The Critical Role of Load Testing in Lifting Operations
Whether for offshore operations, heavy industrial lifts, or infrastructure projects, spreader beams, frames and lifting beams must demonstrate proven strength and reliability before deployment. This includes validation through physical testing, design verification, or third-party certification, depending on the project’s complexity and risk profile.
In this article, we explore the key principles, testing techniques, and certification pathways used for high-capacity lifting equipment, with a focus on spreader beams and lifting frames. We also share how Modulift supports safe lifting through engineered solutions, custom test rigs, and DNV Type Approval.
Proven Performance Through Design, Testing, or Certification
We have supplied thousands of spreader beams and lifting beams around the world that are currently being safely used day-to-day, and meet the requirements of national legislation / standards that apply within the jurisdiction that the equipment is being used.
Load Testing vs. Design Verification
These beams have been either proven by design only, or by design and load testing, depending on the criticality of the lift. A high criticality lift such as an offshore environment may mean that it is essential that spreader beams and lifting beams are load tested prior to the lift, to add an extra layer of verification and piece-of-mind. However, it can become more of a challenge to test beams at higher loads, and sometimes can prove to be impractical.
Third-Party Inspection and Enterprise of Competence
An alternative to carrying out load testing could be by verification of the design by a recognised Enterprise of Competence such as DNV. This could be backed up with a DNV surveyor carrying out a Manufacturing Survey of the manufactured spreader beam or lifting beam, whereby they carry out inspections at various stages such as ‘Tack-up’ stage and the fully welded stage. A further layer of verification could involve carrying out NDT such as Magnetic Particle Inspection (MPI) on the welding of the beam.
DNV Type Approval and Custom Engineering Support
Modulift have obtained Type Approval from DNV for their range of MOD Spreader Beams whereby DNV have carried out a full design review and verification of our manufacturing methods. Modulift also employ DNV to carry out design reviews of one off custom Lifting Beam designs when proof load testing is not practical.
If proof load testing is deemed absolutely necessary, then Modulift can work hard to find a practical solution, often looking to load test beams using hydraulic cylinders to apply the test load. Load testing via a hydraulic system is very cost-effective, and often a lot simpler method of load testing when compared to having to mobilise a high capacity crane and test weights such as water bags for the test.
See below example of a lifting beam where we devised a method of testing in this way:
Standard Load Testing Procedures
When an added layer of assurance is required for projects where load testing of lifting equipment is essential, there are different methods that can be utilised for the load testing of spreader beams / lifting beams or frames.
One popular method is by using a crane to lift the beam or frame, and suspending test weights from it’s lifting points to simulate forces within it’s structure that it would experience during an actual lifting operation in the field.
Worldwide Legislation for ‘below the hook’ lifting equipment have an overall safety factor built into the design of between 2 and 3 times. The ‘proof load’ value i.e. the load value to test the beam or frame to, tends to range from WLL x1.1 up to WLL x2. Testing over the Working Load Limit (WLL) of the beam or frame proves it can lift more than it is designed to safely lift, to add further assurance.
Typically, the proof load is held for several minutes, to allow time for the static and dynamic forces to settle. In addition to proof load testing, it is common to carry out NDT such as Magnetic Particle Inspection on the beam or frame’s welds before and after the proof load test.
Using Hydraulic Cylinders for Large Capacity Beams
At 100 tonnes +, the practicality of testing these beams and frames starts to get prohibitive and costly. As a cost-effective alternative, beams and frames can be tested by using hydraulic cylinders to simulate the lifting forces, using a ‘reaction beam’ to test them against. A test rig using hydraulic cylinders needs to be designed by a competent person who understands the forces within the test rig and beam, to safely and accurately simulate forces during a lifting operation, and to ensure the test rig is strong enough for the test.
Compression Testing for Pin-Ended Spreader Beams
For ‘pin-ended’ modular spreader beams such as the Modulift Mod range, these spreader beams predominately experience axial compressive forces, and therefore can also be easily tested by being pinned into a compression test rig, and compressed using hydraulic cylinders. This is a cost effective and simple method of testing ‘pin-ended’ spreader beams.
For spreader beam designs where using varying top sling lengths means that the top and bottom padeye holes may not cross at the same point on the neutral axis of the beam’s section, this method of testing would not be sufficient, as there are bending forces that need to be taken into account. Pin-ended spreader beam design removes the need to worry about bending due to the load.
Testing High Capacity Beams Beyond 2000 Tonnes
Currently, Modullift are able to test pin-ended spreader beams with WLL’s up to 2200 tonnes in a purpose built compression test rig, with a plan to extend the test rig to 3000 tonnes in the future.
Modulift’s Mod Spreader Beam range can easily be load tested using hydraulic cylinders, due to the unique ‘pin-ended strut’ design. Spreader beams up to 2000t can be quickly and easily load tested, at a fraction of the cost of a crane and test weights.
For these high capacity lifts that are a multiple of thousands of tonnes, Modulift can work to provide a solution with spreader beams in a cascading rig to provide multiple ‘pick points’ to connect to the load, working within the allowable headroom available, to ensure there is a viable solution to test the beams simply and economically prior to the critical lift.