Overhead cranes are used in an industrial setting to facilitate the lifting and relocation of heavy loads. There are a wide variety of overhead crane types and sizes.
When selecting a crane, various criteria will dictate the type appropriate for the job. Standalone cranes are useful in locations where the existing structure is incapable of holding a crane and the load in question. Ceiling-mounted cranes, when the load and structure can bear them, allow lifting without the need to give up floor space. Ceiling mounted cranes can be single-girder, which allows movement of the payload along a straight line, or double girder, which allows placement in two dimensions, anywhere between the girders the crane is mounted on. Monorail cranes are used when the load must be carried along a constant and/or irregular path.
The appropriate crane for a task also depends on the frequency and intensity of its use. Applications requiring a crane to be used for emergency or standby use usually require a different crane than jobs which require frequent lifting of heavy loads. Cranes are rated for various classes of service which depend upon the frequency and intensity of use.