Every offshore lifting operation sits on a foundation of certified equipment. Get the certification wrong — expired proof load, missing EN 10204 §3.1 certificates, incorrect SWL marking — and the entire lift is non-compliant before the hook is in the air. DNV-RP-0232 provides the recommended practice for certification, testing, and periodic inspection of lifting appliances and loose lifting gear used offshore.
This guide walks through the requirements that matter most on the job: what proof load tests are required, at what intervals inspections must happen, and what documentation a surveyor expects to see on site.
1. Scope and Equipment Categories
DNV-RP-0232 applies to lifting appliances and loose lifting gear used in offshore operations. Understanding which category your equipment falls into determines which clauses apply.
Lifting Appliances
Permanently or temporarily installed equipment with integral hoisting mechanisms:
- Offshore cranes (pedestal, knuckle-boom, davit types)
- A-frames and gantries with integral winches
- Tugger winches when used for personnel or critical lifts
- Monorails and travelling hoists
Loose Lifting Gear
Items that connect the load to the appliance — certified and tracked individually:
- Shackles, hooks, swivels, and master links
- Wire rope and fibre slings
- Spreader beams, lifting frames, and modular rigging sets
- Padeyes and trunnions (when assessed as loose gear rather than permanent structure)
2. SWL, WLL, and Rated Capacity — Terminology Defined
The industry uses SWL and WLL interchangeably in conversation, but DNV-RP-0232 distinguishes them carefully. Using the wrong term on a test certificate or nameplate is a common finding.
| Term | Full Name | Definition | Context |
|---|---|---|---|
| SWL | Safe Working Load | Maximum load permitted during normal operation, accounting for dynamic effects and safety factors | Nameplate marking, lift plans, inspection records |
| WLL | Working Load Limit | Maximum static load component — does not account for dynamic amplification | Used in EN/ISO standards for rigging hardware; often equal to SWL for static applications |
| Rated Capacity | — | Maximum load a crane can handle at a given radius (radius-dependent) | Crane load charts; varies with boom angle and outreach |
| Breaking Load (BL) | Minimum Breaking Load | Load at which failure is expected; used to derive WLL via safety factor | Wire rope and chain manufacturer data |
For wire rope slings, the typical safety factor is 5:1 (BL / WLL ≥ 5). For hook blocks and shackles, 4:1 is common. Always confirm against the applicable product standard (EN 13414 for wire rope slings, EN 13889 for shackles).
3. Proof Load Test Requirements
The proof load test is the cornerstone of initial certification. DNV-RP-0232 requires a proof load test before a lifting appliance or item of loose gear is placed into service, and after any repair or modification that affects load-bearing capacity.
Standard Proof Load Factor
The standard proof load is 1.25 × SWL for most offshore lifting appliances and loose lifting gear. This factor must be applied to the full SWL of the equipment — not to a reduced test load.
Proof Load Factors by Equipment Type
| Equipment Type | Proof Load Factor | Reference |
|---|---|---|
| Offshore cranes (complete assembly) | 1.25 × SWL | §5 |
| Wire rope slings | 2.0 × WLL (prototype; 1.25 × WLL production batch) | §5 |
| Shackles and hooks | 2.0 × WLL (prototype); per product standard otherwise | §5 |
| Spreader beams / lifting frames | 1.25 × SWL (static proof load) | §5 |
| Personnel transfer baskets | Special requirements — dynamic test required | §6 |
Post-Test Requirements
After proof load application, the equipment must be examined for:
- No permanent deformation (measure critical dimensions before and after)
- No cracking — visual inspection supplemented by MPI or PT for welds and high-stress zones
- No leakage in hydraulic systems (for crane hoisting systems)
- Full function test at SWL after proof load removal
4. Periodic Inspection Intervals
Initial certification is only the starting point. DNV-RP-0232 establishes a tiered inspection regime for in-service equipment. The interval depends on equipment type, operational environment (offshore is more demanding than onshore), and the consequence of failure.
| Equipment Type | Routine Inspection | Thorough Examination | Overload Test |
|---|---|---|---|
| Offshore cranes | Daily before use + monthly | Annually by competent person | After major repair; not routine |
| Wire rope slings | Before each use | Annually — or after incident | At initial certification only |
| Chain slings | Before each use | Annually | At initial certification only |
| Shackles and hooks | Before each use | Annually or per use-hours | At initial certification (batch test) |
| Spreader beams | Before each use | Annually | At initial certification only |
| Padeyes / trunnions (loose gear) | Before each lift | Annually or after repair | At initial certification only |
The annual thorough examination must be performed by a competent person — typically a DNV-accredited surveyor or an approved third-party inspector. The outcome is documented in an examination report that forms part of the equipment's certification dossier.
5. Required Documentation and Marking
Documentation is as critical as the physical test itself. A surveyor will check the documentation package before the lift begins. Missing or incomplete documents are a CRITICAL finding that stops the operation.
Documentation Package for Each Lifting Item
- Test certificate — proof load test result, load applied, date, tester identity
- Examination certificate — annual thorough examination result, date, competent person sign-off
- Material certificates — EN 10204 §3.1 or §3.2 for all load-bearing components
- Calibration records for test equipment used during proof load
- Repair history (if applicable) — all repairs documented with method and acceptance criteria
- Manufacturer's declaration of conformity (where applicable under PED or ATEX)
Nameplate / Marking Requirements
Every item of certified lifting equipment must be permanently marked with:
| Marking | Format | Example |
|---|---|---|
| Safe Working Load | SWL [tonnes] in clearly legible, durable format | SWL 25 t |
| Unique identification | Serial number or tag number traceable to certificates | LG-2024-047 |
| Year of manufacture | Last two digits minimum | '23 |
| Certification mark | DNV type approval mark or equivalent | DNV ⬡ |
| Test date | Month and year of most recent proof load test | 03/2025 |
6. Material and Manufacturing Requirements
For welded lifting equipment, material traceability is mandatory. DNV-RP-0232 aligns with the material requirements in DNV-ST-0378: all load-bearing steels require EN 10204 §3.1 material certificates as a minimum.
For lifting equipment in Consequence Class 2 or above (as defined in DNV-ST-0378 §3), EN 10204 §3.2 (third-party witnessed mill certification) may be required. Check the design specification — this is often project-specific.
Material Grades Commonly Used
| Steel Grade | Minimum Yield (≤16mm) | Charpy Requirement | Typical Application |
|---|---|---|---|
| S355J2 | 355 MPa | 27 J at −20°C | General lifting structure, spreader beams |
| S355K2 | 355 MPa | 40 J at −20°C | Higher toughness demand, critical welds |
| S420M/ML | 420 MPa | 27 J at −20°C / −50°C | High-capacity lifts, reduced weight targets |
| Quenched & Tempered (e.g. S690QL) | 690 MPa | 30 J at −40°C | High-performance hooks, crane hooks |
For purchased components (shackles, hooks, swivels), the manufacturer's certificate must confirm the material grade and heat treatment. Substituting a standard commercial shackle for a rated offshore shackle is a common error — the distinction lies in the material and testing documentation, not the physical appearance.
7. Design Load Factors and Safety Factors
When designing new lifting equipment to DNV-RP-0232, load factors are applied to the static hook load to derive the design load. These interact with the dynamic amplification requirements of DNV-ST-0378 if the equipment is a padeye or lifting structure.
Load Combination for Design
Utilisation Ratio Limit
For structural components of lifting equipment, the utilisation ratio η must satisfy:
8. NDT Requirements for Lifting Equipment
Non-destructive testing requirements in DNV-RP-0232 are driven by consequence class and weld category. The minimum programme for offshore lifting equipment welds is:
| Weld Type | NDT Method | Coverage | Acceptance Criteria |
|---|---|---|---|
| Structural butt welds (full penetration) | UT + Visual | 100% | Per ISO 5817 Quality Level B |
| Fillet welds (padeye to plate) | MPI (magnetic particle) | 100% of weld toes | Per ISO 23278 |
| Hook and swivel forgings | UT or RT (per product standard) | Per manufacturer QCP | Per EN 10228 |
| Repairs | MPI + UT | 100% of repair area | Same as original weld class |
MPI (magnetic particle inspection) is the preferred method for weld toe inspection because it detects surface-breaking cracks reliably and efficiently. PT (dye penetrant) is acceptable for austenitic stainless steel components where MPI is ineffective.
9. Common Non-Conformances from DNV Surveys
Based on recurring themes in offshore lifting equipment certification, these are the most frequently cited findings:
| Finding | Severity | Root Cause |
|---|---|---|
| Expired annual inspection — equipment still in active use | CRITICAL — stop work | Certificate tracking not integrated with equipment management system |
| Missing EN 10204 §3.1 certificates for load-bearing components | CRITICAL | Commercial grade material substituted without design authority approval |
| SWL marking illegible due to paint or corrosion | CRITICAL — stop work | Maintenance paint applied over nameplate; no re-stamping carried out |
| Proof load test certificate not available on site | MAJOR | Certification dossier held at office; not transmitted to installation |
| Proof load applied to component, not complete assembly | MAJOR | Misinterpretation of requirements; spreader beam tested without slings |
| Wire rope sling with kinked or birdcaged section still in service | CRITICAL — condemn and remove | Visual inspection not carried out before use; sling returned to rack after incident |
| Shackle safety pin replaced with bolt of unknown grade | CRITICAL | Original pin lost; field improvisation |
| Undocumented weld repair to crane hook or load block | CRITICAL | Field weld repair by ship's welder without engineering authority approval |
10. Pre-Lift Certification Checklist
Use this checklist before signing off any offshore lift. Every item should be verified by the lift supervisor and documented on the lift plan.
- SWL markings on all lifting items are legible and match the lift plan configuration
- All items have a valid annual thorough examination certificate — not expired
- Proof load test certificates available on site for all items in the lift set
- Wire rope slings inspected — no kinks, birdcaging, broken wires (>2 in any lay), corrosion, heat damage
- Shackles: correct grade (offshore rated), safety pin installed and moused, no elongation or deformation
- Hooks: safety catch functional, no deformation, opening within manufacturer limits
- Spreader beam or lifting frame: SWL ≥ hook load, no cracks or visible deformation, all pin connections free and lubricated
- EN 10204 §3.1 material certificates available for all load-bearing welded components
- Crane rated capacity at operating radius ≥ total lifted load (including rigging weight)
- Dynamic Amplification Factor confirmed in lift plan — 1.15 for offshore single-crane lifts, 1.25 for tandem or special conditions
- All sling angles within design limits — sling legs ≤ 60° from vertical to avoid overload (cos rule applies)
- Lift plan signed by competent person with authority to sanction the lift
Get Clause-Cited Answers on DNV-RP-0232
DNV-RP-0232 and DNV-ST-0378 are both indexed in Leide's AI Navigator. Ask about proof load requirements, SWL calculations, inspection intervals, or material certificate requirements — and get answers with exact clause references in seconds.