An example of the use of a spreader bar is shown in figure 93 above.
Where bundles of trusses are raised to roof level, caution should be exercised in the removal of the restraining bands (see section 3.11 figure 92). Should these bundles of trusses be stored either on a temporary working platform or at eaves level, the contractor should take the necessary steps to ensure that the supporting structure has sufficient strength and that a storage system as illustrated in either figure 90 or 91 is constructed.
Designated slewing areas should be cordoned off and the movement of operatives either restricted or prohibited within this area during all lifting
At all times, strict adherence with the Contractors method statement should be observed.
Where circumstances and design considerations dictate that pre-assembled sections of roof, such as hips etc., (or indeed, complete roofs) are raised in
one single lifting operation, particular attention should be given to the method of lifting the assembled sections. Such large and unwieldy loads
require that checks should at least be made regarding the following:-
Prevailing weather conditions, with particular reference to wind speed.
A survey of obstacles in the slewing area, including scaffolds, towers and overhead services.
A survey of the accuracy of construction and setting out of the pre-assembled roof structure.
Underground services locations to avoid damage by the use of large cranes etc.