SIST EN 16447:2014

Explosion isolation flap valves

This European Standard describes 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.
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 European Standard is applicable only to the use of explosion isolation flap valves that are intended for avoiding 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 1   The standard assumes that the explosion starts in a vessel and not in ducting.
Explosion isolation flap valves are not designed to prevent the transmission of fire or burning powder transported by the normal process flow.
NOTE 2   It is necessary to take this into account in risk assessments.
This European Standard is only applicable for dust explosions.
This European Standard 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

Diese Europäische Norm beschreibt die allgemeinen Anforderungen an Rückschlagklappen, die zur Ent¬kopplung im Falle einer Staubexplosion verwendet werden. Bei einer Rückschlagklappe zur explosionstech¬nischen 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.
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.
Diese Europäische Norm gilt nur für Rückschlagklappen zur explosionstechnischen Entkopplung, die zur Vermeidung der Ausbreitung von Explosionen aus einem Behälter über Verbindungs¬rohre oder  leitungen in andere Teile der Anlage bestimmt sind. Diese Norm deckt die Trennung bzw. Entkopplung von Behältern ab, die durch Druckentlastung (einschließlich flammenloser Druckentlastung), Explosionsunterdrückung oder explosionsfeste Ausführung geschützt werden.
ANMERKUNG 1   Diese Norm 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.
ANMERKUNG 2   Dies muss bei Risikobeurteilungen berücksichtigt werden.
Diese Europäische Norm gilt nur für Staubexplosionen.
Diese Europäische Norm 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.

Clapet d'isolation d'explosion

La présente Norme européenne décrit 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.
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 définit les méthodes d'évaluation de l'efficacité des vannes à clapet d'isolation d'explosion.
La présente Norme européenne 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 1   La présente norme s’applique uniquement dans les cas où l'explosion se produit à l'intérieur d'une enceinte et non d'un conduit.
Les vannes à clapet d'isolation d'explosion ne sont conçues pour empêcher ni la propagation du feu ni la transmission des particules en combustion par le flux de fonctionnement normal.
NOTE 2   Il est nécessaire de prendre en compte cet aspect lors de l'évaluation des risques.
La présente Norme européenne s'applique uniquement aux explosions de poussières.
Elle n'est applicable ni aux explosions des substances indiquées ci-dessous, ni aux explosions de mélanges contenant certaines de ces substances :
a)   gaz, vapeurs et mélanges hybrides ;
b)   substances chimiquement instables ;
c)   substances explosives ;
d)   substances pyrotechniques.

Eksplozijsko izolacijski ventili

Standard EN 16447 opisuje splošne zahteve za ventile, ki se uporabljajo za izoliranje eksplozije prahu. Eksplozijsko izolacijski ventil je zaščitni sistem, ki preprečuje širjenje eksplozije prahu prek priključenih cevi ali cevovoda v druge dele stroja ali obrata. Eksplozijsko izolacijski ventil lahko širjenje eksplozije prahu prepreči le, če se ta širi v smeri, ki je nasprotna smeri običajnega poteka procesa, in ne prepreči eksplozij, ki se širijo v smeri običajnega poteka procesa. Ta evropski standard določa metode za vrednotenje učinkovitosti eksplozijsko izolacijskih ventilov. Ta evropski standard se uporablja le za eksplozijsko izolacijske ventile, namenjene preprečevanju širjenja eksplozije prek priključenih cevi ali cevovoda iz posode v druge dele instalacije. Standard zajema izolacijo tovrstnih posod, ki so zaščitene s sistemom za razbremenitev tlaka eksplozije (vključno z neplamenskim sistemom za razbremenitev tlaka eksplozije), dušenjem eksplozije ali konstrukcijo, odporno proti eksplozijam.

General Information

• Status: Published
• Public Enquiry End Date: 24-Dec-2012
• Publication Date: 21-Sep-2014
• ICS: 13.230 - Explosion protection
• ICS: 23.060.50 - Check valves
• Technical Committee: EXP - Product for explosive atmospheres
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 31-Jul-2014
• Due Date: 05-Oct-2014
• Completion Date: 22-Sep-2014
• Directive: 2014/34/EU - Directive 2014/34/EU Of The European Parliament And Of The Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres (recast)
• Directive: 94/9/EC - Directive 94/9/EC of the European Parliament and the Council of 23 March 1994 on the approximation of the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres
• Mandate: M/BC/CEN/92/46 - Standardization mandate assigned to CEN/CENELEC concerning equipment and protective systems intended for use in potentially explosive atmospheres
• Ref Project: EN 16447:2014 - Explosion isolation flap valves

Relations

• Revised: oSIST prEN 16447:2025 - Explosion isolation flap valves
• Effective Date: 26-Jul-2023

Overview

EN 16447:2014 (CEN) specifies the general requirements and test methods for explosion isolation flap valves used for dust explosion isolation. The standard defines how flap valves must perform to prevent a dust explosion in a vessel from propagating through connecting pipes or ducts into other plant areas. It applies only to dust explosions and only when the explosion originates in a vessel (not in ducting). EN 16447 clarifies that a flap valve can stop propagation only when the explosion moves against the normal process flow - it does not stop explosions traveling in the normal flow direction.

Key topics and technical requirements

• Scope & limitations
  • Applicable only to dust explosions; excludes gases, vapours, chemically unstable, explosive or pyrotechnic substances.
  • Does not prevent transmission of fire or burning powder carried by the normal process flow - this must be considered in risk assessments.
• Functional principle
  • Valve is held open by normal process flow and closes when flow reverses during an explosion event.
  • Explosion isolation must be ensured during process flow and no-flow periods.
• Mechanical integrity
  • Components must withstand expected explosion loads without losing safety function.
  • Construction can be explosion-pressure resistant or shock-resistant in accordance with EN 14460.
• Experimental testing framework
  • Three test Modules:
    • Module A - Explosion resistance testing: verifies valve integrity under explosion pressures; at least one test per size (largest size for geometrically similar devices).
    • Module B - Flame transmission testing: confirms valve prevents flame/spark propagation; includes tests at various reduced overpressures, ignition positions and flap states (open/closed).
    • Module C - Functional testing: verifies efficacy for intended use and determines minimum/maximum installation distances; always required for new, untested designs.
  • Test inputs include dust combustion properties (KSt, pmax, MIE, MIT), intended use, vessel volumes, installation layout (push/pull flow, ducts, fans, bends).
• Documentation & marking
  • Manufacturer must provide installation/operating instructions, part lists, drawings and test reports.

Applications and users

• Typical users:
  • Process safety engineers and plant designers in powder-processing industries (e.g., food, pharmaceuticals, chemicals, metal powders).
  • Valve and safety-system manufacturers, test laboratories, notified bodies and inspectors.
  • Maintenance teams and risk assessors implementing explosion protection measures.
• Practical applications:
  • Isolating explosion risk between vessels and connected ductwork.
  • Integrating with explosion venting (including flameless venting), suppression systems or explosion-resistant design strategies.

Related standards

• EN 13237 - terms and definitions for equipment in potentially explosive atmospheres
• EN 14373 - explosion suppression systems
• EN 14460 - explosion-resistant equipment
• EN 15089 - explosion isolation systems

EN 16447:2014 provides the test and performance baseline for designing, selecting and validating explosion isolation flap valves as part of a comprehensive dust explosion protection strategy.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Eksplozijsko izolacijski ventiliRückschlagklappen zur explosionstechnischen EntkopplungClapet d'isolation d'explosionExplosion isolation flap valves23.060.50Blokirni ventiliCheck valves13.230Varstvo pred eksplozijoExplosion protectionICS:Ta slovenski standard je istoveten z:EN 16447:2014SIST EN 16447:2014en01-oktober-2014SIST EN 16447:2014SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16447
July 2014 ICS 13.230; 23.060.50 English Version
Explosion isolation flap valves
Vanne à clapet d'isolation d'explosion
Rückschlagklappen zur explosionstechnischen EntkopplungThis European Standard was approved by CEN on 28 May 2014.
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, 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 © 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16447:2014 ESIST EN 16447:2014

1 Scope This European Standard describes 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. 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 European Standard 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 1 This standard 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. NOTE 2 It is necessary to take this into account in risk assessments. This European Standard is only applicable for dust explosions. This European Standard 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, 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 13237, Potentially explosive atmospheres - Terms and definitions for equipment and protective systems intended for use in potentially explosive atmospheres EN 14373, Explosion suppression systems EN 14460, Explosion resistant equipment EN 15089, Explosion isolation systems SIST EN 16447:2014

a)
b) Key 1 fan 2 explosion isolation flap valve 3 vessel Figure 1 — Push flow situation SIST EN 16447:2014

Figure 2 — Pull flow situation 4 Explosion isolation flap valves 4.1 General 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. It 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 long enough 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 or the venting process. 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. 4.2 Mechanical integrity Any part of an explosion isolation flap valve shall be constructed such that it can 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 in accordance with EN 14460. NOTE The explosion pressure acting on the explosion isolation flap valve may be higher than the (reduced) explosion pressure in the connected vessel as a result of pressure piling and/or flame acceleration through the ducting. 5 Experimental testing of efficacy and mechanical integrity 5.1 General The testing shall reflect the intended use. As a minimum the following information is necessary prior to testing: SIST EN 16447:2014

Functional testing. Explosion isolation flap valves shall in principle be tested according to all three modules but where possible the modules can be combined. If a combination is chosen, the critical test conditions from the various modules shall be covered in the combination. For an untested new explosion isolation flap valve module C shall always be carried out. 5.2.2 Module A: Explosion resistance testing Explosion resistance shall be confirmed by explosion testing according to the following procedure: 1) Test arrangement: • The explosion isolation flap valve is mounted to a test vessel according to Figure 3. The explosive atmosphere inside the test vessel and the pipe connecting the valve may be of any type (gas or dust), provided the pressure generated is sufficient to subject the valve to the required pressure. The SIST EN 16447:2014

Key 1 Test vessel 3 Pressure Transducer (Pt) 2 Explosion Isolation Flap Valve 4 Explosion vent Figure 3 — Test arrangement for explosion pressure resistance testing 5.2.3 Module B: Flame transmission testing The main objective of the flame transmission testing is to verify that the explosion isolation flap valve is able to prevent explosion flames from propagating past the explosion isolation flap valve. The tests shall expose the explosion isolation flap valve to the maximum reduced explosion overpressure as indicated in the intended use and a lower one (see “3) number of tests”) and shall include conditions where the valve is open and closed. If there is a locking mechanism it shall not be locked in the closed position before ignition. 1) Test arrangement:
• The test arrangement shall be similar to the one shown in Figure 4. The size of the vessel shall reflect the intended use of the device. The explosive atmosphere in the vessel shall represent an explosibility similar to the highest KSt as specified by the intended use. It has to be assured that the flame reaches the position of the valve. The test arrangement shall include a duct in case it is expected t
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