kSIST FprEN ISO 24664:2024
(Main)Refrigerating systems and heat pumps - Pressure relief devices and their associated piping - Methods for calculation (ISO/FDIS 24664:2024)
Refrigerating systems and heat pumps - Pressure relief devices and their associated piping - Methods for calculation (ISO/FDIS 24664:2024)
1.1 This Standard describes the calculation of mass flow for sizing pressure relief devices for components of refrigerating systems.
NOTE The term "refrigerating system" used in this Standard includes heat pumps.
1.2 This Standard describes the calculation of discharge capacities for pressure relief valves and other pressure relief devices in refrigerating systems including the necessary data for sizing these when relieving to atmosphere or to components within the system at lower pressure.
1.3 This Standard specifies the requirements for selection of pressure relief devices to prevent excessive pressure due to internal and external heat sources, the sources of increasing pressure (e.g. compressor, heaters, etc.) and thermal expansion of trapped liquid.
1.4 This Standard describes the calculation of the pressure loss in the upstream and downstream line of pressure relief valves and other pressure relief devices and includes the necessary data.
1.5 This Standard refers to other relevant standards in Clause 5.
Kälteanlagen und Wärmepumpen - Druckentlastungseinrichtungen und zugehörige Leitungen - Berechnungsverfahren (ISO/FDIS 24664:2024)
1.1 Diese Internationale Norm beschreibt die Berechnung der Massenströme zur Größenbestimmung von Druckentlastungseinrichtungen für Teile von Kälteanlagen.
ANMERKUNG Der in dieser Europäischen Norm verwendete Begriff "Kälteanlage" schließt Wärmepumpen mit ein.
1.2 Diese Internationale Norm beschreibt die Berechnung der Abblaseleistungen von Druckentlastungsventilen und anderen Druckentlastungseinrichtungen in Kälteanlagen einschließlich der hierzu erforderlichen Daten zur Größenbestimmung dieser Einrichtungen, wenn sie ins Freie oder in einen Teil der Kälteanlage mit niedrigerem Druck abblasen.
1.3 Diese Internationale Norm legt die Anforderungen an die Auswahl von Druckentlastungseinrichtungen zur Vermeidung von unzulässigen Drücken, hervorgerufen durch innere und äußere Wärmequellen, Druckerzeuger (z. B. Verdichter, Erhitzer usw.) und die Wärmeausdehnung eingesperrter Flüssigkeit fest.
1.4 Diese Internationale Norm beschreibt die Berechnung des Druckabfalls in den zu und abführenden Leitungen von Druckentlastungsventilen und anderen Druckentlastungseinrichtungen einschließlich der erforderlichen Daten.
Systèmes frigorifiques et pompes à chaleur - Dispositifs de limitation de pression et tuyauteries associées - Méthodes de calcul (ISO/FDIS 24664:2024)
Hladilni sistemi in toplotne črpalke - Tlačne varnostne naprave in njihove napeljave - Metode za izračun (ISO/FDIS 24664:2024)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 24664:2021
01-junij-2021
Hladilni sistemi in toplotne črpalke - Tlačne varnostne naprave in njihove
napeljave - Metode za izračun (ISO/DIS 24664:2021)
Refrigerating systems and heat pumps - Pressure relief devices and their associated
piping - Methods for calculation (ISO/DIS 24664:2021)
Kälteanlagen und Wärmepumpen - Druckentlastungseinrichtungen und zugehörige
Leitungen - Berechnungsverfahren (ISO/DIS 24664:2021)
Systèmes frigorifiques et pompes à chaleur - Dispositifs de limitation de pression et
tuyauteries associées - Méthodes de calcul (ISO/DIS 24664:2021)
Ta slovenski standard je istoveten z: prEN ISO 24664
ICS:
27.080 Toplotne črpalke Heat pumps
27.200 Hladilna tehnologija Refrigerating technology
oSIST prEN ISO 24664:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN ISO 24664:2021
oSIST prEN ISO 24664:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 24664
ISO/TC 86/SC 1 Secretariat: ANSI
Voting begins on: Voting terminates on:
2021-03-25 2021-06-17
Refrigerating systems and heat pumps — Pressure
relief devices and their associated piping — Methods for
calculation
Systèmes de réfrigeration et pompes à chaleur — Dispositifs de surpression et tuyauteries associèes —
Méthodes de calcul
ICS: 27.200; 27.080
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 24664:2021(E)
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. ISO 2021
oSIST prEN ISO 24664:2021
ISO/DIS 24664:2021 (E)
ISO/DIS 24664:2021(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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html.
This document was prepared by the European Committee for Standardization (CEN) Technical
Committee CEN/TC 182, Refrigerating systems, safety and environmental requirements, in collaboration
with ISO Technical Committee ISO/TC 86, Refrigeration and air-conditioning, Subcommittee SC 1, Safety
and environmental requirements for refrigerating systems, in accordance with the Agreement on
technical cooperation between ISO and CEN (Vienna Agreement). 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.
This first edition cancels and replaces EN 13136:2013+A1:2018, which has been technically revised.
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii © ISO 2021 – All rights reserved
oSIST prEN ISO 24664:2021
ISO/DIS 24664:2021 (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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html.
This document was prepared by the European Committee for Standardization (CEN) Technical
Committee CEN/TC 182, Refrigerating systems, safety and environmental requirements, in collaboration
with ISO Technical Committee ISO/TC 86, Refrigeration and air-conditioning, Subcommittee SC 1, Safety
and environmental requirements for refrigerating systems, in accordance with the Agreement on
technical cooperation between ISO and CEN (Vienna Agreement). 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.
This first edition cancels and replaces EN 13136:2013+A1:2018, which has been technically revised.
oSIST prEN ISO 24664:2021
ISO/DIS 24664:2021 (E)
Introduction
This International Standard is based on applicable parts of ISO 4126-1:2013, ISO 4126-2:2018 and
ISO/FDIS 21922:2021.
It is suited to the specific requirements, and includes the data, of refrigerating systems. It provides
means of satisfying the pressure relief devices requirements of EN 378-2:2016 and ISO 5149-2:2014.
oSIST prEN ISO 24664:2021
ISO/DIS 24664:2021 (E)
1 Scope
1.1 This International Standard describes the calculation of mass flow for sizing pressure relief
devices for parts of refrigerating systems.
NOTE The term "refrigerating system" used in this International Standard includes heat pumps.
1.2 This International Standard describes the calculation of discharge capacities for pressure relief
valves and other pressure relief devices in refrigerating systems including the necessary data for sizing
these when relieving to atmosphere or to part of the refrigerating system at lower pressure.
1.3 This International Standard specifies the requirements for selection of pressure relief devices to
prevent excessive pressure due to internal and external heat sources, the sources of increasing pressure
(e.g. compressor, heaters, etc.) and thermal expansion of trapped liquid.
1.4 This International Standard describes the calculation of the pressure loss in the inlet and outlet
lines of pressure relief valves and other pressure relief devices and includes the necessary data.
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/FDIS 21922:2020, Refrigerating systems and heat pumps — Valves — Requirements, testing and
marking
ISO 4126-1:2013+Amd 1:2016, Safety devices for protection against excessive pressure — Part 1: Safety
valves
ISO 4126-2:2018, Safety devices for protection against excessive pressure — Part 2: Bursting disc safety
devices
ISO 817, Refrigerants — Designation system
oSIST prEN ISO 24664:2021
ISO/DIS 24664:2021 (E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/FDIS 21922:2020, ISO 4126-
1:2013 and ISO 4126-2:2018 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
refrigerant
fluid used for heat transfer in a refrigerating system, which absorbs heat at a low temperature and a low pressure
of the fluid and rejects heat at a higher temperature and a higher pressure usually involving changes of the state of
the fluid
3.2
part of the refrigerating system
several components assembled together and exposed to the same pressure in operation or pressure source,
respectively, as determined by the manufacturer
3.3
pressure relief device
pressure relief valve or bursting disc device designed to relieve excessive pressure automatically
3.4
pressure relief valve
pressure actuated valve held shut by a spring or other means and designed to relieve excessive pressure
automatically by starting to open at a set pressure and re-closing after the pressure has fallen below the set
pressure
Note 1 to entry: For the purpose of this standard, the definition of a safety valve as given in ISO 4126-1 is regarded
equivalent to a pressure relief valve.
3.5
pressure vessel
any refrigerant-containing component of a refrigerating system other than:
• coils (including their headers) consisting of pipes with air as secondary fluid;
• piping and its valves, joints and fittings;
• control devices;
• pressure switches, gauges, liquid indicators;
• safety valves, fusible plugs, bursting discs;
• equipment comprising casings or machinery where the dimensioning, choice of material and
manufacturing rules are based primarily on requirements for sufficient strength, rigidity and stability to
meet the static and dynamic operational effects or other operational characteristics and for which
pressure is not a significant design factor. Such equipment may include: pumps and compressors.
Note 1 to entry: The semi-hermetic and open type compressors used in refrigerating systems may be subject to the
exclusion article 1.2.j of the EU Directive 2014/68/EU by referring to the working party group guidelines WPG 1/11, 1/12 and
oSIST prEN ISO 24664:2021
ISO/DIS 24664:2021 (E)
2/34. The compressor manufacturer has to decide on the basis of a case by case assessment, if the exclusion article 1.2.j of the
EU Directive 2014/68/EU is applicable.
Note 2 to entry: This definition is aligned to EU Directive 2014/68 EU.
4 Symbols
For the purposes of this document, the following apply:
Symbol Designation Unit
Actual flow area of the pressure relief device. The flow area at the most
A mm
actual
narrow cross section when the pressure relief device is fully open
A Effective area of the pressure relief device mm
effective
A Calculated flow area of liquid after expansion mm
liq
A Inside area of tube mm
R
A External surface area of the vessel m
surf
A Calculated flow area of vapour after expansion mm
vap
DN Nominal size (see ISO 6708:1995) –
d Actual most narrow flow diameter of the pressure relief device mm
d Inside diameter of tube mm
R
f Darcy friction factor -
Δh Heat of vaporisation kJ/kg
vap
K Capacity correction factor –
cap
Certified coefficient of discharge considering the backpressure ratio
K –
d
p /p and the possible reduced stroke of the pressure relief valve
b 0
K De-rated coefficient of discharge –
dr
K De-rated coefficient of discharge for liquid –
drl
Valve constant (the rate of water flow for a pressure loss of 1 bar at the
K m /h
vs
rated full opening)
K Viscosity correction factor –
visc
L Length of pipe mm
- 1
n Rotational frequency min
p Atmospheric pressure (1,01325 bar) bar
atm
p Back pressure at outlet of pressure relief device, absolute bar
b
p Critical absolute pressure bar
c
p Pressure in connection point bar
connection
p Actual a
...
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