Classification Society & Offshore Crane Design Codes and Terminology Overview

Offshore engineering equipment operates long-term in harsh environments featuring high salt fog, strong wind and waves, and alternating loads. Classification society certification and design standards serve as the core cornerstone for ensuring safe and compliant operation, as well as the critical threshold for enterprises to compete in the global offshore market. Whether for offshore platforms, FPSOs, Crane vessels or special port equipment, all must pass inspections by authoritative classification societies and comply with universally accepted international specifications to achieve smooth operation and market recognition. In this field, Maxtech consistently develops products in line with world-class international standards, integrating compliance, reliability and durability into design and manufacturing, and stands as one of the few domestic brands with full-process offshore certification capabilities.

1. History and Significance of Classification Societies

Essentially, a classification society is an independent institution that establishes and maintains technical standards for ships and offshore facilities. Its origin stems from a fundamental demand: risk control.

The story began in London in 1760. At Lloyd’s Coffee House, shipowners, merchants and underwriters started grading vessel conditions to assess seaworthiness. This marked the prototype of the world’s first classification society — Lloyd’s Register (LR). The initial "A1" rating represented a vessel in optimal condition.

Since then, classification societies have evolved from simple visual inspections into authoritative technical regulators with comprehensive technical systems. They formulate specifications covering material selection, structural design, mechanical manufacturing, electrical installation, safety systems and environmental protection. From design drawing approval to scrapping and dismantling, the entire life cycle of a marine facility is governed by classification society regulations.

Starting from product definition, Maxtech conducts structural calculations, material selection and safety configuration in strict accordance with classification society requirements, ensuring equipment complies with international specifications from the design source.

      2. IACS and Core Member Classification Societies

To unify global technical standards and eliminate confusion caused by conflicting regulations across regions, the International Association of Classification Societies (IACS) was established. IACS members formulate regulations followed by over 90% of the world’s merchant ships, acting as the de facto core standard-setter for the marine industry.

Current full IACS core members are categorized as follows:

• European: DNV, Lloyd’s Register (LR), Bureau Veritas (BV), RINA, Polish Register of Shipping (PRS), Türk Loydu, Croatian Register of Shipping (CRS)
• American: American Bureau of Shipping (ABS)
• Asian: China Classification Society (CCS), Nippon Kaiji Kyokai (ClassNK), Korean Register of Shipping (KR), IRClass

Note: The Russian Maritime Register of Shipping (RS) was once an IACS member but had its membership terminated by IACS voting in March 2022 due to international sanctions and political factors. Türk Loydu officially joined IACS in July 2025 to fill the vacant seat of RS.

     3. Identification of Classification Society Design Standard Codes

3.1 American Bureau of Shipping (ABS): Clear Functional Classification

ABS features an intuitive specification system, with standard codes directly reflecting equipment and structural types.

Identification Features: Standards are preFixed with "API" or "ABS", and API standards are widely cited and adopted in offshore engineering.

Typical Design Standards:

• API 2C: Authoritative standard for offshore cranes, specifying design, construction and testing requirements for fixed and floating platform cranes
• API 6A: Specification for wellhead and christmas tree equipment
• API 5L: Specification for line pipe, the fundamental guideline for pipeline design
• ABS Rules for Building and Classing Steel Vessels: Core classification standard for steel ships

Maxtech’s offshore crane models fully comply with ABS and API 2C requirements, making them a reliable choice for the oil and gas industry.

3.2 DNV: Systematic Specifications Inherited from GL

DNV merged with Germanischer Lloyd (GL) in 2013 to form DNV GL, and rebranded simply as DNV in 2021.

It boasts an extensive and systematic specification system, inheriting GL’s rigorous coding logic.

Identification Features: Standards are marked with "DNV" or "DNVGL" in the format of Sector Code – Serial Number.

Typical Design Standards:

• DNVGL-CG-0125: General specification for offshore structures
• DNVGL-ST-0126: Specification for offshore wind turbine support structures
• DNVGL-RU-SHIP Pt.3 Ch.1: Ship classification specification (Part 3 Hull, Chapter 1)

Maxtech delivers deep-sea operation and Active Heave Compensation (AHC) models meeting DNV criteria to adapt to complex sea conditions.

3.3 Lloyd’s Register (LR): Classic Rules-Based System

As the world’s oldest classification society, LR maintains a complete and rigorous rules system with traditional numbering prefixed by "LR".

Typical Design Standards:

• LR Rules for the Classification of Naval Ships: Classification regulations for naval vessels
• LR Rules and Regulations for the Classification of Ships: Core specification for merchant ships

Equipped with multi-classification society certification capabilities, Maxtech flexibly meets the access requirements of global projects.

3.4 China Classification Society (CCS): Integrated and Independent Standards

CCS draws on advanced international experience while developing independent and distinctive specifications.

Identification Features: Standards are prefixed with "CCS" with clear and explicit naming.

Typical Design Standards:

• Rules for the Classification of Sea-Going Steel Ships: CCS’s core comprehensive specification
• Guidelines for Alternative Design Assessment of LNG Carriers Based on Risk Assessment: Special guideline for innovative LNG vessel design
• Rules for the Classification of Fixed Offshore Platforms: Dedicated specification for offshore engineering structures

All Maxtech product lines are eligible for CCS certification, serving as the preferred compliant solution for domestic projects.

3.5 Other Industry Specifications

1. EN 13852 Series: EU offshore crane standards. EN 13852-1 (general), EN 13852-2 (floating type) and EN 13852-3 (light-duty) specify dynamic load resistance, wind and wave resistance, anti-corrosion performance and CE certification requirements, mandatory for European market access.
2. ISO 19354/19355/19356: ISO marine crane series standards that unify global requirements for structure, testing and configuration to facilitate international technical recognition.
3. GB/T 37443 & GB/T 37450: National standards for China’s offshore platform cranes, aligning with international norms and defining load combination, structural strength, safety devices and anti-corrosion coating criteria.
4. IEC 60204-32: IEC electrical safety standard for cranes, regulating control systems, explosion-proof design, earthing and fault protection to enhance electrical operational reliability.
5. Significance of Design Standard Codes: A Universal Technical Language

Mastering standard codes goes beyond simple recognition; it delivers core practical value:

1. Clarify design basis, defining the technical specifications adopted for drawings and calculation documents
2. Ensure regulatory compliance, as classification society rules are mandatory for structural engineers
3. Facilitate international collaboration, unifying technical terminology and design logic for global project teams
4. Professional Marine Crane Terminology

Complete Equipment & General Terms

• MHC (Mobile Harbor Crane): A tire-mounted large port crane with flexible travel capability for container and bulk cargo handling
• SWP (Shipyard Wharf Platform): Special high-load bearing platform equipment for material handling and equipment installation during ship construction

Structural & Component Terms

• MB (Main Boom): Primary load-bearing jib, determining maximum lifting height and working radius
• KB (Knuckle Boom): Folding articulated jib for space-saving installation and operation in narrow spaces such as cargo holds
• MW (Main Winch): High-torque low-speed winch for heavy-duty primary lifting operations
• WW (Whipline Winch): High-speed auxiliary winch for light-load handling and auxiliary rigging work

Control & Safety Terms

• SWL (Safe Working Load): Also known as rated capacity, referring to the maximum permissible lifting load under specified working conditions
• AOPS (Automatic Overload Protection System): Automatic safety system that cuts off power to prevent overloading and structural damage
• MOPS (Manual Overload Protection System): Backup manual load monitoring and limiting system for AOPS failure scenarios
• LS (Load Sensing): Real-time load monitoring system that transmits operational data to the main control unit
• CT (Constant Tension): System maintaining stable wire rope tension to offset vessel sway in deep-sea operations
• PLC (Programmable Logic Controller): Core control unit serving as the "brain" of crane operation
• SIL (Safety Integrity Level): Classification standard (SIL 1–4) for safety instrument system reliability
• SCADA (Supervisory Control and Data Acquisition): Centralized system for equipment data monitoring and collection
• AHC (Active Heave Compensation): Real-time motion compensation technology to counteract wave-induced vessel movement
• PHC (Passive Heave Compensation): Passive energy absorption compensation via accumulators and pneumatic components

General Marine Terms

• Slewing Bearing: Core connecting component enabling 360° rotation of the crane’s upper structure
• Anemometer: Wind speed monitoring device with alarm and interlock functions for high-wind operational prohibition
• Mooring System: Positioning and anchoring device for extreme weather conditions such as typhoons

Certification & Standard Terms

• Classification Society Approval: Official technical certification verifying compliance with marine safety and design specifications
• API 2C: Offshore platform crane design standard issued by the American Petroleum Institute
• IACS Unified Requirements: Globally recognized unified marine technical specifications
• FEM Regulations: European material handling industry design standards for cranes

Operation Environment Terms

• Offshore Operation: Marine lifting work requiring specialized anti-corrosion and anti-wave design
• Port Operation: High-efficiency mobile lifting operations for terminal cargo handling
• Shipyard Operation: High-precision heavy-duty lifting for ship construction and maintenance

Operational Parameter Terms

• Maximum/Minimum Working Radius: The maximum and minimum horizontal distances from the slewing center to the hook under rated load
• Lifting Height: Vertical distance from the reference datum to the highest hook position
• Service Class: Graded operational intensity determined by service cycle and load spectrum

Classification Principle:

1. Usage Class (U0–U9): Marine deck cranes commonly adopt U4–U6
2. Load Condition (Q1–Q5): Offshore cranes typically apply Q3–Q4
3. Working Class (A1–A8):

• A4–A5: Conventional marine cranes
• A6–A7: Offshore platform and engineering vessel cranes
• A7–A8: Continuous heavy-duty operation

Maintenance Terms

• Daily Inspection: Pre-operation routine safety inspection by on-site operators
• Periodic Maintenance: Scheduled component inspection, lubrication and replacement
• Overhaul: Comprehensive disassembly, inspection and overhaul for long-term service equipment
• Lubrication System: Centralized lubrication device for friction and wear reduction of moving parts

Electrical System Terms

• VFD (Variable Frequency Drive): Motor speed regulation technology for stable and smooth crane operation
• HMI (Human Machine Interface): Interactive touch screen for parameter setting and equipment status monitoring

Safety Marking Terms

• Danger Zone: Restricted high-risk area during crane operation
• Safety Distance: Specified minimum spacing for personnel and surrounding structures
• Limit Switch: Travel limiting device for jib, hoisting and slewing mechanisms

Emerging Technology Terms

• Remote Operation: Wireless remote control technology for unmanned crane operation
• Intelligent Monitoring: Real-time equipment condition monitoring via multi-sensor fusion
• Predictive Maintenance: Fault prediction and early maintenance based on operational big data
• Digital Twin: Virtual full-scale equipment model for simulation, monitoring and optimized design

     4. Practical Application Case

For a BV-certified marine/offshore deck crane, the design must take BV specifications as the core and adopt supplementary international standards. The following is a fully executable standard system in priority order:

      I. Core BV Mandatory Regulations

(1) NR 526 (Primary Rule)

Full Title: Rules for the Certification of Lifting Appliances onboard Ships and Offshore Units (July 2021 Edition)

Coverage: Crane classification, load combination, structural strength and fatigue calculation, material & NDT requirements, mechanical/hydraulic/electrical design, safety devices, stability assessment and factory testing standards

(2) Supplementary BV Specifications

• NR 447: Steel structure design, allowable stress and fatigue assessment
• NR 496: Welding procedure and non-destructive testing criteria
• NR 533: Hydraulic system and pressure vessel design specifications

    5. Internationally Recognized Mandatory Standards

(1) Crane General Design

• ISO 4301-1: Crane working classification
• ISO 8686: Load calculation and combination principles
• EN 13000: Mobile crane design specifications
• API Spec 2C: Offshore crane design (BV fully recognized)

(2) Mechanical & Hydraulic Systems

• ISO 4413: Hydraulic fluid cleanliness classification
• EN 982: Hydraulic system safety design requirements
• ISO 16016: Steel wire rope selection, safety factor and scrap criteria

(3) Electrical & Functional Safety

• IEC 60204-1: Machinery electrical safety (BV mandatory)
• IEC 61508 / IEC 62061: Functional safety and SIL grading
• IEC 60079: Explosion-proof design for oil and gas hazardous areas

(4) Maritime Safety Regulations

• SOLAS Chapter III / V: Marine equipment safety and life-saving regulations
• 1/Circ.1477 & 1663: Marine lifting equipment inspection and test guidelines

3. Chinese National Standards (Domestic Manufacturing)

• GB 3811: General crane design code
• GB 6067.1: Safety code for lifting machinery
• GB/T 12932: Technical specifications for marine cranes

     6. Key BV Certification Design Requirements

      6.1 Load & Working Conditions

Comply with NR 526 for static load, dynamic load, inertial load, wind load and vessel motion load calculation; dynamic amplification factor (DAF): 1.15–1.35 for offshore service; minimum safety factors: steel wire rope ≥5, hook ≥4, main structure ≥2.6

      6.2 Structural Design

Adopt marine high-strength steel (EH36/DH36); corrosion allowance: 3mm for seawater exposure areas, 2mm for atmospheric areas; fatigue assessment in accordance with FEM, IACS and BV NR 447

     6.3 Mechanical Design

Classify mechanism working levels per ISO 4301; adopt dual brake systems with fail-safe design; hydraulic systems comply with ISO 4413 cleanliness and explosion-proof standards

    6.4 Electrical Design

Meet IEC 60204-1 for earthing, insulation and emergency stop design; safety circuits require PL d / Cat.3 / SIL2; offshore equipment adopts IP56/IP67 protection grade and explosion-proof electrical components

    6.5 Mandatory Safety Devices

Weight Limiter, LMI (Load Moment Indicator), travel limit switches, emergency release devices, wind-proof and anti-slip devices

    6.6 Factory & Onboard Testing

1.0×SWL functional test, 1.25×SWL static load test, 1.1×SWL dynamic load test, and full safety device linkage inspection

Maxtech strictly implements the above design and testing requirements, with all equipment passing BV witness tests for one-time certification approval.

     7. Maxtech: Delivering Globally Trusted Offshore Cranes with International Standards

In the global offshore market, compliance and reliability represent core competitiveness. With years of in-depth focus on marine cranes, Maxtech develops high-quality products in line with top international standards, serving as a benchmark for Chinese marine engineering equipment exports.

• Full Classification Society Coverage: Certified by CCS, BV, ABS, DNV, LR, RINA and other mainstream societies for global project access
• Full Standard Compliance: Strict implementation of API 2C, EN 13852, ISO, IEC and GB standards throughout design, manufacturing and inspection
• High Safety & Durability: Dual overload protection, high-precision load monitoring, heavy anti-corrosion coating and high-strength structural design to adapt to high salt fog, frequent operation and extreme temperature environments
• Benchmark Project Case: Customized 3t 39m telescopic offshore crane for DP WORLD, certified by BV and API 2C, achieving stable long-term operation and establishing a classic model for Chinese offshore crane export

Moving forward, Maxtech will continue to focus on high standards, high quality and high reliability, providing safer, smarter and more compliant lifting solutions for global offshore engineering, port logistics and oil & gas development.