Crane Load Testing Explained: Proof Loads & Procedure

Load testing subjects a crane to a controlled, higher-than-normal load to confirm its structural integrity, the performance of its braking and control systems, and the accuracy of its rated capacity. It is a practical demonstration that the crane will do what the manufacturer says it can, under real forces rather than on paper. A visual inspection tells you how a crane looks; a load test tells you how it behaves under stress.

The AS 2550 series and the design requirements of AS 1418 provide the framework for testing. Load testing is not a substitute for inspection — it works alongside structural examination and, where appropriate, non-destructive testing. Together they build a complete picture of whether a crane is fit to return to or remain in service.

Load testing is typically required at defined trigger points in a crane's life rather than on a fixed calendar. The most common triggers are initial commissioning of a new or relocated crane, completion of a structural repair, and any modification that affects load-bearing capacity or the safe working load. In each case the test confirms the crane is safe before it carries production loads.

Testing is also commonly performed as part of a major inspection, after replacement of load-bearing components such as ropes, hooks or structural members, and following an overload event or a period out of service. Manufacturer recommendations, the crane's duty and your WHS obligations all feed into deciding when a test is warranted.

• Commissioning of new, relocated or re-erected cranes
• After structural repairs or modifications affecting capacity
• As part of scheduled major inspections
• Following an overload, impact or other in-service incident
• After replacement of hooks, ropes or load-bearing parts

A proof load is a test load deliberately set above the crane's rated capacity to demonstrate a margin of safety. The exact percentage above the safe working load depends on the crane type, the applicable standard and the manufacturer's specification, so the test load is calculated for the specific machine rather than applied as a blanket figure. Getting this calculation right is essential — too little proves nothing, too much risks damaging sound equipment.

Test loads are applied using calibrated weights, water-filled test bags or a load cell arrangement, each with traceable calibration so the applied force is known and defensible. The competent person planning the test considers the crane's configuration, boom length or span, and the ground or structure supporting the crane, because these all affect how the test load must be managed safely.

A load test follows a planned sequence. Before any load is applied, the crane is inspected and its safety systems checked. The test then typically progresses through the crane's motions — hoisting, lowering, slewing and travelling as applicable — first at rated load and then at the proof load, with the load handled smoothly and observed for any sign of distress. Deflection, drift and brake holding are all monitored.

Throughout the test, the crane is watched for structural movement, unusual noise, hydraulic or mechanical issues and any failure of a safety device to perform. After the proof load is removed, the crane is re-inspected for permanent deformation or damage. Only a crane that performs correctly under load and shows no adverse effects afterwards passes the test.

The value of a load test lies partly in the record it produces. A test report documents the crane's identification, the rated and proof loads applied, the equipment used and its calibration, the motions tested, the results and the conclusion. This certification confirms the crane is fit for service and becomes an essential part of its compliance history.

For regulators such as WorkSafe QLD or WorkSafe WA, and for your own due diligence, this paperwork is proof that verification was carried out properly by a competent person. It also supports insurance requirements and gives asset owners confidence when a crane changes hands or is redeployed to a new site.

Load testing is a job for experienced people with calibrated equipment and a clear method. Cranes Australia carries out proof load testing for mobile, overhead and specialised cranes, calculating the correct test load, running the procedure safely and delivering certification you can rely on.

If you have a newly commissioned, repaired or modified crane that needs load testing, or you want to combine testing with a full inspection, call Cranes Australia on 0416 689 689 and we will arrange it around your operation.