SIST EN 448:2016

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 les réseaux enterrés d'eau chaude - Raccords préisolés, tubes de service en acier, isolation thermique en polyuréthanne 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 fittings23.040.07Cevovodi za daljinsko ogrevanje in njihovi deliPipeline and its parts for district heatICS:Ta slovenski standard je istoveten z:EN 448:2015SIST EN 448:2016en,fr,de01-januar-2016SIST EN 448:2016SLOVENSKI
STANDARDSIST EN 448:20091DGRPHãþD



SIST EN 448:2016



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 448
November 2015 ICS 23.040.40 Supersedes EN 448:2009English Version
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
Tuyaux 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 polyéthylène
Fernwärmerohre - Werkmäßig gedämmte Verbundmantelrohrsysteme für direkt erdverlegte Fernwärmenetze - Verbundformstücke, bestehend aus Stahl-Mediumrohr, Polyurethan-Wärmedämmung und Außenmantel aus Polyethylen This European Standard was approved by CEN on 5 September 2015.
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-CENELEC 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-CENELEC 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 448:2015 ESIST EN 448:2016



EN 448:2015 (E) 2 Contents Page European foreword . 4 Introduction . 5 1 Scope . 6 2 Normative references . 6 3 Terms and definitions . 8 4 Requirements . 10 4.1 Steel parts . 10 4.1.1 General . 10 4.1.2 Quality . 10 4.1.3 Wall thickness and diameter . 10 4.1.4 Bends . 10 4.1.5 T-pieces . 11 4.1.6 Reducers . 12 4.1.7 Anchors . 12 4.1.8 Single use compensators . 12 4.1.9 Caps . 12 4.1.10 Fusion welding of steel fittings . 12 4.1.11 Surface condition . 14 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 . 15 4.4.3 Requirements of polyethylene welding . 16 4.4.4 Leak-tightness of the welded casing pipe . 17 4.4.5 Diameter and wall thickness of the casing . 18 4.4.6 Minimum insulation thickness in bends . 18 4.4.7 Tolerances of the main fitting dimensions . 18 4.5 Surveillance system . 18 5 Test methods . 18 5.1 General . 18 5.2 Test specimens . 19 5.3 Steel parts . 19 5.3.1 Visual surface examination of welds . 19 5.3.2 Leak-tightness test with water . 19 5.3.3 Leak-tightness test with air . 19 5.3.4 Non-destructive examination of welds . 19 5.3.5 NDT of welds . 20 5.4 Casing . 20 5.5 Polyurethane rigid foam insulation (PUR) . 20 5.6 Fitting assemblies . 20 5.6.1 Centre line deviation and angular deviation . 20 5.6.2 Visual examination of welds on casing pipes . 20 5.6.3 Bending test . 20 5.6.4 Minimum insulation thickness . 21 5.7 Surveillance system . 21 SIST EN 448:2016



EN 448:2015 (E) 3 6 Marking . 21 6.1 General . 21 6.2 Steel service pipe . 21 6.3 Casing . 22 6.4 Fitting assembly . 22 6.5 Single use compensators . 22 Annex A (informative)
Guidelines for inspection and testing . 23 A.1 General . 23 A.2 Manufacturer’s type test . 23 A.3 Manufacturer’s quality control . 23 A.4 External inspection . 23 A.5 Extent of inspection . 23 A.6 Manufacturer’s responsibility . 23 Annex B (informative)
Procedures for polyethylene welding . 26 B.1 General . 26 B.2 Recommendations for site, machine and equipment . 26 B.3 Items . 26 B.4 Butt fusion welding . 26 B.5 Extrusion welding . 28 Bibliography . 30
SIST EN 448:2016



EN 448:2015 (E) 4 European foreword This document (EN 448:2015) has been prepared by Technical Committee CEN/TC 107 “Prefabricated district heating and district cooling pipe system”, 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 May 2016, and conflicting national standards shall be withdrawn at the latest by May 2016. 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 448:2009. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 448:2016



EN 448:2015 (E) 5 Introduction EN 448 has been aligned with EN 488 and other relevant European Standards. Other standards from CEN/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; — EN 15698-2, 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. SIST EN 448:2016



EN 448:2015 (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: bend, tee, reducer, single use compensator and anchor. This European Standard applies only to factory made prefabricated fitting assemblies and single use compensators for continuous operation with hot water at various temperatures in accordance with EN 253. This European Standard applies to fitting assemblies with a minimum design pressure of 16 bar (overpressure) complying with EN 13941. This European Standard does not include calculation rules for loads and stresses. The design and installation rules, for the system, are given in EN 13941. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. 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+A2:2015, 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 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 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 10253-2, Butt-welding pipe fittings — Part 2: Non alloy and ferritic alloy steels with specific inspection requirements EN 12814-1, Testing of welded joints of thermoplastics semi-finished products — Part 1: Bend test EN 13018, Non-destructive testing — Visual testing — General principles EN 13941, Design and installation of preinsulated bonded pipe systems for district heating 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 15590-1:2009 modified) SIST EN 448:2016



EN 448:2015 (E) 7 EN ISO 3452-1, Non-destructive testing — Penetrant testing — Part 1: General principles (ISO 3452-1) EN ISO 5579, Non-destructive testing — Radiographic testing of metallic materials using film and X- or gamma rays — Basic rules (ISO 5579) EN ISO 5817, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) — Quality levels for imperfections (ISO 5817) 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) EN ISO 9606-1, Qualification testing of welders — Fusion welding — Part 1: Steels (ISO 9606-1) EN ISO 9692-1:2013, Welding and allied processes — Types of joint preparation — Part 1: Manual metal arc welding, gas-shielded metal arc welding, gas welding, TIG welding and beam welding of steels (ISO 9692-1:2013) EN ISO 9934-1, Non-destructive testing — Magnetic particle testing — Part 1: General principles (ISO 9934-1) EN ISO 10675-1, Non-destructive testing of welds — Acceptance levels for radiographic testing — Part 1: Steel, nickel, titanium and their alloys (ISO 10675-1) EN ISO 11666, Non-destructive testing of welds — Ultrasonic testing — Acceptance levels (ISO 11666) EN ISO 14732, Welding personnel — Qualification testing of welding operators and weld setters for mechanized and automatic welding of metallic materials (ISO 14732) EN ISO 15607, Specification and qualification of welding procedures for metallic materials — General rules (ISO 15607) EN ISO 16810, Non-destructive testing — Ultrasonic testing — General principles (ISO 16810) EN ISO 17636-1, Non-destructive testing of welds — Radiographic testing — Part 1: X- and gamma-ray techniques with film (ISO 17636-1) EN ISO 17636-2, Non-destructive testing of welds — Radiographic testing — Part 2: X- and gamma-ray techniques with digital detectors (ISO 17636-2) EN ISO 17637, Non-destructive testing of welds — Visual testing of fusion-welded joints (ISO 17637) EN ISO 17638, Non-destructive testing of welds — Magnetic particle testing (ISO 17638) EN ISO 17640, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and assessment (ISO 17640) EN ISO 23277, Non-destructive testing of welds — Penetrant testing — Acceptance levels (ISO 23277) EN ISO 23278, Non-destructive testing of welds — Magnetic particle testing — Acceptance levels (ISO 23278) SIST EN 448:2016



EN 448:2015 (E) 8 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 253:2009+A2:2015 and the following apply. 3.1 anchor construction used to transfer the loads from the steel service pipe through the insulation and the casing to a fixed point 3.2 bending angle
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 cap not pre-insulated butt welded fitting to be welded on the end of a pipe or fitting 3.6 fitting reducer, tee, factory-made elbow and bend, cap, welding stub, mechanical joint 3.7 forged T-piece T-piece manufactured by hot forming of either steel pipes or steel plates which are subsequently welded together 3.8 hot formed bend bend manufactured by heating pipe during bending 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 alphanumeric designation of size, common to components in piping systems which are used for reference purposes [SOURCE: EN ISO 6708:1995, 2.1, modified] SIST EN 448:2016



EN 448:2015 (E) 9 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 compensator SUC compensator functioning during pre-heating, but being locked after pre-heating NOTE Single use compensators are not preinsulated units. 3.15 surveillance system system that consists of measuring sections and measuring instruments for surveillance of pipe systems according to EN 14419:2009 3.16 welded tee 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
Key a cold or hot formed bends e tee with welding saddle b butt welding bend or elbows f tee with drawn collar c
g directly welded tee d forged tee
Figure 1 — Examples SIST EN 448:2016



EN 448:2015 (E) 10 4 Requirements 4.1 Steel parts 4.1.1 General The material of the fitting steel parts shall be certified in accordance with EN 10204. If traceability on material is required by the end user it shall be specified at the time of ordering. Corresponding material certificates shall be delivered to the end user if specified at the time of ordering. 4.1.2 Quality The quality of pipe material used for the assembly of fittings shall be in accordance with EN 253:2009+A2:2015, Table 1. The quality of butt welding pipe fittings shall be in accordance with EN 10253-2. NOTE
For Sweden, a deviating situation is applicable for EN 253:2009+A2:2015, Table 1 (see the A-deviation in EN 253:2009+A2:2015, Annex G). 4.1.3 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+A2:2015, Table 2. The tolerances on the outside diameter of the pipe ends shall be in accordance with EN 253:2009+A2:2015, Table 3. Subject to design considerations other wall thicknesses than those given in EN 253:2009+A2:2015, Table 2 may be used, but in no case shall these be less than the minima indicated in EN 253:2009+A2:2015, 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. 4.1.4 Bends 4.1.4.1 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. 4.1.4.2 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+A2:2015, Table 2). The maximum ovality in the bent area shall not exceed 6 %. The formula for the calculation of the ovality is: ()sDDD−=×os maxs min 100 (1) where SIST EN 448:2016



EN 448:2015 (E) 11 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. 4.1.4.3 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. 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. 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. 4.1.4.4 Tolerances of bending angles The deviation from the nominal bending angle shall not exceed the tolerances given in Table 1. Table 1 — Deviations from nominal bending angle Nominal diameter of service pipe Deviation
¶ DN 200 ±2,0° > DN 200 ±1,0° 4.1.5 T-pieces 4.1.5.1 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+A2:2015, Table 2. All other dimensions shall be in accordance with EN 10253-2. 4.1.5.2 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. 4.1.5.3 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
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