SIST EN ISO 13971:2025

SLOVENSKI STANDARD
01-december-2025
Hladilni sistemi in toplotne črpalke - Gibki cevni elementi, blažilniki vibracij,
raztezni spoji in nekovinske cevi - Zahteve in klasifikacija (ISO 13971:2012)
Refrigeration systems and heat pumps - Flexible pipe elements, vibration isolators,
expansion joints and non-metallic tubes - Requirements and classification (ISO
13971:2012)
Kälteanlagen und Wärmepumpen - Flexible Rohrleitungsteile, Schwingungsabsorber,
Kompensatoren und Nichtmetall-Schläuche - Anforderungen und Klassifikation (ISO
13971:2012)
Systèmes de réfrigération et pompes à chaleur - Éléments flexibles de tuyauterie,
isolateurs de vibration, joints de dilatation et tubes non métalliques - Exigences et
classification (ISO 13971:2012)
Ta slovenski standard je istoveten z: EN ISO 13971:2025
ICS:
27.080 Toplotne črpalke Heat pumps
27.200 Hladilna tehnologija Refrigerating technology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 13971
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2025
EUROPÄISCHE NORM
ICS 27.080; 27.200 Supersedes EN 1736:2008
English Version
Refrigeration systems and heat pumps - Flexible pipe
elements, vibration isolators, expansion joints and non-
metallic tubes - Requirements and classification (ISO
13971:2012)
Systèmes de réfrigération et pompes à chaleur - Kälteanlagen und Wärmepumpen - Flexible
Éléments flexibles de tuyauterie, isolateurs de Rohrleitungsteile, Schwingungsabsorber,
vibration, joints de dilatation et tubes non métalliques - Kompensatoren und Nichtmetall-Schläuche -
Exigences et classification (ISO 13971:2012) Anforderungen und Klassifikation (ISO 13971:2012)
This European Standard was approved by CEN on 22 September 2025.

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
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13971:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 13971:2012 has been prepared by Technical Committee ISO/TC 86 "Refrigeration and
air-conditioning” of the International Organization for Standardization (ISO) and has been taken over as
environmental requirements” 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 March 2026, and conflicting national standards shall
be withdrawn at the latest by March 2026.
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 1736:2008.
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 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 13971:2012 has been approved by CEN as EN ISO 13971:2025 without any modification.

INTERNATIONAL ISO
STANDARD 13971
First edition
2012-09-01
Refrigeration systems and heat pumps —
Flexible pipe elements, vibration
isolators, expansion joints and non-
metallic tubes — Requirements and
classification
Systèmes de réfrigération et pompes à chaleur — Éléments flexibles
de tuyauterie, isolateurs de vibration, joints de dilatation et tubes non
métalliques — Exigences et classification
Reference number
ISO 13971:2012(E)
©
ISO 2012
ISO 13971:2012(E)
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
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Published in Switzerland
ii © ISO 2012 – All rights reserved

ISO 13971:2012(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 13971 was prepared by Technical Committee ISO/TC 86, Refrigeration and air-conditioning, Subcommittee
SC 1, Safety and environmental requirements for refrigerating systems.
ISO 13971:2012(E)
Introduction
Flexible pipe elements are used to eliminate impermissible stresses from refrigerating circuits and absorb pipe
expansion or relative movements of components.
Flexible pipe elements are often the weakest part of a refrigerating system and the part most likely to suffer
from fatigue or stress corrosion cracking.
iv © ISO 2012 – All rights reserved

INTERNATIONAL STANDARD ISO 13971:2012(E)
Refrigeration systems and heat pumps — Flexible pipe
elements, vibration isolators, expansion joints and non-metallic
tubes — Requirements and classification
1 Scope
This International standard describes requirements, design and installation of flexible pipe elements (e.g.,
metallic flexible pipe, metallic flexible tube, vibration isolator, expansion joint) and non-metallic tube used in the
refrigerant circuits of refrigerating systems and heat pumps.
It also describes the requirements to qualify the tightness and permeability of non-metallic tubes (e.g., plastic)
used in evaporating and/or condensing sides of refrigerating systems and heat pumps.
This International standard does not apply to flexible pipes that are only occasionally stressed beyond the
elastic limit (e.g., during repair work), or to joints that are free to rotate or hinge.
2 Normative references
The following referenced documents are indispensable for the application 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 175, Plastics — Methods of test for the determination of the effects of immersion in liquid chemicals
ISO 5149-2, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 2:
Design, construction, testing, marking and documentation
ISO 6605:2002, Hydraulic fluid power — Hoses and hose assemblies — Test methods
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
expansion joint
tubular pipe element shaped in such a way that it provides limited movement to accommodate thermal expansion
without reaching its elastic limit
3.2
flexible pipe element
pipe or tube of non-permanent shape linking two parts that are moveable with respect to each other
See Figure 1.
NOTE 1 This generic term includes all types, as defined in 3.1, 3.3 to 3.5, and 3.8 to 3.11.
NOTE 2 Flexible pipe elements may include a plastic barrier in the construction, either as a liner on the inner surface
or as a sandwich in the pipe wall. The main purpose of such a barrier is to reduce the permeation of refrigerant gas.
NOTE 3 This type of pipe is flexible by virtue of the shape into which the tube is bent (e. g., coiled capillary tube).
3.3
flexible pipe element, fixed installed
element used to minimize assembly difficulty by accommodating slight misalignments or relative movement
between components of the refrigerating system
ISO 13971:2012(E)
3.4
flexible pipe element, for intermittent movement
element moving intermittently to take up relative movement between components of the refrigerating system
3.5
flexible pipe element, for significant movement
element moving regularly through significant distance to allow the operation of refrigerating equipment
EXAMPLE Plate freezers.
3.6
maximum allowable pressure
P
S
maximum pressure for which the equipment is designed, as specified by the manufacturer
3.7
maximum/minimum allowable temperature
T
S
maximum/minimum temperature for which the equipment is designed, as specified by the manufacturer
3.8
metallic flexible pipe
readily flexible, small bore pipe, that is capable of movement within its elastic limit during operation of the
refrigerating system or within reasonable plastic deformation range during installation or maintenance
3.9
metallic flexible tube
tubular flexible element designed to bend within defined limits and containing a corrugated metal bellows, the
corrugations of which may be annular or spiral
See Figure 1.
NOTE 1 Metallic flexible tubes can be reinforced by metallic braiding covered either by rubber or plastic but the whole
element should be designed so that, when bent within pre-determined limits, it is not stressed beyond the elastic limit.
NOTE 2 This type of pipe is flexible by virtue of its design and construction, e. g. bellows.
3.10
non-metallic flexible tube
tubular flexible element designed to bend within defined limits
See Figure 1.
NOTE 1 Non-metallic flexible tubes can have smooth bore or corrugated bore and be reinforced to withstand pressure,
vacuum or external impact.
NOTE 2 This type of pipe is flexible by virtue of its material (e. g., elastomer).
NOTE 3 Non-metallic flexible tube is intended to include all pipes made of plastic or rubber, mono-layer or multi-layer,
reinforced or non-reinforced.
3.11
vibration isolator
short, flexible tube usually of metallic construction, that is intended to reduce the effects of vibration from the
compressor to other parts of the refrigerating system or vice versa
2 © ISO 2012 – All rights reserved

ISO 13971:2012(E)
Flexible pipe elements
metallic flexible pipe metallic flexible tube
non-metallic flexible tube
(3.8)
(3.9)
(3.10)
flexibility is flexibility is flexibility is
configuration dependent construction dependent material dependent
(e.g. coils) (e.g. bellows) (e.g. elastomer)
Figure 1 — Types of flexible pipe elements
4 Applications
4.1 General
4.1.1 The refrigerating system shall be so designed and constructed that the components being connected
by the flexible pipe elements and non-metallic tubes cannot move in such a way as to stress the pipe element
beyond its fatigue limit during operation, including start and stop.
4.1.2 Flexible pipe elements and non-metallic tubes shall be installed in accordance with the manufacturer’s
instructions.
4.1.3 Flexible pipe elements, vibration isolators, expansion joints and non-metallic tubes shall be used only
if necessary.
4.2  Flexible pipe elements for significant movements, flexible pipe elements for intermittent
movement and fixed installed flexible pipe elements
Flexible pipe elements for significant movements, flexible pipe elements for intermittent movement and fixed
installed flexible pipe elem
...