Crane proof load test

A crane proof-load test loads a ship or shore crane above its safe working load to prove the structure, machinery, and brakes before certification, the central acceptance test under ILO Convention 152. The proof-load factor is graduated by SWL: 1.25 times the SWL up to 20 tonnes, 5 tonnes added above 20 up to 50 tonnes, and 1.1 times the SWL above 50 tonnes. The load is hoisted, slewed, and luffed at slow speed and held, with the surveyor checking for deflection, slip, and overload-cut function. Results enter the Register of Lifting Appliances; the test is repeated every five years and after substantial repair.