| Case Name |
Leakage of fuel oil caused due to damage to a valve made of cast iron at a refinery |
| Pictograph |
|
| Date |
March 15, 1991 |
| Place |
Yokohama, Kanagawa, Japan |
| Location |
Refinery |
| Overview |
An employee of the subcontractor found a fuel oil leakage near the valve in piping on the pipe rack when rundown started after changing the receiving tank for the fuel oil distillated from the refining section. The leaked fuel oil was recovered after stopping the leakage by closing a valve in the vicinity immediately. The flange of the cast-iron valve was destroyed. The accident occurred because a cast iron valve was used, which is fragile and some bad conditions accumulated. As a result, the flange of the valve was damaged.
It is speculated that a problem in equipment management was a basic factor. |
| Incident |
Fuel oil leaked from piping on the pipe rack at a refinery. The receiving tank for fuel oil distillated from a refining unit was changed, and rundown started. Afterwards, an employee of the subcontractor found a fuel oil leakage near the valve of piping on the pipe rack. Immediately, he informed the foreman of the shipping section. The leaked fuel oil was recovered by a vacuum car with stopping the leakage by closing a valve in the vicinity. |
| Processing |
Manufacture |
| Individual Process |
Rundown and takingout |
| Process Flow |
Fig2.Unit process flow
|
| Substance |
Fuel oil |
| Type of Accident |
Leakage |
| Sequence |
08:45 on March 15th, 1991: The receiving tank for fuel oil distillated from the refining unit was changed, and rundown to the tank started.
About 10:10. An employee of the subcontractor found a fuel oil leakage near the valve of piping on the pipe rack. He reported to the foreman of the shipping section.
About 10:15. The foreman who received the report went to the site at once and confirmed it. He reported to the parties concerned by emergency telephone at the site. The nearest valve was shut, leaked pipe was blocked at the site, and the leakage was stopped. The leaked fuel oil was recovered by a vacuum car.
14:40. The fuel oil in piping was recovered, the valve was changed, and processing was completed. |
| Cause |
Damage to the flange of the valve caused the leakage. The cause is considered to be as follows.
1. A cast-iron valve was used. Cast iron cracks if unreasonable force acts because it is fragile. It should not normally be used for piping of hazardous materials.
2. Combination of flanges used was improper; that is, the valve flange was FF (flat face), and the flange of piping was RF (raised face). RF is used for comparatively high pressures, and the tightening torque is concentrated on a small face. With FF, the tightening torque is distributed to the entire face. Strong force concentrated on a small part of the cast-iron flange.
3. The pipe supports were wider apart than specified in regulations. In addition, because the load of the branch piping was added, more stress than the allowable stress acted at the under part of the valve flange. |
| Response |
The valve near the part that was leaking was closed, and the leakage was stopped.
The leaked oil was recovered by a vacuum car.
An oil fence was extended in the sea to prepare for run-off. |
| Countermeasures |
The cast iron valve was changed to cast steel one.
The piping supports were increased.
When equipment is improved or repaired, the design section checks are made without fail, and safety is confirmed before construction. At the same time, the construction section and the equipment management section confirm safety by checking drawings etc.
The construction section carries out improvements in the construction manual and education based on the revised manual. |
| Knowledge Comment |
Confirmation of safety tends to be careless when improving or repairing piping etc. This might cause an accident. |
| Background |
Equipment management using a cast-iron valve is a problem. Moreover, the flange of a different form (RF and FF) had been used. It is presumed that this was an error of a selection of material or construction it. It is thought that the wider intervals between pipe supports than the design were a violation or an oversight. Looseness of management is a problem. |
| Sequel |
After the accident, similar piping in the factory was checked thoroughly. |
| Incidental Discussion |
A cast iron valve had been used in the past. However, a cast iron valve should not be used for hazardous materials facilities because there is a possibility of its breakage under a strong force, such as when tightening the flange too much because cast iron is fragile. |
| Reason for Adding to DB |
Example of leakage caused due to use of a cast iron valve and misuse of a flange |
| Scenario |
| Primary Scenario
|
Ignorance, Insufficient Knowledge, Insufficient Experience/Study, Organizational Problems, Inflexible Management Structure, Insufficient Education/Training, Planning and Design, Poor Planning, Poor Design, Production, Hardware Production, Wrong Piping Construction, Failure, Fracture/Damage, Cast Iron Valve Damage, Secondary Damage, External Damage, Leakage
|
|
| Sources |
Fire and Disaster Management Agency, Fuel oil spill incident due to the gate valve damage of the transfer office, Accident cases of hazardous materials, 1991, pp.802-803.
High Pressure Gas Safety Inst. of Japan, Fuel oil piping, Fuel oil piping valve damage leakage, Accident examples of Petroleum refinery and Petrochemical units, pp.76-79(1995).
|
| Physical Damage |
A 8-inch valve (made of cast iron) was damaged. |
| Financial Cost |
¥ 1million (Fire and Disaster Management Agency). |
| Field |
Chemicals and Plants
|
| Author |
OGAWA, Terushige (Graduate School of Environment and Information Sciences, Yokohama National University)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
|
