ISO 14520-1:2015

INTERNATIONAL ISO
STANDARD 14520-1
Third edition
2015-12-01
Corrected version
2016-04-01
Gaseous fire-extinguishing systems —
Physical properties and system
design —
Part 1:
General requirements
Systèmes d’extinction d’incendie utilisant des agents gazeux —
Propriétés physiques et conception des systèmes —
Partie 1: Exigences générales
Reference number
ISO 14520-1:2015(E)
©
ISO 2015

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ISO 14520-1:2015(E)

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ISO 14520-1:2015(E)

Contents Page
Foreword .vi
Introduction .viii
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Use and limitations . 6
4.1 General . 6
4.2 Extinguishants . 6
4.2.1 Environmental properties . 7
4.3 Electrostatic discharge . 7
4.4 Compatibility with other extinguishants . 7
4.5 Temperature limitations . 7
5 Safety . 7
5.1 Hazard to personnel . 7
5.2 Safety precautions . 8
5.2.1 General. 8
5.2.2 For normally occupied areas . 8
5.2.3 For normally unoccupied areas.10
5.2.4 For unoccupiable areas .10
5.3 Occupiable areas .10
5.4 Electrical hazards .11
5.5 Electrical earthing .11
5.6 Electrostatic discharge .11
6 System design .12
6.1 General .12
6.2 Extinguishant supply .12
6.2.1 Quantity .12
6.2.2 Quality .12
6.2.3 Container arrangement .12
6.2.4 Storage containers .12
6.3 Distribution .13
6.3.1 General.13
6.3.2 Piping .14
6.3.3 Fittings .14
6.3.4 Pipe and valve supports .15
6.3.5 Valves .16
6.3.6 Nozzles .16
6.3.7 Pressure reducing orifice assembly.17
6.4 Detection, actuation and control systems.17
6.4.1 General.17
6.4.2 Automatic detection .17
6.4.3 Operating devices .17
6.4.4 Control equipment .18
6.4.5 Operating alarms and indicators .18
6.4.6 Hold switches.18
7 Extinguishant system design .18
7.1 General .18
7.2 Specifications, plans and approvals .19
7.2.1 Specifications .19
7.2.2 Working documents .19
7.3 System flow calculations .19
7.3.1 General.19
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ISO 14520-1:2015(E)

7.3.2 Balanced and unbalanced system .19
7.3.3 Friction losses.21
7.3.4 Pressure drop .21
7.3.5 Valves and fittings .21
7.3.6 Piping length .22
7.3.7 Drawings .22
7.3.8 Liquefied gases — Specific requirements .22
7.4 Enclosures .22
7.5 Extinguishant concentration requirements .22
7.5.1 Flame extinguishment . .22
7.5.2 Inerting .24
7.6 Total flooding quantity .24
7.6.1 General.24
7.6.2 Liquefied gases .24
7.6.3 Non-liquefied gas . .24
7.7 Altitude adjustment .25
7.8 Duration of protection .25
7.9 System performance .26
7.9.1 Discharge time .26
7.9.2 Extended discharge .26
8 Commissioning and acceptance .26
8.1 General .26
8.2 Tests .26
8.2.1 General.26
8.2.2 Enclosure check .27
8.2.3 Review of mechanical components .27
8.2.4 Review of enclosure integrity .28
8.2.5 Review of electrical components .28
8.2.6 Preliminary functional tests . .29
8.2.7 System functional operational test.29
8.2.8 Remote monitoring operations (if applicable) .30
8.2.9 Control panel primary power source .30
8.2.10 Completion of functional tests .30
8.3 Completion certificate and documentation.30
9 Inspection, maintenance, testing and training.30
9.1 General .30
9.2 Inspection .31
9.2.1 General.31
9.2.2 Container .31
9.2.3 Hose .31
9.2.4 Enclosures .31
9.3 Maintenance .32
9.3.1 General.32
9.3.2 User’s programme of inspection .32
9.3.3 Service schedule .32
9.4 Training .32
Annex A (normative) Working documents .33
Annex B (normative) Determination of flame-extinguishing concentration of gaseous
extinguishants by the cup burner method .35
Annex C (normative) Fire extinguishment/area coverage fire test procedure for engineered
and pre-engineered extinguishing units .41
Annex D (normative) Method of evaluating inerting concentration of a fire extinguishant .70
Annex E (normative) Door fan test for determining of minimum hold time .72
Annex F (informative) System performance verification .88
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ISO 14520-1:2015(E)

Annex G (informative) Safe personnel exposure guidelines .89
Annex H (informative) Flow calculation implementation method and flow calculation
verification and testing for approvals .96
Bibliography .100
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ISO 14520-1:2015(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 21, Equipment for fire protection and fire fighting,
Subcommittee SC 8, Gaseous media and firefighting systems using gas.
This third edition cancels and replaces the second edition (ISO 14520-1:2006), which has been
technically revised. It also incorporates ISO 14520-1:2006/Cor 1:2007 and ISO/TS 20885:2003.
This corrected version of ISO 14520-1:2015 incorporates the following corrections.
Foreword: the details of documents that ISO 14520-1:2015 cancels and replaces have been amended.
7.6.3: the numerator within brackets in Formula 4 has been corrected (from C to 100).
C.4.1: the numerator within brackets in Formula C.2 has been corrected (from C to 100).
The most important changes in the third edition are as follows.
Methods are given to calculate the effects of atmospheric pressure on the inert gases.
The discharge time for inert gas agents has been increased from a maximum of 60 seconds to a
maximum of 120 seconds for the protection of Class A hazards.
The height at which agent concentrations are to be held following a discharge, and during the hold time,
has been revised to reflect the height of the protected hazard replacing the previous requirement of
10%, 50% and 90% of the enclosure height.
Annexes B, C and E have been modified to reflect experience gained in the areas covered by these
Annexes, since the last edition.
Annex H has been amended to reflect the content of what was previously ISO/TS 13075.
Certain environmental data has been added in the specific agents parts of ISO 14520 and an explanation
and advice on where additional information can be found has been added as Clause 4.2.1.
ISO 14520 consists of the following parts, under the general title Gaseous fire-extinguishing systems —
Physical properties and system design
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ISO 14520-1:2015(E)

— Part 1: General requirements
— Part 2: CF3I extinguishant
— Part 5: FK-5-1-12 extinguishant
— Part 6: HCFC Blend A extinguishant
— Part 8: HFC 125 extinguishant
— Part 9: HFC 227ea extinguishant
— Part 10: HFC 23 extinguishant
— Part 11: HFC 236fa extinguishant
— Part 12: IG-01 extinguishant
— Part 13: IG-100 extinguishant
— Part 14: IG-55 extinguishant
— Part 15: IG-541 extinguishant
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ISO 14520-1:2015(E)

Introduction
Fire fighting systems covered in this part of ISO 14520 are designed to provide a supply of gaseous
extinguishing medium for the extinction of fire.
Several different methods of supplying extinguishant to, and applying it at, the required point of
discharge for fire extinction have been developed in recent years, and there is a need for dissemination
of information on established systems and methods. This part of ISO 14520 has been prepared to meet
this need.
The requirements of this part of ISO 14520 are made in the light of the best technical data known to
the working group at the time of writing but, since a wide field is covered, it has been impracticable
to consider every possible factor or circumstance that might affect implementation of the
recommendations.
It has been assumed in the preparation of this part of ISO 14520 that the execution of its provisions is
entrusted to people appropriately qualified and experienced in the specification, design, installation,
testing, approval, inspection, operation and maintenance of systems and equipment, for whose guidance
it has been prepared, and who can be expected to exercise a duty of care to avoid unnecessary release
of extinguishant.
Attention is drawn to the Montreal Protocol on substances that deplete the ozone layer.
It is important that the fire protection of a building or plant be considered as a whole. Gaseous
extinguishant systems form only a part, though an important part, of the available facilities, but it
should not be assumed that their adoption necessarily removes the need to consider supplementary
measures, such as the provision of portable fire extinguishers or other mobile appliances for first aid or
emergency use, or to deal with special hazards.
Gaseous extinguishants have for many years been a recognized effective medium for the extinction
of inflammable liquid fires and fires in the presence of electrical and ordinary Class A hazards, but
it should not be forgotten, in the planning of comprehensive schemes, that there may be hazards for
which these media are not suitable, or that in certain circumstances or situations there may be dangers
in their use requiring special precautions.
Advice on these matters can be obtained from the appropriate manufacturer of the extinguishant or
the extinguishing system. Information may also be sought from the appropriate fire authority, the
health and safety authorities and insurers. In addition, reference should be made as necessary to other
national standards and statutory regulations of the particular country.
It is essential that fire-fighting equipment be carefully maintained to ensure instant readiness when
required. Routine maintenance is liable to be overlooked or given insufficient attention by the owner of
the system. It is, however, neglected at peril to the lives of occupants of the premises and at the risk of
crippling financial loss. The importance of maintenance cannot be too highly emphasized. Installation
and maintenance should only be done by qualified personnel.
Inspection preferably by a third party, should include an evaluation that the extinguishing system
continues to provide adequate protection for the risk (protected zones, as well as state of the art can
change over time).
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INTERNATIONAL STANDARD ISO 14520-1:2015(E)
Gaseous fire-extinguishing systems — Physical properties
and system design —
Part 1:
General requirements
1 Scope
This part of ISO 14520 specifies requirements and gives recommendations for the design, installation,
testing, maintenance and safety of gaseous fire fighting systems in buildings, plants or other structures,
and the characteristics of the various extinguishants and types of fire for which they are a suitable
extinguishing medium.
It covers total flooding
...