10.11 SAFE USE OF SLEWING JIB CRANES
In addition to any specific instructions relating to the safe use of the crane issued by the manufacturer, the
following points should be observed:
The SWL of a crane is the maximum load for which a crane should be used and must not be exceeded. The weight of the lifting appliance should be allowed for in rating the crane. However, it should be noted that the weight of any slings and other lifting equipment form part of the load and hence may reduce the available effective lifting capacity.
SWL’s apply only to freely suspended loads. Do not use the crane hook or travelling motion of the crane to drag any load along the ground.
Before lifting the load, ensure the lifting appliance chain or rope is vertically above the load. Failure to do this will result in the jib arm swinging and possibly the trolley whipping when the load begins to rise.
Apply the rules for the safe use of all the lifting equipment employed in the lift as detailed in the relevant sections of this code. In particular, take the weight of the load gently, check to ensure that all lifting attachments are correctly and firmly in place, then complete the lift. Lower the load gently and take care to ensure an unrestricted landing area. Whilst these measures are a necessary part of the trial lift, special care is required as suddenly imposed or removed loads on cantilevers can cause the jib beam to whip.
On all occasions, prior to moving the jib arm, ensure that there are no obstructions in the path of the jib or load. The operative must always have a clear vision of the travel path.
When using a crane and/or trolley which has no manual gearing or powered mechanism for movement, i.e. is hand push, it is preferable to move the load by pushing rather than pulling it.
Care must be taken to avoid the load swinging. This can lead to the danger of the operative becoming pinned or trapped by the load. Another danger is that the load will whip outward thus increasing the effective radius and the resultant loads imposed on the mechanisms and structure.
Avoid shock loads.
Exercise great care when handling partially supported loads, such as when moving work pieces in and out of machine tools or removing chucks from lathes. This type of situation can lead to both swinging loads and shock loads.
Powered equipment may place higher dynamic loading on the structure than manual equipment, so conversion of a jib with hand chain hoist to power operated hoist must take this into account. It should also be realised that the rating of the jib arm made allowance for the weight of the hoist that was originally to be used on the crane. If a heavier hoist is fitted, the crane may no longer be suitable for the marked SWL. If any doubt exists, consult a Competent Person.