oSIST prEN 488-1:2023

SLOVENSKI STANDARD
oSIST prEN 488-1:2023
01-september-2023
Cevi za daljinsko ogrevanje - Poviti enocevni sistemi za neposredno vkopana
vročevodna omrežja - 1. del: Tovarniško izdelan sestav jeklenih ventilov za jeklene
delovne cevi, obdane s poliuretansko toplotno izolacijo in zaščitnim plaščem iz
polietilena
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
Fernwärmerohre - Einrohr-Verbundsysteme für direkt erdverlegte Fernwärmenetze - Teil
1: Werkmäßig gefertigte Stahlarmaturenbaueinheit für Stahl-Mediumrohre,
Wärmedämmung aus Polyurethan und einer Ummantelung aus Polyethylen
Tuyaux de chauffage urbain - Systèmes bloqués monotubes pour les réseaux d'eau
chaude enterrés directement - Partie 1 : Assemblages d'appareils de robinetterie en
acier manufacturés pour tubes de service en acier, isolation thermique en polyuréthane
et enveloppe en polyéthylène
Ta slovenski standard je istoveten z: prEN 488-1
ICS:
23.040.07 Cevovodi za daljinsko Pipeline and its parts for
ogrevanje in njihovi deli district heat
23.060.01 Ventili na splošno Valves in general
oSIST prEN 488-1:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN 488-1:2023

---------------------- Page: 2 ----------------------
oSIST prEN 488-1:2023


DRAFT
EUROPEAN STANDARD
prEN 488-1
NORME EUROPÉENNE

EUROPÄISCHE NORM

July 2023
ICS 23.040.07; 23.060.01 Will supersede EN 488:2019
English Version

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
Tuyaux de chauffage urbain - Systèmes bloqués Fernwärmerohre - Einzelrohr-Verbundsysteme für
monotubes pour les réseaux d'eau chaude enterrés direkt erdverlegte Fernwärmenetze - Werkmäßig
directement - Assemblages d'appareils de robinetterie gefertigte Stahl-Absperrarmaturen für Stahl-
manufacturés pour tubes de service en acier, isolation Mediumrohre, Wärmedämmung aus Polyurethan und
thermique en polyuréthane et tube de protection en einer Ummantelung aus Polyethylen
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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 488-1:2023 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Requirements . 6
4.1 General . 6
4.2 Pressure ratings for steel valves . 7
4.2.1 General . 7
4.2.2 Valves without indicated flow direction . 7
4.3 Service temperatures for valves . 7
4.4 Steel parts . 7
4.4.1 Specification . 7
4.4.2 Valve. 7
4.4.3 Valve extension pipes . 7
4.4.4 Surface condition . 8
4.4.5 Welding of steel parts . 8
4.5 Casing . 8
4.6 Polyurethane foam thermal insulation . 8
4.6.1 General . 8
4.6.2 Minimum thickness of thermal insulation . 8
4.7 Valve assembly . 8
4.7.1 General . 8
4.7.2 Thermal insulation series . 8
4.7.3 Ends of valve assembly . 8
4.7.4 Polyethylene welding . 9
4.7.5 End of stem construction . 9
4.7.6 Tolerances of main dimensions .10
4.7.7 Expected thermal life and long term temperature resistance .10
4.7.8 Thermal conductivity .10
4.7.9 Surface conditions at delivery .10
4.7.10 Measuring wires for surveillance systems .10
4.8 Installation, operation and maintenance .10
4.8.1 Installation .10
4.8.2 Operation .10
4.8.3 Maintenance .11
4.9 Resistance to axial forces and bending moments.11
5 Test methods .11
5.1 General conditions and test specimens .11
5.2 Test specimens .11
5.2.1 Type testing of steel parts of the valve .11
5.2.2 Test specimens from casings and polyurethane foam thermal insulation .11
5.3 Steel parts .12
5.3.1 Type test of the steel parts .12
5.3.2 Production testing of steel valves .15
2

---------------------- Page: 4 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
6 Marking . 16
6.1 General . 16
6.2 Steel valve . 16
6.3 Valve extension pipes. 16
6.4 Casing . 16
6.5 Valve assembly . 16
Annex A (informative) Guidelines for inspection and testing . 18
A.1 General . 18
A.2 Manufacturer’s type test . 18
A.3 Manufacturer’s quality control . 18
A.4 Additional inspection . 18
A.5 Extent of inspection . 18
A.6 Manufacturer’s responsibility . 18
Annex B (normative) Resistance to axial force and bending moment . 20
B.1 Axial strength test . 20
B.2 Bending test . 20
Annex C (normative) Resistance to bending forces . 22
C.1 General . 22
C.2 Standard test assembly (four point bending test) . 23
C.2.1 Bending moment due to test load F . 23
C.2.2 Bending Moment due to uniform load q (pipe weight and if applicable the medium
weight) . 23
C.2.3 Bending moment due to valve weight F . 24
v
C.2.4 Total Bending Moment M due to F, P and F . 24
total V
C.2.5 Calculation of test force F. 25
Annex D (informative) Waste treatment and recycling . 26
Bibliography . 27

3

---------------------- Page: 5 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
European foreword
This document (prEN 488-1:2023) has been prepared by Technical Committee CEN/TC 107
“Prefabricated district heating and district cooling pipe system”, the secretariat of which is held by DS.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 488:2019.
The main changes compared to the previous edition are listed below:
— alignment with the structure of EN 253;
— the valves shall be designed for an operating pressure of 2,5 MPa in accordance with 4.2.1;
— the requirements for the valve extension pipes are specified in 4.4.3;
— for the leak-tightness of the seat of the unloaded valves up to DN 400, a distinction is no longer made
between different leakage rates, see 5.3.1.3;
— added requirement: Before measuring the torque, the valve shall be closed for 24 h, see 5.3.1.4;
— when marking the valve assemblies, information about the diffusion barrier is also to be provided,
see 6.5.
The EN 488 series is currently composed of the following parts:
— prEN 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 (this document);
— prEN 488-2, District heating and district cooling pipes - Bonded pipe systems for directly buried hot and
cold water networks - Part 2: Factory made steel valve assembly for draining and venting, polyurethane
thermal insulation and a casing of polyethylene.
4

---------------------- Page: 6 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
Introduction
prEN 488-1 has also been aligned with prEN 448 and other relevant European Standards.
Other standards from CEN/TC 107 are:
— 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
— prEN 448, 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
— prEN 488-2, District heating and district cooling pipes - Bonded pipe systems for directly buried hot and
cold water networks - Part 2: Factory made steel valve assembly for draining and venting, polyurethane
thermal insulation and a casing of polyethylene
— EN 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
— 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 buried hot water networks
- Surveillance systems
— EN 15632 (all parts), District heating pipes - Factory made flexible pipe systems
— prEN 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
— prEN 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 17248, District heating and district cooling pipe systems - Terms and definitions
— EN 17414 (all parts), District cooling pipes - Factory made flexible pipe systems
— EN 17415 (all parts), District cooling pipes - Bonded single pipe systems for directly buried cold water
networks
— EN 17878 (all parts), District heating pipes - Factory made flexible pipe systems with a lower
temperature profile
Waste management and recycling of materials is dealt with in Annex D.
5

---------------------- Page: 7 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
1 Scope
This document specifies requirements and test methods for factory made thermally insulated bonded
valve assemblies for hot water networks in accordance with EN 13941-1, comprising a steel valve, valve
extension pipes, polyurethane (PUR) foam thermal insulation and a casing of polyethylene.
The valve assembly can also include the following additional elements: measuring wires, spacers and
diffusion barriers.
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 19, Industrial valves - Marking of metallic valves
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
prEN 448, 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 736-1, Valves - Terminology - Part 1: Definition of types of valves
EN 10204, Metallic products - Types of inspection documents
EN 12266-1, Industrial valves - Testing of metallic valves - Part 1: Pressure tests, test procedures and
acceptance criteria - Mandatory requirements
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
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 736-1 and EN 17248 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
4 Requirements
4.1 General
Unless otherwise specified, the requirements shall be valid for each single measurement.
For information on suitable guidelines for inspection and testing see Annex A.
6

---------------------- Page: 8 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
4.2 Pressure ratings for steel valves
4.2.1 General
The steel valves shall be designed for use in pipe systems with a maximum operating pressure of 2,5 MPa.
NOTE For pressure testing of the pipe systems, see EN 13941-2.
4.2.2 Valves without indicated flow direction
Valves without an indicated flow direction shall support the pressure load in both directions.
4.3 Service temperatures for valves
The valves shall be able to withstand continuous operation with hot water at various temperatures in
accordance with EN 13941-1 and at a minimum water temperature of 1 °C.
The pressure temperature curve of the manufacturer shall be considered.
4.4 Steel parts
4.4.1 Specification
Steel grades are specified in EN 13941-1.
All steel valves, valve extension pipes and steel components used for manufacturing of valve assemblies
under the scope of this document shall as a minimum be delivered to the manufacturer with an inspection
certificate 3.1 according to EN 10204. The inspection certificate shall on request be passed on to the
customer.
In case a material related inspection certificate 3.1 according to EN 10204 is required by the client who
orders the valve assembly, this request shall be given whilst placing the order with the manufacturer of
the valve assemblies.
NOTE 1 Any later request for provision of such documentation could be too late and possibly can’t be met by the
manufacturer, since the manufacturer organizes the assignment of 3.1 certificates to the steel valves and parts of
the steel service pipes before starting the production.
NOTE 2 For cold-formed steel valve bodies, the material certificates according to EN 10204 apply to the values
of the chemical composition, but not to the values of the mechanical properties.
All components shall be designed in accordance with EN 13941-1, for the actions and stresses that
normally occur during the service life of the valve assembly (or of the component).
4.4.2 Valve
The valve shall be fully welded. Detachable joints, such as flanged or screwed connections, except sealing
system at the stem, shall not be used in the pressurized area.
The quality of the valve body shall match with the quality of the valve extension pipe.
4.4.3 Valve extension pipes
Subject to design considerations other wall thicknesses than those given in EN 253 may be used, but in
no case shall these be less than the minima indicated in EN 253.
The nominal diameter, the outside diameter, the tolerances on the diameter of the pipe ends and the wall
thickness shall be the same as for the service pipes in accordance with EN 253.
7

---------------------- Page: 9 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
4.4.4 Surface condition
The surface conditions of the steel service pipe and the valve body shall be in accordance with EN 253.
4.4.5 Welding of steel parts
Fusion welding between the steel valve and the valve extension pipes also as the pressurized parts of the
steel valve shall be carried out in accordance with prEN 448.
4.5 Casing
Material and casing properties shall be as specified in EN 253.
The polyethylene welding shall be in accordance with prEN 448.
4.6 Polyurethane foam thermal insulation
4.6.1 General
The PUR shall be in accordance with EN 253.
Test specimens from fitting assemblies to establish foam properties shall be taken in accordance with
prEN 448.
4.6.2 Minimum thickness of thermal insulation
The minimum thickness of polyurethane foam thermal insulation shall be in accordance with prEN 448.
4.7 Valve assembly
4.7.1 General
All requirements are valid including the diffusion barrier, if any.
4.7.2 Thermal insulation series
The thermal insulation series shall be in accordance with EN 253,
The minimum thickness of the Polyurethane (PUR) foam thermal insulation shall be in accordance with
prEN 448.
4.7.3 Ends of valve assembly
4.7.3.1 Pipe ends without thermal insulation
The ends of the extension pipes shall be free from insulation according to EN 253.
The ends of the extension pipes shall be prepared for welding according to prEN 448.
4.7.3.2 Diameter and wall thickness of the casing
The outside diameter and the minimum wall thickness after manufacturing of the valve assemblies shall
be in accordance with EN 253.
4.7.3.3 Centre line deviation
The distance between the centre lines of the valve extension pipes and the casing at the ends of the valve
assembly shall not exceed the limits given in EN 253.
The centre line deviation shall be measured between the centre lines with the largest deviation.
8

---------------------- Page: 10 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
4.7.3.4 Angular deviation between valve extension pipes and casing
The angular deviation between the centre lines of the of the valve extension pipes and the casing shall
not exceed the limits given in prEN 448.
The angular deviation shall be measured between the centre lines at the welding end of the valve
assembly.
4.7.3.5 Minimum length of casing
The length of the casing at the ends of the valves shall not be less than the limit given in prEN 448.
4.7.4 Polyethylene welding
The polyethylene welding shall be in accordance with prEN 448.
4.7.5 End of stem construction
To ensure a long service life of the end stem passing through the shrinking sealing, the end of stem
construction shall withstand the aggressive underground condition such as heat, cold, moisture, ground
and salty water. Where the stem construction passes the casing there shall be an arrangement to protect
against water ingress to the thermal insulation.
The stem construction outside the thermal insulation shall be:
— made from stainless steel with at least 16 % of chromium. Factors influencing the corrosion
probability of the stainless steel construction can be assessed according to EN 12502-4.
— Specifically used steel type is documented by appropriate quality management system;
— Under specific installation and operation conditions a chrome content of 16 % alone might not be
sufficient, so that other alloy elements are then recommended.
The protection by corrosion resistant material shall be added at the length of at least 100 mm from the
top of the ‘stem house’, see Figure 1.

Key
L length
H height offset
1 minimum length for corrosion resistant material (100 mm)
2 shrinking sealing
Figure 1 — Main dimensions and anti corrosion protection
9

---------------------- Page: 11 ----------------------
oSIST prEN 488-1:2023
prEN 488-1:2023 (E)
4.7.6 Tolerances of main dimensions
The main dimensions of the valve assembly H and L are shown in Figure 1. The values of L and H shall be
declared by the manufacturer. The tolerances of H and L shall be in accordance with Table 1.
Table 1 — Tolerances of the main dimensions
DN H L
 mm mm
≤ 300 ±5 ±20
> 300 ±10 ±50
4.7.7 Expected thermal life and long term temperature resistance
The expected thermal life and long term temperature resistance shall fulfil the requirements and test
procedure according to EN 253.
The test shall be carried out on a single pipe assembly in accordance with EN 253 using the same foam
recipe and production method as used for the production of twin pipes.
4.7.8 Thermal conductivity
When tested in accordance with EN 253 the thermal conductivity in unaged condition shall be in
accordance with EN 253.
The test shall be carried out on a single pipe assembly in accordance with EN 253 using the same foam
recipe and production method as used for the production of twin pipes.
4.7.9 Surface conditions at delivery
The surface conditions at delivery shall be in accordance with EN 253.
4.7.10 Measuring wires for surveillance systems
Measuring wires, if any, shall comply with EN 14419.
4.8 Installation, operatio
...