EN ISO 21805:2023

Guidance and recommendations on design, selection and installation of vents to safeguard the structural integrity of enclosures protected by gaseous fire-extinguishing systems (ISO 21805:2023)

This document gives guidelines for fulfilling the requirements contained in ISO 6183:2022, 6.4.1 and 7.4.1 and ISO 14520‑1:2023, 5.2.1 h) and 5.3 h), in respect to over- and under-pressurization venting and post-discharge extract.
It considers the design, selection and installation of vents to safeguard the structural integrity of enclosures protected by fixed gaseous extinguishing systems and the post-discharge venting provisions where used.

Anleitung für die Konstruktion, Auswahl und Installation von Druckentlastungsöffnungen zur Sicherstellung der strukturellen Integrität von Gehäusen, die durch ortsfeste Gaslöschanlagen geschützt sind (ISO 21805:2023)

Dieses Dokument enthält Anleitungen für die Erfüllung der Anforderungen von ISO 6183:2022N1, 6.4.1 und 7.4.1, sowie von ISO 14520 1:2023N2, 5.2.1 h) und 5.3 h), in Bezug auf Über  und Unterdruckentlastungsvorrichtungen und die Nachentlüftung.
Es behandelt die Konstruktion, Auswahl und Installation von Entlüftungsvorrichtungen, mit dem Ziel, die strukturelle Integrität von Räumen sicherzustellen, die durch ortsfeste Gaslöschanlagen geschützt werden, und betrachtet die Anforderungen an die Nachentlüftung, sofern verwendet.

Lignes directrices et recommandations relatives à la conception, à la sélection et à l'installation d'évents pour préserver l'intégrité structurelle des enceintes protégées par des systèmes d'extinction d'incendie à gaz (ISO 21805:2023)

Le présent document donne des lignes directrices relatives à la manière de satisfaire aux exigences contenues dans l’ISO 6183:2022, 6.4.1 et 7.4.1 et dans l’ISO 14520‑1:2023, 5.2.1 h) et 5.3 h), en ce qui concerne les évents en cas de surpression et de dépression et l’extraction post-émission.
Il couvre la conception, la sélection et l’installation d’évents permettant de préserver l’intégrité structurelle des enceintes protégées par des systèmes fixes d’extinction d’incendie à gaz et les dispositions de ventilation post-émission lorsqu’ils sont utilisés.

Navodilo in priporočila za projektiranje, izbiro in vgradnjo prezračevalnih naprav za zagotavljanje strukturne integritete namestitvenih prostorov, zaščitenih s sistemi za gašenje s plinom (ISO 21805:2023)

Ta dokument vsebuje smernice za izpolnjevanje zahtev iz standarda ISO 6183:2022, točki 6.4.1 in 7.4.1, in standarda ISO 14520‑1:2023, točki 5.2.1 h) in 5.3 h), glede prezračevanja s podtlakom in nadtlakom ter odzračevanja.
Upošteva projektiranje, izbiro in vgradnjo prezračevalnih naprav za zagotavljanje strukturne integritete namestitvenih prostorov, zaščitenih s fiksnimi sistemi za gašenje s plinom, in določbe za naknadno odzračevanje.

General Information

• Status: Published
• Publication Date: 28-Feb-2023
• ICS: 13.220.10 - Fire-fighting
• ICS: 91.140.30 - Ventilation and air-conditioning systems
• Technical Committee: CEN/TC 191 - Fixed firefighting systems
• Drafting Committee: CEN/TC 191/WG 6 - Gas extinguishing Systems and components
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 01-Mar-2023
• Completion Date: 01-Mar-2023
• Ref Project: SIST EN ISO 21805:2023 - Guidance and recommendations on design, selection and installation of vents to safeguard the structural integrity of enclosures protected by gaseous fire-extinguishing systems (ISO 21805:2023)

Relations

• Replaces: CEN ISO/TS 21805:2019 - Guidance on design, selection and installation of vents to safeguard the structural integrity of enclosures protected by gaseous fire-extinguishing systems (ISO/TS 21805:2018)
• Effective Date: 18-Sep-2019

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2023
Nadomešča:
SIST-TS CEN ISO/TS 21805:2019
Navodilo in priporočila za projektiranje, izbiro in vgradnjo prezračevalnih naprav
za zagotavljanje strukturne integritete namestitvenih prostorov, zaščitenih s
sistemi za gašenje s plinom (ISO 21805:2023)
Guidance and recommendations on design, selection and installation of vents to
safeguard the structural integrity of enclosures protected by gaseous fire-extinguishing
systems (ISO 21805:2023)
Anleitung für die Konstruktion, Auswahl und Installation von Entlüftungen zur
Gewährleistung der strukturellen Integrität von Gehäusen, die durch ortsfeste
Gaslöschanlagen geschützt sind (ISO 21805:2023)
Lignes directrices et recommandations relatives à la conception, à la sélection et à
l'installation d'évents pour préserver l'intégrité structurelle des enceintes protégées par
des systèmes d'extinction d'incendie à gaz (ISO 21805:2023)
Ta slovenski standard je istoveten z: EN ISO 21805:2023
ICS:
13.220.10 Gašenje požara Fire-fighting
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21805
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2023
EUROPÄISCHE NORM
ICS 13.220.10; 91.140.30 Supersedes CEN ISO/TS 21805:2019
English Version
Guidance and recommendations on design, selection and
installation of vents to safeguard the structural integrity of
enclosures protected by gaseous fire-extinguishing
systems (ISO 21805:2023)
Lignes directrices et recommandations relatives à la Anleitung für die Konstruktion, Auswahl und
conception, à la sélection et à l'installation d'évents Installation von Entlüftungen zur Gewährleistung der
pour préserver l'intégrité structurelle des enceintes strukturellen Integrität von Gehäusen, die durch
protégées par des systèmes d'extinction d'incendie à ortsfeste Gaslöschanlagen geschützt sind (ISO
gaz (ISO 21805:2023) 21805:2023)
This European Standard was approved by CEN on 7 August 2022.

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 NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21805:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 21805:2023) has been prepared by Technical Committee ISO/TC 21
"Equipment for fire protection and fire fighting" in collaboration with Technical Committee CEN/TC
191 “Fixed firefighting systems” the secretariat of which is held by BSI.
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 September 2023, and conflicting national standards
shall be withdrawn at the latest by September 2023.
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 CEN ISO/TS 21805:2019.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations 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.
Endorsement notice
The text of ISO 21805:2023 has been approved by CEN as EN ISO 21805:2023 without any modification.

INTERNATIONAL ISO
STANDARD 21805
First edition
2023-02
Guidance and recommendations on
design, selection and installation
of vents to safeguard the structural
integrity of enclosures protected by
gaseous fire-extinguishing systems
Lignes directrices et recommandations relatives à la conception,
à la sélection et à l'installation d'évents pour préserver l'intégrité
structurelle des enceintes protégées par des systèmes d'extinction
d'incendie à gaz
Reference number
ISO 21805:2023(E)
ISO 21805:2023(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 21805:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms.2
5 Use and limitations . 3
6 Safety . 4
6.1 Structural safety . 4
6.2 Personnel safety . 4
7 System design — Pressure-relief venting . 4
7.1 General . 4
7.2 Extinguishant characteristics . . 5
7.2.1 Positive and negative pressurization . 5
7.2.2 Pressure graphs . 5
7.3 Enclosure characteristics . 6
7.4 Pressure-relief vent paths . 6
7.5 Types of pressure-relief vents . 7
7.5.1 General . 7
7.5.2 Gravity vents . 7
7.5.3 Counterweighted flap vent . 7
7.5.4 Electrically-operated vents . 8
7.5.5 Pneumatically-operated vent . 8
7.5.6 Vent accessories . 8
7.6 Pressure-relief vent characteristics . 9
7.6.1 Vent efficiency. 9
7.6.2 Minimum opening pressure . 10
7.6.3 Minimum closing pressure . 10
7.6.4 Fire rating . 10
7.7 Vent location and mounting . 10
7.7.1 Vent location . 10
7.7.2 Vent mounting. 11
7.8 Pressure-relief vent area calculations .12
7.8.1 Use of agent-specific formulae .12
7.8.2 Vent area requirement (non-liquefiable gases) .13
7.8.3 Vent area requirement carbon dioxide . 16
7.8.4 Vent area requirements (liquefiable gases) . 16
7.8.5 Leakage . 22
7.9 Cascade venting calculations . 22
7.9.1 Example calculation 3: Cascade venting calculations for IG-541 (peak
discharge) . 23
7.9.2 Cascade vent arrangements .
...