Friday, October 23, 2009

October 23,2009

(Update: Reports are that the Loadline parted causing a shock load.)

Toronto Canada. A PECCO (Peiner Electric Crane Company formerly out of Millwood NY) 355 or 225 has collapsed. The operator has survived with some bleeding from his head but it is reported that he is not seriously injured. The crane collapsed onto the new construction of a 6 story building that it was helping construct. There were no other reported injuries.
The crane failed in the turntable. Not unlike the New York collapse of the Kodiak tower crane, we have a crane approaching 30 years old still in use, that failed in the turntable. There are a litany of problems that can cause this.

There are sometimes up to 100 bolts that hold that turntable together. If they are not maintained, rust will accumulate. They do need to be periodically replaced. Cranes this old need to be torn down on a regular basis for through inspections.

Rotec or Rubella Bearings need to be disassembled and inspected regularly. Beyond regular wear and tear that can destroy the bearing, cranes get struck by lightning. The resulting electrical surge can arc across bearings and lead them to premature wear.

Metals bend and flex when put under stress. The ductility of the steel and the loads induced determine how much. after 30 years of use, microcracking can result. The cracks in this form are not noticeable and grow over time to the point of failure. All cranes have a useful life span.

Bearings being bought from companies that sell them cheap, may not be making a sound product. If a bearing isn't machined precisely, of the correct grade of steel, and hardened to exacting standards, this may be the result. The question of should I use a $15,000 bearing or a $40,000 bearing should never become a factor. The proper question is, is the bearing made well by a reputable company.

I was erecting a crane (PECCO 2000) that had a bearing not machined properly. As a result, we could not get the crane to spin because the bearing was simply too tight. Once we got it to spin, the operator got scared and stopped immediately. The bearing was so tight that the crane stopped slewing immediately as well. We were erecting the crane and only had the counter jib on. The counter jib bounced back and forth in a torquing motion for ten minutes while we discussed it. end result was that it was a cheap and poorly made bearing. We tore the crane down and started over. There was no savings and it's one of those times where I wasn't sure if I was going to survive what was happening. At least it was on December 23rd so the impact on our families wouldn't have been too much to bear.

I'm standing on a soap box here. If your crane is over 25 years old, stop using it. There are a number of variables that can lead to failure. In this particular crane, you have pendants that have been exposed to the weather for 30 years. What does the core of that cable look like? The outer pendant is 3 inches in diameter and as a result, you'll never be able to inspect that core. They don't have the common sense safety systems such as auto zeroing of the controls. you have to put the control into neutral. I would always look and the sheaves on a PECCO just to be sure everything stopped. In the dark it was simply ugly. The use of these cranes makes sense in business because they are paid for. The risk factors out the profits from a whole fleet of them. Insurance internationally for cranes has gone insane, and it's these old cranes that we have to thank. Go through my blog. We can't fix stupid, but we can certainly fix the structural problems and old design problems.

This operator was lucky. Canada has a great inspection system. But we can't be running these very old cranes. A couple of years ago I saw some old Lindens and Krolls from the 60's up and running in Victoria. I know it feels like a waste, but they have to go.

October 23rd, 2009

The July 6th Liverpool tower crane collapse operator survived. A report is out from the BBC about his condition. Iain Gilham paralyzed from the waist down after having been thrown out of the crane as it was collapsing. Since then he's missed his daughters wedding and the death of his mother. He speaks on the BBC link on a video about the accident.

It's surprising to see how many tower crane operators survive tower crane collapses. Some of the cranes are designed in a way that survivability in a collapse is surprisingly possible. The larger Liebherr's cab is built as a part of the structure. The operator sits in the center of the structure. As a result if the impact isn't great enough to cause extensive internal damage such as tearing the aorta, they may survive. Penetrations into the cab would be the other large concern.

When I was an operator, collapse was a thought that would go through my head, along with the question of what would I do. Of course the answer of swinging the crane, running out, getting into the right spot, all would go out the window as it would happen too fast. Iain Gilham being in a Wolff (Wolff's are no longer distributed in the US so I haven't seen one newer than a 1986 model) the seats aren't designed in a way that would aid you in a accident. Why would you design seat for that? It would be assumed that you'd die in a collapse anyway. But that's not what we are seeing. In my blog alone I can think of a half dozen accidents where operators died that may have lived if they were secured in their seats. Iain may not be paralyzed if he would have been secure in his seat.

I want to suggest that maybe it's time to consider designing seats in a manner that would aid survivability in the event of a collapse. Seat belts just on the lap would add to this survivability. The operators wouldn't be flung out doors and windows and as a result dying from secondary injuries. We all know that most operators would never use them. In some cases in working close to the tower the operators stand up to see straight down. They would have to unbuckle anyway. This argument doesn't negate the value of this added safety in 90% or better of the operations. Seats could be designed with head rests to prevent neck injuries. It would simply be an option and the onus would be on the operator to use his personal protective equipment.

It seems silly to me to be able to survive the actual collapsing of the crane only to be thrown out from a height too great to survive as the crane stops falling. We as an industry should be calling for a change in this safety item. If you are the company that leased Mr. Gilham's crane, wouldn't you wonder why you are going to have to pay millions to settle his legitimate claim for a spinal injury when maybe he could have been 100% physically OK?