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

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+A1:2013, 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.

Fernwärmerohre - Werkmäßig gedämmte Verbundmantelrohrsysteme für direkt erdverlegte Fernwärmenetze - Vorgedämmte Absperrarmaturen für Stahlmediumrohre mit Polyurethan-Wärmedämmung und Außenmantel aus Polyethylen

Diese Europäische Norm legt Anforderungen an und Prüfverfahren für werkmäßig wärmegedämmte Absperr¬armaturen fest, die eine Stahlarmatur, eine Wärmedämmung aus Polyurethan-Hartschaumstoff und eine Um¬mantelung aus Polyethylen umfassen und in direkt erdverlegten Fernwärmenetzen mit werkmäßig gedämmten Verbund-Rohrsystemen nach EN 253 verwendet werden.
Diese Europäische Norm gilt ausschließlich für werkmäßig wärmegedämmte Absperrarmaturen für einen Dauerbetrieb mit Warmwasser bei verschiedenen Betriebstemperaturen nach EN 253:2009+A2:2015, Abschnitt 1, sowie Absperrarmaturen mit einem maximalen Betriebsdruck von 25 bar. Für höhere Drücke gelten zusätzliche Anforderungen.
ANMERKUNG   Für diese Anwendung werden gewöhnlich folgende Grundbauarten von Armaturen eingesetzt: Kugel-ventile, Klappen und Schieber.
Diese Europäische Norm enthält keine Regeln zur Berechnung von Belastungen und Spannungen. Diese sind von der Konfiguration des Systems bei dessen Installation abhängig. Regeln für Auslegung und Installation sind EN 13941 zu entnehmen.

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

La présente Norme européenne spécifie les caractéristiques et les méthodes d’essai des robinets préisolés préfabriqués isolés thermiquement constitués d’un appareil de robinetterie en acier, d’un isolant en mousse rigide de polyuréthanne et d’une protection en polyéthylène pour une utilisation sur des réseaux d’eau chaude enterrés directement comportant des assemblages de tuyaux préisolés conformes à l’EN 253.
La présente Norme européenne s'applique uniquement aux assemblages d'appareils de robinetterie isolés préfabriqués en usine destinés à un fonctionnement en continu avec de l'eau chaude aux diverses températures indiquées dans l'EN 253:2009+A1:2013, Article 1, mais également aux assemblages de robinetterie avec une pression de service maximale de 25 bar. Pour des pressions supérieures, des exigences supplémentaires s'appliquent.
NOTE   Les types de robinet suivants sont communément utilisés dans ce genre d’application : robinets à tournant sphérique, robinets à tournant conique et robinets à papillon.
La présente Norme européenne ne comprend pas de règles de calcul pour les charges et les contraintes. Celles-ci dépendent de la configuration du système lors de son installation. Les règles de conception et d'installation sont données dans l'EN 13941.

Cevi za daljinsko ogrevanje - Izolirani vezani cevni sistemi za podzemeljska toplovodna omrežja - Sestav jeklenih ventilov za jeklene cevi, poliuretansko toplotno izolacijo in zunanji polietilenski plašč

Ta evropski standard določa zahteve in preskusne metode za ventile predizdelanih, toplotno izoliranih sestavov ventilov, sestavljenih iz jeklenih ventilov, trde poliuretanske izolacijske pene in zunanjega polietilenskega plašča za uporabo v podzemeljskih toplovodnih omrežjih z izoliranimi vezanimi sistemi v skladu s standardom EN 253.
Ta evropski standard se uporablja samo za tovarniško izdelane izolirane sestave ventilov za neprekinjeno delovanje z vročo vodo pri različnih temperaturah v skladu s točko 1 standarda EN 253 in sestave ventilov z največjim obratovalnim tlakom 25 barov. Za višji tlak se uporabljajo dodatne zahteve.
OPOMBA: Za to uporabo se običajno uporabljajo naslednje vrste ventilov: krogelni ventili, zasuni in zaporne lopute.
Ta evropski standard ne zajema pravil za izračun obremenitev in napetosti. Te so odvisne od konfiguracije sistema ob vgradnji. Pravila za projektiranje in vgradnjo so navedena v standardu EN 13941.

General Information

Status
Withdrawn
Publication Date
03-Nov-2015
Withdrawal Date
15-Oct-2019
Current Stage
9960 - Withdrawal effective - Withdrawal
Completion Date
16-Oct-2019

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SLOVENSKI STANDARD
SIST EN 488:2016
01-januar-2016
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SIST EN 488:2011+A1:2014
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WRSORYRGQDRPUHåMD6HVWDYMHNOHQLKYHQWLORY]DMHNOHQHFHYLSROLXUHWDQVNR
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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: 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
SIST EN 488:2016 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 488:2016
---------------------- Page: 2 ----------------------
SIST EN 488:2016
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.
---------------------- Page: 3 ----------------------
SIST EN 488:2016
EN 488:2015 (E)
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

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SIST EN 488:2016
EN 488:2015 (E)

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

---------------------- Page: 5 ----------------------
SIST EN 488:2016
EN 488:2015 (E)
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.
---------------------- Page: 6 ----------------------
SIST EN 488:2016
EN 488:2015 (E)
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.
---------------------- Page: 7 ----------------------
SIST EN 488:2016
EN 488:2015 (E)
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)
---------------------- Page: 8 ----------------------
SIST EN 488:2016
EN 488:2015 (E)

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

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.

---------------------- Page: 9 ----------------------
SIST EN 488:2016
EN 488:2015 (E)
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.

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SIST EN 488:2016
EN 488:2015 (E)
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.

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SIST EN 488:2016
EN 488:2015 (E)
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 documented by appropriate quality management system;

NOTE 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

---------------------- Page: 12 ----------------------
SIST EN 488:2016
EN 488:2015 (E)

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 2).
Figure 2 — Anti corrosion protection of the stem construction
4.6.3 Main dimensions of the valve assembly
The main dimensions of the v
...

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