NORSOK STANDARDM-101 Edition 5, October 2011 Structural steel fabrication This NORSOK standard is developed with broad petroleum industry participation by interested parties in the Norwegian petroleum industry and is owned by the Norwegian petroleum industry represented by The Norwegian Oil Industry Association (OLF) and The Federation of Norwegian Industry. Please note that whilst every effort has been made to ensure the accuracy of this NORSOK standard, neither OLF nor The Federation of Norwegian Industry or any of their members will assume liability for any use thereof. Standards Norway is responsible for the administration and publication of this NORSOK standard. Standards Norway Strandveien 18, P.O. Box 242 N-1326 Lysaker NORWAY Copyrights reserved Telephone: + 47 67 83 86 00 Fax: + 47 67 83 86 01 Email:
[email protected] Website: www.standard.no/petroleum NORSOK standard M-101 Edition 5, October 2011 Foreword 5 Introduction 5 1 Scope 6 2 Normative and informative references 2.1 Normative references 2.2 Informative references 6 6 7 3 Terms, definitions and abbreviations 3.1 Terms and definitions 3.2 Abbreviations 7 7 7 4 Selection of steels 4.1 Design classes 4.2 Selection of steel quality level 8 8 8 5 Qualification of welding procedures and welders 5.1 Welding procedure specification (WPS) 5.2 Qualification of welding procedures 5.3 Welding procedure qualification record (WPQR) - Range of approval 5.4 Examination of the test weld 5.5 Welder and welding operators qualifications 8 8 8 9 10 12 6 Fabrication and welding requirements 6.1 General 6.2 Drawings for fabrication 6.3 Welding coordination 6.4 Welding inspection and qualification of welding inspectors 6.5 Forming 6.6 Assembly 6.7 Preparation for coatings 6.8 Preparation and fit-up of weld bevels 6.9 Welding processes 6.10 Welding consumables 6.11 Preheat and interpass temperature 6.12 Production welding 6.13 Post weld heat treatment (PWHT) 6.14 Grinding 6.15 Peening 12 12 12 12 13 13 13 15 15 15 15 15 16 16 17 17 7 Production tests 17 8 Fabrication tolerances 17 9 Non-destructive testing (NDT) 9.1 General 9.2 Qualification of non-destructive testing (NDT) operators 9.3 Extent of visual examination and non-destructive testing (NDT) 9.4 Visual examination and finish of welds 9.5 Radiographic testing 9.6 Ultrasonic testing 9.7 Magnetic particle and penetrant testing 9.8 Acceptance criteria 17 17 18 19 20 20 20 21 21 10 Repair Definitions Correction of welds containing defects Repair by welding Repair welding procedure Correction of distortion 24 24 25 25 25 25 Annex A (Informative) Details for high fatigue utilisation 26 Annex B (Informative) Correlation between steel quality level, MDS number and steel grade/designations 28 10.1 10.2 10.3 10.4 10.5 NORSOK standard Page 3 of 62 NORSOK standard M-101 Edition 5. typical check points 57 Annex G (Normative) Components in stainless steel and Ni-alloys 59 NORSOK standard Page 4 of 62 . October 2011 Annex C (Normative) Qualification of welding consumables by data sheets 30 Annex D (Normative) Welding consumable documented by batch testing 32 Annex E (Normative) Fabrication tolerances 33 Annex F (Informative) Weld inspection. Introduction Edition 5 of this NORSOK standard has been necessary due to an extensive change in referenced international standards. Norwegian Shipowners’ Association and The Petroleum Safety Authority Norway. as far as possible. NORSOK standards will be used to provide the Norwegian industry input to the international standardisation process. D. The NORSOK standards are developed according to the consensus principle generally applicable for most standards work and according to established procedures defined in NORSOK A-001. the relevant NORSOK standard will be withdrawn. E and G are normative. intended to replace oil company specifications and serve as references in the authorities’ regulations. In addition new annexes have been included. NORSOK standards are administered and published by Standards Norway. October 2011 Foreword The NORSOK standards are developed by the Norwegian petroleum industry to ensure adequate safety. Subject to development and publication of international standards. Annex A.NORSOK standard M-101 Edition 5. The Federation of Norwegian Industry. Where relevant. adding the provisions deemed necessary to fill the broad needs of the Norwegian petroleum industry. Some corrections and improvements have also been implemented NORSOK standard Page 5 of 62 . value adding and cost effectiveness for petroleum industry developments and operations. Furthermore. The NORSOK standards are prepared and published with support by The Norwegian Oil Industry Association (OLF). NORSOK standards are. The NORSOK standards are normally based on recognised international standards. Annexes C. B and F are informative. October 2011 Scope This NORSOK standard covers the requirements for fabrication and inspection of offshore steel structures with SMYS < 500 MPa and with a minimum design temperature down to -14 qC. training and qualification of welding personnel Qualification test of welders – Fusion welding – Part 1: Steels Qualification and certification of NDT personnel – General principles Welding – Recommendation for welding of metallic materials .1 Normative references BS 7448. more severe requirements may apply. Latest issue of the references shall be used unless otherwise agreed. Part 1. Metallic products – Types of inspection documents EN 10225. Welding coordination – Tasks and responsibilities ISO 14732. DNV RP D404. Welding – Guidelines for a metallic materials grouping system NORSOK standard Page 6 of 62 . IIW International Welder. notch orientation and examination ISO 9606-4. EN 1011. through reference in this text. 2. Non-destructive testing – Qualification and certification of personnel ISO 14731. Castings – System of dimensional tolerances and machining allowances ISO 9016. Non-destructive testing – Penetrant testing – Part 1: General principles ISO 3690. Destructive tests on welds in metallic materials – impact tests – Test specimen location. Other recognized standards may be used provided it can be shown that they meet the requirements of the referenced standards. Execution of steel structures and aluminium structures – Part 1: Requirements for conformity assessment of structural components EN 10204. and these will be shown on the design drawings. Fracture mechanics toughness tests Guide on methods for assessing the acceptability of flaws in fusion welded structures Unstable fracture Minimum requirements for education. Weldable structural steels for fixed offshore structures – Technical delivery conditions ISO 2553. Welding and allied processes – Classification of geometric imperfections in metallic materials – Part 1: Fusion welding ISO 6847. NOTE 2 For highly fatigue utilized structures. EN 1011-3. Quality requirements for welding of metallic materials – Part 2: Comprehensive quality requirements ISO 6520-1. Welded.(all parts). Welding – Determination of hydrogen indeposited weld metal arising from the use of covered electrodes for welding mild and low alloy steels ISO 3834-2. brazed and soldered joints – Symbolic representation on drawings ISO 3452-1. Welding consumables – Deposition of a weld metal pad for chemical analysis ISO 8062:1994. BS 7910. EN 287-1. EN 473.NORSOK standard M-101 1 Edition 5. For special application steels with SMYS up to 690 MPa may be used. Specification and qualification of welding procedures for metallic materials – General rules ISO 15609-1. 2 Normative and informative references The following standards include provisions and guidelines which. 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 ISO/TR 15608. Welding personnel – Approval testing of welding operators for fusion welding ISO 15607. NOTE 1 Lower minimum design temperatures require project specific evaluations. constitute provisions and guidelines of this NORSOK standard.(all parts) Welding – Recommendation for welding of metallic materials – Part 3: Arc welding of stainless steels EN 1090-1:2009 + EN 1090-1:2009/AC:2010. Specification and qualification of welding procedures for metallic materials – Welding procedure specification – Part 1: Arc welding ISO 15614-1. Approval testing of welders – Fusion welding – Part 4: Nickel and nickel alloys ISO 9712. NORSOK N-004. ISO 17636. ISO 3834-3. definitions and abbreviations apply. Rules for approval of welding inspectors ISO 17025. or that a certain course of action is preferred but not necessarily required 3.2 Abbreviations AFC BS CEV approved for construction British Standard carbon equivalent value (IIW. definitions and abbreviations For the purposes of this NORSOK standard. International Institute of Welding Formula CEV C CTOD DAC DNV EN (pr EN) EWF FCAW crack tip opening displacement distance amplitude curve Det Norske Veritas European Standard (proposal for EN) European Welding Federation flux cored arc welding Mn Cr Mo V Ni Cu 6 5 15 NORSOK standard Page 7 of 62 .3 may verbal form used to indicate a course of action permissible within the limits of this NORSOK standard 3. physical or casual 3. the following terms. October 2011 Hot rolled products of structural steels – (all parts) Hot finished structural hollow sections of non-alloy and fine grain steels – (all parts) Cold formed welded structural hollow sections of non-alloy and fine grain steels – (all parts) Quality requirements for welding of metallic materials – Part 3: Standard quality requirements Terms. 3 Edition 5. unless accepted by all involved parties 3. 2. nickel and nickel alloys General requirements for the competence of testing and calibration laboratories Non-destructive testing of welds – Radiographic testing of fusion-welded Non-destructive testing of welds – Visual testing of fusion welded joints.1 shall verbal form used to indicate requirements strictly to be followed in order to conform to this NORSOK standard and from which no deviation is permitted.1 Terms and definitions 3. 3.4 can verbal form used for statements of possibility and capability.1. Non-destructive testing of welds – Ultrasonic testing of welded joints. EN 10210-(all parts).1. NS 477.2 Informative references EN 10025-(all parts). NORSOK M-601. EN 10219-(all parts).NORSOK standard M-101 ISO 15792-1.1. ISO 17640. ISO 17638. ISO 17637. Non-destructive testing of welds – Ultrasonic testing – Testing of welds in austenitic steels and nickel-based alloys Material data sheets for structural steel Design of steel structures Welding and inspection of piping Welding. ISO 22825. Welding consumables – Test methods – Part 1: Test methods for all-weld metal test specimens in steel. whether material.2 should verbal form used to indicate that among several possibilities one is recommended as particularly suitable.1. NORSOK M-120. without mentioning or excluding others. Non-destructive testing of welds – Magnetic particle testing. 2 Selection of steel quality level The steel quality level will be decided by the designer in compliance with NORSOK N-004.1 Edition 5.2 Qualification of welding procedures Welding procedures used for structures requiring steel quality level I and II for all strength levels and steel quality level III for SMYS t 355 MPa shall be qualified in accordance with ISO 15614-1 and the additional requirements in this NORSOK standard. deposit metal International Institute of Welding International Welder International Welding Technologist International Welding Engineer International Welding Inspector International Organization for Standardization material data sheet main support frame magnetic particle testing non destructive testing outside diameter carbon equivalent (cold cracking susceptibility) Pcm C PT PWHT RT SAW SMYS SQL SS UT VT WPS WPQR penetrant testing post weld heat treatment radiographic testing submerged arc welding specified minimum yield strength steel quality level stainless steel ultrasonic testing visual testing welding procedure specification welding procedure qualification record 4 4. 4.1 Welding procedure specification (WPS) Specification and qualification of welding procedures for metallic materials shall be in accordance with ISO 15607. Reference is made to NORSOK N-004. 5. NORSOK standard Page 8 of 62 .NORSOK standard M-101 FSH HAZ HDM IIW IW IWT IWE IWI ISO MDS MSF MT NDT OD Pcm full screen height heat affected zone hydrogen content. III and IV. 5 Qualification of welding procedures and welders 5. WPS shall be established in accordance with ISO 15609-1. Selection of a better steel quality level in fabrication than the minimum required by the designer shall not lead to more stringent requirements in fabrication. II. and designations on equivalent steels given in NORSOK M-120. Annex B gives the correlation between the steel quality levels I. October 2011 Si Mn Cu Cr Ni Mo V 5B 30 20 60 15 10 Selection of steels Design classes The design classes will be decided by the designer and shall form the basis for selection of SQL. 3. b) CTOD testing as described in 5. PWHT report and chart shall be included in the WPQR.03 CEV (IIW formula) units over the value on the approval test shall require a new qualification test.1 For welding of steels in all strength classes The WPQR is valid within the limitations specified in ISO 15614-1. The number of procedures to be re-qualified shall be sufficient to verify that the HAZ properties of the new material is comparable with that used for the previous qualifications. then an increase of more than 0. For groove angles less than 30°. but not vice versa.3.13 %. g) a qualification of fillet welds carried out on plate thickness equal to or greater than 30 mm.1 i) shall be executed for thicknesses above 30 mm. 5. or half V -groove as deemed most representative for the actual fabrication. Single layer fillet welds qualifies multi-layer. 8. thermomechanically controlled processed or quenched and tempered). f) a decrease in groove angle of more than 10° . then all intermediate heat inputs are also qualified. 2) a welding procedure representing the maximum heat input to be used in fabrication. e) a change in microalloying element or manufacturing technique for steel with SMYS t 400 MPa. NORSOK standard Page 9 of 62 . but not the converse. October 2011 The qualification is primarily valid for the workshop performing the welding tests. h) qualification of WPS with manual welding methods 135 and 136 applies also for partly mechanized and mechanized welding. or a carbon content C t 0. the limitation is +20°/. provided these are removed completely by gouging and grinding. forged) steel to cast steel or converse. b) when the steel to be welded has a Pcm t 0. CTOD testing shall be executed from as welded and PWHT weld assemblies as applicable. a change of material shall require re-qualification of a reduced number of procedures. V and X groove are acceptable for weld metal test. and other workshops under the same technical and quality management. If an approval testing have been performed at both a high and a low heat input level (all specified mechanical testing to be performed for both high and low heat input). applies for all plate and throat thicknesses.4.3.0°.02 Pcm units or 0.1 the following additional requirements apply for welding of steels with SMYS > 500 MPa: a) a change in steel manufacturer. It may also be transferred to and used by a subcontractor. 5.3. with the following clarifications and modifications: a) control of heat input according to ISO 15614-1. NOTE The changes specified in d) and e) above need not require re-qualification if HAZ properties for the material to be welded have been documented from the steel manufacturer for relevant thicknesses and heat input ranges. c) a change from wrought (rolled. Requirements to components in stainless steel and Ni-alloys are given in Annex G. covering the following combined conditions: 1) full penetration buttweld with K-.Range of approval 5. except welding consumables used for root passes only. Assemblies shall be made and tested for the actual combination of steel manufacturer. shall apply. welding process and welding consumable (brand) used.NORSOK standard M-101 Edition 5. The WPQR documentation shall include the material certificates for the base material and filler materials applied in the weld qualification test. d) for all strength levels for SQL I and II and for SMYS > 400 MPa for SQL III.2 For welding of steels with SMYS ! 500 MPa In addition to the requirements given in 5. CTOD testing shall be included in the qualification of welding procedures for weldments with a plate thickness below and equal 50 mm if requested by the designer for the specified steel quality level.21.8. 3) maximum joint thickness (within 10 %). i) CTOD testing shall be included in the qualification of welding procedures for weldments with a plate thickness above 50 mm for all strength levels for steel quality level I and II and for SMYS > 400 MPa for steel quality level III. a change in delivery condition (normalised. If sufficient documentation from the steel manufacturer is not available. c) stress relieving if required/specified by designer.3 Welding procedure qualification record (WPQR) . provided the principles of ISO 3834-2 and ISO 14731 are implemented and documented. e For welds on submerged structures with cathodic protection. Table 1 Type and number of tests Mechanical testing Joint configuration Buttwelds (Tubulars and plates) T-joints (plates) d Tubular joints d Fillet welds Joint thickness mm t ≤ 50 t !50 Tensile test Bend a tests 2 2 4 4 t ≤ 50 t !50 t ≤ 50 t !50 All c c c c Charpy Vnotch tests 4 sets 6 sets b 4 sets 6 sets b 4 sets 6 sets Hardness and e macro 1 1 2 2 2 2 2 CTOD See 5. Test laboratories shall have a quality system in compliance with ISO 17025 or equivalent. x x x x Notch in centre of weld (VWT 0/2). 5 mm from fusion line (VHT 5/2). the Charpy V-notch properties shall be documented on a butt weld joint made with the same consumable and same base material. NORSOK standard Page 10 of 62 . Designation in parenthesis refers to Figure 1 and Table 2 in ISO 9016. The test temperature and energy requirements shall comply with Table 2.1 i). All specimens shall be machined with the notch through the thickness. and welding parameters and thickness within the range qualified for the joint.4 f a Bend tests shall consist of 2 face and 2 root bend specimen for t < 12 mm and 4 side bend specimens for t t 12 mm.4 Edition 5. d T-joints on plates qualify for tubular joints. 2 mm below the surface of the material. b If the dimensions of the joint does not allow Charpy V-notch testing.NORSOK standard M-101 5. The soundness of the weld shall comply with Clause 9.2 b) and 5. x notch in fusion line (VHT 0/b). with the notch in the positions listed below.4. 5. Notch in fusion line (VHT 0/2). CTOD testing shall be documented on a buttweld. f For T-joints with t > 50 mm. c It shall be documented on a butt weld test that the welding consumable used will have sufficient tensile strength. and vice versa.3. two additional sets of Charpy V-notch tests shall be taken from the root area.2 Charpy V-notch testing Sampling of Charpy V-notch impact tests shall be carried out in accordance with ISO 9016. 2 mm from fusion line (VHT 2/2). Testing shall be performed in accordance with ISO 15614-1 and the additional requirements given below. The test weld shall be 100 % examined for both surface and volumetric defects with the relevant NDT methods. October 2011 Examination of the test weld 5.3. Notch in HAZ.4. the hardness limits in NORSOK M001 shall apply in addition to the requirements of ISO 15614-1. For welds with a joint thickness T !50 mm or more.4. with the notch in the following positions: x notch in centre of weld (VWT 0/b). 5. Notch in HAZ.1 General The type and number of tests shall be in accordance with Table 1. 3 Transverse tensile testing Testing shall be carried out in accordance with ISO 15614-1.NORSOK standard M-101 Table 2 Edition 5. NORSOK standard Page 11 of 62 .4 Crack tip opening displacement (CTOD) testing The CTOD-technique with the Bx2B through-thickness notched type specimen according to BS 7448. Other test temperature may be prescribed by the designer.5 mm and 2/3 for 5 mm.4. determination of the actual location of the fatigue crack tip shall be performed after testing. i. The required fracture toughness level shall be decided in design for joints when steel quality level I and II are required. The requirement for minimum CTOD value shall be prescribed by the designer. The fracture shall be located outside the weld metal. No individual value shall be less than 70 % of the minimum average value. CTOD-testing of HAZ can be omitted if relevant CTOD properties in HAZ have been documented previously in accordance with requirements in this NORSOK standard. Part 1. provided the requirements for the essential variables are met. should be used. Reduction factors of energy requirements for subsize specimens shall be 5/6 for 7. 5. For HAZ.e. CTOD-testing of welds shall be carried out with the fatigue notch tip positioned in the coarse grained region of the heat affected zone and in the weld metal. 5. the requirement for minimum CTOD value shall be as for the steel purchase order. Material thickness (mm) t d 12 12 < t d 25 25 < t d 50 t > 50 Energy a requirement a Steel quality level II I SMYS d400 SMYS !500 SMYS d400 °C 400< SMYSd 500 °C °C 0 -20 -40 -40 36 J -20 -40 -40 -40 42 J -20 -40 -40 -40 60 J III SMYS !500 °C 400< SMYSd 500 °C SMYS !500 °C 355d SMYSd 500 °C 0 0 -20 -40 27 J -0 -20 -40 -40 42 J -20 -40 -40 -40 60 J -0 0 -20 -40 27 J 0 -20 -40 -40 42 J °C The minimum average value is given in the table. and specimens may be precompressed. October 2011 Charpy impact test temperatures and energy requirements for welding procedure qualifications. Three valid test specimens shall be obtained for each test position. x 0 °C for submerged parts.4. see EN 10225. maximum 20 % of the fracture surface shall consist of weld metal/HAZ. If not specified. NOTE Test assemblies may be given hydrogen diffusion treatment prior to testing. provided the requirements for the essential variables are met. CTOD-testing of weld metal can be omitted if relevant CTOD properties in weld metal have been documented previously in accordance with requirements in this NORSOK standard. Testing is normally not requested for structures with plate thickness below 40 mm for SMYS d 500 MPa or for structures with plate thickness below 25 mm for SMYS > 500 MPa. the test temperature for design temperature down to -14 °C shall be x -10 °C for splash zone or above. If not specified otherwise. Annex B. Welds in inspection category A and B shall have unique weld number. see IIW. diploma as IW-International Welder (fillet. an internal test according with EN 287-1 and/or ISO 9606-4 is accepted without use of 3 part.plate-pipe welder) within actual welding method and material may be accepted. For fabrication of structural steel in inspection category D and/or E. see ISO 14731. an IWT may be accepted. rd For tack welders. All types of inspection/examination shall be performed by personnel other than those performing and being responsible for the production work. see ISO 14731. 6 Fabrication and welding requirements 6. examination and qualification of welding personnel. dimension (outside diameter and wall thickness). welders shall be qualified with a realistic joint.D and E may be group numbered. The responsible welding coordinator shall be qualified as an IWE. The fabricator shall apply a weld numbering system for identification on all shop drawings and as reference in all documentation. PWHT requirements. October 2011 Welder and welding operators qualifications The welders shall be certified by an accredited body according to EN 287-1 and/or ISO 9606-4. The following information shall be used as relevant: x x x x x material type/grade and grouping number (ISO/TR 15608).5 Edition 5. 6. The shop drawings shall have enough information to enable correct selection of WPS. D and E. if relevant. Minimum requirements for the education. training. The manufacturer shall have an implemented and documented quality system according with ISO 3834-2. responsibility and authority shall be identified for each person/function in a job description. NORSOK standard Page 12 of 62 . representing the minimum angle D to be used in production.1 General All welding work shall be according to recommendations given in relevant part of the EN 1011-series. The manufacturer shall appoint a responsible authorized welding coordinator.3 Welding coordination All welding coordination shall be according to ISO 14731. tasks. Welds in inspection category C. are welding coordinators. 6. For welding in inspection category C. The responsible welding coordinator may delegate welding coordination activities at fabrications sites to an IWT.2 Drawings for fabrication Symbolic presentation of welds shall be according to ISO 2553. ISO 3834-3 may be accepted (used). but only within the same node/essential member and same drawing sheet. required toe grinding. For welding of single sided acute angled tubular joints with D < 70º.NORSOK standard M-101 5. Welding operators shall be certified according to ISO 14732. The level of technical knowledge. All other personnel who are carrying out one or more welding activities according to ISO 14731. If only fabrication/welding in inspection category D and/or E. etc. Annex A. 4 Edition 5. weldability. x the Charpy-V impact value shall comply with the minimum requirements for the steel grade and shall not be more than 25 % lower than the impact value for the material before deformation and strain ageing. The notch shall be located within the plastically strained portion of the material. x the impact testing temperature shall be as specified for the actual steel grade in question. If forming is performed at temperature above 250 qC. the deformation limit without documentation of mechanical properties is 5 %. forming below 250 qC) shall be carried out within the deformation range recommended by the steel manufacturer. October 2011 Welding inspection and qualification of welding inspectors Welding inspector’s tasks and responsibilities is to be familiar with all standards. it shall be documented that the base material properties. If the deformation is more than the above given limits. circumferential and longitudinal weld joints should not be placed in the shaded areas shown in Figure 1. Prior to fabrication start-up. unless otherwise shown on design drawings. The percentage strain due to forming is defined as follows: Percent strain 6. contractor shall implement a system for recording of quality status. Welding inspectors shall be qualified according to NS 477 or EWF/IIW rules for approval of IWI-International Welding Inspector 6. Causes for non-conformance shall be immediately investigated and corrective action shall be taken to prevent further occurrence.NORSOK standard M-101 6. The inspection frequency shall be sufficient to report weekly quality status during fabrication based on welding inspection reports. either heat treatment shall be performed.5 Forming Cold forming of steel (i. weldmetal and HAZ properties satisfy the actual MDS and this NORSOK standard. All inspections shall be reported to the responsible welding coordinator. x one set of 3 impact test specimens shall be tested from the base material in the strained plus artificially aged condition. or strain ageing tests shall be carried out according to the following requirements: x the material shall be permanently strained locally to the actual deformation. x the material shall be artificially aged at 250 qC for 1 h. in the part of the cross section which have received the highest strain.6.1 General In tubular joints.6 Wall thickness x 100 % Forming mid thickness diameter Assembly 6. during and after welding according to typical check points listed in Annex F. rules and specifications. For steel quality level I and II. and continuously verify that all requirements and adequate parts in ISO 3834-2 are implemented and followed. Non-conformance shall require documented investigation/action by the responsible welding coordinator.e. NORSOK standard Page 13 of 62 . Welding inspection shall be performed before. noted as restricted on design drawings. 6. 6. 6. a tapering of 1:4 should be used. hollow sections shall be ventilated. October 2011 W1 W1 W1 W1 W2 W2 W2 W2 W 3 D Longitudinal welds Circumferential welds W1 = 75 mm or minimum 2 times chord thickness W2 = 150 mm or minimum D/4 W3 = 600 mm or minimum D Figure 1 Prohibited location of welds in tubular joints 6. Where steel items shall be hot dip galvanised.7 Straightening of structural members Members distorted by welding shall be straightened according to a detailed work instruction. inspection and documentation procedures and requirements that govern the structural part in question. 6.6.6. 6. Seal welds shall have a throat thickness of at least 3 mm.3 Tapering Tapering shall be in accordance with the requirements given in relevant standards or drawings.6. Maximum temperature for straightening shall not exceed the temperature limit recommended by the steel manufacturer.6.5 Seal/blind-compartments.6 Temporary cut-outs Temporary cut-outs shall not be located in restricted areas as shown on design drawings.2 Splices Splices shall not be located in areas. Temporary cut outs shall have a corner radius not less than 100 mm. Holes shall be made by machine drilling. NORSOK standard Page 14 of 62 .NORSOK standard M-101 Edition 5. Crevices and areas which become inaccessible after fabrication or assembly shall be sealed off from the outside atmosphere.4 Bolting connection Bolting material shall comply with requirements in NORSOK M-001. but it shall in no case be higher than 600 qC.6. Temporary cut-outs shall be closed by refitting the same or an equivalent plate and employing the same welding. If no other requirements are specified. The base material properties shall satisfy the specified requirements after straightening.6. type 2. provided preheating temperature and post weld holding temperature and time is assessed to avoid hydrogen cracking.2. HDM d 5 ml/100 g weld metal. 6. meet the requirements for mechanical properties as specified for the welding procedure qualification. maximum 20 mm in the joint. Prequalification with mock-up structures shall apply if there is a risk for high restraint in welding or erection. II and III are required. Maximum buttering is limited to t/2. 6. The responsible NDT-coordinator/personnel shall be notified every time buttering is performed in any groove. i. 6. This may be achieved through (alternatively): x batch testing including chemical analysis and mechanical properties.NORSOK standard M-101 Edition 5. thickness and weldability. unless otherwise indicated on fabrication drawings. Such consumables shall be delivered with EN 10204.6. in both as welded and (where applicable) PWHT condition.9 Welding processes The welding processes listed in ISO 15614-1 are acceptable. certificate. For self shielded flux cored wire HDM d 8 ml/100 g may be accepted. All welding consumables shall be individually marked. 6. For all steels with SMYS > 500 MPa special precautions shall be taken to verify that selected consumables comply with hydrogen requirements. Annex D is mandatory. Hydrogen testing shall be according to ISO 3690 or equivalent. tack length may be minimum 4 x plate thickness. Except for solid wires such consumables shall be classified by the supplier as extra low hydrogen. x for steels with SMYS > 500 MPa. 6.10 Welding consumables The manufacturers shall ensure that welding consumables applied for joints where steel quality level I. see Annex D.11 Preheat and interpass temperature Preheating above 50 °C should be achieved by electric heating elements. to ensure sufficient weld strength.7 Preparation for coatings Edges of plates and structural shapes which are intended to be coated shall be rounded to approximately 2 mm radius.2). x an established and reliable system of batch certification against accepted supplier data sheets. For material thickness less or equal to 25 mm. Tack welds shall normally have a length of minimum 100 mm. see Annex C.1 in accordance with EN 10204. toughness and homogenity. When certification according to Annex C is used. Welding fluxes shall be supplied with a test report (EN 10204. including a statement of compliance with the welding consumable data sheet and the chemical composition of the weld deposit (elements of the data sheet).8 Preparation and fit-up of weld bevels Permanent backing strips are not accepted. type 2. The WPS shall be supported by a butt weld WPQR. Cutting torches are not allowed for preheating. All attachments in the splash zone shall be attached to the structure by using doubler plates. Stricter requirements than given above may be relevant. Buttering shall be welded in accordance with applicable WPS.e. welding consumables (except welding fluxes) shall be supplied with an inspection certificate type 3. NORSOK standard Page 15 of 62 . October 2011 6. as a minimum. unless shown in fabrication drawings. Consumables for joints in steel quality level III (with SMYS < 355 MPa) and IV and for joining stainless to carbon steel shall be selected with due consideration of base material properties.8 Doubler plates All temporary attachments which shall be flame cut or welded under water shall be attached to the structure by using doubler plates. declaring conformity with the approved product type. the ”straight” edges of K. independent of steel quality level. unless it is documented that possible defects can be detected by the UT technique used.and half V-butt weld grooves shall have a groove º angle of at least 10 . The applicable WPS shall be given directly to the welder and be available at the site of welding at all times A collection of WPS`s on walls or boards are only for general information and not accepted used for welding. All welding of attachments shall comply with the requirements for the structure to which they are attached. or quality level III with yield strength Re > 400 MPa. minimum holding temperature and extended post weld holding temperature for 24 h or more. If not otherwise stated in the WPS. 6. The preheat temperatures used during repair welding should be minimum 50 qC higher than the preheat used for the original weld.2 Attachments Temporary attachments as lifting lugs. For joints in inspection category A. the temporary attachments may be left as is. including preheating temperature. 6. Any occurrence of cracking during production welding shall be investigated. Cracks or other persistent weld defects may lead to revision and requalification of the WPS.12. shall be taken into consideration. Special precautions.4. For C.12 Production welding 6. the PWHT shall be repeated.3 Stainless steel components Permanent or temporary structural elements. be welded from both sides. see annex G. If any welding is conducted after PWHT. the maximum interpass temperature shall not exceed 250 qC measured at the edge of the groove. PWHT shall be carried out in accordance with a procedure which shall include NORSOK standard Page 16 of 62 .13 Post weld heat treatment (PWHT) PWHT shall be required for structural welds in steel quality level I or level II. For restrained joints of complicated design. October 2011 The minimum interpass temperature shall not drop below the minimum required preheat temperature. unless adequate fracture toughness can be documented in the as welded conditions. ladders or other fabrication and erection aids should be removed. when the nominal thickness as defined in ISO 15614-1. Temporary attachments shall be cut minimum 3 mm from the base metal and ground. lugs for scaffolding and assembly. or removed only partially.and C/Mn-steels. equipment. Butt welds in joints where steel quality level I and level II for all strength levels. Welding should be suspended until the cause of cracks and defects has been identified and measures taken to prevent their reoccurrence. 6.12. the 10 should be machined from the root to each plate surface. and qualified by the WPQR. If indicated on design drawings that removal (full or partial) is not required. whenever possible. or steel quality level III for SMYS > 400 MPa are required shall. NOTE Production welding of high strength steels with SMYS > 500 MPa is normally more sensitive to hydrogen cracking than experienced during welding for qualification. The ground area shall be visually examined and magnetic particle/penetrant tested (as relevant) in accordance with the inspection category in question. even if a lower temperature was recorded on the WPQR.NORSOK standard M-101 Edition 5. PWHT may be required for smaller thicknesses. attachments or penetration sleeves in stainless steel materials may be selected for various purposes. º For K-grooves.12. All welding and inspection of welds to carbon steel structures shall as a minimum comply with the requirements for the structure to which they are attached. a maximum interpass temperature of 250 qC may be used. exceeds 50 mm. Requirements for welding and inspection of stainless outfitting structures shall follow similar classification principles as for other structural steel elements. supports for cables.1 General Welding shall be carried out in accordance with the WPS and applicable drawings. 6. Welding consumables shall be selected in accordance with G. The temperatures shall be continuously and automatically recorded on a chart. unless otherwise specified on drawings. control devices. recording equipment. October 2011 heating rate. Normally pregrinding of a groove will be required to assure correct location of peening area. Test coupons shall be welded in a manner which realistically simulates the actual production welding. normally as extension of the production weld.15 Peening Weld improvement by peening shall be performed in accordance with detailed procedures. 9 Non-destructive testing (NDT) 9.14 Grinding When grinding is specified on design drawings or is instructed as a corrective action. Minimum one test coupon is required from each applied welding process. The time delay may be reduced to 24 h for steel grades with SMYS of 355 MPa or lower. 6. 8 Fabrication tolerances Fabrication tolerances shall be in accordance with Annex E. Reference samples for typical joints and sections may be prepared and used for acceptance of treated welds. Double sided heating shall be used as far as possible. the reason for the failure shall be determined and remedial action implemented. The temperature difference between different parts of the structure during soaking time shall not exceed 30 qC within the heated area. Tools for check and measurements shall be described and shall be available during operations. NORSOK standard Page 17 of 62 .2. direction. The holding time and temperature shall be as recommended by the steel manufacturer. and meet the requirements for welding procedure approval tests. insulation. Grinding tools. heating facilities. configuration of structure to be PWHT or details if local PWHT shall be carried out.1 General The inspection category shall be decided by the designer in accordance with NORSOK N-004. surface roughness and profile of grinding as well as peening shall be specified. 7 Production tests Production tests shall be selected on weldments in critical regions to verify that the specified requirements have been meet. and shall be specified on the design drawings. Documentation of correct performance shall include macrophotography. and for steel grades with SMYS of 420 MPa or lower for plate thicknesses below 40 mm. Tools for grinding and peening. Final inspection and NDT of structural steel welds shall not be carried out before 48 h after completion except where PWHT is required. 6. If a production test fails. number and location of thermocouples to be used during PWHT. soaking temperature and time. CTOD testing is not required for production testing. Typical examples of requirements for peening of joints are given in A. provided delayed cracking have not been observed for the materials and/or welding consumables in question.NORSOK standard M-101 x x x x x x x x x Edition 5.1. the grinding shall be performed according to a detailed procedure. surface roughness and final profile shall be specified. Typical examples for requirements for grinding of joints are given in A. cooling rate. Prior to fabrication start-up. rd The NDT operator shall be qualified according to EN 473. if the defect rate approaches 10 % during any stage in production welding. C and D. NS 477 latest revision may be used. 9. At a weekly high defect rate or at repeated occurrence of planar defects. provided that a correct defect rate identification is prepared for each weld method. Two steps of actions apply within trigger level 2. Level 3 (or ISO 9712) or rd equivalent 3 party certification scheme. two trigger levels apply for extended NDT for welds in inspection category B. The defect rates shall be recorded on a weekly basis for VT. Generally. If the defect rate for the weld length where the extended NDT is taken in accordance with Step 1 above exceed 5 %. welded in the same period of time by the specific welder(s) and WPS when the high defect rate was produced. NORSOK standard Page 18 of 62 .2 Qualification of non-destructive testing (NDT) operators Personnel responsible for all NDT activities shall be qualified according to EN 473. table footnote . A low defect rate may be used as basis for a reduction in the extent of NDT for inspection categories B. PT. the final NDT shall be carried out when all heat treatment have been completed. NDT personnel performing visual inspection of welded joints shall be qualified in accordance with EN 473. the higher level of extent of NDT shall be maintained until the weekly defect rate is well below 5 %. October 2011 When PWHT is performed. NDT after repair shall not be included when calculating the defect rate. The defect rate statistics shall be used as a tool in weld quality control. see Table 3. to assure that the weld quality is maintained also with the lower extent of NDT. Unless the causes for defects found leads to immediate and documented preventive actions. contractor shall implement a system for recording of weld defect rates. C and D. Trigger level 2 If a defect rate for any method of 5 % to 10 % for a single week is observed the following two steps of extended NDT shall apply: Step 1. Spot extent shall be increased to 20 %. The defect rate is defined as : (Defect length x 100 %) (Length of tested parts of welds) NOTE “Tested part of welds” means the part that is tested with the same NDT method. Step 2. UT and RT from each production area (geographically split in production areas at the same yard) and shall be reported together with the accumulated defect rate. level 2 or equivalent 3 party certification scheme.NORSOK standard M-101 Edition 5. each NDT method b and each production area. further welding should be held until investigations are completed and corrective actions implemented. A defect rate for any NDT method exceeding 5 % (1 % for MT) for a single week require doubling of the extent of NDT according to the inspection category. the extent shall be increased to 100 % for all welds in question The increased NDT extent shall cover welds of the same inspection categories. The defects shall be reported with reference to the numbering system according with ISO 6520-1. Trigger level 1 If a defect rate for any method exceed 10 % for a single week the extent shall be increased to 100 % for all welds in question. Defect rate shall be based on at least 5 welds or 1 m tested weld length. Cracks detected with any NDT method shall require documented investigation/action by the responsible welding engineer. MT. Causes for defects shall immediately be investigated and corrective actions shall be taken to prevent further occurrence. VT rd level 2 or equivalent 3 party certification scheme. a Increased extent of NDT shall be as defined in relevant Trigger levels in 9. based on experience and documented records with similar joints. The last 100 m shall be continuously updated every week. Partial NDT shall normally be planed for on all shop drawings. October 2011 Operators simply producing radiographs and not performing evaluation. When partial testing is defined for welds in an area. but shall have sufficient training. The specified percentage to be tested in Table 3 refers to the total length of welds in each inspection category. The required level of increased extent shall be maintained until a defect rate below 5 % is reestablished and documented. the testing shall be spread such that the most essential members and nodes are included in the inspection.2 % during the last 100 m of weld. Table 3 Inspection category A a B C a a D E Minimum extent (in %) of non-destructive testing for structural welds Type of connection Buttweld T-connection Fillet/partial Buttweld T-connection Fillet/partial Buttweld T-connection Fillet/partial All connections All connections Visual examination Extent of testing % % RT UT MT 100 100 100 100 100 100 100 100 100 100 100 10 Spot - 100 100 c 20 b 50 b 50 bc 10 b 20 b 20 c spot - 100 100 100 b 100 b 100 b 100 b 20 b 20 b 20 spot - Key Spot means 2 % to 5 %. Testing performed shall be representative for the weld quality. A possible reduction in the extent of NDT shall be considered separately for each welding method and each production area. the NDT operator shall document experience with forged and cast products. If the defect rate exceeds the limits given above. 9.0 % and for MT is < 0. The testing shall be performed on minimum 5 % of welds in inspection category A and B for SAW (12) and FCAW (131 and 136). do not require level 2. the normal extent of NDT shall apply again. NORSOK standard Page 19 of 62 .1. Ultrasonic testing to reveal the presence of possible weld metal transverse cracking shall be included for butt welds with thickness more than 25 mm. c Applies only for partial penetration welds with a penetration depth greater than 12 mm.3 Extent of visual examination and non-destructive testing (NDT) The required minimum extent of examination/testing is given in Table 3. Ultrasonic operators performing inspection of welds in duplex stainless steel material shall be specially rd trained and qualified for the purpose according to EN 473 or equivalent 3 party certification scheme When testing of castings or forgings. provided the defect rate (see 9.1) for UT/RT is < 2. b The extent may be reduced to 50 % of the specified extent. Design drawings may show areas of welds where testing is mandatory.NORSOK standard M-101 Edition 5. and such that areas of welds most susceptible to weld defects are covered. The general film density shall be ≥ 2. providing that the surface finish of the weld cap is sufficiently smooth and in accordance with clause 8 of ISO 17640.6 Ultrasonic testing Ultrasonic testing of welds in plate and tubular butt welds and double side welded tubular joints shall be performed in accordance with ISO 17640. In addition to what is listed in Table 3. For such thicknesses. Reference blocks shall be made with thickness and side-drilled holes in accordance with Table 4.5. Suspect planar indications discovered by RT shall be type determined. intersection welds. c) ultrasonic and radiographic testing shall not overlap. 9. Radiographic testing is normally not applicable for thicknesses above 40 mm. UT shall be replaced with RT. In general. 9. The effective test range of a DAC curve shall be determined by the point at which the curve has fallen to 25 % FSH. For butt welds. and those locations where presence of defects is deemed to be most harmful. This extent shall be maintained for a weld and test length sufficient to conclude that the weld repair percentage is at a reasonable level. Class A. when it will be necessary to raise the curve using reflectors at increased depth. located and sized by UT. October 2011 All WPSs used and welds representing all welding personnel involved in the fabrication shall be subject to NDT. DAC reference curves shall be established. NORSOK standard Page 20 of 62 . (C and D) or (E and F) according to ISO 17640 shall be utilised for the detection of transverse imperfections. the direction of rolling. RT should be considered if UT is not possible. However. shall be tested. However. All indications exceeding -10dB DAC shall be investigated to the extent that they can be evaluated in terms of the acceptance criteria. if X-ray are used. normally to twice the level given in Table 3. The rolling direction shall be clearly identified. ambiguous imperfections revealed by UT shall in addition be tested by RT. d) ultrasonic testing is normally not applicable for thicknesses less than 10 mm. except when 100 % UT is specified. examination level C. b) where radiographic testing is required.0. the following shall apply for inspection category A and B: a) one film at each end for longitudinal welds of tubulars (including tubulars for nodes and stubs). shall be used when plotting indications. 9. the minimum film density may be reduced to 1. The reference block shall be from a steel type that is representative for the steel to be inspected. Where ultrasonic testing is to be performed on steel produced by controlled rolling or thermo mechanical treatment. Ultrasonic testing procedures shall be sufficiently detailed to ensure 100 % of the weld body and heat affected zones are examined for longitudinal defects. The increased initial testing may be accounted for in the overall extent provided the initial testing confirms consistent good workmanship.NORSOK standard M-101 Edition 5. The actual refracted angle for each probe measured from the reference block or as measured on the actual object being examined. During the initial fabrication the extent of UT and MT of inspection category B and C welds shall be intensified. and parallel to.5 Radiographic testing Radiographic testing shall be carried out in accordance with ISO 17636. reference blocks shall be produced both perpendicular to.4 Visual examination and finish of welds The visual examination shall be carried out in accordance with ISO 17637. 5.e. 9. indications with a length/width ratio above 3 and length above 1.5 mm ) are not acceptable.8. All indications exceeding acceptance criteria shall be reported.3 Radiographs The soundness of the welded joint shall comply with the requirements of Table 6. Permanent magnets are not acceptable.NORSOK standard M-101 Edition 5.8. 9. unless more stringent requirements are given. The quality shall comply with the requirements of Table 5. Any linear indications shall be ground and re-examined. MT shall be performed on both external and internal surface as accessible or as required by the designer.2 3 +/-0. Prods are acceptable where the geometry of the welded joint prevents the use of yokes. length. 9. Table 4 Thickness of material to be examined mm 10 < t < 50 50 < t <100 100 < t <150 150 < t <200 200 < t <250 t > 250 9.4 Ultrasonic testing acceptance criteria The acceptance criteria for welds shall comply with Table 7 unless more stringent requirements are specified by the designer.1 General All welds shall comply with the requirements given below. so that the beam forms a small angle with the centreline.7 Calibration reference block requirements Thickness of block Diameter of hole mm 40 or t 75 or t 125 or t 175 or t 225 or t 275 or t mm 3 +/-0. in 9.2 to 9. Rounded indications shall be evaluated in accordance with the requirements of Table 5. than the weld cap is to be dressed smooth or ground flush with the parent material in accordance with clause 8 of ISO 17640.6 All methods All defects shall be repaired according to Clause 10. NORSOK standard Page 21 of 62 .8 Acceptance criteria 9. For non-magnetic materials penetrant testing in accordance with ISO 3452-1 should be used. If the surface finish adjacent to the weld is such that testing with an angle probe using techniques (C and D) or (E and F) along the centre line of the weld is judged to be the only reliable method of examination.8.2 Distance of hole from one surface mm t/2 and t/4 Additional holes are allowed and recommended Magnetic particle and penetrant testing Magnetic particle testing shall be carried out in accordance with ISO 17638. Magnetic yokes using alternating current shall be used. 9. The examination record shall include the position. 9. Scanning is in all cases to be performed from both sides of the weld and in both directions.8.8. 9.8. The same acceptance criteria applies for penetrant testing.2 Visual examination All welds shall show evidence of good workmanship. the echo height. October 2011 Alternatively techniques (X and Y) or (W and Z) according to ISO 17640 can be utilised by placing the probe alongside the weld connection. depth and type of indication.8.8.5 Magnetic particle testing Linear indications (i. NORSOK standard M-101 Edition 5, October 2011 Defects may be accepted by the relevant parties when repair work is considered detrimental to the total integrity of the weld. Such acceptance shall be based on a fitness for purpose evaluation in accordance with BS 7910, DNV RP D404 or other recognised methods. Table 5 Structural steel welds - Visual and MT acceptance criteria for structural steel welds Welding Type of defect Cracks Incomplete penetration or lack of fusion c Undercut Surface porosity Exposed slag Concave root a Excessive pen. Roughness of weld, see Figure 2a and 2b. Misalignment of butt welds, see Figure 2c. Reinforcement of butt welds, see Figure 2d. a Reinforcement of fillet/partial pen. welds, see Figure 2e a and 2f. Symmetry of fillet welds, see Figure 2g. Grinding arc strikes etc. Removal of temporary b attachments Sharp edges Insp. cat. A, B Not acceptable Not acceptable Max. depth 0,5 mm Continuous undercut is not permitted Not acceptable Acceptance criteria Inspection category C, D, E Not acceptable Single - side weld: Length < t/2, max. 10 mm Max. depth 0,75 mm Continuous undercut is not permitted Not acceptable. However, the following defects may be acceptable if it does not conflict with surface treatment requirements: Accumulated pore diameters in any area of 10 mm x 150 mm is not to exceed 15 mm. Max. size of a single pore is t/4 or 4 mm, whichever is the smaller. Max. concavity 0,5 mm if the transition is smoothly formed. Max. 3 mm “U” shall be less than 2,5 mm. Weld surface shall be smooth, without sharp transitions. The bottom of roughness in butt welds shall not be below the base material surface. Max. misalignment (M), 0,15 x t or max. 4 mm, whichever is the smaller. “t” less or equal to 10 mm Max. reinforcement “C” 2 mm “t” greater than 10 mm, up to 25 mm Max. reinforcement “C” 3 mm “t” greater than 25 mm, up to 50 mm Max. reinforcement “C” 4 mm “t” greater than 50 mm Max. reinforcement “C” 5 mm “a” less or equal to 10 mm Max. reinforcement “C” 2 mm “a” greater than 10 mm, up to 15 mm Max. reinforcement “C” 3 mm “a” greater than 15 mm, up to 25 mm Max. reinforcement “C” 4 mm “a” greater than 25 mm Max. reinforcement “C” 5 mm “a” less or equal to 6 mm Max. difference, b - h: 3 mm “a” greater than 6 mm, up to 13 mm Max. difference, b - h: 5 mm “a” greater than 13 mm Max. difference, b - h: 8 mm Grinding of base material shall not exceed 7 % of the wall thickness or max. 3 mm. Repair welding and inspection shall be performed if removal of the base metal exceeds the specified requirements. Minimum 2 mm radius, see 6.7. a Localised reinforcements exceeding the above requirements are acceptable. Temporary attachments shall be cut minimum 3 mm from the base metal and ground smooth. The ground area shall be visually inspected and MT shall be performed in accordance with the inspection category in question. C Defects shall be regarded as a continuous defect if the distance between them is < t. b NOTE When required (see 6.14), grinding of the surface shall be specified. Typical examples of grinding requirements are given in A.1. NORSOK standard Page 22 of 62 NORSOK standard M-101 Edition 5, October 2011 U U 1) Figure 2a Roughness of weld t t c Figure 2b Roughness of weld M Figure 2c Misalignment of butt weld Figure 2d Reinforcement of butt weld b a a a c c h Figure 2e Reinforcement of fillet weld Figure 2f Reinforcement of partial pen. weld Figure 2g Symmetri of fillet weld Figure 2 – Weld defects Table 6 Structural steel welds - RT acceptance criteria Type of defect Inspection category A, B C, D, E Isolated: Pore diameter Max. t/4, but max.6 mm Max. t/3, but max. 6 mm Cluster: Pore diameter Max. 3 mm Max. 4 mm Max. 20 mm Max. 25 mm t/4, max. 6 mm 2t, max. 50 mm t/3, max. 6 mm 4t, max. 100 mm t, max. 25 mm Not acceptable 2t, max. 50 mm Not acceptable Internal porosity a Scattered: Accumulated pore diameters in any 10 mm x150 mm area of weld b Slag inclusions, or piping porosity Width c Length Incomplete penetration, lack of fusion b Length Cracks a b c If more than one pore is located inside a circle of diameter 3 times the pore diameter, the pores are to be considered as a cluster. Defects in a line where the distance between the defect is shorter than the longest defect shall be regarded as one continuous defect. No length limitation for width d 2 mm for t t 20 mm and for width d 1 mm for t 20 mm. NORSOK standard Page 23 of 62 NORSOK standard M-101 Table 7 Description General Cracks Lack of fusion or incomplete penetration Edition 5, October 2011 Structural steel welds - UT acceptance criteria Inspection category Inspection category A+B C, D, E If the type of defect can not be ascertained with certainty the defect shall be repaired when the length exceeds 10 mm and the echo height exceeds the reference curve. Unambiguous cracks are unacceptable regardless of size or amplitude. Internal defects : The echo height exceeds the reference curve: I: Max. length t, Max. length 2t, Max. 25 mm Max. 50 mm NOTE 1 2 3 4 1 2 3 4 5 The echo height is between 50 and 100% of the reference curve: Max. length 2t, Max. length 4t, Max. 50 mm Max. 100 mm II: Slag inclusions Porosity Surface defects are not acceptable except: For root defects in single sided welds, the max. length for which the echo height exceeds the reference curve shall be: Max. length t, Max. length 2t, Max. 25 mm Max. 50 mm When echo height exceeds the reference curve: Max. length 2t, Max. length 4t, Max. 50 mm Max. 100 mm Repair is required if porosity may mask for other defects. 1 2 1 NOTE 1 Type of defect shall be decided by: I: Supplementary non-destructive testing. II: The ultrasonic operator's assessment of the defect, using his knowledge of the welding process, signal geometry, defect position etc. NOTE 2 If elongated defects are situated on line and the distance between them is less than the length of the longest indication, the defects shall be evaluated as one continuous defect. NOTE 3 Defect length is defined as the distance between points where the echo reach or pass 50 % DAC (for defects larger than the beam). For defects smaller than the beam, the maximum amplitude technique may be used. NOTE 4 With UT performed from only one side of the weld with only one surface accessible, the acceptable echo heights are reduced from 100 % to 50 % and from 50 % to 20 %, respectively. NOTE 5 With “internal defects” it is meant defects which are located more than 6 mm from the nearest surface. A defect is classified as a “surface defect” if any part of the defect is located less than 6 mm or t/4, whichever is smaller, from the nearest surface. 10 Repair 10.1 Definitions Weld discontinuities: Irregularities in the body of the weld or on the weld surface classified as either weld imperfection or as weld defect. Weld imperfection: Discontinuities that are within the acceptance criteria defined in Clause 9 and are considered to have no practical limitations on the intended use of the product. Weld imperfections may be left without remedial work. Cosmetic grinding may be performed at the discretion of the fabricator. Weld defect: Discontinuity with a size and/or density that exceeds the acceptance criteria defined in Clause 9. NORSOK standard Page 24 of 62 10. should be straightened in accordance with the requirement in Clause 6.2. Other defects shall be corrected by grinding. 10.3 Repair by welding 10. Crater cracks may be repaired by grinding followed by NDT and subsequent repair welding according to an accepted repair welding procedure. the final weld surface and the transition to the base material shall be smooth. complete removal of the defect shall be confirmed by MT or PT. If necessary. When weld defects are removed by grinding only. The excavated area shall have smooth transitions to the metal surface and allow good access for both NDT after excavation and subsequent repair welding.3. After excavation. the defect shall be completely removed.NORSOK standard M-101 Edition 5. measured at defect depth even if the defect itself is smaller.3. and includes complete removal of the original weld and HAZ. the remaining thickness in the ground area shall be measured. October 2011 10.2 Correction of welds containing defects All repairs shall be carried out in accordance with established procedures. Repair welding is required if the remaining thickness is less than that specified. The excavated groove shall be minimum 50 mm long. Parts distorted by welding. beyond the tolerances. Defects spaced less than 100 mm shall be repaired as one continuous defect. provided the process/consumable is backed up by other welding procedure qualification records (WPQRs).e. If applicable. NORSOK standard Page 25 of 62 . and/or consumable. or a separately qualified procedure. After repair welding the complete weld (i. 10. the repaired area plus at least 100 mm on each side) shall be subjected at least to the same NDT as specified for the original weld. 10. the defective part of the weld shall be cut out for further examination.2 Re-welding Re-welding shall be performed in accordance with the procedures and WPS utilised for the original weld. Mechanical testing may be limited to HAZ Charpy V-notch testing in the original weld. Repair welding may only be carried out twice in the same area. aided by applicable NDT methods.5 Correction of distortion Improperly fitted parts should be cut apart and re-welded in accordance with the applicable qualified WPS. a separate WPS shall be qualified if required by 5. PWHT shall be performed after repair if specified for the original weld. Welds containing cracks shall not be repaired. repair welding or re-welding.4 Repair welding procedure Repair and re-re-repair welding may be performed using the same WPS as for the original weld. until the reason for the cracking has been determined.1 Repair and re-repair welding Before repair welding. Removal of defects shall be verified by local visual inspection. For repairs using a different process. and there shall be no evidence of undercut or overlap. NOTE 3 Minimum radii of weld profiles after blending should not be less than 10 mm. (wichever is less) chord wall TYP.5mm Remove ov erlap flush with plate surface TYP.5 mm below the bottom of any visible undercut and ensuring that no exposed defects remain. NOTE 2 Grinding should extend below plate surface to a minimum of 0. NORSOK standard Page 26 of 62 . using a rotary burr grinder. NOTE 4 Upon completion of blending of toe the whole of the ground surface shall be inspected with 100% visual examination and 100 % MT. TUBULAR JOINT GRINDING DETAIL Blend out to remove edge on undercut Grinding direction Maximum depth below plate surface for blend is not to exceed 1.05 x T1 max. Grinding marks should run at right angels to weld axis and under no circumstances parallel to it. BUTT WELD JOINT GRINDING DETAIL NOTE 1 For removal of undercuts the toe of the weld should be blended in a smooth transition and extended below the plate surface in order to remove the toe defects. S UT O E ID E AC R B Remove sharp edges L AL W T1 T2 = 2mm or 0. (wichever is less) T4 Rotary burr grinder Remove sharp edges Weld rad.1 Typical grinding details TYPICAL GRINDING DETAILS FOR HIGH FATIGUE UTILISATION 3 T T4= 2mm or 0.NORSOK standard M-101 Edition 5. NOTE 5 Ground surface shall be free of any cracks or crack like indications. October 2011 Annex A (Informative) Details for high fatigue utilisation A.05 x T3 max. 2 Requirements for application When peening is planned for the following preparations are required: x x x x x x x x x x nomination of responsible engineer for preparations. All surface defects shall be removed by grinding prior to peening. October 2011 Peening of local area as weld toe or weld trasition is an acceptable method to improve fatigue life of structures. preferably by stone grinding.2. detailed mark up drawings showing all areas of application. The depth of the groove is approximately 0.2 Typical peening details A. Applicable tool for grinding is normally a rotary burr or stone of 6 mm to 8 mm diameter when a single tool hammer is used and 10 mm to 12 mm when a needle hammer is used. tests or other relevant information.5 mm below the original surface. detailed work instructions. radius. All traces from previous grinding shall be completely removed. A needle hammer is normally used when a wider area shall be covered. x quality control measures. x method. NORSOK standard Page 27 of 62 .2. statement on expected or required improvements. fabrication and installation resume. Due to the dependancy of correct performance specific precautions shall be taken when peening is planned for. Applicable tool for peening is normally pneumatic hammers. selection of peening methods to be applied.1 General Edition 5. including x grinding details as tools. Special tools with adjusted curvature shall be prepared in accordance with weld geometry. experiments. e. For local toe peening a single tool hammer is recommended. x tools to be used for peening. Groove depth measuring tools and macro photo is normally applied. as built record index for the final design. Reference specimens shall be prepared for comparison between ground and final peened surfaces. a complete responsibility and personnel matrix. Peening is applied together with grinding where grinding serves the purposes to remove stress risers such as surface defects and to define a steering grove for the tool in the area to be peened. Single hammer peening shall result in a fully covered hammered groove where the surface is smooth with uniform indentation.NORSOK standard M-101 A.g. x documentation of performance and results. As preparation for peening the surface shall be dressed in a way that makes lack of coverage detectable. detailed stepwise procedure for the work. A. Devices for quality control and documentation shall be thoroughly selected. Needle peening shall be applied with a coverage of minimum 200 %. Both grinding and peening require skills and preparations not normally available in fabrication yards. performance and documentation. verification of performance. skill or training. Correct tool is essential to maintain correct peening in compliance with requirements. intensity and extent of peening. depth and direction. documentation on operators experience. 1 3.1 1.1/3.2/3. no.1 2.1/3.1 2.2 3.1 1. Rev.1 1.2/2.1/3.1 2.1 2.1 2.2/2.1 2.1 3.1 1.1 1.1/3.NORSOK standard M-101 Edition 5.1 S355J2 S355K2 S355J2 S355K2 S355G1+N 1.1 2.2/2.2/3.1 2./2.2/2.1 1. Standard Y20 5 Plates Y21 5 Rolled sections Y22 5 Seamless tubulars Y30 Y31 Y32 Y40 Y41 Y42 Y50 5 5 5 5 5 5 5 Plates Rolled sections Seamless tubulars Plates Rolled sections Seamless tubulars Plates Y51 Y52 5 5 Rolled sections Seamless tubulars Y25 Y26 5 5 Plates Rolled sections Y27 4 Seamless tubulars Y28 Y35 Y36 Y37 Y45 Y46 Y47 Y55 3 4 5 5 5 5 5 5 Welded tubulars Plates Rolled sections Seamless tubulars Plates Rolled sections Seamless tubulars Plates Y56 Y57 5 5 Y05 3 EN 10225 EN 10225 Product type Rolled sections Seamless tubulars EN 10025-(all parts) Plates EN 10025-(all parts) Plates and sections Steel grade (see product standard) S355G10+N/G10 +M S355G12+N/G12 +M S355G15+Q/G15 +N S420G2+Q/G2+M S420G4+M S420G6+Q S460G2+Q/G2+M S460G4+M S460G6+Q S500G2+Q/G2+M a S500G4+M a S500G6+Q a 1.1/3.2 2.1 2.1 Y06 3 EN 10225 Y07 3 EN 10210-(all parts) Hot finished seamless tubulars Hot finished tubulars Y08 Y15 Y16 3 3 3 EN 10219-(all parts) EN 10025-(all parts) EN 10219-(all parts) Cold formed tubulars Plates and sections Cold formed tubulars S355NH/S355K2 H S355MLH S420ML S420MLH Y01 5 EN 10025-(all parts) EN 10210-(all parts) EN 10219-(all parts) Plates and sections Hot finished tubulars Cold formed tubulars S235JR S235JRH S235JRH NORSOK standard ISO/TR 15608 1.2/3.1 2/2.2/3.1 Page 28 of 62 .2 2.2/2.1 S355G9+N/G9+M S355G11+N/G11 +M S355G14+Q/G14 +N S355G13+N S420G1+Q/G1+M S420G3+M S420G6+Q S460G1+Q/G1+M S460G3+M S460G6+Q S500G1+Q/G1+M a S500G3+M a S500G6+Q a 1.1/3.2/2.1 2.1 1.1 1.1 3.1 1. MDS number and steel grade/designations Steel quality level I II III MDS No.2/3.2/2.2/2.2 2.2/2.1. October 2011 Annex B (Informative) Correlation between steel quality level.2 3.1 2.1/3.1/3. NORSOK standard Page 29 of 62 .2 1.1 a This steel grade designation is not included in EN 10225. (Note from Table 1 of M-120) NOTE NORSOK material data sheets are published in NORSOK M-120. Rev.NORSOK standard M-101 Steel quality level MDS No. IV Y02 4 Y04 2 Edition 5. October 2011 Standard Product type EN 10025-(all parts) EN 10210-(all parts) EN 10219-(all parts) EN 10025-(all parts) EN 10210-(all parts) EN 10219-(all parts) Plates and sections Hot finished tubulars Cold formed tubulars Plates and sections Hot finished tubulars Cold formed tubulars Steel grade (see product standard) S275JR S275J0H S275J0H S355J0 S355J0H S355J2H ISO/TR 15608 1.3/2. no. Each individual consumable (brand name and dimension) shall be certified per batch. storage etc.B. x chemical analysis limits of weld metal from coated electrodes and cored wires. The chemical elements NORSOK standard Page 30 of 62 . For information also typical properties of a relevant butt weld should be added. The purchaser shall base his selection.1 General The purpose of certification is to verify that each batch of consumables has a chemical composition within limits as specified by the supplier in conformance with a recognised classification standard. Mo. gas metal arc welding. yield strength elongation. relevant approvals and information on packing. Si. Cu. S. except for solid wire (gas tungsten arc welding. P. The data sheet shall give guaranteed limits and/or minimum values for composition and mechanical properties. containing as a minimum the specific tested chemical composition of the wire or weld metal. Data sheets shall also contain product classification according to recognised standards. originating from the same heat. deposited and tested according to ISO 15792-1 and including tensile strength. including any information on drying. manufactured in one continuous run from batch controlled raw materials.2 Data sheet Each welding consumable or combination of consumables shall have a unique data sheet. as applicable: x chemical analysis limits for solid wires and metal powders. as applicable. Minimum: C. The analysis shall include limits for all elements specified in the relevant classification standard and/or intentionally added and for residual elements known to influence weld metal quality.NORSOK standard M-101 Edition 5. to be supported by separate test reports as required and agreed. SAW). notch toughness Charpy-V at -40 ºC. issued as a controlled document within the suppliers quality system. For this specification a batch (or lot) is defined as the volume of product identified by the supplier under one unique batch/lot number.3 Certificate Every batch of consumables shall be supplied with an inspection certificate 3. If the consumable shall be used for welds in PWHT condition. restricted welding parameters etc. using a relevant shielding gas or flux. For information also specified limits for S. For SAW fluxes the analysis shall be given as ranges for all main ingredient and flux basicity as follows: x mechanical properties (range or/and guaranteed minimum) of the weld. x when relevant for the product. C. required to ensure this value in practice. For information also typical weld metal analysis. Nb. determined under defined reference conditions. Cr. Mn. ordering and receiving of consumables upon reviewed and accepted data sheets. Specifically this shall include. Ni. as required for correct application and use of the product. P and N in the core wire or strip. then the properties shall also be documented in PWHT condition in addition to the as-welded condition. C. x diffusible hydrogen content HDM maximum. basic information about CTOD properties. deposited according to ISO 6847. where one diameter may represent all. V. By controlled and certified chemistry the supplier also confirms that mechanical properties of the weld metal fulfil the minimum requirements specified for the product. October 2011 Annex C (Normative) Qualification of welding consumables by data sheets C.1. Other tests may also be agreed between supplier and purchaser. NORSOK standard Page 31 of 62 . based on specific or non-specific type of control.NORSOK standard M-101 Edition 5. Full conformance of chemical composition shall be required to release each batch for fabrication welding. see EN 10204. Certificates shall be actively used by the purchaser to control received consumables against the accepted data sheet. with a statement “below specified maximum” acceptable for residual elements. The supplier may optionally add information about mechanical properties. October 2011 shall conform to those of the data sheets. : x x x x mechanical properties based on a defined butt weld rather than all weld metal test.3 Mechanical properties Unless otherwise specified the properties shall represent all weld metal. SAW fluxes do not require individual testing. testing of hydrogen level. Properties tested shall include x tensile strength. For coated electrodes and cored wires the analysis shall represent the weld metal. with respect to chemistry and mechanical properties. P and N. e. manufactured in one continuous run from batch controlled raw materials.NORSOK standard M-101 Edition 5. deposited according to ISO 6847. with reference to a recognised product classification standard and containing all specified test results. Each individual product (brand name and dimensions) shall be tested once per batch. yield strength and elongation. 3. while SAW wires shall be tested in combination with a selected nominal batch of flux.2 Chemical analysis For solid wires and metal powders the analysis shall represent the product itself.1B. deposited and tested according to ISO 15792-1.4 Documentation Batch tests shall be documented by an inspection certificate in accordance with EN 10204. October 2011 Annex D (Normative) Welding consumable documented by batch testing D. where one diameter may represent all. D. The need for other types of tests shall be evaluated for the application in question. mechanical properties in the PWHT condition. For this specification a batch (or lot) is defined as the volume of product identified by the supplier under one unique batch/lot number. x the main impurities S. D. except for solid wire originating from the same heat. D.g.1 General The purpose of the batch testing is to verify that the consumables remains nominally equivalent to that used for welding procedure qualification. CTOD testing. The analysis shall include x all elements specified in the relevant classification standard and /or intentionally added. or as specified by purchaser. x impact strength Charpy-V at temperatures -40 °C. NORSOK standard Page 32 of 62 . The grid system defines the design origo (location and elevation datum) for a structure. The intention of this annex is to give dimensional tolerances which will ascertain that x x x x x the calculated strength and fatigue resistance is present in the structures. The designer may. NOTE It should be observed that the requirement to fabrication tolerances in this annex may be more strict than the manufacturing tolerances for steel products according to NORSOK M-120. angles or irregularities from an unloaded structure NOTE Opposed to straightness deviation. The grid system is normally denoted in one of the following manners: x x. all parts of the structures are suitable for their intended use. the structures are trustworthy relative to measurements given on the structural drawings. E.1 Scope and objectives This annex defines the maximum allowable dimensional tolerances for offshore steel items and structures. components and elements of a completed structure NOTE The grid system defines the 3D position of any item within a completed structure. transversal and elevation coordinates. the relevant components tolerances are achieved and maintained after the components final incorporation in the completed structure(s). flatness vertical offset at any point from a plane parallel with the surveyed object grid system design reference system for all parts. specify stricter tolerances and additional tolerances. east and height coordinates. x longitudinal. bends. October 2011 Annex E (Normative) Fabrication tolerances E.2 Codes. standards and specifications Reference standards for this annex are ISO 8062:1994 and EN 1090-1:2009. items and structures can be assembled without dimensional rework. however. NORSOK standard Page 33 of 62 .NORSOK standard M-101 Edition 5. These will. E. position deviation aspecified point's actual position relative to it's nominal position NOTE Measured value minus nominal value equals deviation. in case take presedence over this annex.3 Definitions Terminology used in conjunction with this annex: AFC drawing engineering drawings formally approved for construction centreline real or imaginary line that is equidistant from the surface or sides of the (measured) object deflection load imposed curves. x north. y and z coordinates. Specification of detailed and more stringent tolerances for intermediate and final interfaces may also be necessary in order to meet the requirements of this annex in the completed structure. survey reference system reference system constituting of fixed and coordinate determined points. and shall be submitted on request.NORSOK standard M-101 Edition 5.4 General requirements E. 2) dimensional inspection procedures. and where the location and elevation of the fixed points are identifiable relative to the grid system work point marked or imaginary point on a member or structure from which dimensions shall be related E. The plan shall assure that all allowable tolerances for individual elements are not cumulative to the extent of exceeding the allowable tolerance for the complete structure. those tolerances representing the stricter values shall be governing.4. If tolerances given for individual sections and components are conflicting. and in determined distances from grid lines straightness deviation curves. All tolerance requirements are based on nominal values on unloaded structure. the tolerance requirements shall be agreed. October 2011 reference lines marked lines on construction parts and assemblies which are parallel to. E. techniques and dimensional control to assure that all structures can be fabricated and assembled to dimensions within the specified tolerances. c) the following documents shall be prepared prior to start of fabrication: 1) plan for dimensional assurance/inspection.1 Implementation policy of requirements The tolerances given in this annex shall be applied for completed structures.2 Procedures and documents The following procedures and documents shall be prepared: a) plan for fabrication and erection including methods. d) during fabrication and erection deviations outside the specified tolerances shall be identified and informed of in advance of the formal handling of deviations. e) final documentation shall be prepared in correspondence with the requirements for as built documentation and fabrication record. Such tolerances shall be presented in the plan/scope of work for fabrication. The detailed dimensional deviation reports shall be available at all stages in fabrication. The allowable tolerances given for individual members shall not cumulate to give unacceptable deviation for the finished section or complete structure. NORSOK standard Page 34 of 62 . If no appropriate tolerance is stated in this NORSOK standard.4. subject drawings or other regulations/guidelines for the structural fabrication. angles or irregularities from a straight generator NOTE Straightness deviation is regarded to be fabrication imposed irregularities and not caused by elastic deformation. For single elements to be parts of complex structures. bends. specification of detailed and more stringent tolerances for each fabrication and erection sequence may be necessary in order to meet the requirements of this annex in the completed structure. b) dimensional inspection procedures relevant for the structures and any additional specifications needed to those included in this NORSOK standard. from where surveys can be performed. The survey reference system shall use the same numerical values.6. the system's elevation shall be positive upward. or whenever additional permanent survey stations are established. built under significantly different temperature conditions. and the same orientation directions of the system axis as the grid system. For components to be assembled. At all stages during fabrication and erection. and subsequent calculations. shall be established. October 2011 Qualification of inspectors Personnel responsible for dimensional control activities shall have a minimum background of at least 5 years relevant experience in industrial surveying. the Contractor shall ensure that the survey reference system and the fabricated item are shall be in correct position relative to each other. if ship). The survey reference system should be established within the following tolerances: Sections/complete structures: r3 mm Stricter survey reference system tolerances shall be used on components where the requirements of the final product are more stringent than the above tolerance.4 Instrument reliability All instruments used shall be in accurate permanent adjustment. the proposed survey methods shall be described. the system's east axis shall be positive toward east (or starboard.4. Personnel monitoring dimensions and tolerances shall have relevant training in use and understanding of instruments. dimensions shall be computed to the reference temperature and this shall be annotated on any subsequently produced document or report. when this is necessary for future use of the report and the component surveyed. the numerical value should be the same for all disciplines and packages.4.3 Edition 5. NORSOK standard Page 35 of 62 . Permanent survey stations shall be properly constructed and be protected from disturbance.4. E.6 Control methods E. E.NORSOK standard M-101 E. The permanent survey stations shall be re-checked periodically. For components where the tolerance of the product are less than r2 mm.5 Reference temperature Reference temperature for survey activities should be +20 ºC. the reference system shall be adjusted to this fabrication situation. but the final as built survey shall be related to the platform grid system. have current valid control certificates and be subject to a programme of periodic checking. if ship). E.4. All additional or re-checked surveys shall be properly documented. The following apply: x x x x x the system's north axis shall be positive toward platform north (or bow.4.1 Reference system Prior to fabrication a survey reference system related to the grid system. enabling them to perform all necessary controls of own work performance. for special structures such as jackets being built laying down. The field work temperature shall as a minimum be noted on all dimensional reports. for the remaining steps of the construction.2 Marking criteria During layout and assembly of each structural item. Location of hidden stiffeners. if relevant.4.6. October 2011 Figure E.4. A comparison of the interface results prior to erection shall be performed and necessary actions in order to meet the global requirements shall be carried out.Principal reference system Figure E. bulkheads etc. all work points and centrelines.7 Interface criteria All non-adjustable interfaces and interfaces deemed critical prior to erection shall be surveyed and documented. All girders. E.6.1 indicates sample of applicable and practical reference systems.1 . E. The methods and equipment used shall enable verification of the survey accuracy. which are relevant for the remaining steps of the construction. boxes. nodes and other structures shall be properly and clearly marked relative to the grid system at all interfaces. All activities related to measurement and inspection of dimensions and tolerances shall take into account the effects of self weight while the structure is under fabrication. The layout of the reference system may be specially designed to suit the task at hand and the methods chosen for controls. E.3 Accuracy Surveys shall be performed using survey techniques and technology which enables the achievement of a survey accuracy better than the specified tolerances.4. NORSOK standard Page 36 of 62 .NORSOK standard M-101 Edition 5. shall be marked and identified. if relevant for the remaining steps of the construction. All primary datum work points on the structure shall be set out using accepted engineering surveying techniques consistent with the tolerances required by this annex. shall be marked on the outside of the structure to ensure a correct assembly. Eccentricity of non-continuous plating in cruciform joints shall not exceed the following requirements. for t2 > 20 mm = smaller thickness in mm of non-continuous plate = thickness in mm of continuous plate = larger thickness in mm of non-continuous plate e = 2m + t1 – t3 2 For non-continuous plate with different thicknesses. When correcting a misalignment which exceeds the above. for t2 d 20 mm d t1/2 (mm).Cruciform joints NORSOK standard Page 37 of 62 .2B: e e t1 t2 t3 d t1/2 (mm). October 2011 Alignment requirement Requirements to alignments with regard to offsets eccentricity of butt joints and cruciform joints are as follows: a) offset of butt-joints. the section of the thinner member shall be completely inside the section of the thicker. maximum 5 mm.15 x Reference is made to Table 5.8 Edition 5.NORSOK standard M-101 E. see Figure E. m e = misalignment = eccentricity Figure E. The design drawings shall state the position of the intersection points between noncontinuous members. The measurement of offset shall be based upon the centre line of the parts unless otherwise shown on the drawing.2A) shall not exceed 0.4. (see Figure E.2 . the parts shall not be drawn in to a slope greater than 1/2. t1 or 4 mm whichever is the least. The offset of butt-joints. difference greater than 5 mm (for t2 < 20 mm) and 8 mm (for t2 > 20 mm). maximum 8 mm. b) cruciform joints. 3A L L ±0.15 Max.5.3B E.25 ±3 Height Width Inclination of web E.3C d5 L ±0.1 I/H-girders Type of deviation Figure Notation f Ref.10 ±10 Figure E. length L Allow.I/H girders tolerance references NORSOK standard Page 38 of 62 .3 .5 Fabrication tolerances for structural components E. October 2011 E.3 ±0.0 ±3 E.3B V1 H ±1.NORSOK standard M-101 Edition 5.3A E.75 ±10 Curvature/rotation flange Twisting of section E.3B V3 H ±0.5 ±3 E.3B V2 B/2 ±2. length ±0.8 ±3 ±3 ±10 Eccentricity of web on flange Buckling of web E. deviation mm ±10 Lateral or vertical deflection Length E.3B E. % of ref.3B H B V H B H ±0. 4E d5 H ±0.5. October 2011 Box girders Type of deviation Figure Notation Ref. length Allow.3A E.5.4A d1 - E.15 r3 r3 ±3 ±10 Buckling of plates E.3A E. The tolerances are as follows: NORSOK standard Page 39 of 62 . centre lines L H B L r0. deviation of load bearing stiffeners inclusive inclination Twisting E.4D d4 Ref.4B L H B d2 Ref. % of ref.3 ±0.25 r0.3 Tubulars The allowable tolerance given for individual tubular segments shall not be cumulative for the finished tubular. deviation mm ±3 Position deviation at end/interface section Length Height Width Out of straightness E.Box girders tolerance references E. length Max.5 ±10 Pos.4C d3 H.NORSOK standard M-101 E.3A E.5 ±6 Figure E. centre lines - ±5 E.2 Edition 5.4 . W ±0. The maximum allowable deviation from straightness in any 3 m increment of length shall be 3 mm.002 x ODn (see Figure E. x the tolerances in (i) may be increased by 50 % for the remaining length of the tubular (Zone B in Figure E. October 2011 circumference. out of circularity. The external circumference shall not depart from the nominal external circumference by more than the following (see Figure E. Above tubular tolerances apply to welded and not seamless tubulars. whichever is the smallest.001 x L.5) 30 % of the nominal wall thickness or ±10 mm. Maximum difference is not to be more than 0. Out of straightness shall be checked on two longitudinal planes separated by 90q. NORSOK standard Page 40 of 62 . with maximum 10 mm deviation for lengths up to 12 m. out-of roundness (ovality). Local straightness shall be checked on the inside or outside of tubulars with a nominal external diameter greater than 2 000 mm or with a nominal external diameter to nominal wall thickness ratio greater than 65. This tolerance shall not exceed 20 % of the wall thickness.NORSOK standard M-101 a) b) c) d) e) f) g) h) Edition 5. Circularity is defined as the difference between the actual and the average radius. Above 12 m length maximum allowable deviation is 12 mm. The local out-of roundness shall be measured inside or outside over 20q of the circumference.5). both being determined from the optimum centre of the tubular.5): x measured at joints or within ±610 mm from the joint (Zone A in Figure E.7). local out-of straightness. straightness. length.25 % of ODn. Local straightness is defined as the deviation of the shell plate from a straight generator of length (L) parallel to the true centre line of the tubular. whichever is the least. The local out-of roundness shall not deviate from the theoretical curvature by more than e = 0. see Figure E. Ovality is defined as the difference between the measured maximum and minimum internal (or external) diameters and shall not be more than 1 % of the nominal OD (ODn) or 8 mm. Unless otherwise noted. The straightness deviation over tube length (L).6. shall not exceed 0. The tube ends shall be perpendicular to the longitudinal axis within the following tolerances: x unbevelled ends: 5 mm x bevelled ends: 3 mm local out-of roundness. These checks shall be carried out at 45q intervals of arc with L = 3 m. the tubular shall be delivered within following tolerances: Ln + 25 mm x unbevelled ends: La t x bevelled ends: La = Ln r 5 mm tube ends. Tubulars .5 .NORSOK standard M-101 Edition 5.Ovality tolerance Figure E.6 . October 2011 Figure E.Circumfential tolerance Figure E.Tubulars .7 .Tubulars .Local out-of roundness references NORSOK standard Page 41 of 62 . 15 r15 E.8 p2 W1 r0.8 g4 Hg .15% r10 E. deviation mm E.8 r10 r10 E. W 1 r0. October 2011 Panels Type of deviation PANEL SHEET: Out of plane straightness.Deck panels tolerance references NORSOK standard Page 42 of 62 . between girders Local buckles between stiffeners GIRDERS/STIFFENERS: Out of straightness in X and Y direction Position deviation Inclination Out of straightness of web normal to web (web buckles) Figure Notation Ref. length Max.4 Edition 5.5 r5 E. length Allow.8 E.NORSOK standard M-101 E.8 . % of ref.8 p1 W r0.5.75 r10 Figure E. sagging/hogging.8 g1 g2 0.8 g3 W Grid system Hg r0. deviation mm r5 r0. centre line Ref. length Position deviation of interfaces Lateral and vertical straightness of node Lateral and vertical straightness of stiffeners Height of node E. October 2011 Girder nodes Type of deviation Figure Notation Ref.9B E.NORSOK standard M-101 E.15 r5 L.5. length - Max.9B b1 Ref.centre line Ref.9C E.deviation baseplate relative to Z axis NORSOK standard Allow.5 Edition 5.1 r5 s - - r5 E. centre line Ref.9B E. % of ref. centre line L E.9B E.9A d1 f Ref.H r0. deviation stiffeners inclusive inclination Position deviation column interfaces Baseplate flatness/rotation relative to Z axis Pos.centre line - r2 - r3 d3 d4 Page 43 of 62 .9C d2 - r5 - r5 E.9B Pos.9A E.9C E.9A f1 E. October 2011 Figure E.NORSOK standard M-101 Edition 5.Girder nodes tolerances NORSOK standard Page 44 of 62 .9 . length - Max.10C E. % of ref.5 % r10 Ref. W r0.10 % r10 H.10C d3 Radial and tangential stub end deviation Pos.10F d6 d5 Allow.5.Box nodes tolerance references NORSOK standard Page 45 of 62 . centre line L Buckling of plates E. centre line Ref. centre line - r5 - r5 - r5 Figure E. length Position deviation of main box interface Out of straightness E. inclination Offset of centrelines at centre of node E.10E E. October 2011 Box nodes Type of deviation Figure Notation Ref.10B d2 Ref.10D d4 E.10 .10A d1 E. centre line Ref. deviation mm r3 r 0.6 Edition 5. deviation of load bearing stiffeners incl.10E E.NORSOK standard M-101 E. 11A Allow.11B E.2q from the stub angle specified on the design drawings.11A p - E.0 % 1.7 Edition 5.12 V 'D Grid system E.2q of arc r6 1. Tolerances for x x x x circumference. NORSOK standard Page 46 of 62 . Maximum position deviation measured at the intersection of stub end/node shall be r6 mm.11B E. out-of roundness (ovality).5. For stubs longer than 1 stub diameter. length Overlength of stub E.NORSOK standard M-101 E.5. out-of circularity.11C E.A l1 L1 Stub ends perpendicularity E.0025 X nominal diameter.11B P M B N Lx r5 r5 r3 r6 r6 Radial and tangential stub end/ node cans position Position of intersection point node can / stub Internal stiffeners -Position -Inclination of web -Flange width -Bow of web -Rotation of flange -Eccentricity of flange on web -Height of stiffeners h b E.0 % f Wall thickness L 25 % r6 +10/-3 8 1/1200 10 The centre line of stub shall be within 0.11B E. the position deviation between can and stub may be taken at the 1 diameter location. October 2011 Tubular nodes Type of deviation Figure Notation Ref. are defined in E.11B Local straightness of stubs/barrel E. deviation mm +25 -0 +10 -0 r3 0.11A l2 L2 Overlength of node can barrel E. length Max. % of ref.12 E Grid system r6 E.11A Straightness of barrel E.5 % 1.11A E.3 and shall not exceed 0.11. local out-of roundness. B (tolerance references) Fig.NORSOK standard M-101 Edition 5.Tubular nodes NORSOK standard Page 47 of 62 . C (tolerance references . October 2011 Fig.11 .internal stiffeners) Figure E. A Fig. shall be properly marked on each element interface(s) to adjacent main steel. flatness. During installation of cast and forged items. See also ISO 8062:1994.8 Cast and forged elements All relevant tolerances regarding these elements’ geometry (i.NORSOK standard M-101 Edition 5. NORSOK standard Page 48 of 62 . special care shall be taken that the parent plate edges are located within prepared face of casting/forging.5.e. rib centrelines etc. hole positions. The nominal axes. work points. web and rib positions) shall be specified on the design drawings.12 . October 2011 Figure E.Node stub location E. 9 Edition 5. Sylindrical shells subjected to external pressure The maximum deviation from the nominal radius measured at ring stiffeners or at bulkheads shall not exceed the value: G = |ra .10 Conical transitions At both ends of a cone. the maximum deviation from the nominal radius shall not exceed the value: G = |ra .Y1 X2.5.r| ≤ 0. October 2011 Curved and cylindrical shell subject to external pressure For elements including curved shells (such as semi submersible’s pontoons) special dimensional procedures shall be implemented for measurement and computing. decks Footings deviation from elevation a reference E.5. a b Maximum allowable deviation shall also apply to mating surface level at stab-in onto jacket legs. NORSOK standard Page 49 of 62 . Y2.005 r where ra = actual distance from the cylinder axis to the cone wall r = nominal radius at cone end Requirements for internal stiffeners shall be in accordance with E. deviation mm r10 r6 r10 r10 r5 For truss frames without any defined support points the elevation reference should be based on a mean of all levelled points on main steel. E.r| ≤ 0. Y2.6 Assembly tolerances E.NORSOK standard M-101 E. Z2 X2. % of ref.13 E. E.005 r ra = actual distance from the cylinder axis to the shell wall r = nominal radius of the shell Components defined as cylindrical shells shall be specified on design drawings. Includes MSF stab-in nodes and module footing nodes.13 E. H2.13 E.1 Topsides and modules Type of deviation Figure Notation Reference Position of any point of main steel b Position of support node Position of lifting node Elevation of decks and mezz.7.5.6.13 E. length Max.13 X1. H3 H Grid system Grid system Grid system Grid system Grid system Allow. Z2 H1. 6.14C 'f L X±L/1000 Grid system r15 Local tolerances for sliding and pivoting ends shall be specified on the structural drawings.Topside and module tolerance references E. deviation mm ±12 ±6 ±20 12 ±6 E. 'y Grid system S Max.13 .14A Notation Reference 'x.2 Jacket and other tubular frame structures E. plane Position of leg ring stiffeners and diaphragms Inclination of ring stiffeners Straightness of legs/chords Straightness of braces Position of intersecting braces NOTE Figure E.14A E. NORSOK standard Page 50 of 62 .14A E.2.6. October 2011 Figure E.1 Assembly tolerances Type of deviation Position deviation of centre of nodes Rotation of node Distance deviation between two nodes Diagonal distance between column in each hor.14B/C 'f L 6 X±10 E.NORSOK standard M-101 Edition 5. Assembly tolerances NORSOK standard Page 51 of 62 . October 2011 Figure E.NORSOK standard M-101 Edition 5.14 .Jacket and tubular frame structures . NORSOK standard M-101 E. deviation mm a (Vx²+Vy²) F Jacket: Mating surface level at stab-in MSF: Distance between centre of column to centre of any column at stab-in cans Reference E.2. Vy V= Jacket: Distance between centre of column to centre of any column at stab-in cans E.6.3 b) Grid system a The position of the stab-in cans shall.15 F r12 L Grid system r6 r8 b L ±3 r6 As in section E. interface jacket/MSF Type of deviation Figure Notation Horizontal position deviation of centre of stabin cans E. be related to the topside stab-in cones with the tolerances stated above. b The jacket legs shall by preference be cut within above tolerances after grout is cured.6.2 Edition 5. October 2011 Final tolerances for jacket. NORSOK standard Page 52 of 62 . r6 If survey of the deck footings show out-of acceptable elevation/flatness tolerances (see E. J-tube Grid system Max.5.1) the measured deviations shall be considered incorporated when cutting the legs in order to minimise loads due to differential settlements in footings. risers. if the situation allows.15 Vx.15 Ovality of stab-in can Horizontal position deviation of caissons. 3.4 Piles Type of deviation Figure Notation Length Reference Max.Final tolerance jacket interface jacket/MSF E. sleeves.16 d1 As specified on drawing Diameter in driving head E.NORSOK standard M-101 Edition 5. Radius of spacer plates is r5 mm.6.16 P As specified on drawing r50 Pile markings For general tolerances.16 d2 As specified on drawing End perpendicularity in driving head E.2.3 Guides. deviation mm r100 Diameter between spacer plates E.15 .6. NORSOK standard Page 53 of 62 . E. Local alignment of sleeves is 20 mm.2.5. October 2011 Figure E. piles and clamps The position deviation of the centre of pile guides/sleeves shall be r25 mm related to the coordinate system. see E. 6.deviation mm r25 Overall hull/substructure tolerances Type of deviation Figure Reference Global position of column top/bottom Distance between top/bottom of two columns Local position of column top/bottom E.Piles tolerance references E.6. Type of deviation Figure Notation Reference Length - - - E.19 Global grid system NORSOK standard Max.3 Floating production units E.5 Conductor guides The position deviation of the centre of the conductor guides shall be r10 mm related to the coordinate system for top el.6.NORSOK standard M-101 Edition 5.6 Appurtenances Caissons. and r15 mm for the other elevations related to the same coordinate system.6.3. J-tubes and risers.2.16 .1 Semi submersibles and tension leg platforms Max.18 E.18 E. deviation mm r15 r30 Local grid system r5 Page 54 of 62 .17 E.2.17 E. The maximum deviation of any conductor guide from the optimised centreline through all conductor guides shall not vary more than r15 mm. October 2011 Figure E. E. Semi submersibles/tension leg platforms .Local tolerance NORSOK standard Page 55 of 62 .Semi submersibles/tension leg platforms . October 2011 Figure E.Semi submersibles/tension leg platforms .17 .Global tolerance Figure E.NORSOK standard M-101 Edition 5.19 .Global tolerance Figure E.18 . E. and shall be mandatory.4. E.6.NORSOK standard M-101 E. matching holes for bolted connections shall not exceed 2 mm difference in location.6. or specified elsewhere. have smooth transitions and be level to the eye.7. see E. taking into account the structural aspects as well as the mechanical functional tolerances and equipment interface tolerances.4 Installation aids Installation aid structures such as primary and secondary guides and bumpers shall be fabricated and installed in accordance with acceptable tolerances for relevant elements/structures defined in this NORSOK standard. October 2011 Ship Ships should be fabricated using a grid system with origo in the aft perpendicular.7.5 Grillages Load out grillage. and in accordance with E. NORSOK standard Page 56 of 62 .7. fabrication work shall be accurate to within 10 mm of all nominal dimensions.3. E. plates and gratings shall be without visible warping. Based on the grid system a reference system according to E. landing and stairway locations shall not deviate more than 25 mm from the dimensions shown on the AFC drawings.7.2 Edition 5.7. E.1 should be permanently marked onboard the ship. taking into account the structural aspects as well as the mechanical functional tolerances and equipment interface tolerances. E.7 Fabrication tolerances for special items E. fabrication of handrails shall be performed to such a degree of accuracy that when erected.6. E.6 Cranes See EN 1090-1:2009. wherever tolerances are not shown on the drawings.7. E.4.3. members in the vertical plane shall not be out of plumb by more than 6 mm on each 3 000 mm section and not more than 26 mm over the total height of the structure. Specific tolerance requirements are shown on respective drawings. barge grillage and seafastening shall be fabricated and installed in accordance with acceptable tolerances for relevant structures/elements defined in this NORSOK standard.4 Subsea structures Subsea structures should be fabricated according to tolerances given on drawings.8. straight.3 Outfitting structure The following apply: x x x x x x x x this section covers all primary and secondary outfitting structures.1 Crane pedestal Crane pedestal tolerances shall be specified in a separate document to be prepared by the designer. Specific tolerance requirements shall be shown on respective drawings and shall be mandatory. the toprail shall be continuous.2 Skid beams Skid beam tolerances shall be specified in a separate document to be prepared by the designer. the difference in elevation of deck plates and/or grating at joints shall not exceed 2 mm. Registration. marking/coding/traceability and handling. Handling of welding consumables. Job-package: only approved drawings. approval by a third party organisation. confirmation of validity of NDT personnel certificates and approval by a third party organisation. Purging gas. registration. Self control done by the welder. Traceability Equipment: use. typical check points General x x x x x x x x Workshop/worksite in general. Tack-welding (parameter control) and tack welders qualification. Check of weld geometry/size welding symbol on drawing/WPS. Bevelling/cutting. Procedure for tack-welding. Cleaning. maintenance. Welding equipment and use: tools. Checkpoints during welding x x x x x x x x x x x Drawing available Handling of material and welding consumables. if necessary.. welding machine etc. October 2011 Annex F (Informative) Weld inspection. (check of calibration/maintenance). WPS on work place available for the welder and check of various parameter listed in WPS and measuring/calculating heat input (arc energy). welding direction and sequence. Performing and documentation of PWHT. confirmation of validity and prolongation of welders qualifications. Welding performance (placing of run layer. rain etc. Storage and handling of material and welding consumables. rain etc.NORSOK standard M-101 Edition 5. Purging gas if necessary (type and flow-rate). Routines for certification. (check of calibration/maintenance). Checkpoints before welding x x x x x x x x x Drawing Material. Groove geometry. if necessary (type and flow-rate). welding machine etc. Welding equipment and use. instructions and routines. ready for welding. staggering of stop/start. method and temperature. if necessary. Check that all welding coordinators are working according their job-descriptions. Checkpoints after welding x x x x x x x Marking/traceability Are welder identification and WPS number marked closed to weld? Is the used WPS and welder qualification (welding certificate) relevant for the welded joint? Check of “self inspection” done by the welder. transition area and area close to the weld. Weld numbering system and identification/traceability. Welders approval for the welding work. NORSOK standard Page 57 of 62 . latest revision/isometrics and specifications are used. Welding symbols according to ISO 2553. cleaning between layers). Preheating. Interpass temperature and protection against wind. if necessary. Check of weld surface. groove preparation. fit up and staggering of adjacent longitudinal welds. tools. calibration and documentation. Preheating and protection against wind.. registration. NDT qualifications. reporting and documentation.NORSOK standard M-101 x x x Edition 5. Marking. NORSOK standard Page 58 of 62 . cleaning Documentation review (weld summary list). October 2011 Scope of NDT. 3 Welder and welding operators qualifications The requirements of 5. testing and acceptance criteria shall then be as specified in NORSOK M-601.3 Qualification of welding procedures and welders G. Examples of components are x foundation structures for equipment/pipe support in 316L or 22 05 Duplex. x architectural external fire walls in 23 04 Duplex (Lean Duplex). NORSOK standard Page 59 of 62 . G.1 Welding procedure specification WPS shall be established in accordance with ISO 15609-1. Qualification of welding procedures shall be as specified in G. G. For Duplex SS acceptance criteria shall be 27 J or a lateral expansion of minimum 0. 22 05 and 23 04 Duplex stainless steel. All welding shall be by use of qualified WPSs. October 2011 Annex G (Normative) Components in stainless steel and Ni-alloys G. Welding procedures established and qualified in accordance with NORSOK M-601 are acceptable for welding of structural components.5 shall apply. In case any of these tests are required. Micro-structural examination and corrosion test shall be performed as part of the qualification test when these tests are required for the base material.3.38 mm (10 mm x 10 mm specimens).4 Welding consumables x Duplex SS For welding of Duplex SS. x flare tower platform in Alloy 800H/HT. G. a matching consumable with enhanced Ni content compared to the base material shall be used. For Ni alloys welders shall be qualified in accordance with ISO 9606-4.38 mm (10 mm x 10 mm specimens). G.NORSOK standard M-101 Edition 5.2. welding and inspection of structural components in stainless steel and Ni-alloys. Test temperature shall be as specified for the base material.1 Scope The purpose of this annex is to specify modified or additional requirements to fabrication. micro-structural examination could be relevant for 22 05 Duplex.3.2 Qualification of welding procedures Welding procedures shall be qualified in accordance with ISO 15614-1 and the additional requirements of this annex. Charpy impact testing shall be performed as part of the qualification test when testing is required for the base material.g.2 Materials Typical materials can be type 316L austenitic stainless steel. For austenitic SS and Ni alloys acceptance criteria shall be a lateral expansion of minimum 0. ironnickel-chromium alloys (e.3. G. As an example. Alloy 800H/HT).3. 6 Non-destructive testing (NDT) G. shall be used. etc. welding and inspection of structural components in SS and Ni alloys shall follow the same classification principles as for other structural steel elements.6. G.5 General fabrication requirements Requirements for fabrication. Welding of attachments in SS or Ni alloys to carbon steel structures shall comply with the requirements for the structure to which they are attached. alternatively a nickel based alloy. G. which is reserved exclusively for those types of materials.1 shall apply. All welds shall be continuous. as used for welding the stainless steel to itself. The welding processes listed in ISO 15614-1 are acceptable. All fabrication shall be in accordance with recommendations given in EN 1011-3. the same or higher alloyed filler metal.NORSOK standard M-101 Edition 5.2. For welding of higher alloyed stainless steels to carbon steel. Maximum cold forming shall be 10 % for austenitic SS. zinc. are not acceptable.6. Design drawings may show areas of welds where examination is mandatory. Maximum interpass temperature shall be 150 °C. the consumables shall be of the high nickel-chromium type. NORSOK standard Page 60 of 62 .1. Contamination of weld bevels and surrounding areas with low melting point metals such as copper.1 General The inspection category shall be decided by the designer in accordance with NORSOK N-004.6. or parts thereof. G. Intermittent welding is acceptable if the environment can be defined as dry and non-corrosive. as specified in this NORSOK standard. Straightening shall not be performed by application of heat.2 Qualification of NDT-operators The requirements of 9. and 5 % for duplex SS and Ni alloys.3 Extent of NDT The minimum extent of examination is given in Table G. consumables should be of type 309MoL. and shall be specified on the design drawings. Recommended consumables (DT = design temperature in ºC): x DT < 535: ENiCrFe-3 or ERNiCr-3 x 535 ≤ DT ≤ 815: ENiCrFe-2 or ERNiCr-3 x DT > 815: ENiCrMo-3 or ERNiCrMo-3 x Consumables for joining of dissimilar materials For welding of type 316L SS to carbon steel. see 6. Prefabrication of SS and Ni-alloys should be performed in a workshop. G. For calculation of deformation rate. October 2011 x Alloy 800H/HT For welding of Alloy 800H/HT. 2. G. October 2011 Table G.5 and 9.8. NORSOK standard Page 61 of 62 . x Radiographic testing shall be in accordance with 9.5. x weld zones shall in addition be visually inspected on both sides of the weld (where access).8. Personnel shall be qualified as described in 9.4 Type of connection Buttweld T-connection Fillet/partial Buttweld T-connection Fillet/partial Buttweld T-connection Fillet/partial All connections All connections Minimum extent of NDT (%) Visual Examination % 100 100 100 100 100 100 100 100 100 100 100 Extent of testing % RT PT 100 50 20 - 100 100 100 100 100 100 20 20 20 2 to 5 - Procedures and acceptance criteria x Visual inspection and finish of welds: x shall be in accordance with 9.8.NORSOK standard M-101 Edition 5. x darker or more extensive oxidation colours are not acceptable. x Penetrant testing shall be carried out in accordance with ISO 3452-1. Acceptance criteria shall be in accordance with 9. and shall be chemically or mechanically removed. x oxidation levels showing a narrow band of dark brown colour and intermittent spots of blue colour are acceptable.8.7 Repair Repair welding may only be carried out twice in the same area. x Radiographic testing may be replaced with ultrasonic examination for material thickness ≥ 12mm.4. and fulfil the following criteria: x the oxidation levels showing light brown to brown colour are acceptable.1 Inspection category A B C D E G.6. Acceptance criteria shall be in accordance with 9.4 and 9. Ultrasonic examination shall be performed in accordance with ISO 22825.