Luffing tower crane This configuration of crane is widely used in the construction industry. It requires assistance in erection and this is usually provided by a suitable sized mobile crane, erection times vary but on average a time of two to three days can be expected for a crane of thirty metres square. Erection of this type of crane is normally carried out by a crew and an engineer, trained in the specific erection procedures required. At the conclusion of the erection the crane will be subjected to a thorough examination and an application of a 25% overload followed by the setting of the safety devices. Jibs of 50m and longer are available for applications where greater area coverage is required, and tower heights of up to 180m can be readily found for the project that needs this sort of lift height. A range of hoist and trolley winches are offered by the crane manufacturers, providing the crane user with a wide choice of hook speeds and pull combinations. Rail-mounted bases are often available for this type of crane. Cranes of this type are excellent in the role of rapid light weight material handling and when correctly sited and driven will provide comprehensive and efficient lifting services for a large area of a site. Though not usually of very large maximum lifting capacity, average construction industry capacities being between 5000kg and 10000kg, the horizontal jib tower crane can lift its maximum capacity out to a radius in excess of 25% of its total, and at maximum radius a healthy capacity still remains.
