ISO 14520-10:2019

ISO TC 21/SC 8
Date: 2019-10-0107
ISO/PRF 14520-10:2019(E)
ISO TC 21/SC 8
Secretariat: SA
Gaseous fire-extinguishing systems — Physical properties and systems design —
Part 10: HFC 23 extinguishant
Systèmes d'extinction d'incendie utilisant des agents gazeux -- Propriétés physiques et
conception des systèmes -- Partie 10: Agent extincteur HFC 23
Document type:  International Standard
Document subtype:
Document stage:  (30) Committee
Document language:  E
O:\Documents\TC021\SC008\055346 - ISO_NP 14520-10 (Ed
3)\60.00\320\C055346e_converted.doc STD Version 2.1c

Foreword
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This document was prepared by Technical Committee ISO/TC 21, Equipment for fire protection and fire
fighting, Subcommittee SC 8, Gaseous media and firefighting systems using gas.
This fourth edition cancels and replaces the third edition (ISO 14520-10:2016), which has been
technically revised. The main changes compared to the previous edition are as follows
— a new subclause 6.4 on fill density and superpressurization levels has been added.
A list of all parts in the ISO 14520 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
ii © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 14520-10:2019(E)

Gaseous fire-extinguishing systems — Physical properties and
systems design — Part 10: HFC 23 extinguishant
1 Scope
This document contains specific requirements for gaseous fire-extinguishing systems, with respect to
the HFC 23 extinguishant. It includes details of physical properties, specifications, usage and safety
aspects. It is applicable to systems operating at a nominal pressure of 41 bar without nitrogen
superpressurization and 70 bar superpressurized with nitrogen.
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.
ISO 14520-1:2015, Gaseous fire-extinguishing systems — Physical properties and system design — Part 1:
General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14520-1 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
4 Characteristics and uses
4.1 General
Extinguishant HFC 23 shall comply with the specification shown in Table 1.
HFC 23 is a colourless, almost odourless, electrically non-conductive gas with a density approximately
2,4 times that of air.
The physical properties are shown in Table 2.
HFC 23 extinguishes fires mainly by physical means, also by some chemical means.
Table 1 — Specification for HFC 23
Property Requirement
Purity 99,6 % (mol/mol), min.
–6
Acidity 3 × 10 by mass, max.
–6
Water content 10 × 10 by mass, max.
Non-volatile residue 0,01 % by mass, max.
Suspended matter or sediment None visible
Table 2 — Physical properties of HFC 23
Property Units Value
Molecular mass — 70
Boiling point at 1,013 bar (absolute) °C –82,0
Freezing point °C –155,2
Critical temperature °C 25,9
Critical pressure bar abs 48,36
Critical volume cm /mol 133
Critical density kg/m 525
Vapour pressure 20 °C bar abs 41,80
Liquid density 20 °C kg/m 806,6
Saturated vapour density 20 °C kg/m 263,0
Specific volume of superheated m /kg 0,340 9
vapour at 1,013 bar and 20 °C
Chemical formula CHF3
Trifluoromethane
Chemical name
4.2 Use of HFC 23 systems
HFC 23 total flooding systems may be used for extinguishing fires of all classes within the limits
specified in ISO 14520-1:2015, Clause 4.
The extinguishant requirements per volume of protected space are shown in Table 3 for various levels
of concentration. These are based on methods shown in ISO 14520-1:2015, 7.6.
The extinguishing concentrations and design concentrations for n-heptane and surface class A hazards
are shown in Table 4. Concentrations for acetone heptane, methanol and toluene are shown in Table 5,
and inerting concentrations are shown in Table 6.
Table 3 — HFC 23 total flooding quantity
Temperature Specific HFC 23 mass requirements per unit volume of protected space, m/V (kg/m )
vapour
T
volume
Design concentration (by volume)
°C
S
m /kg 10 % 12 % 14 % 15 % 16 % 17 % 18 % 20 % 22 % 24 %
–60 0,242 8 0,457 6 0,561 6 0,670 5 0,726 8 0,784 5 0,843 6 0,904 1 1,029 7 1,161 7 1,300 6
–55 0,249 2 0,445 9 0,547 2 0,653 3 0,708 1 0,764 4 0,821 9 0,880 9 1,003 2 1,131 8 1,267 2
–50 0,255 5 0,434 9 0,533 7 0,637 1 0,690 7 0,745 5 0,801 6 0,859 1 0,978 5 1,103 9 1,236 0
–45 0,261 7 0,424 6 0,521 1 0,622 1 0,674 3 0,727 8 0,782 6 0,838 8 0,955 3 1,077 8 1,206 7
–40 0,268 0 0,414 6 0,508 8 0,607 4 0,658 5 0,710 7 0,764 3 0,819 1 0,932 8 1,052 4 1,178 3
–35 0,274 2 0,405 2 0,497 3 0,593 7 0,643 6 0,694 7 0,747 0 0,800 6 0,911 7 1,028 6 1,151 7
–30 0,280 3 0,396 4 0,486 5 0,580 8 0,629 6 0,679 5 0,730 7 0,783 1 0,891 9 1,006 2 1,126 6
–25 0,286 5 0,387 8 0,476 0 0,568 2 0,616 0 0,664 8 0,714 9 0,766 2 0,872 6 0,984 5 1,102 2
2 © ISO 2019 – All rights reserved

ISO/PRF 14520-10:2019(E)
–20 0,292 6 0,379 7 0,466 0 0,556 4 0,603 1 0,651 0 0,700 0 0,750 2 0,854 4 0,963 9 1,079 3
–15 0,298 7 0,372 0 0,456 5 0,545 0 0,590 8 0,637 7 0,685 7 0,734 9 0,837 0 0,944 3 1,057 2
–10 0,304 7 0,364 7 0,447 5 0,534 3 0,579 2 0,625 1 0,672 2 0,720 4 0,820 5 0,925 7 1,036 4
–5 0,310 8 0,357 5 0,438 8 0,523 8 0,567 8 0,612 9 0,659 0 0,706 3 0,804 4 0,907 5 1,016 1
0 0,316 8 0,350 7 0,430 4 0,513 9 0,557 0 0,601 3 0,646 5 0,692 9 0,789 1 0,890 3 0,996 8
5 0,322 9 0,344 1 0,422 3 0,504 2 0,546 5 0,589 9 0,634 3 0,679 8 0,774 2 0,873 5 0,978 0
10 0,328 9 0,337 8 0,414 6 0,495 0 0,536 5 0,579 1 0,622 7 0,667 4 0,760 1 0,857 6 0,960 1
15 0,334 9 0,331 8 0,407 2 0,486 1 0,526 9 0,568 8 0,611 6 0,655 5 0,746 5 0,842 2 0,942 9
20 0,340 9 0,325 9 0,400 0 0,477 5 0,517 7 0,558 7 0,600 8 0,643 9 0,733 4 0,827 4 0,926 3
25 0,346 8 0,320 4 0,393 2 0,469 4 0,508 9 0,549 2 0,590 6 0,633 0 0,720 9 0,813 3 0,910 6
30 0,352 8 0,314 9 0,386 5 0,461 4 0,500 2 0,539 9 0,580 6 0,622 2 0,708 6 0,799 5 0,895 1
35 0,358 8 0,309 7 0,380 1 0,453 7 0,491 8 0,530 9 0,570 8 0,611 8 0,696 8 0,786 1 0,880 1
40 0,364 7 0,304 7 0,373 9 0,446 4 0,483 9 0,522 3 0,561 6 0,601 9 0,685 5 0,773 4 0,865 9
45 0,370 7 0,299 7 0,367 9 0,439 1 0,476 0 0,513 8 0,552 5 0,592 2 0,674 4 0,760 9 0,851 9
50 0,376 6 0,295 0 0,362 1 0,432 3 0,468 6 0,505 8 0,543 9 0,582 9 0,663 8 0,748 9 0,838 5
55 0,382 6 0,290 4 0,356 4 0,425 5 0,461 2 0,497 8 0,535 3 0,573 7 0,653 4 0,737 2 0,825 4
60 0,388 5 0,286 0 0,351 0 0,419 0 0,454 2 0,490 3 0,527 2 0,565 0 0,643 5 0,726 0 0,812 8
65 0,394 4 0,281 7 0,345 7 0,412 8 0,447 4 0,483 0 0,519 3 0,556 6 0,633 9 0,715 1 0,800 7
70 0,400 4 0,277 5 0,340 6 0,406 6 0,440 7 0,475 7 0,511 5 0,548 2 0,624 4 0,704 4 0,788 7
NOTE  This information refers only to HFC-23 and does not represent any other products containing trifluoromethane as a
component.
Symbols:
m/V is the agent mass requirements (kg/m ), i.e. mass, m, in kilograms of agent required per cubic metre of protected volume, V, to
produce the indicated concentration at the temperature specified;
V is the net volume of hazard (m ), i.e. the enclosed volume minus the fixed structures impervious to extinguishant
cV
m=

100−cS

T is the temperature (°C), i.e. the design temperature in the hazard area;
S is the specific volume (m /kg), the specific volume of superhe
...