Offshore Standards, Explained.
Articles by engineers, for engineers — DNV, NORSOK, EN, ISO. Each piece is grounded in primary clause references and verified with the same Leide pipeline that powers the product.
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Engineering articles on DNV, NORSOK, EN, and ISO standards — written for offshore and marine engineers.
Read article →Bolt Torque Calculator: K-Factor, VDI 2230, and Hydraulic Tensioning
Free bolt torque calculator with VDI 2230 systematic method, K-factor torque, hydraulic tensioning, ASME B16.5 flange presets, and gasket checks. 32 bolt sizes, 15 material grades.
Read article →Weld Sizing Calculator: Directional Method, Simplified Method, and Weld Group Analysis for Offshore Steel
Free weld sizing calculator for fillet, butt, and partial penetration welds. EN 1993-1-8 directional method, AWS D1.1 strength, weld group analysis, and electrode matching.
Read article →DNV-RU-SHIP Pt.2 Ch.1 — Hull Structural Design: Loads, Limit States, and Scantling Requirements
DNV-RU-SHIP Part 2 Chapter 1 hull structural design: hull girder loads, ULS/FLS/ALS limit states, plate thickness, buckling, fatigue, and corrosion addition for DNV-classed vessels
Read article →DNV-RU-SHIP Part 1: Classification Principles, Survey Regime, and Notation System
DNV-RU-SHIP Part 1 overview: classification scope, survey intervals, notation system, flag state interaction
Read article →DNV-RU-SHIP Pt.4 Ch.7: Rotating Machinery on Classified Vessels
DNV-RU-SHIP Pt.4 Ch.7 covers shaft design, gearbox requirements, steering gear, bow thrusters, and vibration limits for rotating machinery on classified
Read article →EN 13445-3: Shell Thickness, Safety Factors, and Weld Joint Coefficients for Unfired Pressure Vessels
EN 13445-3 thickness design rules: cylindrical and spherical shells, nozzle reinforcement, weld joint coefficients
Read article →DNV-CG-0550: What Classification Guidance Documents Are and How They Interact with DNV Rules
DNV-CG-0550 explains how DNV classification guidance documents supplement the Rules for Ships. Learn when CGs are mandatory vs advisory and how they
Read article →DNV-RP-C205 in Practice: Choosing Wave and Wind Inputs for an Offshore Lift
How to select wave and wind inputs for a marine lift using DNV-RP-C205: return periods, operability windows
Read article →DNV-RU-SHIP Pt.4 Ch.6: Lifting Appliances on Classified Ships
DNV-RU-SHIP Pt.4 Ch.6 technical guide: crane design loads, SWL proof testing, dynamic amplification, wire rope requirements
Read article →EN 13445-3 Design-by-Formula vs Design-by-Analysis: When Each Path Applies
When to use EN 13445-3 design-by-formula vs design-by-analysis: applicability limits, required analysis depth
Read article →ISO 19902 vs DNV-OS-C101: Which Standard Governs Your Jacket Design?
Comparing ISO 19902 and DNV-OS-C101 for offshore jacket design: load factors, tubular joint checks, seismic requirements
Read article →How NORSOK Splits Structural Integrity from Lifting — and What It Means for Your Padeye
How NORSOK splits structural integrity (N-001) from lifting operations planning (R-002), and what this means for padeye design responsibility and
Read article →NORSOK N-004 vs DNV-OS-C101: Steel Structure Design on the NCS
NORSOK N-004 vs DNV-OS-C101 for NCS steel structure design: partial factors, tubular joint checks, accidental load requirements
Read article →DNV-OS-A101 Safety Principles: ALARP & Barriers
DNV-OS-A101 covers safety principles for offshore installations: ALARP demonstration, safety barrier management, emergency preparedness
Read article →DNV-OS-C101 Structural Design Principles
DNV-OS-C101 in depth: LRFD load combinations, partial factors, ULS/ALS/FLS/SLS limit states, design load categories
Read article →DNV-OS-D101 Marine and Offshore Machinery Systems: Hydraulic Design Requirements
DNV-OS-D101 covers hydraulic systems, piping design pressure, machinery redundancy, and testing requirements for offshore installations and floating units.
Read article →DNV-OS-E402 Topside Facilities: Process Safety
DNV-OS-E402 covers hazardous area classification, HVAC pressurisation, gas detection thresholds, ESD levels
Read article →DNV-RP-0232: Lifting Equipment Certification — Proof Load, SWL, and Annual Inspection
DNV-RP-0232 requirements for offshore lifting equipment: proof load testing, SWL marking, annual inspection, colour coding
Read article →DNV-RP-A203 Risk Management: ALARP & Barriers
DNV-RP-A203 covers ALARP demonstration, societal risk F-N curves, HAZID/HAZOP methodology, QRA process, bow-tie analysis
Read article →DNV-RP-C203 Fatigue Analysis: S-N Curves, SCF Derivation, DFF Selection, and the Mistakes That Fail Reviews
DNV-RP-C203 fatigue assessment: S-N curve selection, stress concentration factors, DFF requirements, weld improvement
Read article →DNV-RP-C205 Environmental Loads Guide
DNV-RP-C205 covers wave spectra, Morison equation, wind turbulence models, current profiles, and return period selection for offshore structural load
Read article →Wave Load Calculations: DNV-RP-C205 Practical Primer
Regular vs irregular wave kinematics, Morison equation for slender structures, CD and CM selection, and how to get from significant wave height to design
Read article →DNV-RP-F112 Duplex Stainless Steel & HISC
DNV-RP-F112 requirements for duplex stainless steel in subsea: HISC screening, utilisation limits, weld procedure qualification
Read article →DNV-RP-N103 Cathodic Protection: Galvanic vs ICCP, Sacrificial Anode Design, and What Engineers Get Wrong
DNV-RP-N103 cathodic protection for offshore structures: sacrificial anode sizing, ICCP system design, current density requirements
Read article →DNV-RP-N201 Free-Spanning Pipelines: Screening Criteria, VIV Onset, and Fatigue Assessment
DNV-RP-N201 covers free-span screening, VIV onset criteria, ULS and FLS assessment, and intervention criteria for seabed pipelines exposed to current and
Read article →DNV-RU-SHIP Pt.2 Ch.2: Propulsion & Machinery
DNV-RU-SHIP Pt.2 Ch.2 covers main propulsion, boilers, pressure vessels, hydraulic systems, and piping requirements for classified ships.
Read article →DNV-RU-SHIP Pt.2 Ch.4: Ship Piping Systems
DNV-RU-SHIP Pt.2 Ch.4 piping classes I/II/III by fluid hazard, Barlow wall thickness formula, corrosion allowance, valve requirements
Read article →DNV-RU-SHIP Pt.4 Ch.6: Piping Systems on Classified Vessels
DNV-RU-SHIP Pt.4 Ch.6 piping systems: material selection by service, pressure class requirements, testing
Read article →DNV-ST-0194 Lifting Devices: Crane Certification
DNV-ST-0194 marine crane certification: SWL determination, proof load 1.25×SWL, 15-min static hold, periodic inspection intervals
Read article →DNV-ST-0373 Lifting Devices: SWL & Proof Load
DNV-ST-0373 lifting device design: load cases LC1–LC4, DAF selection, yield check criteria, weld class W2, proof load 1.25×SWL
Read article →DNV-ST-0377 Structural Systems: Categorization, Four Limit States, and What Determines NDE Scope
DNV-ST-0377 structural systems: categorization principles, limit state requirements, primary/secondary structure distinction
Read article →Fatigue Analysis for Offshore Lifting Lugs
DNV-ST-0378 Appendix C fatigue assessment for offshore lifting lugs: S-N curves, DFF selection, cycle counting, and weld toe improvement techniques.
Read article →Offshore Container Certification: DNV-ST-0378 & EN 12079 Design and Inspection Checklist
DNV-ST-0378 offshore container certification checklist: structural requirements, SWL markings, padeye design, hydrostatic test
Read article →DNV-ST-0378 Padeye Design: A Complete Guide for Offshore Engineers
All five utilisation checks, DAF selection, pin hole tolerancing, and weld throat sizing for DNV-ST-0378 Appendix E padeye design — with worked examples.
Read article →DNV-ST-0378 vs NORSOK R-002: Two Standards, One Padeye
How DNV-ST-0378 and NORSOK R-002 divide padeye responsibility: structural design vs lifting operations planning, and where the two standards interact.
Read article →DNV-ST-E273: Portable Offshore Units — Dynamic Factors, Skew Loads, and the R-class Regime
DNV-ST-E273 portable offshore units: R00/R30/R45/R60 operational classes, dynamic factors, skew load, out-of-plane hoist angles, padeye Appendix A
Read article →DNV-ST-E407 Subsea Production Systems
DNV-ST-E407 subsea production systems: flowline design, riser integrity, umbilical requirements, pressure containment
Read article →DNV-ST-F101 Submarine Pipeline Systems
DNV-ST-F101 pipeline wall thickness design, collapse under external pressure, on-bottom stability, and installation load calculations for submarine
Read article →DNV-ST-N001: Marine Warranty Survey — Load-out, Transport, Installation Regimes and Documentation Requirements
DNV-ST-N001 marine warranty survey requirements: load-out, sea transport, offshore installation, and the MWS approval process for heavy lift and tow
Read article →DNV-ST-N002: Site-Specific Metocean Assessment for Mobile Offshore Units
DNV-ST-N002 site-specific metocean assessment: return period selection, joint probability analysis, directionality
Read article →EN 10025-2: S235/S275/S355 Structural Steels
EN 10025-2 structural steels: S235/S275/S355/S460 grade selection, sub-grade suffixes (J0/J2/K2), Charpy impact requirements
Read article →EN 10028-7 Stainless Steels for Pressure Equipment
EN 10028-7 stainless and duplex steels for pressure equipment: grades 1.4301, 1.4404, 1.4462, solution annealing requirements, and corrosion test criteria.
Read article →Material Certificates: 2.1, 2.2, 3.1, 3.2 — What Each Means Offshore
EN 10204 material inspection documents explained: 2.1, 2.2, 3.1, and 3.2 certificate types, witness inspection rights
Read article →EN 1090-1 CE Marking for Structural Steel: FPC, DoP, and Notified Body Requirements
EN 1090-1 CE marking requirements for structural steel: Factory Production Control, Declaration of Performance, AVCP systems 2+/3, and Notified Body certification for offshore fabricators
Read article →EN 1090-2 Execution of Steel Structures
EN 1090-2 execution classes EXC1–EXC4, welding qualification requirements, NDT extent, dimensional tolerances
Read article →EN 13001-1: Crane Safety — General Principles and Limit State Design
EN 13001-1 crane safety: limit state design philosophy, crane classification (A groups, load spectrum), dynamic factors, load combinations, and design verification for offshore cranes.
Read article →EN 13445 Unfired Pressure Vessels Guide
Complete guide to EN 13445 parts 1–5: material requirements, design-by-formula, design-by-analysis, inspection & testing
Read article →ISO 19901-1: Metocean Design and Operating Conditions for Offshore Structures
ISO 19901-1 metocean design: wind, wave, current, and environmental data requirements for offshore structures. Return periods, joint probability, hindcast vs measurements, and operational limits.
Read article →ISO 19902 Fixed Steel Offshore Structures
ISO 19902 offshore structure design: tubular joint capacity, pile design, pushover analysis, structural assessment methodology
Read article →ISO 19902: Fixed Steel Offshore Structures — What Engineers Need to Know
ISO 19902 overview: what offshore engineers need to know about jacket design, load combinations, tubular member checks, and interaction with DNV-OS-C101.
Read article →Weld Symbols on Offshore Drawings: ISO 2553 vs AWS A2.4
ISO 2553 weld symbols on offshore drawings: tail, arrow, reference line, and supplementary symbols — plus key differences from AWS A2.4 for international
Read article →Which ISO 2768 Class Should Your Offshore Drawing Specify?
ISO 2768 general tolerances for offshore fabrication: fine (f), medium (m), coarse (c), very coarse (v) classes for linear dimensions and geometric
Read article →ISO 9927-1: Crane Inspection Requirements for Offshore Operations
ISO 9927-1 crane inspection requirements: initial examination, thorough periodic inspection, intervals, inspector competency, and documentation for offshore cranes.
Read article →NORSOK M-001: Material Selection for Offshore Structures — A Practical Guide
NORSOK M-001 material selection for offshore: carbon steel grades, corrosion allowances, CRA requirements, and material class tables for NCS applications.
Read article →NORSOK M-001 vs DNV-OS-C101: Material Selection Cross-Walk for Offshore Structural Steel
How NORSOK M-001 and DNV-OS-C101 align on structural steel selection: material class tables, Charpy requirements
Read article →NORSOK N-001: Structural Design of Offshore Steel Structures — Engineer's Guide
NORSOK N-001 structural design of offshore steel structures: load factors, limit states, accidental design loads
Read article →NORSOK N-003: Actions and Action Effects for Offshore Structures
NORSOK N-003 actions and action effects: permanent, variable, environmental, accidental, and deformation actions for Norwegian offshore structures. Load combinations and partial safety factors.
Read article →NORSOK R-002: Lifting Operations — Lift Categories, Rigging Plans, and Critical Lifts
NORSOK R-002 lifting operations: lift categories (simple/complex/critical), rigging plan requirements, critical lift criteria
Read article →The Cheek Plate Trap: Why More Steel Doesn't Always Help Your Padeye
Why adding a thicker cheek plate doesn
Read article →Padeye Design Calculator: DNV-ST-0378 Checks, DXF Export & Complete Design Guide
Online padeye design calculator with DNV-ST-0378 Appendix E checks, sling angle correction, cheek plate sizing, sensitivity analysis, and DXF export. Design lifting lugs to code in minutes.
Read article →Pipe Flow Calculator: Pressure Drop, Friction Loss & Sizing for Engineers
Online pipe flow calculator with Darcy-Weisbach and Hazen-Williams methods. Compute pressure drop, friction loss, gas velocity limits, valve Cv sizing, and water hammer for DN 15–600 piping systems.
Read article →Pressure Vessel Calculator: ASME VIII & EN 13445 Wall Thickness Design
Online pressure vessel calculator for ASME VIII Div 1 and EN 13445 wall thickness, head design, nozzle reinforcement, and hydrotest — with formulas, tables, and practical design tips.
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