Killed – two workers in California when their personnel basket fell nearly 80 feet.
OSHA has strict requirements regarding hoisting personnel. If these requirements are followed, such accidents should cease to happen. The actual cause of this particular accident is still unknown to the public as the OSHA report will take time to surface. Early speculation is that the hook failed or the basket came off the hook.
Hooks used in personnel hoisting operations “must be capable of supporting, without failure, at least five times the maximum intended load applied” according to OSHA 29 CFR 1926.1431(g)(3). In simple terms the hook will withstand a 500% overload before it will fail at which point it will bend, not break. On a crane as large as the one used in the operation, the weight of the heaviest personnel basket and its contents should not come close to the yield point of the hook.
This begs the other question, how could the master link for the bridle supporting the basket come off the hook?
OSHA requires hooks used for hoisting personnel “must be of a type that can be closed and locked” (1926.1431(g)(1)(i)(A)). Closing the hook’s throat would prevent the basket from coming off the hook. Now let’s assume the hook was not equipped with a latch or the latch was defective.
- The weight of the basket should keep the master link in place in the bowl of the hook.
- For the basket to come off, an upward force would have to be placed on the master link. This could cause the master link to slip over the hook tip.
- An upward force could be generated by hitting an object with the personnel basket.
Purchase Mobile Cranes and Rigging handbook set by Jim Headely and read...
Run for cover! There is a crane in my neighborhood setting roof trusses.
Seriously, there are dozens of crane accidents on YouTube. It seems as if most cranes end up on the roof of the house they were meant to build or reach over.
I think, there are two main reasons for all the videos of crane accidents on YouTube: One is that cranes are interesting to watch, and if they are in a public setting someone is going to take a picture or video of it. The other is that most residential contractors won’t pay for a professional crane company. Instead, they use a taxi rental company, or even worse, they rent a crane from a tool rental company and operate it themselves.
When working in residential areas, there is also the problem of where to setup. Yards, streets, sidewalks, and driveways don’t have the capacity to support a crane. And, of course, you’d have to setup in the street because you can’t mess up an owner’s yard causing the operator to reach over the house to set a pool or spa. Before you know it, the crane runs out of capacity and ends up in someone’s living room.
If you happen to be a spectator, just remember to keep a safe distance!
Today’s heavy lift cranes weigh almost as much as the loads they lift, which means getting them to the job site can be a challenge.
Not only do crane companies need to be experts in the field, they need to be experts in federal and state Department of Transportation requirements for getting equipment to the job site. Even a small company traveling within its own state has to deal with load limits on roads and bridges. They have to know about special vehicle registration, when permits are required, and what permits are required. They need to know when to remove weight from the crane, and how to transport the boom and counterweights separately. Larger companies, traveling over state lines, need to know the subtle differences in requirements from state-to-state or may be faced with large fines, travel delays, or accidents.
Extra planning is required if any part of the travel is off-road or on non-paved roads. The travel plan could call for removing weight from the crane in order to stay within weight requirements on public-paved roads. When going off-road, it may be necessary to use wood, metal or cement matting over the full route of travel, or in extreme cases, building a road that can handle the weight of a crane.
It is always important to consider ground support around the entire working area, not just where the load will be lifted.
It is common to think that if the ground is firm enough under the outriggers toward the lift, then the crane will be supported. However, this 500 ton All-Terrain crane has several tons of counterweight being supported by the outriggers on the opposite side of the crane.
If the crane swings over an outrigger, thousands of pounds per square inch of pressure impacts the float and the ground beneath it. Generally, the times three rule for blocking is adequate, but the actual load pressure on the ground for a crane configured similarly must be calculated. Additionally, a compaction test should be conducted to determine ground support.
After obtaining this information, a proper size blocking can be chosen for lifting the load safely.
Read the entire story at Vertikal.net.
An impatient worker jumps the gun and accidentally rams his forklift into a shelving unit in a Russian Vodka warehouse. The shelving unit toppled onto him as well as another forklift in operation. As the shelving collapsed another shelf was hit and a domino effect echoed throughout the warehouse.
One of the forklift operators walked away from the incident unscathed, the other operator suffered a foot injury.
Collisions are always a potential hazard when there are more than one tower crane on the job site with overlapping coverage. There are anti-collision devices that will attempt to prevent accidents from occurring, but standard operational safety should be the primary source in avoiding collisions.
It is believed that this collision occurred because the Jost hydraulic crane was out of service with its jib raised in the path of the flat-top saddle jib tower crane. The operator sustained head injuries in the collision.
The boom on this 220 ton capacity crane was overloaded while attempting to place an air conditioning unit on a building. Although the load was considered light, it was too far away causing the crane to tip. The operator managed to stop the tipping, but in doing so, created forces that bent the boom.
Read the entire story at Vertikal.net