SIST EN 13941:2009
(Main)Design and installation of preinsulated bonded pipe systems for district heating
Design and installation of preinsulated bonded pipe systems for district heating
This European Standard specifies rules for design, calculation and installation for preinsulated bonded pipe systems for buried hot water distribution and transmission networks (cf. figure 2) with pipe assemblies in accordance with EN 253, for continuous operation with hot water at various temperatures up to 120şC and occasionally with peak temperatures up to 140şC and maximum internal pressure 25 bar (overpressure). Application rule: For larger pipe dimensions and pressures below 25 bar wall thickness bigger than specified in EN 253 can be required for straight pipes, bends and tees. The principles of the standard can be applied to preinsulated pipe systems with pressures higher than 25 bar, provided that special attention is paid to the effects of pressure. Adjacent pipes belonging to the network (e.g. pipes in ducts, valve chambers, road crossings above ground etc.) can be designed and installed according to this standard. The standard assumes use of treated water, which by softening, demineralisation, deaeration, adding of chemicals, or otherwise has been treated to prevent internal corrosion and deposits in the pipes. This standard is not applicable for such units as: - pumps, - exchangers, - boiler installations, tank installations, - consumer installations. However, the full functional ability and durability of such units should be ensured in consideration of the impacts from the district heating system and other impacts occurring from the conditions under which they have been installed. Guidelines for product quality inspection and in situ tests of joints are given in Annex A of EN 448:2003, Annex D of EN 253:2003, Annex A of EN 488:2003 and Annex B of EN 489:2003. Guidelines for welding of polyethylene casing are given in Annex B of EN 448:2003. The estimation of expected life with continuous operation at various temperatures is outlined in Annex B of EN 253:2003.
Auslegung und Installation von werkmäßig gedämmten Verbundmantelrohren für die Fernwärme
Diese Europäische Norm legt Auslegungs-, Berechnungs- und Verlegungsregeln für werkmäßig gedämmte
Verbundmantelrohrsysteme für erdverlegte Warmwasserverteilungs- und -transportnetze (siehe Bild 2) mit
Verbund-Rohrleitungssystemen nach EN 253 fest, die für den Dauerbetrieb mit Warmwasser bei unterschiedlichen
Temperaturen bis 120 °C und gelegentlichen Spitzentemperaturen bis 140 °C sowie bei
maximalem Innendruck von 25 bar (Überdruck) vorgesehen sind.
Anwendungsregel:
Für größere Rohrmaße und Drücke unter 25 bar kann für gerade Rohre, Bögen und T-Stücke eine höhere Wanddicke als die in EN 253
festgelegte erforderlich sein.
Die Grundsätze der Norm können auf werkmäßig gedämmte Rohrleitungssysteme mit Drücken über 25 bar angewendet werden,
vorausgesetzt, die Auswirkungen der Drücke werden besonders beachtet. Angrenzende Rohre, die zum Netz gehören (z. B. Rohre in
Kanälen, Armaturenschächten, oberirdische Straßenüberquerungen usw.), können entsprechend dieser Norm ausgelegt und verlegt
werden.
Die Norm setzt die Verwendung von aufbereitetem Wasser voraus, das durch Enthärtung, Entsalzung, Entlüftung,
Zusatz von Chemikalien oder auf andere Art und Weise so behandelt worden ist, dass innere Korrosion
und Ablagerungen in den Leitungen vermieden werden.
Diese Norm gilt nicht für Geräte bzw. Anlagen, wie z. B.
- Pumpen;
- Wärmetauscher;
- Kesselanlagen, Behälteranlagen;
- Einrichtungen der angeschlossenen Kundenanlagen.
Die volle Funktionsfähigkeit und Dauerhaftigkeit derartiger Geräte und Anlagen muss jedoch sichergestellt
werden, indem die Einwirkungen des Fernwärmenetzes und andere aus den Bedingungen resultierende
Einwirkungen berücksichtigt werden, unter denen sie installiert wurden.
Richtlinien für Produktqualitätskontrollen und Vor-Ort-Prüfungen von Verbindungen sind in Anhang A von
EN 448:2003, Anhang D von EN 253:2003, Anhang A von EN 488:2003 und Anhang B von EN 489:2003
angegeben.
Conception et installation des systèmes bloqués de tuyaux pré-isolés pour les réseaux enterrés d''eau chaude
La présente Norme européenne spécifie les règles de conception, de calcul et d'installation de systèmes bloqués
de tuyaux préisolés pour réseaux enterrés de distribution et de transmission d'eau chaude (voir Figure 2) avec des
tuyaux préisolés conformes à l’EN 253, pour une exploitation en continu avec de l’eau chaude à différentes
températures jusqu’à 120 °C, et occasionnellement avec des pics de température jusqu’à 140 °C et une pression
interne maximale de 25 bar (surpression).
Règle d’application :
Pour des tuyaux plus gros et des pressions inférieures à 25 bar, des épaisseurs de paroi plus importantes que celles spécifiées dans l’EN 253
peuvent être requises pour les tubes droits, les coudes et les tés.
Les principes de la présente norme peuvent être appliqués à des systèmes de tuyaux préisolés avec des pressions supérieures à 25 bar,
pourvu qu’il soit porté une attention spéciale aux effets de la pression. Les tuyaux adjacents appartenant au réseau (par exemple tubes en
caniveaux, chambres de vanne, traversée de route en aérien, etc.) peuvent être conçus et installés conformément à la présente norme.
La présente norme suppose l'utilisation d'eau traitée, par adoucissement, déminéralisation, désaération, ajout de
substances chimiques, ou par tout autre moyen permettant d'éviter la corrosion interne et les dépôts dans les
tuyaux.
La présente Norme n'est pas applicable aux éléments tels que :
a) pompes ;
b) échangeurs ;
c) chaudières, réservoirs ;
d) installations destinées au consommateur.
Cependant, il convient que la capacité et la durabilité maximales de ces éléments soient garanties par rapport aux
impacts provenant du système de chauffage urbain et aux autres impacts apparaissant dans les conditions dans
lesquelles ils ont été installés.
Les lignes directrices relatives à l’inspection de la qualité et aux essais sur site des produits sont indiquées à
l'Annexe A de l’EN 448:2009, à l'Annexe D de l’EN 253:2009, à l'Annexe A de l’EN 488:
Načrtovanje in vgradnja izoliranih vezanih cevnih sistemov za daljinsko ogrevanje
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Auslegung und Installation von werkmäßig gedämmten Verbundmantelrohren für die FernwärmeConception et installation des systèmes bloqués de tuyaux pré-isolés pour les réseaux enterrés d''eau chaudeDesign and installation of preinsulated bonded pipe systems for district heating91.140.10Sistemi centralnega ogrevanjaCentral heating systemsICS:Ta slovenski standard je istoveten z:EN 13941:2009SIST EN 13941:2009en,fr,de01-september-2009SIST EN 13941:2009SLOVENSKI
STANDARDSIST EN 13941:20041DGRPHãþD
SIST EN 13941:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13941July 2009ICS 91.140.10Supersedes EN 13941:2003
English VersionDesign and installation of preinsulated bonded pipe systems fordistrict heatingConception et installation des systèmes bloqués de tuyauxpréisolés pour les réseaux enterrés d'eau chaudeAuslegung und Installation von werkmäßig gedämmtenVerbundmantelrohren für die FernwärmeThis European Standard was approved by CEN on 23 May 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial 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.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre:
Avenue Marnix 17,
B-1000 Brussels© 2009 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13941:2009: ESIST EN 13941:2009
EN 13941:2009 (E)
2 Contents Page Foreword . 5Introduction . 61Scope . 82Normative references . 83Terms and definitions, units and symbols . 103.1Terms and definitions . 103.2Units and symbols . 144General considerations for system design . 174.1General requirements . 174.2Service life. 174.3Preliminary investigations . 174.4Determination of project class . 184.5Design documentation . 205Components and materials . 235.1Basic requirements . 235.2Steel pipe components . 245.3Polyurethane foam insulation . 275.4PE casing . 275.5Expansion cushions . 275.6Valves and accessories . 276Actions and limit states . 286.1General . 286.2Simplified analysis procedure . 306.3Actions . 306.4Limit states. 327Installation. 427.1General . 427.2Transportation and storage . 427.3Excavation of pipe trench . 437.4Installation of pipes and components . 437.5Welding of the steel pipe and testing of the steel welds . 447.6Strength pressure test and leak tightness test . 527.7Assembly of casing pipes, joint installation and site insulation . 537.8Backfilling of trench . 547.9Pipe bends and other components . 557.10Setting into operation . 567.11Special constructions . 567.12Construction work during the operation stage . 57Annex A (normative)
Design of piping components under internal pressure . 58A.1General . 58A.2Symbols . 58A.3Straight pipe and bends . 59A.3.1Straight pipes . 59A.3.2Bends . 59A.4Tees and branch connections. 59A.4.1General aspects and limitations . 59A.4.2Reinforcement . 60SIST EN 13941:2009
EN 13941:2009 (E)
3A.5Reducers and extensions . 62A.5.1General . 62A.5.2Minimum wall thickness of the cone . 62A.5.3Offset reducers . 63A.6Dished ends . 63A.6.1General . 63A.6.2Minimum required wall thickness for internal pressure . 64A.6.3Straight cylindrical shells . 64Annex B (informative)
Geotechnics and pipe-soil interaction . 65B.1Scope . 65B.1.1General . 65B.1.2General requirements . 65B.2Symbols and units . 65B.3Soil parameters for global analysis (pipe-soil interaction) . 66B.3.1Modelling pipe-soil interaction . 66B.3.2Pipe to soil friction (axial) . 67B.3.3Coefficient of horizontal soil reaction (lateral) . 69B.3.4Combined stiffness of PUR foam, expansion cushions and soil . 73B.4Characteristic values for soil loads and soil parameters . 75B.4.1General . 75B.4.2Soil mechanics study . 76B.5Specific requirements for stability . 77B.5.1General . 77B.5.2Vertical stability . 77B.5.3Horizontal stability . 79B.6Specific requirements for parallel excavations . 79B.6.1General . 79B.6.2Reduced friction . 79B.7Requirements for soft soils and settlement areas . 79B.7.1General . 79B.7.2Differential settlements . 80B.8Ovalization and circumferential stresses from top load . 80B.8.1Traffic load . 80B.8.2Stresses and ovalization from top load . 82B.8.3Deflection . 85Annex C (informative)
Global- and cross sectional analysis . 86C.1General . 86C.2Symbols . 86C.3Survey of limit states for steel . 88C.4Locations to be assessed . 89C.4.1Components to be considered . 89C.4.2Areas to be considered . 91C.5Actions . 92C.5.1General . 92C.5.2Action cycles . 92C.6Global analysis . 93C.6.1General . 93C.6.2Flexibility . 94C.6.3Boundary conditions . 95C.6.4Boundary conditions for
pipe systems with single use compensators (SUC’s) . 98C.7Calculation of stresses . 101C.7.1General . 101C.7.2Simplified procedure . 101C.7.3Cross section analyses, steel . 101C.7.4Straight pipes . 103C.7.5Bends . 105C.7.6Tees . 107C.7.7Other components . 112SIST EN 13941:2009
EN 13941:2009 (E)
4 C.7.8PUR foam and PE casing . 115C.8Fatigue analysis . 116C.8.1Fatigue strength data . 116C.8.2Fatigue strength data, detailed design . 117C.8.3Design fatigue lives . 117C.9Further actions . 117Annex D (informative)
Calculation of heat losses . 118D.1General . 118D.2Heat loss per pipe pair . 118D.3Insulance of the soil . 119D.4Insulance of the insulation material . 119D.5Insulance of the heat exchange between flow and return pipe . 119Bibliography . 120 SIST EN 13941:2009
EN 13941:2009 (E)
5Foreword This document (EN 13941:2009) 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 2010, and conflicting national standards shall be withdrawn at the latest by January 2010. 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 13941:2003. 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, 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. SIST EN 13941:2009
EN 13941:2009 (E)
6 Introduction The standard has been prepared by JWG1, a joint working group with CEN/TC 267 "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 B, C and D have status as application rules. SIST EN 13941:2009
EN 13941:2009 (E)
7This 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 the intentions of the standard and in due consideration of the development taking place in the field it concerns. It is therefore assumed that the user of the standard has the requisite technical insight and that the user of the standard has adequate knowledge of legal and other external regulations that are of consequence to the practical application of the standard. Special cases may occur within the scope of this standard in which its contents do not cover. An evaluation whether the contents cover shall be made in any specific case where the standard is used. Presently CEN/TC 107 "Pre-fabricated district heating pipe systems" is preparing standards for preinsulated flexible pipes and surveillance systems. SIST EN 13941:2009
EN 13941:2009 (E)
8 1 Scope This European Standard specifies rules for design, calculation and installation for preinsulated bonded pipe systems for buried hot water distribution and transmission networks (cf. figure 2) with pipe assemblies in accordance with EN 253, for continuous operation with hot water at various temperatures up to 120ºC and occasionally with peak temperatures up to 140ºC and maximum internal pressure 25 bar (overpressure). Application rule: For larger pipe dimensions and pressures below 25 bar wall thickness bigger than specified in EN 253 can be required for straight pipes, bends and tees. The principles of the standard can be applied to preinsulated pipe systems with pressures higher than 25 bar, provided that special attention is paid to the effects of pressure. Adjacent pipes belonging to the network (e.g. pipes in ducts, valve chambers, road crossings above ground etc.) can be designed and installed according to this standard. The standard assumes use of treated water, which by softening, demineralisation, deaeration, adding of chemicals, or otherwise has been treated to prevent internal corrosion and deposits in the pipes. This standard is not applicable for such units as: a) pumps, b) exchangers, c) boiler installations, tank installations, d) consumer installations. However, the full functional ability and durability of such units should be ensured in consideration of the impacts from the district heating system and other impacts occurring from the conditions under which they have been installed. Guidelines for product quality inspection and in situ tests of joints are given in Annex A of EN 448:2009, Annex D of EN 253:2009, Annex A of EN 488:2009 and Annex B of EN 489:2009. Guidelines for welding of polyethylene casing are given in Annex B of EN 448:2009. The estimation of expected life with continuous operation at various temperatures is outlined in Annex B of EN 253:2009. 2 Normative references The following referenced documents are indispensable for the application 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 253:2009, 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 287-1, Qualification test of welders – Fusion welding – Part 1: Steels EN 444, Non-destructive testing – General principles for radiographic examination of metallic materials by X- and gamma-rays SIST EN 13941:2009
EN 13941:2009 (E)
9EN 448:2009, 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 473, Non-destructive testing – Qualification and certification of NDT personnel – General principles EN 488, 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 EN 489:2009, 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 571-1, Non destructive testing – Penetrant testing – Part 1: General principles EN 583-1, Non-destructive testing – Ultrasonic examination – Part 1: General principles EN 970, Non-destructive examination of fusion welds – Visual examination EN 1289, Non-destructive examination of welds – Penetrant testing of welds – Acceptance levels EN 1290, Non-destructive examination of welds – Magnetic particle examination of welds EN 1291, Non-destructive examination of welds – Magnetic particle testing of welds – Acceptance levels EN 1418, Welding personnel – Approval testing of welding operators for fusion welding and resistance weld setters for fully mechanized and automatic welding of metallic materials EN 1435, Non-destructive examination of welds – Radiographic examination of welded joints EN 1712, Non-destructive examination of welds – Ultrasonic examination of welded joints – Acceptance levels EN 1714, Non-destructive examination of welds – Ultrasonic examination of welded joints EN 10204, Metallic products – Types of inspection documents EN 10216-2, Seamless steel tubes for pressure purposes – Technical delivery conditions – Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties EN 10217-1, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 1: Non-alloy steel tubes with specified room temperature properties EN 10217-2, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 2: Electric welded non-alloy and alloy steel tubes with specified elevated temperature properties EN 10217-5, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 5: Submerged arc welded non-alloy and alloy steel tubes with specified e
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Conception et installation des systèmes bloqués de tuyaux pré-isolés pour les réseaux enterrés d''eau chaudeDesign and installation of preinsulated bonded pipe systems for district heating91.140.10Sistemi centralnega ogrevanjaCentral heating systemsICS:Ta slovenski standard je istoveten z:prEN 13941kSIST prEN 13941:2009en01-marec-2009kSIST prEN 13941:2009SLOVENSKI
STANDARD
kSIST prEN 13941:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMFINAL DRAFTprEN 13941January 2009ICS 91.140.10Will supersede EN 13941:2003
English VersionDesign and installation of preinsulated bonded pipe systems fordistrict heatingConception et installation des systèmes bloqués de tuyauxpré-isolés pour les réseaux enterrés d''eau chaudeThis draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the TechnicalCommittee CEN/TC 107.If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations whichstipulate 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 languagemade by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has thesame 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.Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice andshall not be referred to as a European Standard.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2009 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. prEN 13941:2009: EkSIST prEN 13941:2009
prEN 13941:2009 (E)
2 Contents Page Foreword . 5Introduction . 61Scope . 82Normative references . 83Terms and definitions, units and symbols . 103.1Terms and definitions . 103.2Units and symbols . 154General considerations for system design . 174.1General requirements . 174.2Service life. 184.3Preliminary investigations . 184.4Determination of project class . 194.5Design documentation . 215Components and materials . 245.1Basic requirements . 245.2Steel pipe components . 255.3Polyurethane foam insulation . 285.4PE casing . 285.5Expansion cushions . 285.6Valves and accessories . 286Actions and limit states . 296.1General . 296.2Simplified analysis procedure . 316.3Actions . 316.4Limit states. 337Installation. 437.1General . 437.2Transportation and storage . 447.3Excavation of pipe trench . 447.4Installation of pipes and components . 447.5Welding of the steel pipe and testing of the steel welds . 457.6Strength pressure test and leak tightness test . 537.7Assembly of casing pipes, joint installation and site insulation . 547.8Backfilling of trench . 557.9Pipe bends and other components . 567.10Setting into operation . 577.11Special constructions . 577.12Construction work during the operation stage . 58Annex A (normative)
Design of piping components under internal pressure . 59A.1General . 59A.2Symbols . 59A.3Straight pipe and bends . 60A.3.1Straight pipes . 60A.3.2Bends . 60A.4Tees and branch connections. 60A.4.1General aspects and limitations . 60A.4.2Reinforcement . 61kSIST prEN 13941:2009
prEN 13941:2009 (E)
3A.5Reducers and extensions . 63A.5.1General . 63A.5.2Minimum wall thickness of the cone . 64A.5.3Offset reducers . 64A.6Dished ends . 64A.6.1General . 64A.6.2Minimum required wall thickness for internal pressure . 65A.6.3Straight cylindrical shells . 65Annex B (informative)
Geotechnics and pipe-soil interaction . 67B.1Scope . 67B.1.1General . 67B.1.2General requirements . 67B.2Symbols and units . 67B.3Soil parameters for global analysis (pipe-soil interaction) . 68B.3.1Modelling pipe-soil interaction . 68B.3.2Pipe to soil friction (axial) . 69B.3.3Coefficient of horizontal soil reaction (lateral) . 71B.3.4Combined stiffness of PUR foam, expansion cushions and soil . 75B.4Characteristic values for soil loads and soil parameters . 78B.4.1General . 78B.4.2Soil mechanics study . 78B.5Specific requirements for stability . 79B.5.1General . 79B.5.2Vertical stability . 79B.5.3Horizontal stability . 81B.6Specific requirements for parallel excavations . 81B.6.1General . 81B.6.2Reduced friction . 82B.7Requirements for soft soils and settlement areas . 82B.7.1General . 82B.7.2Differential settlements . 82B.8Ovalization and circumferential stresses from top load . 82B.8.1Traffic load . 82B.8.2Stresses and ovalization from top load . 85B.8.3Deflection . 88Annex C (informative)
Global- and cross sectional analysis . 89C.1General . 89C.2Symbols . 89C.3Survey of limit states for steel . 92C.4Locations to be assessed . 93C.4.1Components to be considered . 93C.4.2Areas to be considered . 95C.5Actions . 96C.5.1General . 96C.5.2Action cycles . 96C.6Global analysis . 97C.6.1General . 97C.6.2Flexibility . 98C.6.3Boundary conditions . 99C.6.4Boundary conditions for
pipe systems with single use compensators (SUC’s) . 102C.7Calculation of stresses . 105C.7.1General . 105C.7.2Simplified procedure . 105C.7.3Cross section analyses, steel . 105C.7.4Straight pipes . 107C.7.5Bends . 109C.7.6Tees . 112C.7.7Other components . 117kSIST prEN 13941:2009
prEN 13941:2009 (E)
4 C.7.8PUR foam and PE casing . 120C.8Fatigue analysis . 121C.8.1Fatigue strength data . 121C.8.2Fatigue strength data, detailed design . 122C.8.3Design fatigue lives . 122C.9Further actions . 122Annex D (informative)
Calculation of heat losses . 124D.1General . 124D.2Heat loss per pipe pair . 124D.3Insulance of the soil . 125D.4Insulance of the insulation material . 125D.5Insulance of the heat exchange between flow and return pipe . 126Bibliography . 127 kSIST prEN 13941:2009
prEN 13941:2009 (E)
5Foreword This document (prEN 13941:2009) 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 Formal Vote. This document will supersede EN 13941:2003. kSIST prEN 13941:2009
prEN 13941:2009 (E)
6 Introduction The standard has been prepared by JWG1, a joint working group with CEN/TC 267 "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 B, C and D have status as application rules. kSIST prEN 13941:2009
prEN 13941:2009 (E)
7This 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 the intentions of the standard and in due consideration of the development taking place in the field it concerns. It is therefore assumed that the user of the standard has the requisite technical insight and that the user of the standard has adequate knowledge of legal and other external regulations that are of consequence to the practical application of the standard. Special cases may occur within the scope of this standard in which its contents do not cover. An evaluation whether the contents cover shall be made in any specific case where the standard is used. Presently CEN/TC 107 "Pre-fabricated district heating pipe systems" is preparing standards for preinsulated flexible pipes and surveillance systems. kSIST prEN 13941:2009
prEN 13941:2009 (E)
8 1 Scope This European Standard specifies rules for design, calculation and installation for preinsulated bonded pipe systems for buried hot water distribution and transmission networks (cf. figure 2) with pipe assemblies in accordance with EN 253, for continuous operation with hot water at various temperatures up to 120ºC and occasionally with peak temperatures up to 140ºC and maximum internal pressure 25 bar (overpressure). Application rule: For larger pipe dimensions and pressures below 25 bar wall thickness bigger than specified in EN 253 can be required for straight pipes, bends and tees. The principles of the standard can be applied to preinsulated pipe systems with pressures higher than 25 bar, provided that special attention is paid to the effects of pressure. Adjacent pipes belonging to the network (e.g. pipes in ducts, valve chambers, road crossings above ground etc.) can be designed and installed according to this standard. The standard assumes use of treated water, which by softening, demineralisation, deaeration, adding of chemicals, or otherwise has been treated to prevent internal corrosion and deposits in the pipes. This standard is not applicable for such units as: pumps, exchangers, boiler installations, tank installations, consumer installations. However, the full functional ability and durability of such units should be ensured in consideration of the impacts from the district heating system and other impacts occurring from the conditions under which they have been installed. Guidelines for product quality inspection and in situ tests of joints are given in Annex A of EN 448:2003, Annex D of EN 253:2003, Annex A of EN 488:2003 and Annex B of EN 489:2003. Guidelines for welding of polyethylene casing are given in Annex B of EN 448:2003. The estimation of expected life with continuous operation at various temperatures is outlined in Annex B of EN 253:2003. 2 Normative references The following referenced documents are indispensable for the application 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 253:2003, 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 287-1, Qualification test of welders – Fusion welding – Part 1: Steels EN 444, Non-destructive testing – General principles for radiographic examination of metallic materials by X- and gamma-rays kSIST prEN 13941:2009
prEN 13941:2009 (E)
9EN 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 473, Non-destructive testing – Qualification and certification of NDT personnel – General principles EN 488, 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 EN 489:2003, 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 571-1, Non destructive testing – Penetrant testing – Part 1: General principles EN 583-1, Non-destructive testing – Ultrasonic examination – Part 1: General principles EN 970, Non-destructive examination of fusion welds – Visual examination EN 1289, Non-destructive examination of welds – Penetrant testing of welds – Acceptance levels EN 1290, Non-destructive examination of welds – Magnetic particle examination of welds EN 1291, Non-destructive examination of welds – Magnetic particle testing of welds – Acceptance levels EN 1418, Welding personnel – Approval testing of welding operators for fusion welding and resistance weld setters for fully mechanized and automatic welding of metallic materials EN 1435, Non-destructive examination of welds – Radiographic examination of welded joints EN 1712, Non-destructive examination of welds – Ultrasonic examination of welded joints – Acceptance levels EN 1714, Non-destructive examination of welds – Ultrasonic examination of welded joints EN 10204, Metallic products – Types of inspection documents EN 10216-2, Seamless steel tubes for pressure purposes – Technical delivery conditions – Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties EN 10217-1, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 1: Non-alloy steel tubes with specified room temperature properties EN 10217-2, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 2: Electric welded non-alloy and alloy steel tubes with specified elevated temperature properties EN 10217-5, Welded steel tubes for pressure purposes – Technical delivery conditions – Part 5: Submerged arc welded non-alloy and alloy steel tubes with specified elevated temperature properties EN 13018, Non-destructive testing – Visual testing – General principles EN 13480-3:2002, Metallic industrial piping – Part 3: Design and calculation EN 25817:1992, Arc-welded joints in steel – Guidance on quality levels for imperfections (ISO 5817:1992) EN ISO 3834-1, Quality requirements for fusion welding of metallic materials – Part 1: Criteria for the selection of the appropriate level of quality requirements (ISO 3834-1:2005) EN ISO 3834-2, Quality requirements for fusion welding of metallic materials – Part 2: Comprehensive quality requirements (ISO 3834-2:2005) kSIST prEN 13941:2009
prEN 13941:2009 (E)
10EN ISO 3834-3, Quality requirements for fusion welding of metallic materials – Part 3: Standard quality requirements (ISO 3834-3:2005) EN ISO 3834-4, Quality requirements for fu
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