FprEN 17878-1
(Main)District heating pipes - Factory made flexible pipe systems with a lower temperature profile - Part 1: Classification, general requirements and test methods
District heating pipes - Factory made flexible pipe systems with a lower temperature profile - Part 1: Classification, general requirements and test methods
This document specifies classification, general requirements and test methods for flexible, factory made, buried district heating pipe systems.
This document is intended to be used only in conjunction with EN 17878-2 or EN 17878-3, as applicable.
This document is applicable to a maximum operating temperature of 80 °C and a maximum operating design pressure up to 1,0 MPa.
The pipe systems are designed for a service life of at least 50 years. For pipe systems with plastic service pipes, the respective temperature profiles are specified in EN 17878-2:2023 and EN 17878-3:2023.
For the transport of other liquids, for example potable water, additional requirements can be applicable.
Fernwärmerohre - Flexible Rohrsysteme mit einem niedrigeren Temperaturprofil - Teil 1: Klassifikation, allgemeine Anforderungen und Prüfungen
Dieses Dokument legt die Klassifikation, allgemeine Anforderungen und Prüfverfahren für flexible, werkmäßig hergestellte, erdverlegte Fernwärmenetze fest.
Dieses Dokument ist ausschließlich für die Anwendung in Verbindung mit EN 17878-2 oder EN 17878-3, wie jeweils zutreffend, vorgesehen.
Dieses Dokument ist für eine maximale Betriebstemperatur von 80 °C und einen maximalen zulässigen Betriebsdruck bis einschließlich 1,0 MPa anwendbar.
Die Rohrsysteme sind für eine Nutzungsdauer von 50 Jahren ausgelegt. Für Rohrsysteme mit Mediumrohren aus Kunststoff sind die entsprechenden Temperaturprofile in EN 17878-2:2023 und EN 17878-3:2023 festgelegt.
Für den Transport von anderen Flüssigkeiten, wie z. B. Trinkwasser, können zusätzliche Anforderungen gelten.
Tuyaux de chauffage urbain - Systéme de tuyaux flexibles préisolés - Partie 1: Classification, exigences générales et méthodes d'essai
No Scope Available
Cevi za daljinsko ogrevanje - Tovarniško izdelani gibki cevni sistemi z nižjim temperaturnim profilom - 1. del: Klasifikacija, splošne zahteve in preskusne metode
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 17878-1:2022
01-september-2022
Cevi za daljinsko ogrevanje - Tovarniško izdelani gibki cevni sistemi z nižjim
temperaturnim profilom - 1. del: Klasifikacija, splošne zahteve in preskusne
metode
District heating pipes - Factory made flexible pipe systems with a lower temperature
profile - Part 1: Classification, general requirements and test methods
Fernwärmerohre - Flexible Rohrsysteme mit einem niedrigeren Temperaturprofil - Teil 1:
Klassifikation, allgemeine Anforderungen und Prüfungen
Tuyaux de chauffage urbain - Systéme de tuyaux flexibles préisolés - Partie 1:
Classification, exigences générales et méthodes d'essai
Ta slovenski standard je istoveten z: prEN 17878-1
ICS:
23.040.07 Cevovodi za daljinsko Pipeline and its parts for
ogrevanje in njihovi deli district heat
23.040.20 Cevi iz polimernih materialov Plastics pipes
oSIST prEN 17878-1:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 17878-1:2022
DRAFT
EUROPEAN STANDARD
prEN 17878-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2022
ICS 23.040.07
English Version
District heating pipes - Factory made flexible pipe systems
with a lower temperature profile - Part 1: Classification,
general requirements and test methods
Tuyaux de chauffage urbain - Systéme de tuyaux Fernwärmerohre - Flexible Rohrsysteme mit einem
flexibles préisolés - Partie 1: Classification, exigences niedrigeren Temperaturprofil - Teil 1: Klassifikation,
générales et méthodes d'essai allgemeine Anforderungen und Prüfungen
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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17878-1:2022 E
worldwide for CEN national Members.
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Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and symbols . 7
3.1 Terms and definitions . 7
3.2 Symbols, indices and abbreviations . 7
4 Classification . 11
5 Design requirements . 11
5.1 Thermal insulation properties . 11
5.2 Bending test . 11
5.2.1 Flexibility . 11
5.2.2 Ovality . 12
5.2.3 Cracks . 12
5.3 Resistance to external load. 12
5.3.1 Ring stiffness . 12
5.3.2 Impact resistance . 12
5.4 Thermal insulation . 12
5.4.1 Compressive creep. 12
5.4.2 Water absorption at elevated temperatures . 12
5.4.3 Density of thermal insulation . 13
5.5 Casing . 13
5.5.1 UV stability . 13
5.5.2 Thermal stability of the material . 13
5.5.3 Stress crack resistance of the material . 13
5.5.4 Use of rework material . 13
5.6 Surveillance systems . 13
6 Test methods . 14
6.1 General . 14
6.2 Bending test . 14
6.2.1 Flexibility . 14
6.2.2 Ovality test . 15
6.2.3 Cracks in the thermal insulation . 15
6.3 Compressive creep. 16
6.3.1 General . 16
6.3.2 Principles of testing . 16
6.3.3 Test apparatus. 16
6.3.4 Test specimen . 18
6.3.5 Test procedure . 18
6.3.6 Test force and expression of results . 18
7 Marking . 20
7.1 General marking aspects . 20
7.2 Minimum marking information . 20
2
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8 Manufacturer's information . 21
Annex A (normative) Thermal conductivity of factory made pipes – Test procedure . 22
A.1 General . 22
A.2 Requirements . 22
A.2.1 Test specimen . 22
A.2.2 Operating temperature . 22
A.2.3 Types of apparatus . 22
A.3 Apparatus . 22
A.3.1 Guarded end apparatus . 22
A.3.2 Calibrated end apparatus . 22
A.3.3 Dimensions . 23
A.3.4 Heater pipe surface temperature . 23
A.4 Test specimen . 23
A.4.1 Conditioning . 23
A.4.2 Surface temperature measurement . 23
A.4.3 Location of temperature sensors . 23
A.5 Procedure . 23
A.5.1 Test length . 23
A.5.2 Diameter and dimension measurement. 23
A.5.3 Thickness of casing . 25
A.5.4 Ambient requirements . 25
A.5.5 Test pipe temperature . 25
A.5.6 Power supply . 25
A.5.7 Axial heat loss . 26
A.5.8 Test period and stability . 26
A.6 Calculations - Thermal conductivity . 26
Annex B (informative) Determination of design values for the radial thermal resistance . 28
Annex C (informative) Guidelines for inspection and testing . 29
Bibliography . 31
3
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European foreword
This document (prEN 17878-1:2022) has been prepared by Technical Committee CEN/TC 107
“Prefabricated district heating and district cooling pipe systems”, the secretariat of which is held by DS.
This document is currently submitted to the CEN enquiry.
This document is read in conjunction with prEN 17878-2:2022 and prEN 17878-3:2022.
This document is part of the standard series EN 17878, District heating pipes — Factory made flexible pipe
systems with a lower temperature profile:
— Part 1: Classification, general requirements and test methods;
— Part 2: Bonded system with plastic service pipes; requirements and test methods;
— Part 3: Non bonded system with plastic service pipes; requirements and test methods.
4
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Introduction
District heating technology has developed rapidly since its origin and especially in recent times. Today,
there are different generations of district heating networks. The technologies of these generations are
driven by the different heat sources and operating temperatures used.
CEN/TC 107 provides a set of European standard series for rigid and flexible piping systems in district
heating to suit all generations and requirements of district heating networks in the market.
The standard documents ensure quality for pre-fabricated piping systems in district heating.
This standard series covers flexible, pre-fabricated piping systems for operation conditions as described
in the scope of this document.
5
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1 Scope
This document specifies classification, general requirements and test methods for flexible, factory made,
buried district heating pipe systems.
This document is applicable to a maximum operating temperature of 80 °C and a maximum operating
design pressure up to 1,0 MPa.
The pipe systems are designed for a service life of at least 50 years. For pipe systems with plastic service
pipes. The respective temperature profiles are specified in prEN 17878-2:2022 and prEN 17878-3:2022.
NOTE For the transport of other liquids, for example potable water, additional requirements can be applicable.
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.
EN 253, 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 1605, Thermal insulating products for building applications - Determination of deformation under
specified compressive load and temperature conditions
EN 1606, Thermal insulating products for building applications - Determination of compressive creep
EN 12085, Thermal insulating products for building applications - Determination of linear dimensions of
test specimens
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 14419, District heating pipes - Bonded single and twin pipe systems for buried hot water networks -
Surveillance systems
EN 17248, District heating and district cooling pipe systems - Terms and definitions
prEN 17878-2:2022, District heating pipes - Flexible pipe systems with a lower temperature profile - Part
2: Bonded system with plastic service pipes; requirements and test methods
prEN 17878-3:2022, District heating pipes - Flexible pipe systems with a lower temperature profile - Part
3: Non bonded system with plastic service pipes; requirements and test methods
EN 60811-406:2012, Electric and optical fibre cables - Test methods for non-metallic materials - Part 406:
Miscellaneous tests - Resistance to stress cracking of polyethylene and polypropylene compounds
EN ISO 845, Cellular plastics and rubbers - Determination of apparent density (ISO 845)
EN ISO 3127, Thermoplastics pipes - Determination of resistance to external blows - Round-the-clock
method (ISO 3127)
EN ISO 9967, Thermoplastics pipes - Determination of creep ratio (ISO 9967)
EN ISO 9969, Thermoplastics pipes - Determination of ring stiffness (ISO 9969)
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EN ISO 11357-6, Plastics - Differential scanning calorimetry (DSC) - Part 6: Determination of oxidation
induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT) (ISO 11357-6)
EN ISO 16871, Plastics piping and ducting systems - Plastics pipes and fittings - Method for exposure to
direct (natural) weathering (ISO 16871)
ISO 6964, Polyolefin pipes and fittings — Determination of carbon black content by calcination and
pyrolysis — Test method
ISO 16770, Plastics — Determination of environmental stress cracking (ESC) of polyethylene — Full-notch
creep test (FNCT)
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 17248 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 https://www.iso.org/obp
3.2 Symbols, indices and abbreviations
For the purposes of this document, the following symbols in Table 1, indices in Table 2 and abbreviations
in Table 3 apply.
Table 1 — Symbols
Symbol Description Unit
2
projected area of the service pipe (length · width)
A
mm
d
inner diameter of the service pipe mm
1
actual diameter of casing, measured with measuring tape mm
D
De deviation of service pipe %
D minimum casing diameter, measured with calliper mm
min
D maximal casing diameter, measured with calliper mm
max
d
inner diameter of the service pipe at the peak of a corrugation mm
1p,
d
inner diameter of the service pipe at the trough of a corrugation mm
1,t
d
outer diameter of the service pipe mm
2
d
outer diameter of the service pipe at the peak of a corrugation mm
2p,
d
outer diameter of the service pipe at the trough of a corrugation mm
2t,
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Symbol Description Unit
d
inner diameter of the casing mm
3
d
inner diameter of the casing at the peak of a corrugation mm
3p,
d
inner diameter of the casing at the trough of a corrugation mm
3t,
d
outer diameter of the casing mm
4
d
outer diameter of the casing at the peak of a corrugation mm
4,p
d
outer diameter of the casing at the trough of a corrugation mm
4t,
force N
F
f ageing factor /
a
f moisture factor /
m
F
force resulting from weight N
weight
g
2
acceleration due to gravity
m/s
length of the test specimen m
L
mass of the service pipe including the water inside kg
M
O ovality %
P area related test load MPa
test
area related load on the cross section of the test specimen of the thermal
P
MPa
weight
insulation material
heat flow rate W/m
Q
r
bending radius in the axis of the pipe mm
radial thermal resistance m⋅K/W
R
R
radial thermal resistance of the return pipe m⋅K/W
r
s
thickness mm
s
thickness of test specimen after load testing and temperature testing mm
STB
t thickness of the casing mm
λ thermal conductivity of the thermal insulation at 50 °C W/(m⋅K)
50
λ
thermal conductivity of the casing W/(m⋅K)
C
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Symbol Description Unit
calculation value of the thermal conductivity of the thermal insulation
λ
W/(m⋅K)
design
material
λ thermal conductivity of the thermal insulation W/(m⋅K)
I
λ
thermal conductivity of the soil W/(m⋅K)
soil
λ thermal conductivity of the service pipe W/(m⋅K)
S
ϑ temperature at the inner diameter of the service pipe K
1
ϑ
temperature at the inner diameter of the service flow pipe K
1f,
ϑ
temperature at the inner diameter of the service return pipe K
1,r
ϑ temperature at the outer diameter of the service pipe K
2
ϑ temperature at the inner diameter of the casing K
3
ϑ
temperature at the outer diameter of the casing K
4
ϑ
flow temperature K
f
ϑ
mean temperature of the thermal insulation K
i,mean
ϑ
return temperature K
r
∑ compression of the thermal insulation %
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Table 2 — Indices
Symbol Definition
1 position at the inner diameter of the service pipe
2 position at the outer diameter of the service pipe
3 position at the inner diameter of the casing
4 position at the outer diameter of the casing
50 at 50 °C
a ageing
amb ambient
ax axial
C casing or casing pipe
cor corrective
design design
f flow
I thermal insulation
mean mean
min minutes
p peak of a corrugation
r return
S service pipe
soil soil
steel steel
t trough of a corrugation
test test
weight weight
x placeholder for 1,2,3 or 4
ϑ
average temperature
av
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Table 3 — Abbreviations
Abbreviation Name
PB-H polybutene homopolymer
PE-HD high density polyethylene
PE-MD medium density polyethylene
PE-LD low density polyethylene
PE-LLD linear low-density polyethylene
PE-RT poleythylene of raised temperature resistance
PE-X cross linked polyethylene
4 Classification
This document shall only be used in conjunction with part 2 or 3, as applicable. Table 4 shows an
overview of the different classification systems and its field of application according to part 2 and 3.
The detailed classification including the specific temperature profile and the design pressure is specified
in Clause 4 of the relevant part 2 and 3.
Table 4 — Classification system
Field of application
Service Pipe
Part of this
Continuous Maximum
pipe assembly
Design
standard
operating operating
material design
pressure
temperature temperature
MPa °C °C
2 plastics bonded 0,6, 0,8 or 1,0 70 80
3 plastics non bonded 0,6, 0,8 or 1,0 70 80
5 Design requirements
5.1 Thermal insulation properties
The manufacturer shall submit values for the heat loss of buried pipe assemblies for all pipe dimensions
in accordance to EN 13941-1, rounded to 0,1 W/m. The coefficient of thermal conductivity of soil shall be
taken for dry soil: λ = 1,0 W/(m⋅K).
soil
NOTE Annex A specifies how to determine thermal conductivity, and Annex B informs about design values for
the radial thermal resistance.
5.2 Bending test
5.2.1 Flexibility
The flexibility of the pipe assembly is verified by testing at the minimum bending radius (see 6.2.1). The
manufacturer of the pipe assembly shall declare the minimum installation bending radii for all
dimensions produced, related to the central axis of the pipe assembly.
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The declared minimum installation bending radius of the pipe assembly according to this document shall
not exceed thirty times the outer diameter of the casing.
When bending to the minimum radius, the service pipe and the casing of the pipe assembly shall not
break.
5.2.2 Ovality
The ovality of the outer casing shall not exceed 30 % when measured according to 6.2.2.
5.2.3 Cracks
Cracks in the thermal insulation layer shall not exceed a width of 5 mm when tested according 6.2.3.
NOTE With a crack size below 5 mm the number of cracks is not relevant for the integrity of the pipe system,
because the temperature on the casing will not be influenced.
5.3 Resistance to external load
5.3.1 Ring stiffness
The ring stiffness shall be tested according to EN ISO 9969 where the diameter of the test specimen is the
inner diameter of the casing determined at the cross section of the pipe assembly. The ring stiffness of
2
the pipe assembly shall be at least 4 kN/m and the ring stiffness divided by the creep ratio according to
EN ISO 9967 shall be at least 0,8.
NOTE The deformation of buried pipes with and without traffic load can be calculated according to EN 1295-1.
5.3.2 Impact resistance
The impact resistance shall be tested according to EN ISO 3127. The casing of pipe assemblies and joint
casings shall show no cracks when exposed to an impact of 4 J.
5.4 Thermal insulation
5.4.1 Compressive creep
The compressive creep shall be tested according to 6.3. The thermal insulation shall not be compressed
by more than 10 %.
5.4.2 Water absorption at elevated temperatures
The water absorption shall be tested according to EN 253. The water absorption shall not exceed the
limits of one of the test options specified in Table 5.
Table 5 — Test option for water absorption
Test option Test temperature Water absorption (by
volume)
°C %
A 100 10
B 80 1
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5.4.3 Density of thermal insulation
5.4.3.1 General
3
The manufacturer shall declare a reference density in kg/m with tolerances for the pipe assemblies
produced which may differ between different dimensions.
5.4.3.2 Bonded system
Bonded systems are covered by prEN 17878-2:2022. The measurement of the density shall be done in
accordance with EN 253.
5.4.3.3 Non bonded system
Non bonded systems are covered by prEN 17878-3:2022. The measurement of the density shall be done
in accordance with EN ISO 845.
5.5 Casing
5.5.1 UV stability
Casings shall be made of a material containing at least 2 % by mass of carbon black determined in
accordance with ISO 6964.
2
Alternatively, after an exposure of the pipe assembly to an energy of ≥ 3,5 GJ/m in accordance with
EN ISO 16871, the requirements of 5.2 and 5.3 shall be met.
NOTE The UV stability requirement is for storage purposes, only.
5.5.2 Thermal stability of the material
The oxidation induction time of the material to be used for the casing shall be at least 20 m
...
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