Oesign and installation of preinsulated bonded pipe systems for district heating

EN 13941:2009 + Design and installation of preinsulated bonded pipe systems for district heating

EUROPEAN STANDARD

NORME EUROPEENNE

EUROPAISCHE NORM

Supersedes EN 13941:2009
English Version
Design and installation of preinsulated bonded pipe systems fordistrict heating
This European Standard was approved by CEN on 23 May 2009 and includes Corrigendum 1 issued by CEN on 11 November 2009 and Amendment 1 approved by CEN on 15 May 2010.
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 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 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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

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Contents Page
Foreword 5
Introduction 6
1 Scope 8
2 Normative references _8
3 Terms and definitions, units and symbols 10
3.1 Terms and definitions 10
3.2 Units and symbols 15
3.2.1 Units 15
3.2.2 Symbols 16
4 General considerations for system design 18
4.1 General requirements 1 4.2 Service life 18
4.3 Preliminary investigations 18
4.4 Determination of project class 1S
4.4.1 Risk assessment 19
4.4.2 Project classes 20
4.5 Design documentation 22
4.5.1 General 22
4.5.2 Operational data 22
4.5.3 Data related to the pipeline 22
4.5.4 Specifications for quality control 24
5 Components and materials 25
5.1 Basic requirements 25
5.1.1 E) General 5.1.2 B) Non standardised components 5.2 Steel pipe components 25
5.2.1 General 25
5.2.2 Technical delivery conditions and documentation 26
5.2.3 Characteristic values for steel 26
5.2.4 Specific requirements for bends and tees 27
5.2.5 Specific requirements for reducers and extensions 28
5.2.6 Specific requirements for other components 28
5.3 Polyurethane foam insulation 28
5.4 PE casing 29
5.5 Expansion cushions 29
5.6 Valves and accessories 29
5.6.1 General requirements 29
5.6.2 Marking and documentation 29
6 Actions and limit states 30
6.1 General 30
6.2 Simplified analysis procedure 32
6.3 Actions 32
6.3.1 General 32
6.3.2 Classification of actions 32
6.4 Limit states 34
6.4.1 General 34
6.4.2 Limit states for service pipes of steel 34
6.4.3 Composite stress conditions 42
6.4.4 Limit states for PUR and PE 43
6.4.5 Limit state for PE 43
6.4.6 Limit states for valves 44
7 Installation 44
7.1 General 44
7.2 Transportation and storage 45
7.3 Excavation of pipe trench 45
7.4 Installation of pipes and components 45
7.4.1 General 45
7.4.2 Steel pipes 46
7.4.3 PUR-PE Joints 46
7.4.4 Accessories 46
7.4.5 Expansion zones 46
7.5 Welding of the steel pipe and testing of the steel welds 46
7.5.1 General 46
7.5.2 Quality system for the different project classes 47
7.5.3 Qualification of the welding procedures 49
7.5.4 Welding consumables 49
7.5.5 Place and position of the weld 49
7.5.6 Performance of welding work 49
7.5.7 Special procedures 52
7.5.8 Documentation 54
7.6 Strength pressure test and leak tightness test 54
7.7 Assembly of casing pipes, joint installation and site insulation 55
7.8 Backfilling of trench 55
7.9 Pipe bends and other components 56
7.9.1 Pipe bends 56
7.9.2 Branches 56
7.9.3 Valves and accessories 57
7.10 Setting into operation 57
7.10.1 General 57
7.10.2 Filling with water for initial operation 57
7.10.3 Surveillance system 57
7.11 Special constructions 58
7.11.1 Special components 58
7.11.2 Above-ground pipelines with preinsulated pipes 58
7.11.3 Insertion into casing pipe 58
7.12 Construction work during the operation stage 58
Annex A (normative) Design of piping components under internal pressure 60
A.1 General 60
A.2 Symbols 60
A.3 Straight pipe and bends 61
A.4 Tees and branch connections 61
A.5 Reducers and extensions 64
A.6 Dished ends 65
Annex В? (informative) Geotechnics and pipe-soil interaction 67
B.1 Scope 67
B.2 Symbols and units 67
B.3 Soil parameters for global analysis (pipe-soil interaction) 68
B.4 Characteristic values for soil loads and soil parameters 78
B.5 Specific requirements for stability 79
B.6 Specific requirements for parallel excavations 82
B.7 Requirements for soft soils and settlement areas 82
B.8 Ovalization and circumferential stresses from top load 82
Annex C (informative) Global- and cross sectional analysis 89
C.1 General 89
C.2 Symbols 89
C.3 Survey of limit states for steel 91
C.4 Locations to be assessed 92
C.5 Actions 95
C.6 Global analysis 96
C.7 Calculation of stresses 103
C.8 Fatigue analysis 119
C.9 Further actions 120
Annex D (informative) Calculation of heat losses 121
D.1 General 121
D.2 Heat loss per pipe pair 121
D.3 Insulance of the soil 122
D.4 Insulance of the insulation material 122
D.5 Insulance of the heat exchange between flow and return pipe 123
Annex E (informative) |ac) National Bibliography 125Foreword
This document (EN 13941:2009+A1:2010) has been prepared by Technical Committee CEN/TC 107 “Prefabricated district heating 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 January 2011, and conflicting national standards shall be withdrawn at the latest by January 2011.
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 includes Corrigendum 1 issued by CEN on 11 November 2009 and Amendment 1 approved by CEN on 15 May 2010.
This document supersedes E) EN 13941:2009 The start and finish of text introduced or altered by amendment is indicated in the text by tags E) The modifications of the related CEN Corrigendum have been implemented at the appropriate places in the text and are indicated by the tags (ac> ( 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Introduction
The standard has been prepared by JWG1, a joint working group with CEN/TC267 "Industrial piping and pipelines".
According to the scope from CEN/TC 107:
—? The task of CEN/TC 107/TC267/JWG1 is to specify rules for design, calculation and installation for preinsulated bonded pipe systems for underground hot water networks with pipe assemblies co-ordinated with EN 253, EN 448, EN 488 and EN 489.
—? CEN/TC 107/TC267/JWG1 may also specify rules for functional tests for preinsulated bonded pipe systems for underground hot water networks.
—? The basic rules for design, calculation and installation should be based on functional requirements.
—? The purpose of the work is to provide uniform basis for the design, construction and operation of district heating systems, to ensure that the system is reliable and efficient and safe for the surrounding area, the environment and public health.
—? Joint assemblies for pipe systems dealt with should be co-ordinated with EN 489.
This standard takes account of experience acquired, of new knowledge available, of the behaviour of material and of distribution of stresses and allowable deformations and also evolution in installation techniques.
When use is made of the standard, the different sections of which it is made up must be interpreted as being interdependent and, because of this, cannot be dissociated.
The standard consists of a main part and four annexes.
Depending on the character of the individual clauses, distinction is made in this standard between Principles and Application Rules.
The principles comprise:
—? general statements, definitions and requirements, for which there is no alternative, as well as
—? requirements and analytical models for which no alternative is permitted unless specifically stated.
The principles are printed in normal typeface (10 point font).
The application rules are generally recognised rules, which follow the principles and satisfy their requirements.
Application rule:
The application rules and comments to principles and application rules are printed in a 8 point font. This is an application rule.
It is permissible to use alternative design rules from the application rules given in this standard, provided that it is shown that the alternative rule accords with the relevant principles and it is at least equivalent with regard to the resistance, serviceability and durability achieved by the system.
Annex A is part of the standard (principles). Annexes This standard contains a number of requirements aimed at ensuring the sound execution of distribution networks for district heating. To the extent possible, the requirements specified in this standard are functional requirements.
The requirements and regulations contained in this standard should be assessed and applied in compliance with