DIN SPEC 1808813:2019 Structures For Wind Turbines And Platforms Part 13: Execution Of Offshore Steel Structures; Text In German And English

DIN SPEC 1808813:2019 Structures For Wind Turbines And Platforms Part 13: Execution Of Offshore Steel Structures; Text In German And English Scope The document defines requirements for the execution of steel structures for offshore wind installations including foundation elements. The document supplements the provisions of DIN EN 10902:201809. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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. DIN 180883:201901, Structures for wind turbines and platforms — Part 3: Steel structures DIN EN 10112:200105, Welding — Recommendation for welding of metallic materials — Part 2: Arc welding of ferritic steels; German version EN 10112:2001 DIN EN 10902:201809, Execution of steel structures and aluminium structures — Part 2: Technical requirements for steel structures; German version EN 10902:2018 DIN EN 1369, Founding — Magnetic particle testing DIN EN 1370, Founding — Examination of surface condition DIN EN 15591, Founding — Technical conditions of delivery — Part 1: General DIN EN 15592, Founding— Technical conditions of delivery — Part 2: Additional requirements for steel castings DIN EN 199311, Eurocode 3: Design of steel structures — Part 11: General rules and rules for buildings

Datum:2019 Dezember DIN SPEC 18088-13 Structures for wind turbines and platforms — Part 13: Execution of Offshore Steel structures; Text in German and English Tragstrukturen fiir Windenergieanlagen und Plattformen — Teil 13: Ausfiihrung von Offshore-Stahlbauten; Text Deutsch und Englisch Structures des éoliennes Stand 2019-12 allemand et anglais et des plateformes — Partie 13: Exécution des structures offshore en acier; Texte en DIN SPEC 18088-13:2019-12 Contents Page Foreword Introduction Scope Normative references -6 Terms and definitions 4.1 Specifications and documentation Execution specification 9 52 5.3 5.4 5.4.1 Constituent products Identification, inspection documents and traceability Structural steel products Steel castings Mechanical properties 9 10 11 11 Structural bolting assemblies for preloading Grouting materials 15 15 4.1.2 5.4.2 5.6 5.6.4 5.9 6.2 6.4 6.4.1 6.5 6.5.3 6.5.4 6.6 6.61 6.6.3 7.1 7.5.5 7.5.18 7.6 7.6.2 Non-destructive testing Mechanical fasteners Preparation and assembly Identification Cutting General Shaping Flame straightenin; Cold forming Holing Dimensions of hole: Execution of holing Welding General Preheating Shear Keys Acceptance criteria Fatigue requirement: Mechanical fastening 8.5 8.5.1 Tightening of preloaded bolting assemblies General 10 Surface treatment 11 11.2 Geometrical tolerances Essential tolerances 12 Inspection, testing and correction 8.5.7 Execution classes 10.2 11.2.2 Tolerances and gaps at fatigue-loaded joints Preparation of steel surfaces for paints and related products Manufacturing tolerance: 13 15 15 15 15 15 15 15 16 16 16 16 DIN SPEC 18088-13:2019-12 12.4 Welding 12.4.1 General 12.4.2 Inspection after weldin; 12.5 Mechanical fastening 12.5.2 Inspection and testing of preloaded bolted connection: Annex B (normative) Geometrical Tolerances B.2 Manufacturing tolerances E1 E2 E3 E4 General Welded joints in hollow sections Rules for start and stop pos: Preparation of joint faces Assembly of the tubular node Annex F (normative) Corrosion protection Surfaces in preloaded connections ® Annex E (informative) DIN SPEC 18088-13:2019-12 Foreword This document has been prepared by Working Committee NA 005-08-14 AA “Fabrication of steel structures (national mirror committee for CEN/TC 135 and ISO/TC 167)” of DIN-Normenausschuss Bauwesen (DIN Standards Committee Building and Civil Engineering) Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights DIN shall not be held responsible for identifying any or all such patent rights DIN SPEC are not part of the German body of standards A DIN SPEC developed in accordance with the prestandard procedure is the result of standards work which DIN does not publish as a standard because there are certain reservations regarding content, or because it was not prepared in accordance with the normal procedures for standards work No draft has been published for the present DIN SPEC Stand 2019-12 We welcome feedback on this DIN SPEC — preferably in the form of a file with a table, e-mailed to nabau@din.de The template for this table is available for download from http://www.din.de/stellungnahme — or send a hard copy to DIN-Normenausschuss Bauwesen (DIN Standards Committee Building and Civil Engineering), Deutsches Institut fiir Normung e V., 10772 13267 Berlin / Germany) Berlin (Address: Saatwinkler Damm 42/43, DIN SPEC 18088-13:2019-12 Introduction The document is an application-specific supplement to DIN EN 1090-2:2018-09 on steel structures for offshore wind installations It reflects the special design and production characteristics of these products All other provisions of EN 1090-2 remain fully valid where not otherwise excluded or limited here Stand 2019-12 The structure of DIN EN 1090-2:2018-09 was used for this Specification to make it easier to use the two documents together The numbering of DIN EN 1090-2:2018-09 has been continued in the numbering of text of the present document DIN SPEC 18088-13:2019-12 Scope The document defines requirements including foundation elements for the execution of steel structures for offshore wind installations The document supplements the provisions of DIN EN 1090-2:2018-09 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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 DIN 18088-3:2019-01, Structures for wind turbines and platforms — Part 3: Steel structures DIN EN 1011-2:2001-05, Welding — Recommendation for welding of metallic materials — Part 2: Arc welding of ferritic steels; German version EN 1011-2:2001 DIN EN 1090-2:2018-09, Execution of steel structures and aluminium requirements for steel structures; German version EN 1090-2:2018 structures— Part 2: Technical DIN EN 1369, Founding — Magnetic particle testing DIN EN 1370, Founding — Examination of surface condition DIN EN 1559-1, Founding — Technical conditions of delivery — Part 1: General DIN EN 1559-2, castings Founding— Technical conditions of delivery— Part 2: Additional requirements for steel DIN EN 1993-1-1, Eurocode 3: Design of steel structures — Part 1-1: General rules and rules for buildings DIN EN 1993-1-8:2010-12, Eurocode 3: Design of steel structures — Part 1-8: Design of joints; German version EN 1993-1-8:2005 + AC:2009 DIN EN 1993-1-8/NA, National Annex— structures — Part 1-8: Design of joints DIN EN 1993-1-10:2010-12, Nationally determined parameters— Eurocode Eurocode 3: Design of steel structures — 3: Design Part 1-10: Material through-thickness properties; German version EN 1993-1-10:2005 + AC:2009 of steel toughness and DIN EN 10025-1, Hot rolled products of structural steels — Part 1: General technical delivery conditions DIN EN 10025-3, Hot rolled products of structural steels— Part 3: Technical delivery conditions for DIN EN 10025-4, Hot rolled products of structural steels— thermomechanical rolled weldable fine grain structural steels Part 4: Technical delivery conditions for normalized/normalized rolled weldable fine grain structural steels Stand 2019-12 DIN EN 10029, Hot-rolled steel plates mm thick or above — Tolerances on dimensions and shape DIN EN 10051, Continuously hot-rolled strip and plate/sheet cut from wide strip of non-alloy and alloy steels — Tolerances on dimensions and shape DIN EN 10067, Hot rolled bulb flats — Dimensions and tolerances on shape, dimensions and mass DIN EN 10130, Cold rolled low carbon steel flat products for cold forming — Technical delivery conditions DIN SPEC 18088-13:2019-12 DIN EN 10131, Cold rolled uncoated and zinc or zinc-nickel electrolytically coated low carbon and high yield strength steel flat products for cold forming — Tolerances on dimensions and shape DIN EN 10160, Ultrasonic testing of steel flat product of thickness equal to or greater than mm (reflection method) DIN EN 10163-2, Delivery requirements for surface sections — Part 2: Plate and wide flats DIN EN 10164, Steel products with improved product — Technical delivery conditions conditions deformation of hot-rolled steel plates, properties perpendicular wide flats and to the surface of the DIN EN 10204, Metallic products — Types of inspection documents DIN EN 10210-2, Hot finished steel structural hollow sections — Part 2: Tolerances, DIN EN 10219-1, Cold formed Technical delivery conditions welded structural hollow sections of non-alloy and fine grain steels — Part 1: properties dimensions and sectional DIN EN 10219-2, Cold formed welded steel structural hollow sections — Part 2: Tolerances, dimensions and sectional properties for fixed offshore structures — Technical delivery conditions DIN EN 10225, Weldable structural steels DIN EN 10306, Iron and steel — Ultrasonic testing ofH beams with parallel flanges and IPE beams DIN EN 10340, Steel castings for structural uses DIN EN 12668-1, Non-destructive testing— Characterization and verification of ultrasonic examination DIN EN 12668-2, Non-destructive equipment— Part 2: Probes testing— Characterization and verification of ultrasonic examination DIN EN 12668-3, Non-destructive testing— equipment - Part 3: Combined equipment Characterization and verification of ultrasonic examination equipment— Part 1: Instruments DIN EN 12681-1, Founding — Radiographic testing — Part 1: Film techniques DIN EN 14399-4, High-strength structural bolting assemblies for preloading — Part 4: System HV — Hexagon bolt and nut assemblies DIN EN 14399-6, washers High-strength structural bolting assemblies for preloading— Part 6: Plain chamfered DIN EN 14399-8, High-strength structural bolting assemblies for preloading — Part 8: System HV - Hexagon fit bolt and nut assemblies Stand 2019-12 DIN EN ISO 2063, Thermal spraying — Zinc, aluminium and their alloys DIN EN ISO 5579, Non-destructive testing — Radiographic testing of metallic materials using film and X- or gamma rays — Basic rules DIN EN ISO 5817:2014-06, Welding— Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) — Quality levels for imperfections (ISO 5817:2014); German version EN ISO 5817:2014 DIN SPEC 18088-13:2019-12 DIN EN ISO 6520-1, Welding and allied processes— materials — Part 1: Fusion welding Classification of geometric imperfections in metallic DIN EN ISO 8501-3, Preparation of steel substrates before application of paints and related products — — Visual assessment of surface cleanliness — Part 3: Preparation grades of welds, edges and other areas with surface imperfections DIN EN ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel DIN EN ISO 9934-1, Non-destructive testing — Magnetic particle testing — Part 1: General principles DIN EN ISO 10863, Non-destructive testing of welds— technique (TOFD) Ultrasonic testing — Use of time-of-flight diffraction DIN EN ISO 10893-2, Non-destructive testing of steel tubes— Part 2: Automated eddy current seamless and welded (except submerged arc-welded) steel tubes for the detection of imperfections testing of DIN EN ISO 10893-3, Non-destructive testing of steel tubes — Part 3: Automated full peripheral flux leakage testing of seamless and welded (except submerged arc-welded) ferromagnetic steel tubes for the detection of longitudinal and/or transverse imperfections DIN EN ISO 10893-8, Non-destructive testing of steel tubes —Part 8: Automated ultrasonic testing of seamless and welded steel tubes for the detection of laminar imperfections DIN EN ISO 10893-10, Non-destructive testing of steel tubes — Part 10: Automated full peripheral ultrasonic testing of seamless and welded (except submerged arc-welded) steel tubes for the detection of longitudinal and/or transverse imperfections DIN EN ISO 10893-11, Non-destructive testing of steel tubes— Part 11: Automated ultrasonic testing of the weld seam of welded steel tubes for the detection of longitudinal and/or transverse imperfections DIN EN ISO 11666, Non-destructive testing of welds — Ultrasonic testing — Acceptance levels DIN EN ISO 13588, Non-destructive testing of welds— technology DIN EN ISO 13920, Welding— angles; shape and position General Ultrasonic testing — Use of automated phased array tolerances for welded constructions— Dimensions for lengths and DIN EN ISO 15613, Specification and qualification of welding procedures for metallic materials — Qualification based on pre-production welding test DIN EN ISO 15614-1, Specification and qualification of welding procedures for metallic materials— Welding procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys DIN EN ISO 15626, Acceptance levels Non-destructive testing of welds— Time-of-flight diffraction technique (TOFD)— Stand 2019-12 DIN EN ISO 16810, Non-destructive testing — Ultrasonic testing — General principles DIN EN ISO 17640:2018-03, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and assessment (ISO 17640:2017); German version EN ISO 17640:2017 DIN EN ISO 19232-3, Non-destructive testing — Image quality of radiographs — Part 3: Image quality classes ASTM E 446, Standard Reference Radiographs for Steel Castings Up to in (50,8 mm) in Thickness DIN SPEC 18088-13:2019-12 DASt 021:2013-09, DASt Guideline — Hot-galvanized bolting assemblies M39 to M72 as in DIN EN 14399-4, DIN EN 14399-6 Terms and definitions For the purposes apply of this document, the terms and definitions given in DIN EN 1090-2, and the following DIN and DKE maintain terminological databases for use in standardization at the following addresses: —_ DIN-TERMinologieportal: available at https://www.din.de/go/din-term — DKE-IEV: available at http://www.dke.de/DKE-IEV 3.16 shear key structural element on top of steel surfaces which is used to transfer shear stresses Note 1toentry: Shear keys are used in grouted connections to transfer loads into the concrete 3.17 structural tube cold-formed circular hollow according to this standard Note 1toentry: conical 4.1 4.1.2 section made of structural steel which can be fabricated as a welded part Structural tubes may have circumferential and longitudinal welds The shape can be cylindrical or Specifications and documentation Execution specification Execution classes The following rules apply in addition to DIN EN 1090-2:2018-09, 4.1.2 Execution classes shall be specified DIN EN 1993-1-1 and DIN 18088-3 and documented when carrying out analyses according to Welds which join constituent products or components of different execution classes shall be assigned to the highest execution class If the weld can be assigned to the lower execution class, then this shall be specified and documented by the structural designer Constituent products 5.2 Identification, inspection documents and traceability The following rules apply in addition to DIN EN 1090-2:2018-09, 5.2 q In the case of structural steels for which a 3.1 inspection document is mandatory, the chemical composition shall contain the information on 15 elements (C, Mn, Si, S, P, Al, N, Cu, Cr, Nb, V, Ti, Mo, Ni, B) DIN SPEC 18088-13:2019-12 5.3 Structural steel products 5.3.1 General The following rules apply in addition to DIN EN 1090-2:2018-09, 5.3.1 The following lines are to be added to DIN EN 1090-2:2018-09, Table2 Table — Product standards for structural carbon steels Products Technical delivery requirements Dimensions Tolerances Hot rolled bulb flats ? DIN EN 10025 DIN EN 10067 DIN EN 10067 Plates, flats, wide flats DIN EN 10225 Not applicable DIN EN 10029 DIN EN 10051 Flat products, t< mm DIN EN 10130 DIN EN 10130 DIN EN 10131 Hot finished hollow sections DIN EN 10225 DIN EN 10210-2 DIN EN 10210-2 Cold formed hollow sections DIN EN 10225 DIN EN 10219-2 DIN EN 10219-2 @ Equivalence shall be demonstrated where products have been manufactured according to other technical delivery conditions The following properties shall be documented within the component specification: — Steel grade (yield strength); —_ Steel group (impact energy/ sample position/ test temperature) NOTE Rules for selection materials in the case of cold forming are specified Stand 2019-12 supplemented in DIN 18088-3:2019-01, 6.3 Fracture toughness and strain ageing in DIN EN 1993-1-10 and are —_ Delivery condition (AR, N, M, Q); — “Z” quality class as specified in DIN EN 10164; —_ Strain age testing in accordance to DIN EN 10225 and compliance with the additional requirements in DIN 18088-3; — Test classes for imperfections of hollow sections in accordance with DIN EN ISO 10893-8; — Test classes for imperfections of welded hollow sections in accordance with DIN EN ISO 10893-3 or DIN EN ISO 10893-11; — Test classes for imperfections of seamless hollow sections in accordance with DIN EN ISO 10893-10; — Test classes for imperfections of flat products in accordance with DIN EN 10160 DIN EN 10306 shall be applied for rolled sections by analogy DIN EN ISO 10893-2 or If cold forming is to be carried out, this shall be taken into account by the designer when defining the steel groups 10 DIN SPEC 18088-13:2019-12 Table III — Testing according to DIN EN ISO 5817 Reference no as in Imperfection DIN EN ISO 6520-1 5071 Requirement for quality level B designation Linear misalignment | h < 0,1 t, but max between plates specification, 6mm or according to component at the root side of one-sided welds max mm or % of the seam width if this can be guaranteed for the entire seam length 5072 Linear misalignment | h < 0,1 t, but max 6mm or according to component between tubes specification, at the root side of one-sided welds max.2mm or % of the seam width guaranteed for the entire seam length 505 Incorrect weld toe if this can be Feature to be used The one-sided linear misalignment (planned or unplanned), which is to be unilaterally compensated by the seam itself in a butt weld, shall not exceed 1/4 of the seam width Planned linear misalignment due to changes in wall thickness at butt joints require chamfering of the thicker sheet to the thinner sheet with a 1:4 pitch if the seam width cannot compensate for the total scheduled and worst-case misalignment with a 1:4 pitch Mechanical fastening 8.5 Tightening of preloaded bolting assemblies 8.5.1 General The following rules supplement DIN EN 1090-2:2018-09, 8.5.1: For HV system bolting assemblies of sizes M39 to M72 preloading force Tục” and the modified torque method with tightening method k-class K1, the nominal apply in accordance to DIN EN 1993-1-8/NA by analogy The tightening torques M, needed for other to achieve the nominal preloading force Tục” by means are given in DASt 021:2013-09, Table The process parameters qualification tests tightening methods shall be determined of procedure The following rule replaces the penultimate paragraph in DIN EN 1090-2:2018-09, 8.5.1 No bolting assembly shall be used if the lubrication conditions not comply with those in the as-delivered condition Stand 2019-12 8.5.7 Tolerances and gaps at fatigue-loaded joints The following rule supplements DIN EN 1090-2:2018-09, 8.5: A tolerance management plan shall be part of the component specification It is mandatory for specifying manufacturing and assembly tolerances comply with the assumed on-site boundary conditions 18 DIN SPEC 18088-13:2019-12 10 Surface treatment 10.2 Preparation of steel surfaces for paints and related products The following rules supplement DIN EN 1090-2:2018-09, 10.2: For expected lives of corrosion protection greater than 15 years and corrosivity categories greater than C3, the preparation grades shall be as specified for P2 or P3, see Table IV Table IV — Preparation grades for offshore structures Description Preparation grade according to DIN EN ISO 8501-3 Welds 1.1 Welding spatter P3 Surface shall be free of all welding spatter 1.2 Rippled/ profiled weld P2 Surface shall be dressed (e.g by grinding) to remove irregular and sharp-edged profiles 1.3 Welding slag P3 Surface shall be free from welding slag 1.4 Undercut P2 Surface as obtained 1.5 Weld porosity P3 Surface shall be free from visible pores 1.6 End craters P3 Surface shall be free from visible end craters P3 Egdes shall be rounded with a radius of not less than mm 2.2 Edges made by punching, | P3 shearing, sawing or drilling Egdes shall be rounded with a radius of not less than mm 2.3 Thermally cut edges P3 Cut surfaces are to be refinished and edges 3.1 Pits and craters P2 Pits and craters shall be sufficiently open to allow penetration of paint 3.2 Shelling P3 Surface shall be free from visible shelling 3.3 Roll-overs/ roll laminations/ cut laminations P3 Surface shall be free from visible roll-overs/ laminations 3.4 Rolled-in extraneous P3 Surface shall be free from rolled-in extraneous matter 3.5 Grooves and gouges P2 The radius of grooves and gouges shall be not less than mm 3.6 Indentations and roll P2 Indentations and roll marks shall be smooth Edges 2.1 Rolled edges with a radius of not less than 2mm shall be rounded Surfaces generally matter Stand 2019-12 marks For requirement P3 according to DIN EN ISO 8501-3, surfaces of hot-rolled steel products according to DIN EN 10163-2, class B or better, not have to be reworked, but shall fulfil at least the requirements of P2 regarding the feature 3.1 from Table IV 19 DIN SPEC 18088-13:2019-12 11 Geometrical tolerances 11.2 Essential tolerances 11.2.2 Manufacturing tolerances The following rules supplement the DIN EN 1090-2:2018-09, 11.2.2: 11.2.2.6 Welded Structural tubes Tolerance class D on length requirements and class G on straightness according to DIN EN ISO 13920 are be used for structural tubes, if no other requirements arise due to further processing or defined otherwise in the component specification Out of roundness tolerances according to DIN EN 1090-2:2018-09, Table B.11, Criteria are to be applied to structural tubes wit r/t-ratio < 15 (> 3,2 % DCF) Note Component specification can establish higher requirements The feasibility measuring horizontally positioned thin walled tubes may be limited due to deformation under dead weight Requirements on Misalignment of plates according to DIN EN 1090-2:2018-09, Table B.11, Criteria are not valid Maximum eccentricities are governed by fulfilment of misalignment requirement according to Table III at both sides of the plates Quality class A can be applied within the stability assessment according to EN 1993-1-6, if the requirements according to Table III are complied 11.2.2.9 Ring flanges Manufacturing tolerances for ring flanges in accordance to Table V shall be complied after welding at shop floor Any deviating or additional requirements from design shall be respected in accordance to the component specification Table V — Tolerances for ring flanges after welding at shop floor Criteria Accepted deviation Flatness max 2,0 mm by 360° und 1,0 mm by 30° Flange thickness —2,0/+3,0 mm Wall thickness at neck According to DIN EN 10029 class B by analogy Outer and inner diameter d —dyom ŠS +3 mm Out ofroundness đmax — đmịn Š 6mm Pitch circle diameter each hole địg — đạọm S+#1mm Circumferential position of holes Plate thickness mm @ b hours S275 - S500 Above S500 Delivery conditions N and M Delivery condition Q t25 16 48 These values apply to the nominal parent material thickness ¢ of a full penetration weld For different plate thicknesses the greater thickness shall be applied For individual partial penetration butt welds the governing criterion is the plate thickness, but for pairs of partial penetration butt welds welded simultaneously it is the sum of the weld thicknesses s The time between weld completion and commencement of NDT shall be stated in the NDT report In the case of “cooling period only” this will last until the weld is cool enough for NDT to commence The following rules supplement DIN EN 1090-2:2018-09, 12.4.2.1: Hold times may be further reduced if it has been shown that delayed cracking does not occur during the process used If heat treatment or mechanical treatment are to be carried out, the NDT shall be performed after the heat q final treatment For welding performed offshore, minimum hold times shall be specified on a case-by-case basis 21 DIN SPEC 18088-13:2019-12 12.4.2.3 Routine inspection and testing The second paragraph in DIN EN 1090-2:2018-09, 12.4.3 is substituted by the following provisions: For EXC1 and EXC2 welds, the extent of supplementary NDT shall be as specified in DIN EN 1090-2:2018-09, Table 24 For EXC3 welds and higher, the scope of supplementary NDT shall be as in Table VII For EXC1 and EXC2 welds, plates with thicknesses smaller than mm defects not need to be tested for inner Table VII — Extent of routine supplementary NDT for EXC3 welds for offshore support structures Type of weld Scope of testing? for particular inspection method VT MT(PT) | UT Tower Butt welds at cans (circumferential and longitudinal welds) 100 % 20% 20% Butt welds at flanges (circumferential welds) 100 % 20% 100 % Full penetration welds (T-joint butt welds, e.g trunnions, hoisting eyes) 100 % 20% 20% Non full penetration welds (T-joint with fillet welds, doublings) 100 % 20% — Butt welds at cans (circumferential and longitudinal welds) 100 % 20% 100 % Butt welds at flanges (circumferential welds) 100 % 100% | 100% Full penetration welds (T-joint butt welds, e.g trunnions, hoisting eyes) 100 % 100% | 100% Non full penetration welds (T-joint with fillet welds, doublings) 100 % 100 % — Cans ofjacket tubes including piles 100 % 20% 100 % 'Welds in jacket structures 100 % 100% | 100% structural 100 % 10 % 10% secondary structural 100 % 10% — Shear keys for grouted joints 100 % 20% — Surfaces after removal of assembling aids 100 % 100 % — Foundation structure Full penetration welds, butt welds between components at non dynamically loaded joints Non full penetration welds, fillet welds between components at non dynamically loaded joints @ All welds that are not accessible during operation or which are only very hard to test shall be tested over their entire length using an appropriate NDT method Key Stand 2019-12 VT MT PT UT 22 secondary visual testing magnetic particle testing penetration testing Ultrasonic testing DIN SPEC 18088-13:2019-12 12.4.2.8 Alternative NDT-Methods The following rules supplement DIN EN 1090-2:2018-09, 12.4.2: Conventional ultrasonic testing (with a single transducer) can be replaced by phased array testing (UT PA) in accordance with DIN EN ISO 13588 together with the time of flight diffraction method (UT TOFD) in accordance with DIN EN ISO 10863 If conventional ultrasonic testing is replaced as specified above, testing instructions are to be drawn including at least the following information up, — application limits in terms of weld geometry; — the minimum test categories and acceptance levels in accordance with the required quality level of DIN EN ISO 5817 Compliance with these requirements shall be ensured The results of phased array testing (UT PA) shall be related to the quality levels of DIN EN ISO 5817 accordance with DIN EN ISO 13588 together with DIN EN ISO 17640 and DIN EN ISO 11666 in The results of the time of flight diffraction method (UT TOFD) shall be related to the quality levels of DIN EN ISO 5817 in accordance with DIN EN ISO 10863 together with DIN EN ISO 15626 12.4.2.9 UT at tubular node connections for EXC3 The following rules supplement DIN EN 1090-2:2018-09, 12.4.2: A test for UT testing is required prior to welding and the area to be scanned by the probe shall be marked on each individual part after their assembly and prior to welding If there is a deviation from the requirements of Table A.5 as in DIN EN ISO 17640:2018-03 in the case of full penetration welds at node connections due to limited access (e.g when it is not possible to test the inside of a flange), verifiability shall be proven using reference blocks and/or software modelling The achievable acceptance level is to be confirmed by the designer 12.5 Mechanical fastening 12.5.2 Inspection and testing of preloaded bolted connections 12.5.2.9 Ring flange connections The following rules apply in addition to DIN EN 1090-2:2018-09, 12.5.2: Preloaded bolts with tightening in accordance with connections in offshore foundation structures The Stand 2019-12 DIN EN 1993-1-8/NA for rotational component specification tightening DIN EN 1993-1-8 shall be used for ring flange standard preloading force FpcŸ according to techniques is to be used unless otherwise stated in the — Once the production has been completed, the flatness deviations of the flanges according to Table V shall — The be observed In the assembled state, the area at the tower wall is decisive slope ag of the exterior flange surfaces (Figure I) shall not exceed the limit value of 2% after preloading Slopes greater than ag prior to preloading have no effect on fatigue damage as long as they are reduced to a value below the limit value during the preloading process 23 DIN SPEC 18088-13:2019-12 No more than 90 % of the standard preloading force F, ¢* shall be applied when verifying fatigue safety In principle, the preloading of the bolts is to be inspected and the bolts retightened, if necessary, during the first six months after installation, but at the earliest after the number of operating hours specified in the maintenance manual If the limit values for the flange gaps specified in the execution documents are not complied with, appropriate measures shall be taken, such as filling the fatigue-relevant flange gaps with shims prior to preloading, see 8.5.7 in this document NOTE All flange gaps k in the area of the tower wall (see Figure I) are relevant for the fatigue stress range of the bolts, especially if they only extend over a part of the circumference, The influence on the fatigue damage increases as the extension |, over the circumference decreases, meaning that the ratio of k/l is decisive a) L-Flange b) T-Flange Figure I — Imperfections in ring flange connections of tubular steel towers q 24 DIN SPEC 18088-13:2019-12 Annex B (normative) Geometrical Tolerances B.2 Manufacturing tolerances In DIN EN 1090-2:2018-09, Table B.12 criterion no shall be substituted by the following: oe No Criterion Gap joints: Parameter A ——*† A l2 Gapg bracing {| Functional Tolerances Permitted Permitted deviationA Class and Class Class Class No requirement | A= +5 mm A=+3mm deviation A between components: g>(' +t;+ 50) \⁄⁄ / Essential Tolerances where ¢; and £; are the wall thicknesses of braces - Stand 2\ g 25 DIN SPEC 18088-13:2019-12 Annex E (informative) Welded joints in hollow sections Subclauses E.1 to E.4 in DIN EN 1090-2:2018-09 are to be supplemented by the following rules: E.1 General Hollow profile joints (tubular nodes) for offshore structures always have completely circumferential, mostly multilayered welding seams They are predominantly not subjected to static stresses but to dynamic stresses, or they are part of a construction with such a loading Structural engineering, manufacturing and testing shall be carefully coordinated considering these details, see 12.4.2.9 Special requirements regarding the construction materials are determined during the design stage The specifications of the structural engineer are to be complied with, and any discrepancies are to be clarified These joints can be welded on one side or both sides When welding only from the outside, the designs shown in Figure E.2 to Figure E.4 in DIN EN 1090-2:2018-09 are to be used, including the supplements to this standard Furthermore, because the design required “to ensure a smooth transition between those parts of the weld that are butts and those that are fillets“, (see first paragraph of DIN EN 1090-2:2018-09, E.5) is particularly important, further explanations and recommendations are given here Welding from both sides is normally ordered if the value of the non-static loads requires this E.2_ Rules for start and stop positions At joints with full penetration, welded from one side, according to DIN EN 1090-2:2018-09, Figure E.2, tack welds need to be completely removed before welding the root At joints with full penetration, welded from both sides, tack welds are to be removed in a way which secures that the sealing run can be welded without inclusions, a lack of fusion and an incomplete penetration At residual root welding seams for joints with full penetration, welded from one side (see DIN EN 1090-2:2018-09, Figure E.2), an effective fusion of the plate edges all the way to the rear surface has to be guaranteed This can be achieved with the design of the welding preparations bevel outlet (dimension c > mm), the selection of the welding technology, the arc characteristics and the process parameters, and is to be proven by means of work samples At multi-pass welded joints, start and end positions of the weld are to be distributed in a way that clusters are avoided Procedures are necessary for avoiding welding defects at new start positions of the weld If necessary, the previous end position of the weld is to be cleaned and ground Stand 2019-12 The design of the outer shape of the weld becomes more and more important with an increasing wall thickness of the nozzle tube The structural engineer is to define the details of the geometry 26 DIN SPEC 18088-13:2019-12 E.3 Preparation of joint faces The necessary shapes at the tube ends are generated by thermal cutting Metal-cutting processes such as milling are also possible An alternative procedure is unrolling the tube’s contour (including the bevel cutting for the welding preparation), cutting the two-dimensional cutting parts and rolling the plates to a cylindrical pipe section after The cut is to be based on a non-manual, reproducible process The cut has to be made on the brace side, the chord is not cut The joint between chord and brace is to be created by means of arc welding Basically, the geometry of welded tube-to-tube joints in hollow sections is defined by six parameters: — Crossing distance sof the tubes axes (a crossing distance s < (D,, — D,)/2 is acceptable); — _ Ratio of brace diameter to chord diameter; — Brace wall thickness W,; — Angle a < 90°, as angle between the intersecting or crossing tube axes; — Angle £, as weld opening angle at butt welds, necessary for welding purposes; — Angle y, as - in terms of cutting technology - the maximal possible bevel angle, defined as the dihedral angle between the cutting direction and the normal vector at the tube surface (see Figure E.1); Key Stand 2019-12 Stub or brace Canor chord Figure E.1 — Angles at the tubular node 27 DIN SPEC 18088-13:2019-12 Between an intersecting angle a of 90° and around 60° the geometric conditions make it possible to create a circumferential butt weld according to Figure E.2 The limit of 60° calculations and can differ depending on the values of f and y is the result of complex geometric = ry ay, Key [1 ` Heel Toe Limit weld opening angle Figure E.2 — Weld preparation for circumferential butt weld At smaller intersecting angles a an outer circumferential butt weld is impossible and is usually replaced by a combination of a butt weld and a fillet weld (Figure E.3) Up to a transition point the brace is prepared for butt welding, which will adapt to the chord surface in a transition zone to create the conditions for fillet welding Unless otherwise required in the component specification, the value of the a-measure of the fillet weld should be similar to the wall thickness of the brace The transition from butt to fillet weld has to be Stand 2019-12 welded in a way that the joint surfaces are melted completely and lack of fusion is avoided Flat-angle transitions are unfavorable and are to be avoided The fillet weld should start and end smoothly and the steady reduction of it has to be positioned on top of the previously welded butt weld smooth transition of the fillet weld Figure E — Tube connection as combination butt and fillet weld DIN SPEC 18088-13:2019-12 The angle between the flank of the brace and the cut (Figure E.4) should not be greater than 90°, even if this increases the weld opening angle f avoiding lack of fusion Figure E.4 — Flank angle at the saddle of the brache The brace will have a typical, discrete cutting flank contour which is divided into butt weld, fillet weld and transition zones (Figure E.5) Key transition zone fillet weld butt weld and 2019-12 Figure E.5 — Weld regions 29 g DIN SPEC 18088-13:2019-12 For brace inner diameters of > 600 mm a welding preparation as a combination of outer and inner weld is possible, which creates a full penetration weld (Figure E.6) Figure E.6 — Accessibility to the inside at braces with DS > 600 mm The transition zone in which the welding preparation changes from outside to inside can be longer Within this zone a K-seam (Figure E.7) is created in which the welding seam smoothly merges from the outside to the inside Key transition zone Welding preparation changes from outside to inside Figure E.7 — Weld sections at combination of outer and inner weld E.4 Assembly of the tubular node Stand 2019-12 If there is more than one brace within the node, overlapping welding distances according to Annex B of this document are to be maintained 30 seams are prohibited Minimal DIN SPEC 18088-13:2019-12 Annex F (normative) Corrosion protection F.4 Surfaces in preloaded connections The following rule applies in addition to DIN EN 1090-2:2018-09, F.4: The contact surfaces of ring flanges in EXC3 shall be thermally sprayed (metallized) F.6.2 Metal spraying The following rule applies in addition to DIN EN 1090-2:2018-09, F.6.2: In case of thermal spraying of the contact surfaces of ring flanges in EXC3, the surface shall be sand blasted Stand 2019-12 with Sa ¥% in deviation from DIN EN ISO 2063 The nominal layer thickness shall be = 80 um 31 DIN SPEC 18088-13:2019-12 Bibliography E DIN 18088-5, Structures for wind turbines and platforms— Part 5: Joints between steel structures and concrete structures DIN EN 10163-3, Delivery sections — Part 3: Sections requirements for surface condition of hot-rolled steel plates, wide flats and DIN EN 10210-1, Hot finished structural steel hollow sections — Part 1: Technical delivery conditions DIN EN ISO 9013, Thermal cutting — Classification of thermal cuts — Geometrical product specification and quality tolerances DIN EN ISO 17637, Non-destructive testing of welds — Visual testing of fusion-welded joints Stand 2019-12 ASTM E 192, Standard Reference Radiographs of Investment Steel Castings for Aerospace Applications 32