| Case Name |
A load which had been suspended fell because of unscheduled work. |
| Pictograph |
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| Location |
A fuel tank construction site |
| Overview |
At the fuel tank construction site, when a truck crane was whirling, a suspended PC (prestressed concrete) bar steel lost its balance, and it fell to the bottom of the site. When a worker who was working at the bottom of the site moved to duck away from the falling steel, he was caught his foot on a reinforced bar which was being assembled, and he got injured. |
| Incident |
A worker who intended to avoid the falling object fell down and broke his bone. |
| Sequence |
* At the bottom of the tank construction site, the worker dealing with reinforced steel was carriyng out the assembly operation. This work was carried out by ten workers at their fixed places as arranged on the previous day
* At that time, the chief of another section invited the staff of the site to carry out an unscheduled work, and this invitation was accepted on the spot.
* The work was to carry the PC bar steel to the site, to hang and whirl it above the assembly operation field by a track crane, and to discharge it at the temporary space in the afternoon.
* The method for suspending the load was to arrange the PC bar steel on the single cylinder pipe and the square timber, and then to lift the single cylinder pipe by a slinging wire.
* As a cradle to prevent the PC bar steel from deflecting, the square timber was fixed at its edge and its central part with annealing wire, and another part was fixed with three bundling wires.
* On the first time, the crane lifted, whirled and discharged the load easily. However, when whirling for the second time, the load was broken, and the annealing wire and bundling wire were cut off, and all the PC steel bars fell to the bottom of the site.
* When the worker who noticed it escaped, he broke his left rib, which took one month to heal. |
| Cause |
* The detailed work planning and manual on the discharging operation had not been prepared.
* The work path and arrangement of the unscheduled operation had not been determined, and communication and coordination of the schedule with other traders were insufficient.
* The possibility od the slipping of the single cylinder pipe and the slinging wire and cutting of the annealing wire and the bundling wire had not been considered.
* There was no person who made a sign, and no measures were taken to keep workers out of the working area within the operating radius was taken. |
| Response |
* A particular kind of metal fitting for suspension, which was available for suspending equipment at 3 points, was used. And, in order to prevent slipping, a shackle was used, and all the PC steel bars and the square timber were tied by annealing wire. |
| Countermeasures |
* For the entire operation, the books of procedure for safe operation should be prepared, and comprehension of them should be carried out thoroughly. In case of changing the contents of operation, what should be done before starting the operation is to invite the general director of health and safety and to receive his instruction.
* Election of a person who makes a sign, prohibition of working at the same time both at the top and at the bottom of the field, and compliance with the measures to keep out of the working area within the operating radius. |
| Knowledge Comment |
* The change to the operation planning should be communicated thoroughly to the workers concerned.
* A work plan should be drafted on all the crane operations such as lifting a load and pulling it down, and the countermeasures should be taken.
* Prohibition of working at the same time both at the top and at the bottom of the field, and compliance with the measure to keep out of the working area within the operating radius. |
| Background |
* Even though this operation was unscheduled, it was carried out without checking up the working method and having a meeting about it, because it was a simple job involving pulling down a load. As a result, a worker who intended to avoid the falling object fell down, and the disaster came about.
* As the background of this disaster, the victim was the third subcontract worker, and it can be said that the lower a worker is, the less the communication with him is considered. |
| Reason for Adding to DB |
There are lots of disasters because of insufficiency of communication. |
| Scenario |
| Primary Scenario
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Carelessness, Insufficient Precaution, Ignorance of Procedure, Insufficient Communication, Insufficient Analysis or Research, Insufficient Prior Research, Poor Value Perception, Poor Safety Awareness, Organizational Problems, Poor Management, Non-Regular Operation, Change in Operation, Incorrect Reaction, Poor Communication, Malicious Act, Rule Violation, Failure, Fracture/Damage, Bodily Harm, Harm to Physical Well-being, Bodily Harm, Injury
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| Number of Injuries |
1 |
| Field |
Civil Engineering
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| Author |
HOJO, Tetsuo (Institute of Technologists)
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