prEN 17248

SLOVENSKI STANDARD
01-marec-2026
Sistemi daljinskega ogrevanja in hlajenja - Izrazi in definicije
District heating and district cooling pipe systems - Terms and definitions
Fernwärme- und Fernkälterohrsysteme - Begriffe
Canalisations pour le chauffage urbain et réseaux d’eau glacée - Termes et définitions
Ta slovenski standard je istoveten z: prEN 17248
ICS:
01.040.23 Tekočinski sistemi in sestavni Fluid systems and
deli za splošno rabo (Slovarji) components for general use
(Vocabularies)
23.040.07 Cevovodi za daljinsko Pipeline and its parts for
ogrevanje in njihovi deli district heat
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2026
ICS 01.040.23; 23.040.07 Will supersede EN 17248:2019
English Version
District heating and district cooling pipe systems - Terms
and definitions
Canalisations pour le chauffage urbain et réseaux d'eau Fernwärme- und Fernkälterohrsysteme - Begriffe
glacée - Termes et définitions
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 107.
If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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.
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.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17248:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
Bibliography . 23
European foreword
This document (prEN 17248:2026) has been prepared by Technical Committee CEN/TC "107", the
secretariat of which is held by DS.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 17248:2019.
In comparison with the previous edition, the following technical modifications have been made:
— deleted terms and definitions for butt welded bend, directly welded T-piece, forged T-piece, hot
formed bend, cold formed bend, induction bend, induction bending, T-piece with drawn collar
— added terms and definitions for lower confidence limit of the predicted hydrostatic strength σLPL
and pipe element,
— added modifications to terms and definitions for pre-stressing, factory made thermal joint
insulation, plug, sleeve, closure, sealing patch and pipe assembly
Introduction
This document compiles a vocabulary of terms, with their definitions, applied in the field of district
heating and district cooling systems. Only terms which are particular to the pertinent field in CEN/TC
107 are included.
The other standards from CEN/TC 107 are:
— EN 253 [1], District heating pipes — Bonded single pipe systems for directly buried hot water networks
— Factory made pipe assembly of steel service pipe, polyurethane thermal insulation and a casing of
polyethylene;
— EN 448 [2], District heating pipes —Bonded single pipe systems for directly buried hot water networks
— Factory made fitting assemblies of steel service pipes, polyurethane thermal insulation and a casing
of polyethylene;
— EN 488-1, District heating pipes - Bonded single pipe systems for directly buried hot water networks
- Part 1: Factory made steel valve assembly for steel service pipes, polyurethane thermal insulation
and a casing of polyethylene;
— EN 488-2, District heating and district cooling pipes - Bonded pipe systems for directly buried hot and
cold water networks - Factory made steel valve assembly for draining and venting, polyurethane
thermal insulation and a casing of polyethylene;
—
prEN 489-1 , District heating pipes – Bonded single and twin pipe systems for buried hot water
networks – Part 1: Joint casing assemblies and thermal insulation for hot water networks in
accordance with EN 13941-1;
—
prEN 489-2 , District heating pipes – Bonded single and twin pipe systems for buried hot water
networks – Part 1: Joint casing assemblies;
—
EN 13941-1 , District heating pipes - Design and installation of thermal insulated bonded single and
twin pipe systems for directly buried hot water networks — Part 1: Design;
—
EN 13941-2 , District heating pipes - Design and installation of thermal insulated bonded single and
twin pipe systems for directly buried hot water networks — Part 2: Installation;
— EN 14419, District heating pipes — Bonded single and twin pipe systems for directly buried hot water
networks — Surveillance systems;
— EN 15632-1, District heating pipes - Factory made flexible pipe systems - Part 1: Classification, general
requirements and test methods;
— EN 15632-2, District heating pipes - Factory made flexible pipe systems - Part 2: Bonded system with
plastic service pipes; requirements and test methods;
— EN 15632-3, District heating pipes - Factory made flexible pipe systems - Part 3: Non bonded system
with plastic service pipes; requirements and test methods;
— EN 15632-4, District heating pipes - Factory made flexible pipe systems - Part 4: Bonded system with
metal service pipes; requirements and test methods;
Under preparation.
Under preparation.
Under preparation.
Under preparation.
— EN 15698-1, District heating pipes — Bonded twin pipe systems for directly buried hot water networks
— Part 1: Factory made twin pipe assembly of steel service pipes, polyurethane thermal insulation
and one casing of polyethylene;
— EN 15698-2, District heating pipes — Bonded twin pipe systems for directly buried hot water networks
— Part 2: Factory made fitting and valve assemblies of steel service pipes, polyurethane thermal
insulation and one casing of polyethylene;
— EN 17414-1, District cooling pipes - Factory made flexible pipe systems - Part 1: Classification, general
requirements and test methods;
— EN 17414-2, District cooling pipes - Factory made flexible pipe systems - Part 2: Bonded system with
plastic service pipes; requirements and test methods;
— EN 17414-3, District cooling pipes - Factory made flexible pipe systems - Part 3: Non bonded system
with plastic service pipes; requirements and test methods;
— EN 17415-3, District cooling pipes - Bonded single pipe systems for directly buried cold water
networks - Part 3: Factory made steel valve assembly for steel or plastic service pipe, polyurethane
thermal insulation and a casing of polyethylene;
— EN 17415-2, District cooling pipes - Bonded single pipe systems for directly buried cold water
networks - Part 2: Factory made fitting assemblies of steel or plastic service pipe, polyurethane
thermal insulation and a casing of polyethylene;
— EN 17878-1, District heating pipes - Factory made flexible pipe systems with a lower temperature
profile - Part 1: Classification, general requirements and test methods;
— EN 17878-2, District heating pipes - Factory made flexible pipe systems with a lower temperature
profile - Part 2: Requirements and test methods for bonded systems with plastic service pipes;
— EN 17878-3:2024, District heating pipes - Factory made flexible pipe systems with a lower
temperature profile - Part 3: Requirements and test methods for non bonded systems with plastic
service pipes;
— CEN/TS 17889, District heating pipes - Factory made flexible pipe systems - Classification,
requirements and test methods for bonded or non-bonded system with thermoplastic reinforced
service pipes (TRSP);
—
prEN 18213-1 , District heating and district cooling pipes - Bonded single and twin pipe systems
for directly buried hot and cold water networks - Part 1: Qualification testing of fitter;
—
prEN 18213-2 , District heating and district cooling pipes - Bonded single and twin pipe systems
for directly buried hot and cold water networks - Part 2: Qualification testing of PE-Welder;
—
CEN/TR , District heating and cooling systems — Supplementary information on usage of CEN/TC
107 standards.
Under preparation.
Under preparation.
Under preparation.
1 Scope
This document compiles a vocabulary of terms, with their definitions, applied in the field of district
heating and district cooling systems.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1
above ground installation
installation method where the pipe is not surrounded by soil
3.2
action cycle
impact comprising of one full action course, ranging from a minimum (maximum) level through an
average value to a maximum (minimum) level and back
Note 1 to entry: See Figure 1 for the principle of action cycles.
Key
1 one action cycle
2 action, stress or deformation range
3 maximum level of the action, stress or deformation
4 minimum level of the action, stress or deformation
Figure 1 — Action cycle
3.3
artificial ageing
keeping the service pipe (3.112) at a defined, elevated temperature for a certain time while also
exposing the casing (3.11) to a defined temperature
3.4
ageing factor
fa
factor without a dimension which expresses the ageing of the thermal insulation (3.135) in relation to
the expected service life
3.5
applicant
person who has submitted an application to be admitted into the certification process
[SOURCE: EN 13067:2020 [3], 3.2]
3.6
assembly of measuring elements
process where a fitter (3.35) or PE-welder during the assembly of joint casing systems (3.53) connects
measuring elements (3.67) into a measuring section (3.69)
3.7
assessment
process that evaluates the fulfilment of the requirements of a certification scheme
[SOURCE: EN 13067:2020 [3], 3.3, modified]
3.8
batch
specified quantity of material made under the same uniform production conditions in one production
run by one manufacturer
3.9
bending angle
α
deviation in direction of the pipe centre lines
Note 1 to entry: For the principle of deviation in direction of the pipe centre lines see Figure 2 .
Figure 2 — Principle of deviation in direction of the pipe centre lines
3.10
bonded system
pipe element (3.92) which is bonded by thermal insulation (3.135)
3.11
casing
outer layer of polythene, which may contain a diffusion barrier, intended to protect the thermal
insulation (3.135) and service pipe (3.112) from the effects of ground water, moisture and mechanical
damage
3.12
candidate
applicant who has fulfilled specified prerequisites and has been admitted to the certification process
[SOURCE: EN 13067:2020, 3.4]
3.13
certificate
document issued by the certificate issuing authority under the provisions of reference to a standard
document, indicating that the named person or product has fulfilled the certification requirements
Note 1 to entry: In prEN 18213-1 and prEN 18213-2 the named person is the candidate who has fulfilled the
certification requirements.
3.14
centre line deviation
deviation between the centre line of the service pipe (3.112) and the centre line of the casing (3.11)
3.15
characteristic value
value of a stochastic variable which, at a probability of 95 %, will not be exceeded
3.16
closure
thermo-adhesive cover used to bind the ends of the wraparound sealing sleeve
3.17
cold laying
method of pipeline laying where the pipes are installed and put into operation without pre-stressing,
in which the yield strength of the service pipe (3.112) material may be exceeded
3.18
connection point
accessible place outside the pipe system where a measuring instrument can be connected to a
measuring section
EXAMPLE        The place could be in a shaft, in a house connection, in a measuring post, in a cabinet, etc.
3.19
continuous operating temperature
temperature at which the pipe system is designed to operate continuously
3.20
creep
slow progressive strain under the influence of stress
3.21
deformation-controlled action
action called forth by enforced deformation or movement
EXAMPLE        Examples of deformation-controlled actions are thermal expansion or deformation differences,
caused by soil settling.
3.22
density
mass of a body of a material divided by the volume of the body
3.23
design pressure
internal pressure equal to or greater than the maximum operating pressure against the pipe wall at any
point or in any section of the pipeline at design temperature
3.24
design temperature range
temperature range which, in combination with the design pressure, determines the basis for the
strength/expansion calculation
3.25
detection of moisture
detection of moisture-related parameters with measuring instruments
Note 1 to entry: Only moisture in the thermal insulation due to defects or bad workmanship is relevant.
Note 2 to entry: The parameters could be electrical resistance and/or impedance.
3.26
deviation in surveillance systems
result of comparing the values for moisture-related parameters measured by the surveillance system
with the values given in the technical documentation
3.27
disorder
electrical interruption and/or short circuit in a measuring section (3.69)
3.28
distribution pipeline
pipeline leading from transmission pipeline or substation to house connection or directly to a
domestic substation
Note 1 to entry: For the principle of the structure of district heating or district cooling pipe system, see Figure 3 .
Figure 3 — Principle for the structure of district heating or district cooling pipe system
Key
1 transmission pipeline
2 distribution pipeline
3 house connection
4 domestic substation
→ flow direction
— flow line
- - - return line
Figure 3 — Principle for the structure of district heating or district cooling pipe system
3.29
double sealing
two-sealing systems independently installed and tested on the same joint, not influencing each other
negatively and thus independently functioning during the service life
3.30
electrofusion welding
simultaneous softening of two PE parts to be welded together under contact pressure by a heating
element placed between them when contact pressure is present
Note 1 to entry: The PE parts to be welded are e.g. welded shrink joint casing systems according to EN 489-1.
Note 2 to entry: The heating element can, for example, be an electrically conductive heating grid to be installed
during joint assembly or an electrically conductive wire stamped into the joint casing in the form of a meander.
3.31
equivalent stress
stress calculated with sign from the membrane or resulting stress by Tresca or by von Mises’ equations
3.32
factory-made
pre-insulated
medium components of pipes, fittings and valve assemblies covered with thermal insulation and casing
applied at the factory
3.33
factory-made joint thermal insulation
preformed thermal insulation (3.135) unit installed in joint casing system (3.53) at the factory
EXAMPLE        Half shells.
3.34
fatigue strength
stress range or deformation range of constant magnitude which, under given circumstances, just causes
fatigue failure
3.35
fitter
person installing a sealed joint casing system (3.53)
Note 1 to entry: The process is described in the EN 489 series of standards.
3.36
fitting
component used to connect, redirect, or terminate pipes within the system ⏎
EXAMPLE        reducer, T-piece, bend, dished head (cap)
3.37
fitting assembly
factory-made product consisting of at least one fitting (3.36), thermal insulation (3.135) and casing
(3.11)
3.38
fixing bars
steel plates in twin pipe systems used for bonding of flow and return pipes, to eliminate differences in
expansion between the flow and the return pipe in a straight pipe section
3.39
flexible pipe
pipe characterized by their flexibility and pipe structure allowing large deflections without a significant
increase in bending stresses
Note 1 to entry: Flexible pipes are made of materials such as plastic or metal allowing them to be delivered as coils
or wound on drums.
3.40
force-controlled action
action which maintains its magnitude irrespectively of the deformation of the structure
EXAMPLE        Internal pressure, pipe-weight and top load from soil and traffic.
3.41
fusion compatibility
ability of two materials to be fused together
3.42
heated tool welding
welding method where the surfaces of PE parts are heated by touching a hot element, and then pressed
together to form a strong bond after the plate is removed
Note 1 to entry: This welding process is used in the manufacturing of casings for e.g. fitting assemblies and is
described in EN 448.
3.43
horizontal bend
bend in the horizontal plane
Note 1 to entry: In twin-pipe systems, a d
...