. It does not stop explosions running in the normal process flow direction. This European Standard specifies methods for evaluating the efficacy of explosion isolation flap valves.
This document is applicable only to explosion isolation flap valves which are intended to avoid explosion propagation from a vessel, into other parts of the installation via connecting pipes or ducts. The standard covers isolation of such vessels that are protected by explosion venting (including flameless venting), explosion suppression or explosion-resistant design.
NOTE 2 This document is only applicable to cases where the explosion starts in a vessel and not in pipes or ducting.
Explosion isolation flap valves are not designed to prevent the transmission of fire or burning powder transported by the normal process flow.
Very weak explosions can still lead to an isolation failure. This residual risk is not covered by this document.
NOTE 3 It is necessary to take this into account in risk assessments.
Explosion isolation flap valves that are kept open by a retention mechanism that prevents valve closure under gravity when there is no process air flow, require a certain explosion over-pressure to overcome the forces of the retention mechanism and to start closure. Such devices do not fall under the scope of this document, but fall under the scope of EN 15089.
This document is only applicable for dust explosions.
This document is not applicable for explosions of materials listed below, or for mixtures containing some of those materials:
a) gases, vapours and hybrid mixtures;
b) chemically unstable substances;
c) explosive substances;
d) pyrotechnic substances.
Rückschlagklappen zur explosionstechnischen Entkopplung
Dieses Dokument beschreibt die allgemeinen Anforderungen an Rückschlagklappen, die zur Entkopplung im Falle einer Staubexplosion verwendet werden. Bei einer Rückschlagklappe zur explosionstechnischen Entkopplung handelt es sich um ein Schutzsystem, das verhindert, dass sich eine Staubexplosion über Verbindungsrohre oder -kanäle in andere Teile der Apparatur oder Anlagenbereiche ausbreitet.
ANMERKUNG 1 Eine Rückschlagklappe zur explosionstechnischen Entkopplung wird auch als verfahrenstechnische Einrichtung (Rückschlagklappe) verwendet, um zu verhindern, dass Arbeitnehmer an ihren Arbeitsplätzen einer Staubwolke ausgesetzt werden, wenn der Durchfluss im Normalbetrieb oder bei einer Prozessabschaltung gestoppt wird. Diese Funktion, die nicht mit der explosionstechnischen Entkopplung zusammenhängt, fällt nicht in den Anwendungsbereich dieser Europäischen Norm.
Eine Rückschlagklappe zur explosionstechnischen Entkopplung kann die Ausbreitung einer Staubexplosion nur dann stoppen, wenn diese in Gegenrichtung zum üblichen Prozessstrom erfolgt. Sie verhindert nicht die Ausbreitung von Explosionen in Richtung des üblichen Prozessstroms. Diese Europäische Norm legt Verfahren für die Bewertung der Wirksamkeit von Rückschlagklappen zur explosionstechnischen Entkopplung fest.
Dieses Dokument gilt nur für Rückschlagklappen zur explosionstechnischen Entkopplung, die zur Vermeidung der Ausbreitung von Explosionen aus einem Behälter über Verbindungsrohre oder -leitungen in andere Teile der Anlage bestimmt sind. Diese Norm deckt die Trennung bzw. Entkopplung von Behältern ab, die durch Explosionsdruckentlastung (einschließlich flammenloser Druckentlastung), Explosionsunterdrückung oder explosionsfeste Ausführung geschützt werden.
ANMERKUNG 2 Dieses Dokument ist nur auf Fälle anwendbar, bei denen die Explosion ihren Ausgang in einem Behälter und nicht in Rohren oder Rohrleitungen nimmt.
Rückschlagklappen zur explosionstechnischen Entkopplung sind nicht dafür vorgesehen, die Übertragung von Bränden oder brennendem Staub durch den regulären Prozessstrom zu verhindern.
Auch sehr schwache Explosionen können zu einem Entkopplungsversagen führen. Dieses Restrisiko wird in diesem Dokument nicht behandelt.
ANMERKUNG 3 Dies muss bei Risikobeurteilungen berücksichtigt werden.
Rückschlagklappen zur explosionstechnischen Entkopplung, die durch einen Rückhaltemechanismus offen gehalten werden, der das Schließen der Klappe durch Schwerkraft verhindert, wenn kein Luftstrom des Arbeitsprozesses vorhanden ist, benötigen einen bestimmten Explosionsüberdruck, um die Kräfte des Rückhaltemechanismus zu überwinden und das Schließen einzuleiten. Solche Geräte fallen nicht in den Anwendungsbereich dieses Dokuments, sondern in den Anwendungsbereich von EN 15089.
Dieses Dokument gilt nur für Staubexplosionen.
Dieses Dokument gilt nicht für Explosionen der nachfolgend aufgelisteten Stoffe oder von Gemischen, die derartige Stoffe enthalten:
a) Gase, Dämpfe und hybride Gemische;
b) chemisch instabile Stoffe;
c) Explosivstoffe;
d) pyrotechnische Materialien.
Vannes à clapet d’isolation d’explosion
Le présent document spécifie les exigences générales pour les vannes à clapet d’isolation d’explosion de poussières. Une vanne à clapet d’isolation d’explosion est un système de protection qui empêche une explosion de poussières de se propager par la tuyauterie ou les canalisations dans d’autres parties d’un appareil ou d’une installation.
NOTE 1 Une vanne à clapet d’isolation d’explosion est également utilisée comme un équipement de procédé (vanne à clapet antiretour), afin d’éviter d’exposer les employés à un nuage de poussières sur les lieux de travail, lorsque le flux est interrompu dans le cadre du fonctionnement normal, ou à la suite d’un arrêt de procédé. Cette fonction, qui n’a pas de lien avec l’isolation d’explosion, ne relève pas du domaine d’application de la présente Norme européenne.
Une vanne à clapet d’isolation d’explosion peut arrêter la propagation d’une explosion de poussières uniquement lorsque ladite explosion se propage dans la direction opposée à celle du flux de fonctionnement normal. La vanne n’entrave pas les explosions qui se propagent dans la direction normale du flux de fonctionnement. La présente Norme européenne spécifie les méthodes d’évaluation de l’efficacité des vannes à clapet d’isolation d’explosion.
Le présent document s’applique uniquement aux vannes à clapet d’isolation d’explosion destinées à éviter la propagation d’une explosion survenant dans une enceinte vers d’autres parties de l’installation par la tuyauterie ou les conduits. La présente norme couvre l’isolation des enceintes protégées par décharge d’explosion (y compris la décharge d’explosion sans flamme), par suppression d’explosion ou par leur conception qui leur permet de résister aux explosions.
NOTE 2 Le présent document s’applique uniquement dans les cas où l’explosion se produit à l’intérieur d’une enceinte et non d’une tuyauterie ou d’un conduit.
Les vannes à clapet d’isolation d’explosion ne sont pas conçues pour empêcher la propagation du feu, ni la transmission de particules en combustion, résultant du flux de fonctionnement normal.
De très faibles explosions peuvent tout de même provoquer une défaillance d’isolement. Ce risque résiduel n’est pas couvert par le présent document.
NOTE 3 Il est nécessaire de prendre en compte cet aspect lors de l’évaluation des risques.
Les vannes à clapet d’isolation d’explosion qui sont maintenues en position ouverte par un mécanisme de retenue, lequel empêche la fermeture de la vanne sous l’effet de la gravité, en l’absence de flux d’air de fonctionnement, exigent une certaine surpression d’explosion afin de dépasser la capacité du mécanisme de retenue et d’initier la fermeture. De tels dispositifs ne relèvent pas du domaine d’application du présent document, mais de celui de l’EN 15089.
Le présent document s’applique uniquement aux explosions de poussières.
Le présent document ne s’applique pas aux explosions des matières énumérées ci dessous ni aux mélanges contenant certaines de ces matières :
a) gaz, vapeurs et mélanges hybrides ;
b) substances chimiquement instables ;
c) substances explosives ;
d) substances pyrotechniques.
Eksplozijsko izolacijski ventili
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2025
Eksplozijsko izolacijski ventili
Explosion isolation flap valves
Rückschlagklappen zur explosionstechnischen Entkopplung
Vannes à clapet d’isolation d’explosion
Ta slovenski standard je istoveten z: prEN 16447
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
23.060.50 Blokirni ventili Check valves
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2025
ICS 13.230 Will supersede EN 16447:2014
English Version
Explosion isolation flap valves
Vannes à clapet d'isolation d'explosion Rückschlagklappen zur explosionstechnischen
Entkopplung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 305.
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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye 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
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16447:2025 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 5
3 Terms and definitions . 5
4 Explosion isolation flap valves . 6
4.1 General. 6
4.2 Essential requirements . 7
5 Experimental testing of efficacy and mechanical integrity . 7
5.1 General. 7
5.2 Test procedures . 8
5.3 Testing report . 14
6 Environmental aspects . 15
7 Information for use . 15
8 Marking . 16
Annex A (informative) Example pressure time curve describing explosion phenomena
occurring with dust explosions in a connected vessel – flap valve configuration . 18
Annex B (informative) Examples of controlled flap valve release mechanisms for the
alternative method used in testing with pull mode situations . 20
Annex C (informative) Examples of parameters that may influence the minimum and
maximum installation distance in functional testing . 25
Annex D (informative) Guidance to determine flow situation (pull/push) in multi-fan
configurations . 26
Annex E (informative) Significant changes between this document and EN 16447:2014. 27
Annex ZA (informative) Relationship between this European Standard and the essential
health and safety requirements of Directive 2014/34/EU aimed to be covered . 29
Bibliography . 32
European foreword
This document (prEN 16447:2025) 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 document is currently submitted to the CEN Enquiry.
This document will supersede EN 16447:2014.
The significant changes between this document and EN 16447:2014 are given in Annex E.
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.
1 Scope
This document specifies the general requirements for flap valves used for dust explosion isolation. An
explosion isolation flap valve is a protective system, which prevents a dust explosion from propagating
via connecting pipes or ducts into other parts of apparatus or plant areas.
NOTE 1 An explosion isolation flap valve is also used as a process equipment (back pressure flap valve), to
prevent the exposure of workers to dust cloud at workplaces when the flow is stopped in normal operation or by a
process shut down. This function which is not related to explosion isolation is not in the scope of this European
Standard.
An explosion isolation flap valve can only stop the propagation of a dust explosion when it propagates
against the direction of the normal process flow. It does not stop explosions running in the normal
process flow direction. This European Standard specifies methods for evaluating the efficacy of explosion
isolation flap valves.
This document is applicable only to explosion isolation flap valves which are intended to avoid explosion
propagation from a vessel, into other parts of the installation via connecting pipes or ducts. The standard
covers isolation of such vessels that are protected by explosion venting (including flameless venting),
explosion suppression or explosion-resistant design.
NOTE 2 This document is only applicable to cases where the explosion starts in a vessel and not in pipes or
ducting.
Explosion isolation flap valves are not designed to prevent the transmission of fire or burning powder
transported by the normal process flow.
Very weak explosions can still lead to an isolation failure. This residual risk is not covered by this
document.
NOTE 3 It is necessary to take this into account in risk assessments.
Explosion isolation flap valves that are kept open by a retention mechanism that prevents valve closure
under gravity when there is no process air flow, require a certain explosion over-pressure to overcome
the forces of the retention mechanism and to start closure. Such devices do not fall under the scope of
this document, but fall under the scope of EN 15089.
This document is only applicable for dust explosions.
This document is not applicable for explosions of materials listed below, or for mixtures containing some
of those materials:
a) gases, vapours and hybrid mixtures;
b) chemically unstable substances;
c) explosive substances;
d) pyrotechnic substances.
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 14460:2018, Explosion resistant equipment
EN 13237:2024, Potentially explosive atmospheres — Terms and definitions for equipment and protective
systems intended for use in potentially explosive atmospheres
EN 14373:2021+A1:2025, Explosion suppression systems
EN 15089:2009, Explosion isolation systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 13237:2024,
EN 14373:2021+A1:2025 and EN 15089:2009 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
explosion source
vessel from which the explosion originates
3.2
push flow situation
situation where the fan is located upstream (with reference to the direction of the normal process flow)
of the explosion source
a) explosion isolation flap valve positioned between fan and the explosion source
b) fan positioned between explosion isolation flap valve and the explosion source
Key
1 fan
2 explosion isolation flap valve
3 vessel
Figure 1 — Push flow situation
3.3
pull flow situation
situation where the fan is located downstream (with reference to the direction of the normal process
flow) of the explosion source
Figure 2 — Pull flow situation
3.4
maximum explosion overpressure at the valve
p
valve,max
resulting maximum overpressure measured on the pipeline close to the explosion isolation flap valve side
exposed to the explosion
4 Explosion isolation flap valves
4.1 General
An explosion isolation flap valve is installed such that the normal process air flow passes in one direction
through the valve and keeps it open. It closes when the air flow reverses due to a dust explosion event.
The valve shall stay closed to avoid flames from transmitting during an explosion event (see Note 1).
Explosion isolation shall also be ensured during periods without process flow.
NOTE 1 Re-opening of the valve is possible e.g. due to pressure oscillations caused by the fan, the venting process
or by flow and pressure oscillations in the pipe on the explosion isolation flap valve side which is not exposed to the
explosion.
Explosion isolation flap valves shall be equipped with a locking mechanism preventing re-opening after
the explosion took place. They may also be equipped with an indication that monitors if the valve is
locked.
Explosion isolation flap valves may also be equipped with an indication that signals the presence of dust
accumulations inside the valve that could potentially corrupt the good functioning in case of an explosion.
Also, they may be equipped with provisions to connect an automated dust cleaning system.
Explosion isolation flap valves are designed to be connected to ducting. The valve housing is fitted with
inlet and outlet connections to connect with the ducting.
NOTE 2 Adapters are often used to connect to an oversize valve.
NOTE 3 Sometimes the presence of a flap valve causes an increase of the maximum reduced explosion pressure
in the vented vessel p compared to a situation where no flap valve is present in the pipe. Quantification of these
red,max
effects will become part of a future revision of EN 14491 and is not part of this document.
4.2 Essential requirements
• Explosion isolation flap valves shall prevent an explosion flame from propagating via connecting
pipes or ducts from one part of the installation into other parts or plant areas.
• The explosion isolation flap valve as installed or any of its components shall not introduce ignition
hazards, such as electrostatic discharge, mechanical friction, electrical sparks, hot surfaces, or hot
gases (according to EN 1127-1:2019).
• The explosion isolation flap valve shall withstand the loads imposed by any explosion that can be
expected in accordance with its intended use, without losing its ability to perform its safety function.
The construction can be either explosion-pressure resistant or explosion-pressure shock resistant
according to EN 14460:2018.
NOTE 4: Sometimes the explosion pressure acting on the explosion isolation flap valve pvalve,max is higher than
the (reduced) explosion pressure in the connected vessel pred,max as a result of pressure piling and/or flame
acceleration through the ducting.
• Installation instructions, service and maintenance requirements and intervals shall be specified in
the system documentation. (See Clause 7)
...
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