SIST EN 448:2025
(Main)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
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
This document specifies requirements and test methods for factory made thermally insulated bonded fitting assemblies for hot water networks in accordance with EN 13941-1, comprising a steel service pipe, in most cases a steel fitting, polyurethane (PUR) foam thermal insulation and a casing of polyethylene.
The fitting assembly can also include the following additional elements: measuring wires, spacers and diffusion barriers.
This document specifies the characteristics of the following fitting assemblies:
- bends, T-pieces, and reducers.
This document applies to fitting assemblies with a design pressure of at least 1,6 MPa.
Fernwärmerohre - Einrohr-Verbundsysteme für direkt erdverlegte Fernwärmenetze - Werkmäßig gefertigte Formstückbaueinheiten, bestehend aus Stahl-Mediumrohren, einer Wärmedämmung aus Polyurethan und einer Ummantelung aus Polyethylen
Dieses Dokument legt die Anforderungen und Prüfverfahren für werkmäßig gefertigte, wärmegedämmte Verbundformstücke für Fernwärmenetze in Übereinstimmung mit EN 13941 1 fest, die aus einem Stahl-Mediumrohr, in den meisten Fällen einer Stahlarmatur, einer Wärmedämmung aus Polyurethan-Schaum (PUR) und einer Ummantelung aus Polyethylen bestehen.
Das Verbundformstück kann darüber hinaus die folgenden zusätzlichen Bauteile umfassen: Messdrähte, Abstandhalter und Diffusionsbarrieren.
In diesem Dokument sind die Eigenschaften der folgenden Verbundformstücke festgelegt:
- Bögen, T Stücke und Reduzierstücke.
Dieses Dokument gilt für Verbundformstücke mit einem Auslegungsdruck von mindestens 1,6 MPa.
Tuyaux de chauffage urbain - Systèmes bloqués monotube pour les réseaux enterrés d'eau chaude pour des réseaux d'eau chaude enterrés directement - Assemblages de raccords manufacturés pour tubes de service en acier, isolation thermique en polyuréthane et tube de protection en polyéthylène
Le présent document spécifie les exigences et les méthodes d’essai applicables aux assemblages de raccords bloqués manufacturés isolés thermiquement pour les réseaux d’eau chaude, conformément à l’EN 13941-1, comprenant un tube de service en acier, dans la majorité des cas un raccord en acier, une isolation thermique en mousse de polyuréthane (PUR) et une protection en polyéthylène.
L’assemblage de raccord peut également comprendre les éléments supplémentaires suivants : câbles de mesure, entretoises et barrières anti-diffusion.
Le présent document couvre les assemblages de raccords suivants :
- coude, té et réducteur.
Le présent document s’applique aux assemblages de raccords ayant une pression minimale de conception de 1,6 MPa.
Cevi za daljinsko ogrevanje - Poviti enocevni sistemi za neposredno vkopana vročevodna omrežja - Tovarniško izdelana armatura iz jeklenih delovnih cevi, obdanih s poliuretansko toplotno izolacijo in zaščitnim plaščem iz polietilena
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Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2025
Cevi za daljinsko ogrevanje - Poviti enocevni sistemi za neposredno vkopana
vročevodna omrežja - Tovarniško izdelana armatura iz jeklenih delovnih cevi,
obdanih s poliuretansko toplotno izolacijo in zaščitnim plaščem iz polietilena
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
Fernwärmerohre - Einrohr-Verbundsysteme für direkt erdverlegte Fernwärmenetze -
Werkmäßig gefertigte Formstückbaueinheiten, bestehend aus Stahl-Mediumrohren,
einer Wärmedämmung aus Polyurethan und einer Ummantelung aus Polyethylen
Tuyaux de chauffage urbain - Systèmes bloqués monotube pour les réseaux enterrés
d'eau chaude pour des réseaux d'eau chaude enterrés directement - Assemblages de
raccords manufacturés pour tubes de service en acier, isolation thermique en
polyuréthane et tube de protection en polyéthylène
Ta slovenski standard je istoveten z: EN 448:2025
ICS:
23.040.07 Cevovodi za daljinsko Pipeline and its parts for
ogrevanje in njihovi deli district heat
23.040.40 Kovinski fitingi Metal fittings
91.140.65 Oprema za ogrevanje vode Water heating equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 448
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2025
EUROPÄISCHE NORM
ICS 23.040.07; 23.040.45 Supersedes EN 448:2019
English Version
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
Tuyaux de chauffage urbain - Systèmes bloqués Fernwärmerohre - Einrohr-Verbundsysteme für direkt
monotubes pour les réseaux d'eau chaude enterrés erdverlegte Fernwärmenetze - Werkmäßig gefertigte
directement - Assemblages de raccords manufacturés Formstückbaueinheiten, bestehend aus Stahl-
pour tubes de service en acier, isolation thermique en Mediumrohren, einer Wärmedämmung aus
polyuréthane et tube de protection en polyéthylène Polyurethan und einer Ummantelung aus Polyethylen
This European Standard was approved by CEN on 27 January 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 448:2025 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 8
4 Requirements . 8
4.1 Steel parts . 8
4.1.1 Specification . 8
4.1.2 Wall thickness and diameter . 9
4.1.3 Bends . 9
4.1.4 T-pieces .10
4.1.5 Reducers .10
4.1.6 Welding of steel parts .10
4.1.7 Surface condition .15
4.2 Casing .15
4.3 Polyurethane foam thermal insulation .15
4.4 Fitting assembly .15
4.4.1 General .15
4.4.2 Thermal insulation series .15
4.4.3 Fitting ends .15
4.4.4 Angle between casing segments of bend and minimum length .16
4.4.5 Polyethylene welding .16
4.4.6 Diameter and wall thickness of the casing .17
4.4.7 Minimum thickness of the thermal insulation in fitting assembly .18
4.4.8 Tolerances of the main fitting dimensions .18
4.4.9 Expected thermal life and long term temperature resistance .18
4.4.10 Thermal conductivity .18
4.4.11 Surface conditions at delivery .19
4.4.12 Measuring wires for surveillance system .19
5 Test methods .19
5.1 General .19
5.2 Test specimens .19
5.3 Steel parts .19
5.3.1 Leak-tightness test with water .19
5.3.2 Visual leak-tightness test by air with over pressure .20
5.3.3 Visual leak-tightness test by air with below atmospheric pressure.20
5.4 Casing .20
5.4.1 Visual testing of weld seams on casing .20
5.4.2 Bending test of weld seams on casing .23
5.5 Fitting assembly .24
5.5.1 Centre line deviation and angular deviation .24
5.5.2 Minimum thickness of the polyurethane foam thermal insulation .24
5.5.3 Thermal conductivity in unaged condition .24
6 Marking .24
6.1 General . 24
6.2 Steel service pipe . 25
6.3 Steel fittings . 25
6.4 Casing . 25
6.5 Fitting assembly . 25
Annex A (informative) Guidelines for inspection and testing . 26
Annex B (informative) Procedures for casing welding . 29
Annex C (informative) Waste treatment and recycling . 32
Bibliography . 33
European foreword
This document (EN 448:2025) has been prepared by Technical Committee CEN/TC 107 “District heating
and cooling systems”, the secretariat of which is held by DS.
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 September 2025, and conflicting national standards shall
be withdrawn at the latest by September 2025.
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 448:2019.
— two more ultrasonic testing methods for testing of welds are added to Table 4;
— alignment with the structure of EN 253;
— according to 4.1.3.3, the requirements for hot-formed bends are to be agreed between purchaser and
supplier;
— anchors are no longer included;
— single use compensators and caps are no longer included; they are covered by EN 13941-1;
— for steel welding, requirements for the welding contractor and welding consumables are specified in
4.1.6.1 and 4.1.6.3;
— requirements for steel weld preparation are omitted;
— requirements for distance between parallel weld seams are specified in 4.1.6.5.2;
— preparation of set-on branch with steel plate for reinforcement has been added in 4.1.6.5.3;
— requirement for imperfections of weld seams in 4.1.6.6.1 has been adapted to EN 13941-2;
— non-destructive testing (NDT) of weld seams in 4.1.6.6.2 is adapted to EN 13941-2;
— test methods for leak testing of steel weld seams have been clarified in 5.3;
— requirements for visual inspection of PE weld seams in 5.4.1 have been revised and explanatory
figures have been added;
— requirements for marking of fitting assemblies have been added in 6.5;
— recommendations for qualifications of PE welders have been added to B.1.
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 organisations 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.
Introduction
Other standards from CEN/TC 107 are:
— EN 253, District heating pipes — Bonded single pipe systems for directly buried hot water networks —
...
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