SIST EN 488:2011

SLOVENSKI STANDARD
oSIST prEN 488:2009
01-junij-2009
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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: prEN 488
ICS:
23.040.10 Železne in jeklene cevi Iron and steel pipes
23.060.01 Ventili na splošno Valves in general
91.140.65 Oprema za ogrevanje vode Water heating equipment
oSIST prEN 488:2009 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 488:2009

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oSIST prEN 488:2009
EUROPEAN STANDARD
DRAFT
prEN 488
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2009
ICS 23.060.01 Will supersede EN 488:2003
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 tuyaux Fernwärmerohre - Werkmässig gedämmte
pré-isolés pour les réseaux d''eau chaude enterrés Verbundmantelrohrsysteme für direkt erdverlegte
directement - Robinets pré-isolés pour tubes de service en Fernwärmenetze - Vorgedämmte Absperrarmaturen für
acier, isolation thermique en polyuréthane et tube de Stahlmediumrohre mit Polyurethan-Wärmedämmung und
protection en polyéthylène Außenmantel 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 Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland 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
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 488:2009: E
worldwide for CEN national Members.

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oSIST prEN 488:2009
prEN 488:2009 (E)
Contents Page
Foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Requirements. 9
4.1 Pressure ratings for valves . 9
4.1.1 General . 9
4.1.2 Valves without indicated flow direction . 9
4.2 Service temperatures for valves . 9
4.3 Steel parts . 9
4.3.1 Valve Body . 9
4.3.2 Valve steel pipe. 9
4.3.3 Welding ends . 9
4.3.4 Welding . 11
4.4 Casing . 12
4.4.1 General . 12
4.4.2 Requirements for polyethylene welding . 12
4.4.3 Diameter and wall thickness of the casing . 12
4.5 Polyurethane rigid foam insulation (PUR) . 12
4.5.1 General . 12
4.5.2 Minimum insulation thickness . 12
4.6 Valve assembly . 12
4.6.1 Ends of valve assembly . 12
4.6.2 End of stem construction . 12
4.6.3 Tolerances on the main dimensions . 13
4.6.4 Installation of measuring elements . 14
4.7 Requirements for effective operation and maintenance . 14
4.8 Resistance to axial forces and bending moments. 15
5 Testing, test methods and test requirements . 15
5.1 General . 15
5.2 Test specimens. 15
5.2.1 General . 15
5.2.2 Test specimens for type testing steel parts of valve . 15
5.2.3 Test specimens from casings and polyurethane foam . 15
5.3 Steel parts . 15
5.3.1 Type test . 15
5.3.2 Leak-tightness of shell and stem casing . 16
5.3.3 Leak-tightness of the seat . 16
5.3.4 Torque load measurement of unloaded valve . 16
5.3.5 Axial compressive force test . 16
5.3.6 Axial tensile force test . 17
5.3.7 Bending test . 17
5.3.8 Testing of steel welds . 18
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
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5.7 Surveillance system . 18
5.8 Leak testing of valves . 18
6 Marking . 18
6.1 General . 18
6.1.1 Steel valve . 18
6.1.2 Casing . 19
6.1.3 Valve assembly . 19
7 Installation and maintenance . 19
Annex A (informative) Guidelines for inspection and testing . 20
Annex B (normative) Resistance to axial force and bending moment . 22
Annex C (normative) Resistance to bending forces . 24

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oSIST prEN 488:2009
prEN 488:2009 (E)
Foreword
This document (prEN 488:2009) has been prepared by Technical Committee CEN /TC 107, "Prefabricated
district heating pipe systems", the secretariat of which is held by DS.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 488:2003.
Annex A is informative.
This document includes a Bibliography.

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Introduction
The first edition of EN 488 was approved in 1994. A complete revised standard was published in 2003. The
main areas of the current revision are:
In general the whole standard has been edited to make it more readable requirements and test methods have
been separated therefore clause numbers have changed and clauses have been split up in other clauses.
Exact references for changes are not always possible.
a) The scope has been amended. The standard applies no longer only to insulated valve assemblies for
continuous operation with hot water at various temperatures in accordance with EN 253:2008, clause 1
but also to the valve assemblies with a maximum operation pressure of 25 bar. For higher pressure
additional demands apply. It is also explained that the calculation rules of loads and stresses are not
included. They depend on the configuration of the system as it is installed. The design and installation
rules are given in EN 13941:2003.
b) In Clause 3 ‘terms and definitions’, definitions for the nominal pressure (PN) and the nominal size (DN) are
added; A figure giving an example of a valve assembly and its components has been added.
c) Clause 4 ‘requirements’
 it is added that flange or screwed connections shall not be used except in the non-pressurized area
e.g. for the stem extensions (clause 4.3.1);
 the requirements for the use of stop devices are amended (clause 4.7);
 the minimum water temperature has been adjusted to 4 ºC (clause 4.2);
 the new clause 4.3.3 has been changed and adjusted to EN 13941:2003 and the text in
EN 448:2008;
 Clause 4.1.6 has become Clause 4.8 “resistance to axial forces bending moments” and has been
rewritten totally. For instance Clauses 5.3.1.4 and 5.3.1.6 have therefore been become renumbered
and rewritten;
 additions have been made to the requirements to the corrosion protection of the stem (see 4.6);
 the clause ‘increase in diameter’ has been changed to ‘diameter and wall thickness of the casing’
(see 4.4.3);
 a table with the tolerances of the main dimensions has been added together with a figure to explain
the dimensions (see 4.6.3);
 a clause was added about the installation of measuring elements for surveillance (see 4.6.4).
d) Clause 5 ‘test methods’
 the clause ‘construction testing of the valves’ has been adjusted to make the order of test more clear
(see 5.3.1);
 a test for the surveillance system is added (see 5.7).
e) Clause 6 ‘marking’
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 for the casing the date of manufacture has been changed to year and week of manufacture (see
6.1.2);
 for the valve assembly, the type of blowing agent has been added (see 6.1.3).
f) Annex A ‘guidelines for inspection and testing’
 the clause about quality surveillance had been changed in quality control (see A.2);
 a table for the valve fitting inspection had been added.
g) Former Annex B, the guidelines for installation of the valves has been deleted. New annexes B and C
have been added, in which the actual testing is included.
h) The former Table 1 “Service pipe dimensions and test forces” has been changed due to cold layer
conditions. Therefore the compressive forces have been adapted. In this table the maximum allowable
bending moments have been included and the table has been moved to Annex B.
i) A description of the test method for bending forces has been added in Annex C.

In general, references were changed were needed. If possible references to European standards were used.
For information on the minimum expected thermal life with operation at various temperatures with respect to
PUR foam performance see EN 253:2003.
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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 standard applies only to insulated valve assemblies for continuous operation with hot water at various
temperatures in accordance with EN 253:2008, clause 1 and the valve assemblies with a maximum operation
pressure of 25 bar. For higher pressures additional demands apply.
Guidelines for quality inspection are given in annex A of this standard.
NOTE For this application the following valve types are commonly used: ball valves, gate valves, and butterfly valves.
This standard does not include calculation rules of 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
This European Standard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text, and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to
this European Standard only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies (including amendments).
EN 19, Marking of general purpose industrial valves
EN 253:2008, 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 448:2003, 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 12266-1:2003, Industrial valves – Testing of valves – Part 1: Pressure tests, test procedures and
acceptance criteria – Mandatory requirements
EN 13941:2003, Design and installation of preinsulated bonded pipe systems for district heating
EN 14419:2004, District heating pipes – Preinsulated bonded pipe systems for directly buried hot water
networks – Surveillance systems
EN ISO 9001, Quality management systems – Requirements (ISO 9001:2000)
3 Terms and definitions
For the purposes of this European Standard, the terms and definitions given in EN 253 and EN 448 apply.
For definition of types of valves see EN 736-1.
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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 It comprises the letters PN followed by a dimensionless number.
NOTE 2 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 The designation PN is not meaningful unless it is related to the relevant component standard number.
NOTE 4 The allowable pressure of a pipe work component depends on the PN number, the material and design of the
component, its allowable temperature, etc., and is given in tables of pressure/temperature ratings specified in the
appropriate standards.
3.2
nominal size (DN)
numerical metric designation of size is common to components in piping systems of any one size
3.3
valve assembly
assembly of valve body and stem, valve steel pipe or welded end, PE- casing and PUR-foam
NOTE 5 Figure 1 gives an example a valve assembly and its components.

Key
a Valve body and d Service pipe
stem
b Welded ends or e Insulation
valve steel pipe
c Valve assembly

Figure 1  Example valve assembly components
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3.4
valve steel pipe
pipe part of the valve welded to the valve body
3.5
welding end on valve
welding end of the valve body
3.6
steel service pipe
service pipe according to EN 253:2008
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 test pressure of 1, 5 times the maximum operating pressure 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 253:2008, clause 1 and at a minimum water temperature of 4 °C.
4.3 Steel parts
4.3.1 Valve Body
The valve body shall be fully welded. Flange or screwed connections shall not be used except in the non-
pressurized area e.g. for the stem extensions.
4.3.2 Valve steel pipe
The quality of the valve steel pipe or welded end, to be welded to the valve body shall match with the steel
quality of the valve body.
The external diameter of the valve steel pipe at the welding ends shall match with the external diameter of the
welding ends of the valve body respectively the connecting steel service pipe.
4.3.3 Welding ends
The welding ends of the valve assembly shall match with the service pipe in accordance with EN 253:2008,
clause 4.2.2.
Pipe ends shall be prepared in accordance with the welding procedure used. When using covered electrodes
or gas-shielded metal-arc welding, pipe ends and fittings with equal wall thickness shall be prepared in
accordance with EN-ISO 9692:1994, Table 1.
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Table 2 of this standard is derived from EN-ISO 9692:1994 Table 1 and gives the relation between wall
thickness and reference number in Table 1.

Table 2  Preparation of service pipe ends, valve steel pipe and valve body ends for weldings
according to EN-ISO 9692:1994, Table 1

Wall thickness T of service Reference number table 1
pipe or valve steelpipe end of ISO 9692-1
T < 3 mm 1.2
3 mm ≤ T ≤ 10 mm 1.3
T > 10 mm 1.5

Welding ends with different wall thicknesses shall be prepared and adapted for misalignment in accordance
with table 3 and Figure 2 of this standard.
Table 3 - Adaptation of misalignment and difference in wall thickness
Misalignment Adaptation Remark
Difference in wall thickness
Misalignment h ≤ 0,3 t, max. 1 mm Figure 2 detail A Adjust to outside diameter
Misalignment 1 mm < h ≤ 10 mm Adaptation of pipe ends
Misalignment h > 10 mm Extra fitting Preinsulated reduction piece,
Length ≥ 5 times misalignment
Figure 2 detail B Adaptation of thicker wall t'
Differences in wall thickness: t' ≤ 1,5 t
n
Figure 2 detail C Adaptation both sides
Differences in wall thickness: t' > 1,5 t
n


Misalignment and preparation of butt welding ends shall be in accordance with Figure 2.
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Figure 2  Misalignment and preparation of butt welding ends
If the valve is painted, the welding ends shall be free from paint for at least 100 mm.
4.3.4 Welding
Fusion welding between steel valves and steel valve pipe, respectively between steel valve pipe and steel
service pipes shall be carried out in accordance with prEN 448:2008, clause 4.1.9.
To make a good welding the quality of the steel of the valve body shall match with steel of the service pipes in
accordance with 4.3.2 of this standard.
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4.4 Casing
4.4.1 General
The casing shall be in accordance with EN 448:2003, clause 4.2 and EN 253:2008.
4.4.2 Requirements for polyethylene welding
The general requirements for polyethylene welding shall be in accordance with EN 448:2003, clause 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 448:2003, clause 4.4.5.
4.5 Polyurethane rigid foam insulation (PUR)
4.5.1 General
The polyurethane rigid foam insulation (PUR) shall be in accordance with prEN 448:2008, clause 4.3.
4.5.2 Minimum insulation thickness
The minimum insulation thickness shall be in accordance with EN 448:2003, clause 4.4.6.
4.6 Valve assembly
4.6.1 Ends of valve assembly
4.6.1.1 General
The ends of the valve steel pipe of the valve assembly shall be prepared for welding according 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 service pipe and the casing at the ends of the valve assembly
shall not exceed the limits, given in EN 253:2008, 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 service pipe at the length of
0
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
The selection of the materials is the responsibility of the manufacturer, provided that they satisfy the following
requirements.
The valve shall be protected against corrosion during the service life of the valve assembly.
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The valve construction shall withstand the aggressive underground condition such as heat, cold, moisture,
ground water and salty water.
Where the stem construction passes through the casing, there shall be an arrangement to protect against
water ingress to the insulation.
The stem construction outside the insulation shall be made of corrosion resistant material or be permanently
protected against corrosion. This protection has to be added at the length of at least 100 mm from the top of
the ‘stem house’ (see Figure 3).

Figure 3  Anti corrosion protection of the stem construction

4.6.3 Tolerances on the main dimensions
The tolerances of the main fitting dimensions shown in Figure 4 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

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Figure 4  Main dimensions
4.6.4 Installation of measuring elements
Measuring elements for surveillance systems shall be installed in accordance with EN 14419:2004, clause 6.3.
4.7 Requirements for effective operation and maintenance
The design of the valve shall make it possible to operate the valve outside the insulation.
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/ 35 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
27/32 mm.
Valves shall be provided with a stop device that can be replaced without removing the insulation. Alternatively
an integrated stop device can be used. The integrated stop device must be designed to resist a maximum
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