EN 488:2019

SLOVENSKI STANDARD
01-januar-2020
Nadomešča:
SIST EN 488:2016
Cevi za daljinsko ogrevanje - Poviti enocevni sistemi za neposredno vkopana
vročevodna omrežja - 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
- Factory made steel valve assembly for steel service pipes, polyurethane thermal
insulation and a casing of polyethylene
Fernwärmerohre - Werkmäßig gedämmte Verbundmantelrohrsysteme für direkt
erdverlegte Fernwärmenetze - Vorgedämmte Absperrarmaturen für Stahlmediumrohre
mit Polyurethan-Wärmedämmung und Außenmantel aus Polyethylen
Tuyaux de chauffage urbain - Systèmes bloqués monotubes pour les réseaux d'eau
chaude enterrés directement - Assemblages d'appareils de robinetterie manufacturés
pour tubes de service en acier, isolation thermique en polyuréthane et tube de protection
en polyéthylène
Ta slovenski standard je istoveten z: EN 488:2019
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
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 488
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2019
EUROPÄISCHE NORM
ICS 23.060.01 Supersedes EN 488:2015
English Version
District heating pipes - Bonded single pipe systems for
directly buried hot water networks - Factory made steel
valve assembly for steel service pipes, polyurethane
thermal insulation and a casing of polyethylene
Tuyaux de chauffage urbain - Systèmes bloqués Fernwärmerohre - Werkmäßig gedämmte
monotubes pour les réseaux d'eau chaude enterrés Verbundmantelrohrsysteme für direkt erdverlegte
directement - Assemblages d'appareils de robinetterie Fernwärmenetze - Vorgedämmte Absperrarmaturen
manufacturés pour tubes de service en acier, isolation für Stahlmediumrohre mit Polyurethan-
thermique en polyuréthane et tube de protection en Wärmedämmung und Außenmantel aus Polyethylen
polyéthylène
This European Standard was approved by CEN on 12 August 2019.

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, Turkey 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 488:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Requirements . 6
5 Testing, test methods and test requirements . 10
6 Marking . 15
7 Installation and maintenance . 16
Annex A (informative) Guidelines for inspection and testing . 17
Annex B (normative) Resistance to axial force and bending moment . 19
Annex C (normative) Resistance to bending forces . 21
Annex D (informative) Waste treatment and recycling . 25
Bibliography . 26
European foreword
This document (EN 488:2019) 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 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 April 2020, and conflicting national standards shall be
withdrawn at the latest by April 2020.
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 488:2015.
In comparison with the previous edition, the main changes in this new edition of EN 488 are:
— editorial changes to the new structure of standards prepared by the Technical Committee
CEN/TC 107.
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, Turkey and the
United Kingdom.
Introduction
EN 488 has also been aligned with EN 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;
— EN 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 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 directly buried hot water
networks — Surveillance systems;
— EN 15632 (all parts), District heating pipes — Pre-insulated flexible pipe systems;
— 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 17248, District heating and district cooling pipe systems — Terms and definitions.
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, rigid
polyurethane foam thermal insulation and a casing of polyethylene.
The valve assembly could 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
EN 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 10088-1:2014, Stainless steels — Part 1: List of stainless steels
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 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 17248, District heating and district cooling pipe systems — Terms and definitions
EN ISO 12944-2, Paints and varnishes — Corrosion protection of steel structures by protective paint
systems — Part 2: Classification of environments (ISO 12944-2)
EN ISO 12944-5, Paints and varnishes — Corrosion protection of steel structures by protective paint
systems — Part 5: Protective paint systems (ISO 12944-5)
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 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
4 Requirements
4.1 Pressure ratings for valves
4.1.1 General
The valves shall be designed for use in pipe systems with a maximum operating pressure of 1,6 MPa or
2,5 MPa.
The valves shall be able to withstand a strength test pressure of the district heating system of 1,3
times the maximum operating pressure at ambient temperature in open and closed position.
4.1.2 Valves without indicated flow direction
Valves without an indicated flow direction shall support the pressure load in both directions.
4.2 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 4 °C.
4.3 Steel parts
4.3.1 General
Steel grades are specified in EN 13941-1.
All valves, steel 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 customer
who orders the factory made valve assemblies, this information shall be given while placing the order
with the manufacturer of the factory made valve assemblies.
Any later request for provision of such documentation can be too late and can possibly not be met by
the manufacturer, since the manufacturer shall organize the assignment of 3.1 certificates to valves and
valve assemblies before starting the production.
4.3.2 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.
4.3.3 Valve extension pipe
The quality of the valve body shall match with the quality of the valve extension pipe.
4.3.4 Welding ends
The welding ends of the valve assembly shall match with the service pipe in accordance with
EN 13941-2.
Pipe ends shall be prepared in accordance with EN 448.
4.3.5 Welding of steel parts
Fusion welding between valves and valve extension pipe, shall be carried out in accordance with
EN 448
The quality of the steel at the welding ends of the valve or valve assembly shall match with steel of the
service pipes.
Welding of pressurized parts of the valve assembly shall comply with EN 448.
4.4 Casing
4.4.1 General
The casing shall be in accordance with EN 448 and EN 253.
4.4.2 Requirements for polyethylene welding
The general requirements for polyethylene welding shall be in accordance with EN 448.
4.4.3 Diameter and wall thickness of the casing
The outside diameter and the minimum wall thickness of the casing shall be in accordance with EN 253.
4.5 Polyurethane (PUR) foam thermal insulation
4.5.1 General
The requirements for thermal insulation shall be the same as in EN 253 when tested in accordance with
5.5 of this document.
4.5.2 Minimum thickness of thermal insulation
The minimum thickness of thermal insulation shall be in accordance with EN 448.
4.6 Valve assembly
4.6.1 Ends of valve assembly
4.6.1.1 General
The ends of the valve extension pipe of the valve assembly shall be prepared for welding according to
4.3.3 and shall be free from thermal insulation in accordance with EN 253.
4.6.1.2 Centre line deviation
The distance between the centre lines of the valve extension pipe 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.
4.6.1.3 Angular deviation
The angular deviation between the centre lines of the not insulated ends of the valve extension pipe at
the length of 100 mm from the ends shall not exceed 2°.
The angular deviation shall be measured between the centre lines with the largest deviation.
4.6.2 End of stem construction
To ensure a long service life of the end stem passing through the casing, it 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 as defined in EN 10088-1:2014, 3.1, however minimum specified Cr-
content is 16 %. 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.
— or made from carbon steel and protected by a paint system securing durability range “high”
according to EN ISO 12944-5. Underground installed valves shall be suitable for corrosivity
categories of Im1, Im2 and Im3 according to EN ISO 12944-2 and for atmospheric-corrosivity
categories C5-M and C5-I according to EN ISO 12944-2.
Specifically used paint system shall be according to EN ISO 12944-5 and documented by
appropriate quality management system.
The protection by corrosion resistant material or corrosion protecting paint 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 High offset
Figure 1 — Anti corrosion protection of the stem construction
4.6.3 Main dimensions of the valve assembly
The main dimensions of the valve assembly H and L are shown in Figure 2.
The values of the main dimensions “L” and “H” shall be declared by the manufacturer.
The tolerances of the valve assembly dimensions shown in Figure 2 shall be in accordance with Table 1.
Table 1 — Tolerances on the main valve dimensions
DN H L
mm mm
≤ 300 ±5 ±20
> 300 ±10 ±50
Figure 2 — Main dimensions
4.6.4 Installation of measuring elements
Measuring elements for surveillance systems shall be in accordance with EN 14419.
4.7 Requirements for effective operation and maintenance
The design of the valve shall make it possible to operate the valve outside the thermal insulation and
the casing.
The valve shall close when turned clockwise and open when turned anti-clockwise.
The stem construction shall make it possible to manoeuvre the valve by means of a T key from ground
level.
NOTE 1 Commonly used keyways are 19 mm, 27 mm, 36 mm, 50 mm and 60 mm or conical quadrangle
27 mm/ 32 mm.
Butterfly valves with nominal diameter DN 100 and larger, ball valves and gate valves with nominal
diameter DN 200 and larger shall be provided with a gear or a connection for an actuator to ensure
controlled manoeuvring of the valve.
NOTE 2 Commonly used keyways for connections for actuators are 60 mm, 70 mm and 90 mm, or conical
quadrangle 27 mm/32 mm.
Valves shall be provided with a stop device that can be replaced without removing the thermal
insulation and the casing. Alternatively, an internal stop device can be used. The internal stop device
shall be designed to resist a maximum strength torque of at least twice the maximum operating torque
specified by the manufacturer with a minimum of 150 Nm in the fully open and fully closed position of
the valve. Using an internal stop device, the valve stem shall be designed to resist a maximum strength
torque of at least 1,5 times the designed strength torque of the stop device.
The sealing around the stem shall be capable of being maintained without removing the thermal
insulation and the casing.
4.8 Resistance to axial forces and bending moments
The resistance of the valves to axial forces and bending moments shall comply with Table B.1.
5 Testing, test methods and test requirements
5.1 General
This clause specifies test methods, test sequence, test conditions and required test results for type and
production testing.
Where test requirements specified in this document differ from those in other standards referred to, the
requirements described in this document shall apply.
NOTE Informative Annex A of this d gives guidelines for inspection and testing.
5.2 Test specimens
5.2.1 General
Test specimens shall be representative for the production.
5.2.2 Test specimens for type testing steel parts of valve
The tests for axial forces, bending moments and torque are type tests for a range of valves with the
same construction principle, design and materials.
To qualify a whole product range with the same construction principle, design and materials, two valve
sizes within this product range shall be tested. The qualification shall be valid from half the size of the
smaller valve (but limited by smallest valve size of the product range under consideration) and twice
the size of the bigger valve (but limited by the largest valve size of the product range under
consideration) which were tested.
If the construction principle, design and materials are not the same for the whole product range, the
product range shall be split in separate ranges (where the construction principle, design and materials
are the same) and the above mentioned rule shall be applied to each split range. The manufacturer is
responsible to ensure that the complete test sequence as specified in this document is carried out and
all test results are documented.
5.2.3 Test specimens from casings and thermal insulation
The test specimens from casing and thermal insulation shall be taken in accordance with EN 448.
5.3 Steel parts
5.3.1 General
This clause describes the type test and production test of the steel parts.
5.3.2 Type test of the steel parts
5.3.2.1 General
The type test shall be done on the same valve.
The type test shall be carried out on the same valve for the whole test sequence and executed in the
order given in Table 2. The mandatory clauses shall be carried out as a minimum in the test program.
Table 2 — Overview and sequence of the type test program
Test sequence Name of the test
Mandator Optional
y clauses clauses
5.3.2.2 Leak-tightness of shell and stem casing of the unloaded valve
5.3.2.3 Leak-tightness of the seat of the unloaded valve
5.3.2.4  Torque load measur
...