February 24 - Heavy lifts are often referred to as 'critical' simply because it is the biggest lift the company has ever undertaken, but that should not be the determining factor, according to the SC&RA's new Guide to Mobile Crane Safety Management.
There are certain aspects of some lifts that necessitate the classification of 'critical' because they present exceptional risk; only a small percentage of the lifts on most projects would be expected to fall into a critical lift category, informed the SC&RA.
If a large portion of the lifting work legitimately results in this classification, the overall project risk exposure is undesirably high, says the association, noting that there are several criteria within most lift classification systems that could cause a large segment of lifts to be categorised as critical.
As an example, if cranes are continuously found to be working at over 90 percent of their capacity, it might be time to reduce risk by simply deploying larger cranes. This is not to say that cranes cannot perform at 90 percent of their capacity, suggests the SC&RA guide.
Cranes in sound condition are fully capable of lifting 100 percent of the values shown within their published load rating charts and depicted on the operator's in-cab electronic display; but it is still important to recognise and understand which lifting variables can reduce the crane's lifting capability below the load rating chart values, stated the association.
Important examples of such factors are: poor crane condition; exceptionally eccentric reeving of the boom tip; improper use of outriggers; poor/soft supporting soil; crane not level within manufacturer's specifications; side loading of the boom; excessive swing speed; rapid acceleration/deceleration of the load; impact loading; high wind speeds; and exceptionally cold weather.
Written by Ronald Kohner P.E. and Robert Hontz, the 104-page Guide to Mobile Crane Safety Management was published to fortify the SC&RA's ongoing efforts to reduce crane and lifting accidents. It defines substantial changes in tools, technologies and perspectives over the last two decades.
SC&RA members can purchase this guide for USD99 and by non-members for USD199.