This document provides the classification of tower cranes for construction work as defined in ISO 4306-3, and gives specific requirements for steel supporting structure, mechanisms, ropes and further components basing on standard service conditions, mainly expressed by the following:
—    the number of working cycles;
—    the load spectrum factor;
—    the average displacements; and
—    additional values for factors to be used at the structural or mechanical calculation.
Tower cranes for construction work are exclusively equipped with a hook as load-handling device.
For tower cranes intended to be used for other purposes and/or equipped with other load handling devices, other values according to the specified usage of the tower crane may result.