Explosion suppression systems

This document describes the basic requirements for the design and application of explosion suppression systems. This document also specifies test methods for evaluating the effectiveness and the scale up of explosion suppression systems against defined explosions. This document covers:
— general requirements for explosion suppression system components;
— evaluating the effectiveness of an explosion suppression system;
— evaluating the scale up of an explosion suppression system;
— development and evaluation of design tools for explosion suppression systems;
— installation, operation and maintenance instructions for an explosion suppression system.
This document is applicable only to explosion suppression systems intended for the protection of closed, or essentially closed, enclosures in which an explosion could result as a consequence of ignition of an explosible mixture, e.g. dust-air, gas(vapour)-air, dust-gas(vapour)-air and mist-air.
This document is not applicable for explosions of materials listed below, or for mixtures containing some of those materials:
— unstable materials that are liable to dissociate;
— explosive materials;
— pyrotechnic materials;
— pyrophoric materials.

Explosions-Unterdrückungssysteme

Dieses Dokument Norm beschreibt die Grundanforderungen für die Konstruktion und Anwendung von Explosions-Unterdrückungssystemen. Dieses Dokument legt außerdem Prüfverfahren zur Beurteilung der Wirksamkeit und Reichweite von Explosions-Unterdrückungssystemen bei bestimmten Explosionen fest. Dieses Dokument behandelt:
— allgemeine Anforderungen an Komponenten für Explosions-Unterdrückungssysteme;
— Bewerten des Leistungsvermögens eines Explosions-Unterdrückungssystems;
— Bewerten der Reichweite eines Explosions-Unterdrückungssystems;
— Entwicklung und Bewertung einer Konstruktionsanleitung für Explosions-Unterdrückungssysteme;
— Einbau-, Betriebs- und Instandhaltungsanweisungen für ein Explosions-Unterdrückungssystem.
Dieses Dokument gilt nur für Explosions-Unterdrückungssysteme, die zum Schutz von geschlossenen oder im Wesentlichen geschlossenen Gehäusen vorgesehen sind, in denen eine Explosion durch die Zündung eines explosionsfähigen Gemisches, z. B. Staub/Luft, Gas(Dampf)/Luft, Staub/Gas(Dampf)/Luft und Ne-bel/Luft, entstehen könnte.
Dieses Dokument ist nicht anwendbar bei Explosionen von nachstehend aufgeführten Stoffen oder Ge-mischen, die diese Stoffe enthalten:
— instabile Stoffe, die möglicherweise zerfallen können;
— Explosivstoffe;
— pyrotechnische Materialien;
— pyrophore Stoffe.

Systèmes de suppression d’explosion

Le présent document décrit les exigences minimales de conception et d’application des systèmes de suppression d’explosion. Il spécifie également des méthodes d’essai pour l’évaluation de l’efficacité et de l’extrapolation des systèmes de suppression d’explosion par rapport { des explosions définies. Le présent document couvre les points suivants :
— les exigences générales concernant les composants des systèmes de suppression d’explosion ;
— l’évaluation de l’efficacité d’un système de suppression d’explosion ;
— l’évaluation de l’extrapolation d’un système de suppression d’explosion ;
— le développement et l’évaluation d’outils de conception pour les systèmes de suppression d’explosion ;
— des instructions relatives à l’installation, au fonctionnement et { la maintenance d’un système de suppression d’explosion.
Le présent document s’applique uniquement aux systèmes de suppression d’explosion destinés { protéger des enveloppes fermées ou en majeure partie fermées, dans lesquelles une explosion peut être la conséquence de l’inflammation de mélanges explosibles de type poussière-air, gaz (vapeur)-air, poussière-gaz (vapeur)-air et brouillard-air, par exemple.
Le présent document ne s’applique pas aux explosions des matières énumérées ci-dessous ni aux mélanges contenant certaines de ces matières :
— matières non stables susceptibles de se dissocier ;
— matières explosives ;
— matières pyrotechniques ;
— matières pyrophoriques.

Sistemi za dušenje eksplozij

Ta dokument opisuje osnovne zahteve za projektiranje in uporabo sistemov za dušenje eksplozij. Ta dokument določa tudi preskusne metode za vrednotenje učinkovitosti in nadgradnje sistemov za dušenje eksplozij v primerih navedenih eksplozij. Ta dokument obravnava:
– splošne zahteve za komponente sistemov za dušenje eksplozij;
– vrednotenje učinkovitosti sistema za dušenje eksplozij;
– vrednotenje nadgradnje sistema za dušenje eksplozij;
– razvoj in vrednotenje orodij za projektiranje sistemov za dušenje eksplozij;
– navodila za namestitev, delovanje in vzdrževanje sistema za dušenje eksplozij.
Ta dokument se uporablja samo za sisteme za dušenje eksplozij, namenjene za zaščito zaprtih oziroma v osnovi zaprtih prostorov, v katerih bi lahko prišlo do eksplozije zaradi vžiga eksplozivne mešanice, npr. prah-zrak, plin (hlapi)-zrak, prah-plin (hlapi)-zrak in meglica-zrak.
Ta dokument se ne uporablja za eksplozije spodaj navedenih snovi ali za mešanice, ki vsebujejo nekatere od teh snovi:
– nestabilne snovi, ki se lahko ločijo;
– eksplozivne snovi;
– pirotehnične snovi;
– piroforne snovi.

General Information

Status
Published
Public Enquiry End Date
21-Apr-2019
Publication Date
24-Jan-2022
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
10-Nov-2021
Due Date
15-Jan-2022
Completion Date
25-Jan-2022

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SLOVENSKI STANDARD
SIST EN 14373:2022
01-marec-2022
Nadomešča:
SIST EN 14373:2006
Sistemi za dušenje eksplozij
Explosion suppression systems
Explosions-Unterdrückungssysteme
Systèmes de suppression d’explosion
Ta slovenski standard je istoveten z: EN 14373:2021
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
SIST EN 14373:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 14373:2022

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SIST EN 14373:2022


EN 14373
EUROPEAN STANDARD

NORME EUROPÉENNE

November 2021
EUROPÄISCHE NORM
ICS 13.230 Supersedes EN 14373:2005
English Version

Explosion suppression systems
Systèmes de suppression d'explosion Explosions-Unterdrückungssysteme
This European Standard was approved by CEN on 27 September 2021.

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, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14373:2021 E
worldwide for CEN national Members.

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SIST EN 14373:2022
EN 14373:2021 (E)
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Symbols and abbreviations (EN 14373) . 8
5 Explosion suppression . 9
5.1 Design . 9
5.2 General function . 10
5.3 Requirements for explosion suppression systems . 11
6 Environmental aspects . 15
6.1 General. 15
6.2 Suppressant . 15
6.3 Actuators and other components . 15
7 Experimental testing of the efficacy of an explosion suppression system . 15
7.1 Information to be submitted prior to testing . 15
7.1.1 General. 15
7.1.2 Intended use . 16
7.1.3 Information on the parts of the suppression system . 16
7.1.4 Calculation model . 17
7.2 Testing . 17
7.2.1 General requirements for test setup . 17
7.2.2 Test program for non metallic dusts . 17
7.2.3 Test program for metal dust . 21
7.2.4 Test program for gas . 21
7.2.5 Test program for hybrid mixtures of non metallic dust and gas . 22
7.2.6 Test program for mist-air mixtures . 22
7.3 Parameters to be measured . 22
7.4 Test report . 23
8 Instructions . 24
8.1 General. 24
8.2 Installation of cables . 24
8.3 Assembling . 25
8.3.1 General. 25
8.3.2 Process information requirements . 25
8.4 Commissioning . 25
8.4.1 General. 25
8.4.2 Instructions for hand-over . 25
8.4.3 Commissioning report . 25
8.5 Safety . 26
8.6 Maintenance . 26
9 Marking and packaging . 26
9.1 General. 26
9.2 Parts of the explosion suppression system . 26
9.3 Explosion suppression system . 28
Annex A (informative) Development of an explosion suppression calculation model . 29
2

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SIST EN 14373:2022
EN 14373:2021 (E)
A.1 General . 29
A.2 Extinction. 29
A.3 Functional tests for model development . 30
A.4 Model validation . 31
Annex B (informative) Applications. 32
B.1 General . 32
B.2 Hazard definition . 32
B.3 Typical process equipment . 33
B.3.1 Spray dryers . 33
B.3.1.1 Introduction . 33
B.3.1.2 Definition of elements . 33
B.3.1.3 Dust concentration . 34
B.3.1.4 Protection concept . 35
B.3.1.5 Isolation . 35
B.3.1.6 Advanced inerting . 35
B.3.1.7 Flame Duration . 35
B.3.1.8 Interlocking . 35
B.3.2 Clean volumes . 35
B.3.3 Elevators . 35
B.3.4 Elongated enclosures . 36
B.3.5 Pipes . 36
B.3.6 Occupied spaces . 36
Annex C (informative) Extrapolation to larger volumes . 38
Annex D (informative) Significant changes between this European Standard and
EN 14373:2005 . 42
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of EU Directive 2014/34/EU aimed to be covered . 44
Bibliography . 46

3

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SIST EN 14373:2022
EN 14373:2021 (E)
European foreword
This document (EN 14373:2021) 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 May 2022, and conflicting national standards shall be
withdrawn at the latest by November 2022.
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 14373:2005.
The significant changes between this document and EN 14373:2005 are given in Annex D.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this
document.
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, Turkey and the United
Kingdom.
4

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SIST EN 14373:2022
EN 14373:2021 (E)
1 Scope
This document describes the basic requirements for the design and application of explosion suppression
systems. This document also specifies test methods for evaluating the effectiveness and the scaling up of
explosion suppression systems against defined explosions. This document covers:
— general requirements for explosion suppression system parts;
— evaluating the effectiveness of an explosion suppression system;
— evaluating the scale up of an explosion suppression system to larger than tested volumes;
— development and evaluation of design tools for explosion suppression systems;
— installation, operation and maintenance instructions for an explosion suppression system.
This document is applicable only to explosion suppression systems intended for the protection of closed,
or essentially closed, enclosures in which an explosion could result as a consequence of ignition of an
explosible mixture, e.g. dust-air, gas(vapour)-air, dust-gas(vapour)-air and mist-air.
This document is not applicable for explosions of materials listed below, or for mixtures containing some
of those materials:
— unstable materials that are liable to dissociate;
— explosive materials;
— pyrotechnic materials;
— pyrophoric materials.
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 13237:2012, Potentially explosive atmospheres - Terms and definitions for equipment and protective
systems intended for use in potentially explosive atmospheres
EN 15233:2007, Methodology for functional safety assessment of protective systems for potentially
explosive atmospheres
EN 15967:2011, Determination of maximum explosion pressure and the maximum rate of pressure rise of
gases and vapours
EN 14034-1:2004+A1:2011, Determination of explosion characteristics of dust clouds - Part 1:
Determination of the maximum explosion pressure pmax of dust clouds
EN 14034-2:2006+A1:2011, Determination of explosion characteristics of dust clouds - Part 2:
Determination of the maximum rate of explosion pressure rise (dp/dt)max of dust clouds
5

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SIST EN 14373:2022
EN 14373:2021 (E)
EN IEC 60079-0:2018, Explosive atmospheres - Part 0: Equipment - General requirements (IEC 60079-
0:2017)
EN 60079-14:2014, Explosive atmospheres - Part 14: Electrical installations design, selection and erection
(IEC 60079-14:2013)
1
EN 60529:1991, Degrees of protection provided by enclosures (IP Code) (IEC 60529:1989)
EN ISO 80079-36:2016, Explosive atmospheres - Part 36: Non-electrical equipment for explosive
atmospheres - Basic method and requirements (ISO 80079-36:2016)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1127-1:2019 and
EN 13237:2012 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
high rate discharge suppressor
HRD-suppressor
vessel with opening mechanism, which upon activation discharges an explosion suppressant at a high
rate
3.2
suppressant
substance contained in the HRD-suppressor which, when dispersed into an enclosure to be protected,
can arrest and mitigate a developing explosion in that enclosure
3.2.1
powder suppressant
powder with recognised flame extinguishing properties such as products based on monoammonium
phosphate, potassium bicarbonate or sodium bicarbonate
3.2.2
liquid suppressant
substance stored as a liquid with recognised flame extinguishing properties such as cold or hot water
3.3
dispersion pressure
p
s
pressure in HRD-suppressor to disperse the suppressant, which is provided by gas, chemical reaction or
the application of heat

1
As impacted by amendments EN 60529:1991/A1:2000 and EN 60529:1991/A2:2013.
6

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SIST EN 14373:2022
EN 14373:2021 (E)
3.4
suppressant charge
M
s
mass of the suppressant contained within the suppressor
3.5
explosion detector
device that responds to an explosion (e.g. developing pressure and/or radiation) and provides a signal to
the control and indicating equipment
Note 1 to entry: See 3.10.
3.6
activation pressure
p
a
pressure at which the control and indicating equipment activates the high rate discharge suppressor(s)
3.7
maximum reduced (suppressed) explosion pressure
p
red,max
maximum explosion overpressure generated by an explosion of an explosive atmosphere in an enclosure
at optimum fuel concentration, after effective explosion venting or explosion suppression
3.8
explosion suppression
technique limiting and/or avoiding the destructive effect of an explosion by the deployment of
suppressant
3.9
explosion suppression system
arrangement comprising one or more explosion detectors, control and indicating equipment and one or
more high rate discharge suppressors aiming at achieving explosion suppression
3.10
control and indicating equipment
CIE
safety device, which is an electronic system which controls, records and monitors the status of the
explosion protection system and initiates the explosion protection devices upon detection
Note 1 to entry: The CIE is intended to activate the explosion protection devices and to initiate alarm systems and
process shutdown.
3.11
dispersion nozzle
device fitted on a HRD-suppressor and designed to distribute the suppressant throughout the enclosure
to be protected
3.12
compact enclosure/cubic enclosure
enclosures having a length (height) to diameter ratio of less than 2
7

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SIST EN 14373:2022
EN 14373:2021 (E)
3.13
elongated enclosures
enclosures with a length (height) to diameter ratio of 2 to 10
3.14
pipe
construction with a length (height) to diameter ratio greater than 10
3.15
hazard sector
three-dimensional space for which the explosion suppression system is designed to be active
3.16
lowest observable adverse effect level
LOAEL
lowest concentration of the suppressant at which an adverse toxicological or physiological effect has been
observed
3.17
suppression model
mathematical calculation which predicts the course of an explosion, the action of the suppression system
and its interaction with the explosion, in order to enable an accurate design of explosion suppression
systems
3.18
maximum throw
maximum distance from a suppressor at which the concentration of the expelled suppressant is still
sufficiently high to extinguish an explosion flame
3.19
arming
enabling the explosion suppression system for fault free operation
3.20
activation
initiation of the high rate discharge suppressor to discharge
3.21
discharge
opening and consequential emptying of the high rate discharge suppressor
3.22
lock out
mechanical device to prevent discharge of the high rate discharge suppressor
4 Symbols and abbreviations (EN 14373)
CIE control and indicating equipment
C heat capacity at constant pressure
p
HRD high rate discharge
IP ingress protection
8

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SIST EN 14373:2022
EN 14373:2021 (E)
K maximum rate of pressure rise to be applied and determined according to
max
EN 14034-2:2006+A1:2011 for a certain dust and dust concentration normalised to a
3
1 m volume or according to EN 15967:2011 for a certain gas or vapour and gas or
3
vapour concentration normalised to a 1 m volume
K minimum rate of pressure rise to be applied and determined according to
min
EN 14034-2:2006+A1:2011 for a certain dust and dust concentration normalised to a
3
1 m volume or according to EN 15967:2011 for a certain gas or vapour and gas or
3
vapour concentration normalised to a 1 m volume
K maximum rate of pressure rise of a dust determined according to
St
3
EN 14034-2:2006+A1:2011 normalised to a 1 m volume
L/D length-to-diameter ratio
LEL lower explosion limit
LOAEL lowest observable adverse effect level
MIE minimum ignition energy
MIT minimum ignition temperature of a dust cloud
MSDS material safety data sheets
M suppressant charge
s
p
activation pressure
a
p maximum explosion overpressure of a dust determined according to
max
EN 14034-2:2006+A1:2011 or gas or vapour determined according to EN 15967:2011
p reduced (suppressed) overpressure
red
p maximum reduced (suppressed) explosion pressure
red,max
p dispersion pressure
s
p pressure transducer
t
S laminar burning velocity
u
TPED Transportable Pressure Equipment Directive
PED Pressure Equipment Directive
V volume
5 Explosion suppression
5.1 Design
Explosion suppression systems shall be designed to extinguish propagating flames and to reduce the
maximum explosion pressure, p to a reduced explosion pressure (p ), following an ignition in the
max, red
protected enclosure. Successful explosion suppression implies that the p will not exceed the strength
red
of the protected equipment. Explosion suppression systems can be applied to flammable gases, mists,
dusts or hybrid mixtures.
See Annex B for examples of applications of explosion suppression systems.
9

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SIST EN 14373:2022
EN 14373:2021 (E)
5.2 General function
Explosion suppression is a protective measure for enclosures, where a gas, mist, dust or hybrid mixture
explosion is detected and arrested during incipient stages (see Figure 1).

Key
1 suppressor
2 explosion detector (D)
a The explosive atmosphere in an enclosure is ignited. The enclosure is provided with one (or more) explosion
detectors (D) and one (or more) suppressors (1).
b The explosion is detected by the explosion detector(s).
c The control and indicating equipment CIE (not shown) has received the signal from the explosion detector(s)
and activated the suppressor(s). The suppressor(s) has (have) started to inject suppressant into the
enclosure.
d The suppressant cloud reaches the explosion flame.
e The flame is extinguished: the explosion is suppressed.
Figure 1 — Stages in explosion suppression of an enclosure
The performance of an explosion suppression system depends on:
— the response time of the system: time until explosion is detected + response time of the various items
+ time required to inject sufficient suppressant into the enclosure;
— the suppressant dispersion: spatial distribution, as a function of time;
— the effectiveness of the suppressant.
Explosion suppression measures shall be designed and installed such that their operational effectiveness
is assured.
The effectiveness of a suppression system is dependent on many factors also related to the application:
— volume and geometry of the component to be protected;
— reactivity of the combustible dust:
• p maximum explosion pressure,
max
• K explosion rate constant,
St
— process conditions: airflow and turbulence;
10

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SIST EN 14373:2022
EN 14373:2021 (E)
— detection pressure threshold value;
— type and efficiency of explosion suppressors;
— number, and geometric distribution of suppressors;
— propellant pressure.
5.3 Requirements for explosion suppression systems
An explosion suppression system consists of at least one: explosion detector, HRD suppressor, complete
with suppressant / dispersion nozzle and connected to control and indicating equipment (CIE).
Essential requirements are:
— the overall requirement of the explosion suppression system is to detect an explosion in the incipient
stage and to have a fast response to allow for the dispersion of suppressant and extinguishment of
the flame in order to limit the maximum reduced explosion pressure below the admissible pressure
of the protected equipment - Experimental validation shall be performed as described in Clause 7;
— the system as installed or any of its parts shall not introduce ignition hazards, such as electrostatic
discharge, mechanical friction, electrical sparks, hot surfaces:
• All electrical and non-electrical equipment and components, as parts of explosion suppression
system, intended for use in potentially explosive atmospheres, shall be designed and constructed
in conformity with the required categories for group II equipment to ensure avoidance of any
ignition sources as detailed in EN 1127-1:2019.
• Any electrical equipment as a part of an explosion suppression system installed and located in
hazardous areas shall conform to the requirements of EN 60079-14:2014 through at least
EN IEC 60079-0:2018 and relevant type(s) of protection.
• Any non-electrical equipment as a part of an explosion suppression system installed and located
in hazardous areas shall conform to the requirements of EN ISO 80079-36:2016 and relevant
type(s) of protection.
— the activation of the suppression system shall not result in dangerous ejected parts;
— the explosion suppression system shall have a defined reliability for safety-functions according to
the intended use (see 5.3 h);
— if discharging the suppressant during maintenance or inspection can result in injury, the explosion
suppression system shall have safe provisions in place to prevent an unintended suppressor
discharge prior to performing such operations;
— the supplier shall provide instructions which ensure safe operation of the explosion suppression
system and the system is always armed when explosible atmospheres are present and is disarmed
and locked out before access to be inside protected equipment is granted (see 8.5);
— the explosion suppression system shall avoid operation of the protected process by provision of a
safe signal interface through the CIE so that operation cannot be started or resumed until the
suppression system is armed and fault free;
— relevant parts of the explosion suppression system directly exposed to the explosion shall be capable
of withstanding the expected maximum explosion pressure.
11

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SIST EN 14373:2022
EN 14373:2021 (E)
NO
...

SLOVENSKI STANDARD
oSIST prEN 14373:2019
01-april-2019
Sistemi za dušenje eksplozij
Explosion suppression systems
Explosions-Unterdrückungssysteme
Systèmes de suppression d’explosion
Ta slovenski standard je istoveten z: prEN 14373
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
oSIST prEN 14373:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 14373:2019

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oSIST prEN 14373:2019


DRAFT
EUROPEAN STANDARD
prEN 14373
NORME EUROPÉENNE

EUROPÄISCHE NORM

January 2019
ICS 13.230 Will supersede EN 14373:2005
English Version

Explosion suppression systems
Systèmes de suppression d'explosion Explosions-Unterdrückungssysteme
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, 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.

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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14373:2019 E
worldwide for CEN national Members.

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Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Explosion suppression . 9
4.1 Objectives . 9
4.2 General function . 9
4.3 Essential requirements . 9
5 Environmental aspects . 12
5.1 General . 12
5.2 Suppressant . 13
5.3 Actuators and other components . 13
6 Experimental testing of the efficacy of an explosion suppression system . 13
6.1 Required information . 13
6.1.1 General . 13
6.1.2 Intended use . 13
6.1.3 Information on the components of the suppression system . 13
6.1.4 Calculation model . 14
6.2 Testing . 14
6.2.1 General requirements for test setup . 14
6.2.2 Test program for non metallic dusts . 15
6.3 Test program for metal dust . 17
6.4 Test program for gas . 17
6.5 Test program for hybrid mixtures . 18
6.6 Measuring techniques . 18
6.7 Test Report . 18
7 Instructions . 20
7.1 General . 20
7.2 User manual . 20
7.3 Installation of cables . 20
7.4 Assembling . 20
7.4.1 General . 20
7.4.2 Assembly . 20
7.5 Commissioning . 21
7.5.1 General . 21
7.5.2 Instructions for hand-over . 21
7.5.3 Commissioning report . 21
7.6 Safety . 21
7.7 Maintenance . 22
8 Marking and packaging . 22
8.1 General . 22
8.2 Explosion suppression system components. 22
8.3 Explosion suppression system . 23
8.4 Omission of markings . 23
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Annex A (informative) Development of an explosion suppression calculation model . 24
Annex B (informative) Applications . 27
Annex C (informative) Extrapolation to larger volumes . 33
Annex D (informative) Significant changes between this European Standard and
EN 14373:2005 . 37
ANNEX ZA (informative) Relationship between this European Standard and the essential
requirements of EU Directive 2014/34/EU aimed to be covered . 39
Bibliography . 41
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European foreword
This document (prEN 14373:2019) 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 14373:2005.
This document has been prepared under a standardization request given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of
EU Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this
document.
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1 Scope
This document describes the basic requirements for the design and application of explosion
suppression systems. This document also specifies test methods for evaluating the effectiveness and the
scale up of explosion suppression systems against defined explosions. This document covers:
— general requirements for explosion suppression system components;
— evaluating the effectiveness of an explosion suppression system;
— evaluating the scale up of an explosion suppression system;
— development and evaluation of design tools for explosion suppression systems;
— installation, operation and maintenance instructions for an explosion suppression system.
This document is applicable only to explosion suppression systems intended for the protection of
closed, or essentially closed, enclosures in which an explosion could result as a consequence of ignition
of an explosible mixture, e.g. dust-air, gas(vapour)-air, dust-gas(vapour)-air and mist-air.
This document is not applicable for explosions of materials listed below, or for mixtures containing
some of those materials:
— unstable materials that are liable to dissociate;
— explosive materials;
— pyrotechnic materials;
— pyrophoric materials.
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.
prEN 1127-1:2018, Explosive atmospheres — Explosion prevention and protection — Part 1: Basic
concepts and methodology
EN 13237:2012, Potentially explosive atmospheres — Terms and definitions for equipment and protective
systems intended for use in potentially explosive atmospheres
EN 15233:2007, Methodology for functional safety assessment of protective systems for potentially
explosive atmospheres
EN 15967:2011, Determination of the maximum explosion pressure and the maximum rate of pressure
rise of gases and vapours
EN 14034-1:2004+A1:2011, Determination of explosion characteristics of dust clouds — Part 1:
Determination of the maximum explosion pressure pmax of dust clouds
EN 14034-2:2006+A1:2011, Determination of explosion characteristics of dust clouds — Part 2:
Determination of the maximum rate of explosion pressure rise (dp/dt)max of dust clouds
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EN 61508-1:2010, Functional safety of electrical/electronic/programmable electronic safety-related
systems — Part 1: General requirements
EN 61508-2:2010, Functional safety of electrical/electronic/programmable electronic safety-related
systems — Part 2: Requirements for electrical/electronic/programmable electronic safety-related systems
EN 61508-3:2010, Functional safety of electrical/electronic/programmable electronic safety-related
systems — Part 3: Software requirements
EN 61508-4:2010, Functional safety of electrical/electronic/programmable electronic safety-related
systems — Part 4: Definitions and abbreviations
EN 61508-5:2010, Functional safety of electrical/electronic/programmable electronic safety-related
systems — Part 5: Examples of methods for the determination of safety integrity levels
EN 61508-6:2010, Functional safety of electrical/electronic/programmable electronic safety-related
systems — Part 6: Guidelines on the application of IEC 61508-2 and IEC 61508-3
EN 61508-7:2010, Functional safety of electrical/electronic/programmable electronic safety-related
systems — Part 7: Overview of techniques and measures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in prEN 1127-1:2018,
EN 13237:2012 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
HRD-suppressor
vessel with opening mechanism, which upon activation discharges an explosion suppressant at a high
rate
Note 1 to entry: HRD is the abbreviation of High Rate Discharge.
3.2
suppressant
substance contained in the HRD-suppressor which, when dispersed into an enclosure to be protected,
can arrest and mitigate a developing explosion in that enclosure
Note 1 to entry: Two categories of suppressants are in general use, separately or in combination:
— powder suppressant;
— liquid suppressant.
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3.2.1
powder suppressant
powder with recognised flame extinguishing properties such as products based on monoammonium
phosphate, potassium bicarbonate or sodium bicarbonate
Note 1 to entry: Such suppressants can contain additives to improve their flow properties and their
effectiveness
3.2.2
liquid suppressant
substance stored as a liquid with recognised flame extinguishing properties such as water and
halogenated alkanes, cold or hot
Note 1 to entry: Additives can be included to provide frost protection, and/or to improve the suppressant
effectiveness.
3.3
dispersion pressure
p
s
pressure in HRD-suppressor to disperse the suppressant, which is provided by gas, chemical reaction or
the application of heat
3.4
suppressant charge
M
s
mass of the suppressant contained within the suppressor
3.5
explosion detector
device that responds to an explosion (e.g. developing pressure and/or radiation) and provides a signal
to the control and indicating equipment
Note 1 to entry: See 3.10.
3.6
activation pressure
p
a
pressure at which the CIE activates the HRD-suppressor(s)
3.7
maximum reduced (suppressed) explosion pressure
p
red,max
maximum explosion overpressure generated by an explosion of an explosive atmosphere in an
enclosure at optimum fuel concentration, after effective explosion venting or explosion suppression
3.8
explosion suppression
technique limiting and/or avoiding the destructive effect of an explosion by the deployment of
suppressant
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3.9
explosion suppression system
arrangement comprising one or more explosion detectors, CIE and one or more HRD-suppressors
aiming at achieving explosion suppression
3.10
control and indicating equipment
CIE
electronic system which controls, records and monitors the status of the explosion protection system
and initiates the explosion protection devices upon detection
Note 1 to entry: On detection of an incipient explosion, the CIE activates the explosion protection devices and
initiates alarm systems and process shutdown.
3.11
dispersion nozzle
device fitted on a HRD-suppressor and designed to distribute the suppressant throughout the enclosure
to be protected
3.12
compact enclosure/cubic enclosure
enclosures having a length (height) to diameter ratio of less than 2
3.13
elongated enclosures
enclosures with a length (height) to diameter ratio of 2 to 10
3.14
pipe
construction with a length (height) to diameter ratio greater than 10
3.15
hazard sector
three-dimensional space for which the explosion suppression system is designed to be active
3.16
LOAEL
lowest concentration of the suppressant at which an adverse toxicological or physiological effect has
been observed
Note 1 to entry: LOAEL is the abbreviation of Lowest Observable Adverse Effect Level.
3.17
suppression model
mathematical calculation which predicts the course of an explosion, the action of the suppression
system and its interaction with the explosion, in order to enable an accurate design of explosion
suppression systems
3.18
maximum throw
maximum distance from a suppressor at which the concentration of the expelled suppressant is still
sufficiently high to extinguish an explosion flame
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4 Explosion suppression
4.1 Objectives
Explosion suppression systems shall be designed to extinguish propagating flames and to reduce the
maximum explosion pressure, P to a reduced explosion pressure (P ), following an ignition in
max, red
the protected enclosure. In general, successful explosion suppression implies that the P will not
red
exceed the strength of the protected equipment. Explosion suppression systems can be applied to
flammable gases, mists, dusts or hybrid mixtures.
4.2 General function
Explosion suppression is a protective measure for enclosures, where a gas, mist, dust or hybrid mixture
explosion is detected and arrested during incipient stages (see Figure 1).

Key
1 supressor
a The explosive atmosphere in an enclosure is ignited. The enclosure is provided with one (or more)
explosion detectors (D) and one (or more) suppressors (1).
b The explosion is detected by the explosion detector(s).
c The control and indicating equipment CIE (not shown) has received the signal from the explosion
detector(s) and activated the suppressor(s). The suppressor(s) have started to inject suppressant into
the enclosure.
d The suppressant cloud reaches the explosion flame.
e The flame is extinguished: the explosion is suppressed.
Figure 1 — Stages in explosion suppression of an enclosure
The performance of an explosion suppression system depends on:
— the response time of the system: time until explosion is detected + response time of the various
components + time required to inject sufficient suppressant into the enclosure;
— the suppressant dispersion: spatial distribution, as a function of time;
— the effectiveness of the suppressant.
4.3 Essential requirements
An explosion suppression system consists of at least one: explosion detector, HRD suppressor, complete
with suppressant / dispersion nozzle and connected to control and indicating equipment (CIE).
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Essential requirements are:
— the overall requirement of the explosion suppression system is to detect an explosion in the
incipient stage and to have a fast response to allow for the dispersion of suppressant and
extinguishment of the flame in order to limit the maximum reduced explosion pressure below the
admissible pressure of the protected equipment - Experimental validation shall be performed as
described in Clause 6;
— the system as installed or any of its components shall not introduce ignition hazards, such as
electrostatic discharge, mechanical friction, electrical sparks, hot surfaces;
— the activation of the suppression system shall not result in dangerous ejected parts;
— the explosion suppression system shall have a defined reliability for safety-functions according to
the intended use (see 4.3 d);
— if discharging the suppressant during maintenance or inspection can result in injury, the explosion
suppression system shall have provisions in place to prevent an unintended suppressor discharge
prior to performing such operations;
— the suppression system shall be configured to prevent unintended arming;
— the supplier shall provide instructions which ensure safe operation of the explosion suppression
system and the system is always activated when explosible atmospheres are present and is
disarmed before access to be inside protected equipment is granted (see 7.6);
— the explosion suppression system shall avoid operation of the protected process by provision of a
safe signal interface through the CIE so that operation cannot be resumed until the suppression
system is armed and fault free.
Other essential requirements are:
a) Explosion Detector
An explosion detector shall detect the onset of the explosion in time to allow for achieving
successful suppression.
b) Control and Indication Equipment (CIE)
The components and software used in the Control and Indication Equipment (CIE) shall ensure
explosion suppression system functionality by undertaking the following:
— process detection signals;
— initiate the suppressors;
— initiate interlocks/alarms;
— enable safe isolation;
— enable an automatic and orderly safe-mode of the protected process upon activation,
fault/trouble condition.
c) Emergency power
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Emergency power shall be specified and facilitated such that full uninterrupted unchanged
explosion protection functionality is ensured at least 4 h after a mains power failure.
d) Explosion Suppressors
Explosion suppressors shall inject sufficient suppressant into the protected enclosure in the
required time. Either monitored mechanical blocking or other monitored provisions to prevent
unintended activation shall be present.
NOTE 1 The performance of suppressors depends upon at least:
— volume, shape and outlet diameter of the suppressor;
— filling ratio and pressure inside the suppressor;
— opening time of the suppressor;
— characteristics of the dispersion nozzle and the suppressant.
e) Dispersion nozzle
The dispersion nozzle shall spread the suppressant into the protected enclosure to achieve both
required throw and spatial distribution / concentration.
NOTE 2 The performance of a dispersion nozzle depends upon at least:
— design of the nozzle;
— characteristics of the suppressor and the suppressant.
Depending on the intended use specific dispersion nozzles can be applied, with special
performances, for example to obtain strong directional effects.
f) Suppressant
The suppressant shall have dispersion characteristics and extinguishing properties allowing for
extinguishing an explosion flame for a given fuel type.
NOTE 3 The properties influencing these characteristics include:
— the particle/droplet size distribution;
— chemical and thermal properties.
Apart from the effectiveness in explosion suppression of the suppressant applied, also the
compatibility of the suppressant with the process shall be considered:
— temperature stability;
— any adverse reaction with the process products;
— toxicity levels of the suppressant.
g) Installation, commissioning, service and maintenance
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Installation instructions, service and maintenance requirements and intervals shall be specified in
the system documentation (see Clause 7).
h) Reliability and functional safety
The functional safety of the suppression system shall be quantified by the manufacturer according
to EN 61508-1:2010, EN 61508-2:2010, EN 61508-3:2010, EN 61508-4:2010, EN 61508-5:2010,
EN 61508-6:2010, EN 61508-7:2010 and EN 15233:2007.
The reliability of the system shall be ensured by monitoring of as a minimum the following:
1) wiring circuits for continuity, earth faults and open circuits;
2) mains power supply;
3) emergency power supply;
4) system safety interlock circuitry;
5) system-disabling interlock circuitry;
6) electrically operated actuating devices;
7) detection devices;
8) health monitoring of HRD Suppressors (e.g. pressure).
In addition one shall assess the functional safety. As a minimum the following aspects shall be
addressed:
a) design faults in the hardware;
b) adverse environmental conditions, including electromagnetic disturbance;
c) design faults in the software.
In case of an identifiable fault such that the safety function of the system cannot be guaranteed to
the agreed level of safety integrity, the suppression system shall provide a fail-safe means to place
the installation into a safe condition.
5 Environmental aspects
5.1 General
Dispositions shall be taken to limit the impact of the explosion suppression devices on the environment.
Materials shall be selected to optimize product durability and lifetime and consideration shall be made
to avoiding the selection of rare or hazardous materials. Consideration shall be made to using recycled
or reused materials, and to the selection of materials which can then be subsequently recycled.
Packaging design shall consider using recycled materials, and materials that need little energy for their
manufacture, and shall minimize waste.
It shall be taken into account that each combustion process can generate toxic decomposition products.
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After activation of a suppression system the installation shall be cleaned up properly with duly
precautions regarding toxicity of the suppressant. Also the combustible material may have been
affected by the suppressant and by the combustion and may exhibit toxic properties. Waste and
cleaning materials shall be disposed according to the manufacturer instructions and to the enforced law
in respect of environmental protection to limit any risk of water and soil pollution.
5.2 Suppressant
During explosion suppression a large quantity of the suppressant is released into the process. The
manufacturer’s instructions shall address the following items:
— food compatibility;
— toxicity of the suppressant;
— corrosion of equipment.
Depending on the application, non-toxic, non-corrosive and food compatible suppressants should be
preferred.
5.3 Actuators and other components
Other components including actuators (after activation) can affect the environment and shall be
handled accordingly.
6 Experimental testing of the efficacy of an explosion suppression system
6.1 Required information
6.1.1 General
Before testing the manufacturer shall describe the intended use and shall provide detailed information
on the suppression system.
As a minimum, the following information shall be provided prior to testing.
6.1.2 Intended use
The manufacturer shall provide limits of applications. The minimum requirements are listed below:
a) explosive atmosphere type including fuel type (K , p ,
...

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