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

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

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

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
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

- 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

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

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.
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

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.
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 material shall after welding have mechanical characteristics comparable with the parent metal. SIST EN 448:2009

Wall thickness T of service pipe fittings or fitting end Reference number table1 of EN ISO 9692-1:2003 T < 3 mm 1.2 3 mm ≤ T ≤ 10 mm 1.3 T > 10 mm 1.5
Pipe ends and fittings with different wall thicknesses shall be prepared and adapted for misalignment in accordance with Table 3 and Figure 2 of this standard. Table 3 - Adaptation of misalignment and difference in wall thickness Misalignment
Difference in wall thickness AdaptationRemarkMisalignment
h ≤
0,3 t, max. 1 mm Figure 2 detail A
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