EN 488:2015

SLOVENSKI STANDARD
01-januar-2016
1DGRPHãþD
SIST EN 488:2011+A1:2014
&HYL]DGDOMLQVNRRJUHYDQMH,]ROLUDQLYH]DQLFHYQLVLVWHPL]DSRG]HPHOMVND
WRSORYRGQDRPUHåMD6HVWDYMHNOHQLKYHQWLORY]DMHNOHQHFHYLSROLXUHWDQVNR
WRSORWQRL]RODFLMRLQ]XQDQMLSROLHWLOHQVNLSODãþ
District heating pipes - Preinsulated bonded pipe systems for directly buried hot water
networks - Steel valve assembly for steel service pipes, polyurethane thermal insulation
and outer 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 de tuyaux préisolés pour les réseaux
d'eau chaude enterrés directement - Robinets préisolés pour tubes de service en acier,
isolation thermique en polyuréthane et tube de protection en polyéthylène
Ta slovenski standard je istoveten z: EN 488:2015
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
November 2015
EUROPÄISCHE NORM
ICS 23.060.01 Supersedes EN 488:2011+A1:2014
English Version
District heating pipes - Preinsulated bonded pipe systems
for directly buried hot water networks - Steel valve
assembly for steel service pipes, polyurethane thermal
insulation and outer casing of polyethylene
Tuyaux de chauffage urbain - Systèmes bloqués de Fernwärmerohre - Werkmäßig gedämmte
tuyaux préisolés pour les réseaux d'eau chaude Verbundmantelrohrsysteme für direkt erdverlegte
enterrés directement - Robinets préisolés pour tubes Fernwärmenetze - Vorgedämmte Absperrarmaturen
de service en acier, isolation thermique en für Stahlmediumrohre mit Polyurethan-
polyuréthane et tube de protection en polyéthylène Wärmedämmung und Außenmantel aus Polyethylen
This European Standard was approved by CEN on 5 September 2015.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 488:2015 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Requirements . 8
4.1 Pressure ratings for valves . 8
4.1.1 General . 8
4.1.2 Valves without indicated flow direction . 8
4.2 Service temperatures for valves . 9
4.3 Steel parts . 9
4.3.1 General . 9
4.3.2 Valve. 9
4.3.3 Valve extension pipe . 9
4.3.4 Welding ends . 9
4.3.5 Welding of steel parts . 9
4.4 Casing . 9
4.4.1 General . 9
4.4.2 Requirements for polyethylene welding . 9
4.4.3 Diameter and wall thickness of the casing . 10
4.5 Polyurethane rigid foam insulation (PUR) . 10
4.5.1 General . 10
4.5.2 Minimum insulation thickness . 10
4.6 Valve assembly . 10
4.6.1 Ends of valve assembly . 10
4.6.2 End of stem construction . 10
4.6.3 Main dimensions of the valve assembly . 11
4.6.4 Installation of measuring elements . 12
4.7 Requirements for effective operation and maintenance . 12
4.8 Resistance to axial forces and bending moments. 12
5 Testing, test methods and test requirements . 13
5.1 General . 13
5.2 Test specimens . 13
5.2.1 General . 13
5.2.2 Test specimens for type testing steel parts of valve . 13
5.2.3 Test specimens from casings and polyurethane foam . 13
5.3 Steel parts . 13
5.3.1 General . 13
5.3.2 Type test of the steel parts . 13
5.3.3 Production testing of valves . 17
5.4 Casing . 18
5.4.1 General . 18
5.4.2 Leak-tightness of the welded casing . 18
5.5 Polyurethane rigid foam insulation . 18
5.6 Valve assembly . 18
5.7 Surveillance system . 18
6 Marking . 18
6.1 General . 18
6.2 Steel valve . 18
6.3 Casing . 18
6.4 Valve assembly . 19
7 Installation and maintenance . 19
Annex A (informative) Guidelines for inspection and testing . 20
A.1 General . 20
A.2 Manufacturer’s type test . 20
A.3 Manufacturer’s quality control . 20
A.4 External inspection . 20
A.5 Extent of inspection . 20
A.6 Manufacturer’s responsibility . 20
Annex B (normative) Resistance to axial force and bending moment . 22
B.1 Axial strength test . 22
B.2 Bending test . 22
Annex C (normative) Resistance to bending forces . 24
C.1 General . 24
C.2 Standard test assembly (four point bending test) . 25
Bibliography . 29

European foreword
This document (EN 488:2015) 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 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 May 2016, and conflicting national standards shall be
withdrawn at the latest by May 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN 488:2011+A1:2014.
In comparison with the previous edition, the main changes in EN 488:2015 are:
— improvement and simplification of the type test of the steel valve. The cycle test has been
integrated in the test sequence;
— the formulae in Annex C for the calculation of bending forces have been improved. C.1.3 of
EN 488:2011+A1:2014 concerning alternative test application for diameters DN ≤ 200 mm, has
been deleted.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, 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 — Preinsulated bonded pipe systems for directly buried hot water
networks — Pipe assembly of steel service pipe, polyurethane thermal insulation and outer casing of
polyethylene;
— EN 448, District heating pipes — Preinsulated bonded pipe systems for directly buried hot water
networks — Fitting assemblies of steel service pipes, polyurethane thermal insulation and outer casing
of polyethylene;
— EN 489, District heating pipes — Preinsulated bonded pipe systems for directly buried hot water
networks — Joint assembly for steel service pipes, polyurethane thermal insulation and outer casing of
polyethylene;
— EN 13941, Design and installation of preinsulated bonded pipe systems for district heating;
— EN 14419, District heating pipes — Preinsulated bonded 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 — Preinsulated bonded twin pipe systems for directly buried hot
water networks — Part 1: Twin pipe assembly of steel service pipe, polyurethane thermal insulation
and outer casing of polyethylene;
— EN 15698-2, District heating pipes — Preinsulated bonded twin pipe systems for directly buried hot
water networks — Part 2: Fitting and valve assembly of steel service pipes, polyurethane thermal
insulation and outer casing of polyethylene.
1 Scope
This European Standard specifies requirements and test methods for valves of prefabricated thermally
insulated valve assemblies comprising a steel valve, rigid polyurethane foam insulation and an outer
casing of polyethylene for use in directly buried hot water networks with pre-insulated pipe assemblies
in accordance with EN 253.
This European Standard applies only to factory made prefabricated insulated valve assemblies for
continuous operation with hot water at various temperatures in accordance with
EN 253:2009+A2:2015, Clause 1 and the valve assemblies with a maximum operation pressure of
25 bar. For higher pressures, additional demands apply.
NOTE For this application, the following valve types are commonly used: ball valves, gate valves, and
butterfly valves.
This European Standard does not include calculation rules for loads and stresses. These depend on the
configuration of the system as it is installed. The design and installation rules are given in EN 13941.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 253:2009+A2:2015, District heating pipes — Preinsulated bonded pipe systems for directly buried hot
water networks — Pipe assembly of steel service pipe, polyurethane thermal insulation and outer casing of
polyethylene
EN 448:2015, District heating pipes — Preinsulated bonded pipe systems for directly buried hot water
networks — Fitting assemblies of steel service pipes, polyurethane thermal insulation and outer 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 12502-4, Protection of metallic materials against corrosion — Guidance on the assessment of
corrosion likelihood in water distribution and storage systems — Part 4: Influencing factors for stainless
steels
EN 13941:2009+A1:2010, Design and installation of preinsulated bonded pipe systems for district heating
EN 14419, District heating pipes — Preinsulated bonded pipe systems for directly buried hot water
networks — Surveillance systems
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 253:2009+A2:2015 and
EN 448 and the following apply. For types of valves, the terms and definitions given in EN 736-1 apply.
3.1
nominal pressure (PN) class
alphanumeric designation used for reference purposes related to a combination of mechanical and
dimensional characteristics of a component of a pipe work system
Note 1 to entry: It comprises the letters PN followed by a dimensionless number.
Note 2 to entry: The number following the letters PN does not represent a measurable value and should not be
used for calculation purposes except where specified in the relevant standard.
Note 3 to entry: The designation PN is not meaningful unless it is related to the relevant component standard
number.
Note 4 to entry: The maximum allowable pressure of a pipework component depends on the PN number, the
material and design of the component, its maximum allowable temperature, etc. The relevant European
Component standards include tables of specified pressure/temperature ratings or, in minimum, include rules how
to determine pressure/temperature ratings.
Note 5 to entry: It is intended that all components with the same PN and DN designations have the same mating
dimensions for compatible flange types.
[SOURCE: EN 1333:2006, 2.1, modified – added Note 1 to entry.]
3.2
maximum operation pressure
maximum internal pressure acting against the pipe wall at any point or in any section of the pipeline at
a given operating temperature
[SOURCE: EN 13941:2009+A1:2010, 3.1.19, modified]
3.3
nominal size
DN
alphanumeric designation of size, common to components in piping systems which are used for
reference purposes
[SOURCE: EN ISO 6708:1995, 2.1, modified]
3.4
valve assembly
assembly of valve, valve extension pipe, PE-casing and PUR-foam
Note 1 to entry: Figure 1 gives an example of a valve assembly and its components.
Key
a valve
b valve extension pipe
c valve assembly
d service pipe
e insulation
Figure 1 — Example valve assembly components
3.5
valve
part of the valve assembly supplied by the valve manufacturer (with or without valve extension pipe)
3.6
valve extension pipe
pipe part of the valve assembly welded to the valve
Note 1 to entry: The valve extension may be required before the insulation process. This can be done by the
valve manufacturer or the insulation manufacturer. The valve can be extended with valve extension pipes before
insulation or delivered by the valve manufacturer with extensions.
3.7
steel service pipe
service pipe according to EN 253:2009+A2:2015
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 16 bar or
25 bar.
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 253:2009+A2:2015 and at a minimum water temperature of 4 °C.
4.3 Steel parts
4.3.1 General
All valves, steel pipes and steel components used for manufacturing of valve assemblies under the scope
of this European Standard shall as a minimum be delivered to the manufacturer with an inspection
certificate 3.1 according to EN 10204. The manufacturer shall keep documentation of the inspection
certificates.
In case a material related inspection certificate 3.1 according to EN 10204 is required by the client who
orders the preinsulated valve assemblies, this information shall be given while placing the order with
the manufacturer of the preinsulated valve assemblies.
NOTE Any later request for provision of such documentation can be too late and can possibly not be met by
the manufacturer, since the manufacturer has to 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 253:2009+A2:2015, 4.2.2.
Pipe ends shall be prepared in accordance with EN 448:2015, 4.1.10.3.
4.3.5 Welding of steel parts
Fusion welding between valves and valve extension pipe, shall be carried out in accordance with
EN 448:2015, 4.1.10.
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 448:2015, 4.1.10.2 and
4.1.10.5.
4.4 Casing
4.4.1 General
The casing shall be in accordance with EN 448:2015 and EN 253:2009+A2:2015.
4.4.2 Requirements for polyethylene welding
The general requirements for polyethylene welding shall be in accordance with EN 448:2015, 4.4.3.
4.4.3 Diameter and wall thickness of the casing
The outside diameter and the minimum wall thickness of the PE casing shall be in accordance with
EN 448:2015, 4.4.5.
4.5 Polyurethane rigid foam insulation (PUR)
4.5.1 General
The requirements for PUR shall be the same as in EN 448:2015, 4.3 when tested in accordance with 5.5
of this European Standard.
4.5.2 Minimum insulation thickness
The minimum insulation thickness shall be in accordance with EN 448:2015, 4.4.6.
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 insulation for a minimum length of 150 mm. The tolerance in the declared
value shall be ± 10 mm.
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 253:2009+A2:2015, Table 7.
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
insulation.
The stem construction outside the 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 d
...