Friday, June 6, 2008

March 15th 2008

New York A Favelle Favco diesel luffer collapsed during climbing preperation. The collar was being installed when reportedly a piece of nylon rigging failed. While the cause of this rigging failure may be debated for years to come, the mechanics of failure are quite obvious.

The collar surrounds the tower. If released physics will dictate that it can only fall straight down. When it reaches the next collar since there were a total of three on the crane, it was highly unlikely that collar would be able to support the sudden shock load from above. Unfortunately the mid collar broke free from it's locked position on the tower and it's connections to the struts. Together the collars impacted the first, lower most collar which didn't stand a chance. At this point the back moment of the crane was too much for the mast as the crane was past the max free standing height and gravity continued it's dirty work.

I have not seen the rigging used on this collar. however, it is critical that you calculate out your rigging as a three legged pick. You must inspect the rigging. If Nylon eyes are stiff, it can be cause for removal from service. If any ripping is present in the eyes, it can be cause for removal from service. If the eye does not naturally fit in it's location and must be forced, you can cause an uneven lay promoting tearing and substantially weakening a strap that you think is overkill. Proper use of $20 worth of rigging may have saved seven lives here. But again, I haven't seen the rigging or pictures of how it was set up and can only speculate from news reports and one very specific picture.

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