This International Standard sets forth general conditions, requirements, methods and parameter values for performing proof-of-competence determinations of the steel structures of cranes based upon the limit state method. It is intended to be used together with the loads and load combinations of the applicable parts of ISO 8686. This International Standard is general and covers cranes of all types. Other International Standards may give specific proof-of-competence requirements for particular crane types. Proofs of competence, by theoretical calculations and/or testing, are intended to prevent hazards related to the performance of the structure by establishing the limits of strength, e.g. yield, ultimate, fatigue, brittle fracture. According to ISO 8686-1, there are two general approaches to proof-of-competence calculations: the limit state method employing partial safety factors, and the allowable stress method employing a global safety factor. The allowable stress method is a permitted alternative to the limit state method as set forth in this International Standard. Proof-of-competence calculations for components of accessories (e.g. hand rails, stairs, walkways, cabins) are not covered by this International Standard. However, the influence of such attachments on the main structure needs to be considered. NOTE Proof of competence for elastic stability is to be covered by another International Standard.