EN 13941:2009+A1:2010

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 préisolés 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 13941:2009+A1:2010SIST EN 13941:2009+A1:2010en,fr,de01-september-2010SIST EN 13941:2009+A1:2010SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 13941:2009+A1
July 2010 ICS 23.040.10; 91.140.10 Supersedes EN 13941:2009 English Version
Design and installation of preinsulated bonded pipe systems for district heating
Conception et installation des systèmes bloqués de tuyaux préisolés pour les réseaux enterrés d'eau chaude
Auslegung und Installation von werkmäßig gedämmten Verbundmantelrohren für die Fernwärme 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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B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13941:2009+A1:2010: ESIST EN 13941:2009+A1:2010

Design of piping components under internal pressure . 60A.1General . 60A.2Symbols . 60A.3Straight pipe and bends . 61A.4Tees and branch connections . 61A.5Reducers and extensions . 64A.6Dished ends . 65Annex B (informative)
Geotechnics and pipe-soil interaction . 67B.1Scope . 67B.2Symbols and units . 67B.3Soil parameters for global analysis (pipe-soil interaction) . 68B.4Characteristic values for soil loads and soil parameters . 78B.5Specific requirements for stability . 79B.6Specific requirements for parallel excavations . 82B.7Requirements for soft soils and settlement areas . 82B.8Ovalization and circumferential stresses from top load . 82Annex C (informative)
Global- and cross sectional analysis . 89C.1General . 89C.2Symbols . 89SIST EN 13941:2009+A1:2010

Calculation of heat losses . 121D.1General . 121D.2Heat loss per pipe pair . 121D.3Insulance of the soil . 122D.4Insulance of the insulation material . 122D.5Insulance of the heat exchange between flow and return pipe . 123Annex E
(informative)
˜˜˜˜National A-deviations™™™™ . 124Bibliography . 125 SIST EN 13941:2009+A1:2010

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+A1:2010

Key 1
One action cycle 2
Temperature or stress range Figure 1 — Action cycle 3.1.3 bonded system system consisting of a service pipe, insulating material and casing, which are bonded by the insulating material 3.1.4 cold installed preinsulated bonded pipes district heating systems where the pipes are installed and taken into operation without prior pre-stressing by pre-heating 3.1.5 creep slow progressive strain under the influence of stresses 3.1.6 design pressure
internal pressure equal to or greater than the maximum operating pressure at any point of the pipeline acting in a component or pipe section multiplied by a partial safety factor 3.1.7 design temperature maximum temperature used for the design of a component or pipe section 3.1.8 displacement-controlled action action called forth by enforced deformation or movement, e.g. thermal expansion or settling 3.1.9 distribution pipeline pipeline leading from place of production or transmission line to heating installations. Distribution mains are primarily main pipelines or house service connections, see Figure 2. 3.1.10 ductile materials materials which with good approximation are linearly elastic up to the yield stress or to the 0,2% proof stress, and which have a minimum elongation at rupture of 14 % SIST EN 13941:2009+A1:2010

Key 1
Transmission system 2
Distribution system 3
Transmission pipe 4
Main pipe 5
House service connection 6
Supply pipe 7
Consumer 8
Return pipe 9
Valve chamber 10
Heat production 11
Heat exchanger station 12
Pump station Figure 2 — Distribution and transmission systems 3.1.16 installation temperature temperature arising from the ambient conditions during laying or installation, prevalent at the time when action is taken 3.1.17 main pipeline pipeline supplying several heating installations. See Figure 2. SIST EN 13941:2009+A1:2010

maximum internal pressure acting against the pipe wall at any point or in any section of the pipeline at a given operating temperature Application rule: This is generally the internal pressure needed to take account of the static head, friction losses and required outlet pressure. 3.1.20 operating temperature water temperature in a component or pipe section during specified operating conditions 3.1.21 pre-heated system system which, after being assembled, but before backfilling, is heated to a pre-heating temperature allowing the system to expand without introducing additional stresses
3.1.22 preinsulated systems systems assembled at site consisting of prefabricated pipe elements and components with integrated protective casing, insulation and service pipe 3.1.23 pressure over-pressure or sub-pressure as compared to normal atmospheric pressure. Unless otherwise indicated, pressure refers to gauge pressure. 3.1.24 pre-stressing temperature temperature applied during pre-stressing of a pre-heated system Application rule: The pre-heating temperature is chosen such as approximately average axial stress is obtained, compared to the axial stress levels at ambient temperature and maximum operating temperature. 3.1.25 reference stress stress calculated (with sign) from the membrane or resulting stresses by Tresca or by von Mises’ formula Application rule: The formulae are presented in 6.4.3. 3.1.26 resulting stresses all stresses occurring in one point, i.e. membrane stresses plus stresses varying over the wall thickness 3.1.27 service life span of time during which the network is expected to function without major replacements, given normal maintenance and operation conditions as described in the project SIST EN 13941:2009+A1:2010

m (metre)
mm (millimetre) Mass
kg (kilogram) Force
N (Newton) Stress
N/mm² (Newton per square millimetre) Pressare
Pa (Pascal = Newton per square metre) Other units applied: Temperature
°C (degree centigrade) Pressure
bar (1 bar = 105 Pa = 0,1 N/mm2) 3.2.2 Symbols Table 1 — Symbols Symbol Name A Area c Cohension of the soil, fabrication tolerance D Diameter of casing d Diameter of service pipe E Modulus of elasticity F Friction force f Design stress, friction force per area unit, deflection G Selfweight I Momentum of inertial i Stress intensification factor L Friction length l Length M Bending moment N Normal force, number of full action cydes n Number p Internal pressure Re Specified minimum upper yield strength Rm Tensile strength R Bend radius r Pipe radius T Temperature SIST EN 13941:2009+A1:2010

Table 2 — Indices a : Action min : Minimum b : Branch pipe (at tee connections) n : Nominal, number (of fatigue cycles) c : Casing o : Outer, outside d : Design r : Run pipe (at tees) fat : Fatigue res : Resulting i : Inner, inside u : Fracture j : Reference v : Vertical m : Mean, membrane, material
NOTE Separate symbol lists are found in Annexes A, B and C. SIST EN 13941:2009+A1:2010

Installation expenses, maintenance expenses and operating expenses arising throughout the service life of the system should be included in the assessment of the system. The assessment of operating properties should pay regard to the possibilities of inspection and maintenance. 4.2 Service life When a system designed according to this standard is subject to temperatures exceeding 120 oC, for periods such that the requirement for a service life of 30 years at continuous operation at 120 oC, calculated in accordance with Annex B of EN 253:2009, is exceeded, the service life of components subject to ageing must be assessed. Application rule: The minimum requirements for the type test of EN 253 (based on the shear strength between PUR foam and steel pipe) is a service life of
30 years for continuous operation at 120 oC. If the cumulative ageing requires a lifetime exceeding the equivalence of 30 years at 120 oC special documentation for the ageing properties are required. 4.3 Preliminary investigations Preliminary investigations comprising an assessment of all conditions of importance to a district heating project shall be carried out. These preliminary investigations shall elucidate matters in the planning, design, execution and operating stages as well as consequences of any kind of failure of the system. The principal basis of the preliminary investigation is the main data for the current system, e.g.:
 function,
 pressure and temperature,
 dimensions,
 depth of burial,
 geotechnical and groundwater parameters, etc. Application rule:
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