SIST EN 448:2009

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.RG]HPHOMVNDFernwärmerohre - Werkmäßig gedämmte Verbundmantelrohrsysteme für direkt erdverlegte Fernwärmenetze - Verbundformstücke, bestehend aus Stahl-Mediumrohr, Polyurethan-Wärmedämmung und Außenmantel aus PolyethylenTuyaux de chauffage urbain - Systèmes bloqués de tuyaux préisolés pour des réseaux d'eau chaude enterrés directement - Raccords préisolés pour tubes de service en acier, isolation thermique en polyuréthane et tube de protection en polyéthylèneDistrict 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 polyethylene91.140.65Oprema za ogrevanje vodeWater heating equipment23.040.40Kovinski fitingiMetal fittings23.040.10Železne in jeklene ceviIron and steel pipesICS:Ta slovenski standard je istoveten z:EN 448:2009SIST EN 448:2009en,fr,de01-maj-2009SIST EN 448:2009SLOVENSKI
STANDARDSIST EN 448:20041DGRPHãþD



SIST EN 448:2009



EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 448February 2009ICS 23.040.40Supersedes EN 448:2003
English VersionDistrict heating pipes - Preinsulated bonded pipe systems fordirectly buried hot water networks - Fitting assemblies of steelservice pipes, polyurethane thermal insulation and outer casingof polyethyleneTuyaux de chauffage urbain - Systèmes bloqués de tuyauxpréisolés pour des réseaux d'eau chaude enterrésdirectement - Raccords préisolés pour tubes de service enacier, isolation thermique en polyuréthane et tube deprotection en polyéthylèneFernwärmerohre - Werkmäßig gedämmteVerbundmantelrohrsysteme für direkt erdverlegteFernwärmenetze - Verbundformstücke, bestehend ausStahl-Mediumrohr, Polyurethan-Wärmedämmung undAußenmantel aus PolyethylenThis European Standard was approved by CEN on 3 January 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 448:2009: ESIST EN 448:2009



EN 448:2009 (E) 2 Contents Foreword . 4 1 Scope . 6 2 Normative references . 6 3 Terms and definitions . 7 4 Requirements . 9 4.1 Steel parts . 9 4.1.1 Quality . 9 4.1.2 Wall thickness and diameter . 9 4.1.3 Bends . 10 4.1.4 T-pieces . 11 4.1.5 Reducers . 11 4.1.6 Anchors . 11 4.1.7 Single use compensators . 11 4.1.8 Dish or end caps . 11 4.1.9 Fusion welding of steel fittings . 11 4.1.10 Surface condition. 15 4.2 Casing . 15 4.3 Polyurethane rigid foam insulation (PUR) . 15 4.4 Fitting assemblies. 15 4.4.1 Fitting ends . 15 4.4.2 Angle between casing segments of bend and minimum length . 16 4.4.3 Requirements of polyethylene welding . 16 4.4.4 Leak-tightness of the welded casing pipe . 18 4.4.5 Diameter and wall thickness of the casing . 19 4.4.6 Minimum insulation thickness in bends . 19 4.4.7 Tolerances of the main fitting dimensions . 19 4.5 Surveillance system . 19 5 Test methods . 20 5.1 General . 20 5.2 Test specimens . 20 5.3 Steel parts . 20 5.3.1 Visual surface examination of welds . 20 5.3.2 Leak-tightness test with water . 20 5.3.3 Leak-tightness test with air . 20 5.3.4 Non-destructive examination of welds . 20 5.3.5 NDT of welds . 21 5.4 Casing . 21 5.5 Polyurethane rigid foam insulation (PUR) . 21 5.6 Fitting assemblies. 21 5.6.1 Centre line deviation and angular deviation . 21 5.6.2 Visual examination of welds on casing pipes . 21 5.6.3 Bending test . 21 5.6.4 Minimum insulation thickness . 22 5.7 Surveillance system . 23 6 Marking . 23 6.1 General . 23 6.2 Steel service pipe. 23 6.3 Casing . 23 6.4 Fitting assembly. 23 6.5 Single use compensators . 23 Annex A (informative)
Guidelines for inspection and testing. 25 A.1 General . 25 A.2 Manufacturer’s type test . 25 A.3 Manufacturer’s quality control . 25 A.4 External inspection . 25 A.5 Extent of inspection. 25 SIST EN 448:2009



EN 448:2009 (E) 3 A.6 Manufacturer’s responsibility . 25 Annex B (informative)
Procedures for polyethylene welding . 28 B.1 General. 28 B.2 Recommendations for site, machine and equipment . 28 B.3 Items. 28 B.4 Butt fusion welding . 28 B.4.1 Equipment . 28 B.4.2 Welding procedure . 29 B.5 Extrusion welding . 30 B.5.1 Equipment . 30 B.5.2 Welding procedure . 31 Annex C (informative)
Main changes from EN 448:2003 . 32 Bibliography . 34
SIST EN 448:2009



EN 448:2009 (E) 4 Foreword This document (EN 448:2009) 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 August 2009, and conflicting national standards shall be withdrawn at the latest by August 2009. 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 448:2003. The main changes from EN 448:2003 have been listed in the informative Annex C. 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 448:2009



EN 448:2009 (E) 5 Introduction The first edition of EN 448 was approved in 1994. A completely revised standard was published in 2003. The main areas of the current revision have been listed in Annex C. The main reason for drafting the EN 448:2009 is the aligning with EN 13941 and with other relevant recent European standards. For information on the minimum expected thermal life with operation at various temperatures with respect to PUR foam performance see EN 253:2009, Annex B. The other standards from 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 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, 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. SIST EN 448:2009



EN 448:2009 (E) 6 1 Scope This European Standard specifies requirements and test methods for fittings of prefabricated thermally insulated pipe-in-pipe assemblies comprising a steel service fitting from DN 20 to DN 1200, rigid polyurethane foam insulation and an outer casing of polyethylene for use in directly buried hot water networks with preinsulated pipe assemblies in accordance with EN 253. This European Standard covers the following fittings: bends, T-pieces, reducers, single use compensators and anchors. This European Standard applies only to insulated fitting assemblies and single use compensators for continuous operation with hot water at various temperatures in accordance with EN 253:2009, Clause 1. This European Standard applies to fitting assemblies with a minimum design pressure of 16 bar (overpressure) complying with EN 13941. Guidelines for quality inspection are given in Annex A of this European Standard. Procedures for PE-welding are given in Annex B of this European Standard. NOTE This European Standard does not include rules for calculation of loads and stresses. 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 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 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 10253-2:2007 Butt-welding pipe fittings – Part 2: Non alloy and ferritic alloy steels with specific inspection requirements EN 12517-1, Non-destructive testing of welds – Part 1: Evaluation of welded joints in steel, nickel, titanium and their alloys by radiography – Acceptance levels EN 12814-1, Testing of welded joints of thermoplastics semi-finished products – Part 1: Bend test EN 13941, Design and installation of preinsulated bonded pipe systems for district heating SIST EN 448:2009



EN 448:2009 (E) 7 EN 14419:2009, District heating pipes – Preinsulated bonded pipe systems for directly buried hot water networks – Surveillance systems EN 14870-1, Petroleum and natural gas industries - Induction bends, fittings and flanges for pipeline transportation systems – Part 1: Induction bends (ISO 15590-1:2001 modified) EN ISO 5817, Welding – Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) – Quality levels for imperfections (ISO 5817:2003, corrected version:2005, including Technical Corrigendum 1:2006) EN ISO 8501-1, Preparation of steel substrates before application of paints and related products – Visual assessment of surface cleanliness – Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings (ISO 8501-1:2007) EN ISO 9692-1:2003, Welding and allied processes - Recommendations for joint preparation - Part 1: Manual metal-arc welding, gas-shielded metal-arc welding, gas welding, TIG welding and beam welding of steels (ISO 9692-1:2003) EN ISO 15607, Specification and qualification of welding procedures for metallic materials – General rules (ISO 15607:2003) ISO 17636, Non-destructive testing of welds - Radiographic testing of fusion-welded joints 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 253:2009 and the following apply. 3.1 anchor steel construction used to transfer the axial load from the steel service pipe through the insulation and the casing to a fixed point 3.2 bending angle αααα
deviation in direction of the steel pipe centre lines 3.3 butt welded bend
bend manufactured either by hot bending of steel pipe or by hot forming of steel plates which are subsequently welded together 3.4 cold formed bend
bend manufactured by cold bending of steel pipe 3.5 dish or end cap
not pre-insulated butt welded fitting to be welded on the end of a pipe or pipe element 3.6 fitting
pipe element 3.7 forged T-piece
T-piece manufactured by hot forming of either steel pipes or steel plates which are subsequently welded together 38 hot formed bend
bend manufactured by heating pipe during bending SIST EN 448:2009



EN 448:2009 (E) 8 3.9 induction bend
bend manufactured by induction bending 3.10 induction bending
continuous bending process which utilizes induction heating to create a narrow, circumferential, heated band around the material being bent 3.11 nominal size, DN numerical metric designation of size is common to components in piping systems of any one size 3.12 pipe element reducer, tee, factory-made elbow and bend, flange, cap, welding stub, mechanical joint 3.13 reducer
butt welding fitting to be welded between two steel pipes of different diameters 3.14 single use compensators
single use compensators with one-off expansion has facilities of absorbing expansion in the pipe system when it is heated up first time NOTE By locking the expansion facility (by welding) future expansions in the pipe system will be absorbed as tensile and compressive stresses. Single use compensators are not pre-insulated. 3.15 surveillance system system that consists of measuring sections and measuring instruments for surveillance of pipe systems according to EN 14419 3.16 welded T-piece
butt welding fitting manufactured by welding together pieces of steel pipes with or without the use of a welding saddle or a drawn collar on the main pipe 3.17 welding saddle
butt welding fitting to be welded into the main pipe for the welded connection between the main pipe and the branch pipe in a T-piece NOTE For examples of fittings see Figure 1.
SIST EN 448:2009



EN 448:2009 (E) 9
Key
a Cold or hot formed bends b Butt welding bend or elbows c Bending angle, α d Forged T-piece e T-piece with welding saddle f T-piece with drawn collar g Directly welded T-piece Figure 1 — Examples 4 Requirements 4.1 Steel parts 4.1.1 Quality The quality of pipe material used for the assembly of fittings shall be in accordance with EN 253:2009, Table 1. The quality of butt welding pipe fittings shall be in accordance with EN 10253-2. NOTE 1 Steel material P235GH, referred to in EN 253, is most similar to the material, P235GH and P235TR2, referred to in EN 10253-2. NOTE 2 For Sweden a deviating situation is applicable for EN 253:2009, Table 1 (see the A-deviation in EN 253:2009, Annex G). 4.1.2 Wall thickness and diameter According to the scope of this European Standard all components shall be designed for a minimum of 16 bar. NOTE if the fitting assemblies have to be used in situations with pressures higher than 16 bar, extra calculations will be necessary.
The minimum nominal wall thickness of all components shall prior to processing be at least the same as for the straight pipes. The nominal diameter, the outside diameter and the minimum nominal wall thickness shall be the same as for the straight pipes in accordance with EN 253:2009, Table 2. The tolerances on the outside diameter of the pipe ends shall be in accordance with EN 253:2009 Table 3. SIST EN 448:2009



EN 448:2009 (E) 10 Subject to design considerations other wall thicknesses than those given in EN 253:2009, Table 2 may be used, but in no case shall these be less than the minima indicated in EN 253:2009, Table 2. All components shall be designed in accordance with EN 13941, for the actions and stresses that normally occur during a system's entire service life. 4.1.3 Bends 4.1.3.1 Butt welding bends The dimensions shall be in accordance with EN 10253-2 with the exception that the bend radius shall be ≥ 1,5 times the outer diameter. 4.1.3.2 Cold formed bends Cold formed bends shall be produced from seamless pipe or longitudinal welded pipes. At cold formed bends made of longitudinal welded pipes the weld bead shall be welded to factor V=1 (calculation stress = 100%). After bending, the minimum wall thickness of the bent pipe shall be not less than 85 % of the nominal wall thickness of the straight pipe (see EN 253:2009, Table 2). The maximum ovality in the bent area shall not exceed 6 %. The formula for the calculation of the ovality is: ()100 min smax s×−=sDDDo (1) where: o
is the ovality, in % Ds max is the maximum outside diameter; Ds min
is the minimum outside diameter in the same cross section in the bended area; Ds is the specified outside diameter. There shall be no folding in the bent area. Waves can be accepted, when the maximum height between trough and crest of the wave does not exceed 25 % of the nominal wall thickness of the bent pipe. 4.1.3.3 Hot-formed bends
For hot-formed bends manufactured from straight pipes by means of inductive heating (induction bends), no heat treatment is necessary as far as this method is applied with unalloyed or low-alloyed steel with [Mo] < 0.65 %. Hot-formed bends shall be supplied in conformity with EN 14870-1. If for the bending other heating methods are applied, heat treatment following the bending of the pipes is required. NOTE 1 If a hot-formed bend has to be made from line pipe, this should be specified to the pipe manufacturer at the time of ordering so that they can take this into account when selecting the (chemical) composition of the pipe material and the welding filler material. NOTE 2 It is recommended to determine per batch, diameter, wall thickness and bend radius, through mechanical testing, that the bends comply with the applicable material specifications. It is customary that a representative bend or an (additional) section of a bend of adequate length be manufactured during the production process and that 10 % of the bends be tested. 4.1.3.4 Tolerances of bending angles The deviation from the nominal bending angle shall not exceed the tolerances given in Table 1.
SIST EN 448:2009



EN 448:2009 (E) 11 Table 1 — Deviations from nominal bending angle Nominal diameter of service pipe Deviation ≤ DN 200 ± 2,0° > DN 200 ± 1,0°
4.1.4 T-pieces 4.1.4.1 Forged T-pieces The wall thickness T and T1 - see EN 10253-2 - shall be at least the same as those for the straight pipes (see EN 253:2009, Table 2). All other dimensions shall be in accordance with EN 10253-2. 4.1.4.2 Welding saddles Welding saddles shall be of the type which shall be welded into the wall of the main pipe. The wall thickness of the welding saddles shall be at least the same as the wall thicknesses of the main pipes and the branch pipes which shall be welded to the saddles. 4.1.4.3 Welded T-pieces Welded T-pieces shall be manufactured either by using welding saddles or by drawing a collar on which the branch pipe is welded or by welding the branch pipe directly to the main pipe. The wall thickness of the collar shall be at least the same as that for the branch pipe (see EN 253:2009, Table 2). The collar shall be drawn opposite the welding seam in the main pipe. 4.1.4.4 Tolerances of angles between branch pipes and main pipes The branch pipes shall be perpendicular to the main pipes within a tolerance of ± 2,0°. 4.1.5 Reducers Reducers shall be in accordance with EN 10253-2, except for the wall thicknesses T and T1 - see EN 10253-2 - which shall be at least the same as for the straight pipes (see EN 253:2009 Table 2) to be welded to the fittings. 4.1.6 Anchors Anchors shall be designed for and marked with the maximum axial force. The lifetime of the system shall not be influenced by the anchors construction. 4.1.7 Single use compensators A single use compensator shall comply with the requirements of EN 13941. 4.1.8 Dish or end caps A dish or end cap shall be in accordance with EN 10253-2 and comply with the requirements of EN 13941. 4.1.9 Fusion welding of steel fittings 4.1.9.1 Filler material Filler mat
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