| Case Name |
Fire of residue oil which leaked from carelessly opened valves at an atmospheric distillation unit |
| Pictograph |
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| Date |
August 11, 1997 |
| Place |
Yokkaichi, Mie |
| Location |
Refinery |
| Overview |
The flow rate display of residue oil piping became unstable in usual operation at an atmospheric distillation unit in a refinery. When the block valve was slightly opened for inspection, hot residual oil blew off, ignited, and a fire occurred. The drain plug of a seal pot was removed and the block valve of lead piping was also opened together. |
| Incident |
At an atmospheric distillation unit of a refinery, abnormalities were found in the display of a flow meter on residue oil piping. For checking and cleaning, a drain plug of a seal pot of lead piping was removed, and a block valve of lead piping was opened slightly. Then, hot residue oil blew off and ignited, and four operators were injured.
Lead piping: Piping that conveys the pressure of a process to a sensor of various measurements, and process fluid itself is usually contained. It is dead-end piping.
Seal pot: In this case, a small vessel installed at lead piping, and it separates gas and fluid. |
| Processing |
Manufacture |
| Individual Process |
Distillation |
| Substance |
Fuel oil |
| Type of Accident |
Leakage, fire |
| Sequence |
The display of a flow meter for residue oil became unstable during usual operation at an atmospheric distillation unit. An operator went and opened the drain plug of the seal pot of lead piping connected to residue oil piping for inspection. As the block valve of lead piping was opened slightly, hot residual oil blew off.
13:45. The oil that blew off was ignited and a fire occurred. Four operators suffered severe injuries. Three self fire engines and 48 fire fighters turned out. The atmospheric distillation unit was stopped immediately, and residue oil piping was isolated.
13:49. The public fire department was notified. Eight fire engines and 53 fire fighters turned out. Fire extinguishing and cooling with a fixed foam extinguishing system and chemical fire engines were performed.
13:59. The fire was extinguished. |
| Cause |
During non-routine check work, a block valve was opened slightly, with a drain plug of a seal pot of lead piping of a flow meter was opened. As it has the same effect as having opened both double valves to the atmosphere, naturally process fluid leaked. As leaked fluid was hot (about 320 °C) residual oil (auto-ignition temperature of 300 °C), it ignited. |
| Response |
An emergency shutdown of the atmospheric distillation unit.
Isolation of residue oil piping. |
| Countermeasures |
Preparing a manual for checking and cleaning lead piping.
Restudy of work standards, work instructions, and work regulations.
Promoting a special safety education plan. |
| Knowledge Comment |
Basics are not written in a work manual. Before using the operation manual of a unit, basic education on hazardous substances should be given to the person who may treat the hazardous materials. |
| Background |
It was perfectly careless, human error. A substance comes out only when a drain plug of a seal pot is removed. If a valve connected to a seal pot is opened in such a state, naturally process fluid must leak. It is common sense for an operator prior to an operation manual, and if he does not know such a thing, the operator should not take charge of operation and construction. Maybe, he must have misunderstood something. |
| Reason for Adding to DB |
Example of leakage caused due to opening of two valves on the same line |
| Scenario |
| Primary Scenario
|
Ignorance of Procedure, Disregard of Procedure, Mis-take of Valve Open/Close, Organizational Problems, Poor Management, Slackness of Management, Malicious Act, Rule Violation, Safety Rule Violation, Secondary Damage, External Damage, Leakage/Fire, Bodily Harm, Injury, 4 person injured
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| Sources |
Fire and Disaster Management Agency, Leakage and fire of residual oil piping at the Atmospheric distillation unit, Accident cases of dangerous materials, 1997, pp.80-81.
High Pressure Gas Safety Inst. of Japan, The high pressure gas protection overview, 1998 edition, pp.160-161 (1998).
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| Number of Injuries |
4 |
| Physical Damage |
The surface area of 50 square meters of an atmospheric distillation unit. 192 L leakage of residue oil, and damage by fire. A residue oil flow sensor was damaged by fire. Thermal insulation of peripheral equipment was damaged by fire. |
| Financial Cost |
¥ 90,000. (Fire and Disaster Management Agency). |
| Field |
Chemicals and Plants
|
| Author |
ITAGAKI, Haruhiko (Japan National Institute of Occupational Safety and Health)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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