| Case Name |
Fire and explosion during repair of a fuel service tank at a thermal power station |
| Pictograph |
|
| Date |
May 26, 1987 |
| Place |
Shinagawa, Tokyo, Japan |
| Location |
Power station |
| Overview |
There occurred a fire and an explosion at a power plant of an electric power company. Remodeling of fuel supply piping was being carried out near a 200 kL fuel service tank for supplying fuel to the power generator boiler. Air vent piping of the fuel feed pump ignited during cutting. The fire spread and the tank exploded. As there was no valve in the piping to the tank, combustible vapor in the tank vapor phase moved into the piping. |
| Incident |
A fire and an explosion occurred during repair work for fuel piping in the power station of an electric power company. The accident occurred on cutting air vent piping leading to a fuel service tank from a fuel feed pump. Flames were propagated in the piping, an explosion occurred in the service tank, and a fire in the tank and in the oil retaining wall occurred. As the power station was close to the city center, there was extensive smoke damage. Refer to Fig2. |
| Processing |
Storage |
| Individual Process |
Other |
| Substance |
Crude oil |
| Type of Accident |
Explosion, leakage, Fire |
| Sequence |
1. Use of a power generation unit including the burning tank was stopped for a turnaround shutdown in early April.
2. In the tank, there was a large amount of mixed oil of remained crude oil and gas oil, which was used for cleaning after stopping the tank.
3. Welding started to change air vent piping at discharge of a fuel feed pump as a part of rearrangement of fuel oil piping to the power generator boiler.
4. The tank exploded suddenly. |
| Cause |
1. The air vent piping to be welded was connected to the tank without any valve in the connecting piping.
2. Part of the light component of crude and gas oil in the tank evaporated, evaporated gas went into the air vent piping from the upper part of the tank, and a flammable atmosphere was formed.
3. It is assumed the gas was ignited by a welding flame, the fire spread through the air vent piping, and the gas exploded when the flames reached the tank. |
| Countermeasures |
1. Safety system procedures should be drafted and applied.
2. Danger of construction should be assessed.
3. Education and training to maintain safety should be carried out on above items.
It is necessary to totally restudy how to secure safety in general.
The easy-peel-off structure of the tank by which the roof moves from the side wall was prevented by welding a handrail. This structure is for preventing total destruction of the tank. The easy-peel-off structure is a part of the basic design philosophy of a cone roof tank. Other tanks of a similar structure should be inspected. |
| Knowledge Comment |
Although the appearance of crude oil is similar to fuel oil, it is a mixture of many hydrocarbons including a low boiling point component, and its fire properties are similar to gasoline (flash point is often 0 °C or less). A combustible gas-air mixture will be generated in the tank vapor phase by mixed with gas oil if there is no nitrogen blanket. |
| Background |
1. Hot work started for piping connected to a tank where a large amount of light hydrocarbon fractions remained without isolation. It seems that safety measures for hot work were not taken. Usually a blind plate should be inserted near the tank from the welding point or part of the piping should be removed.
2. The owner company (the operation side) should have the main responsibility for securing safety on performing repairs. It is speculated that there might not have been safety consciousness.
3. The cause of the destruction of the tank was lack of movement between the ceiling and the sidewall because of welding a handrail. The ceiling of the tank must come off easily from the sidewall. |
| Incidental Discussion |
Although the company is a major Japanese company, its safety countermeasures are doubtful. Safety countermeasures related to the atmosphere are the responsibility of the operating company when construction is being carried out by subcontractors. |
| Reason for Adding to DB |
Example of fire during hot work at piping connected directly to a tank |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Ignorance, Insufficient Knowledge, No Understanding of Crude oil Property, Planning and Design, Poor Planning, Insufficient Planning of Repair, Usage, Maintenance/Repair, Cutting by Fire, Bad Event, Chemical Phenomenon, Evaporation, Secondary Damage, External Damage, Explosion, Bodily Harm, Death, 4 person died, Bodily Harm, Injury
|
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| Sources |
Kazutoshi Hasegawa, Japan Soc. for Safety Engineering edition, Fire and explosion-three examples of petroleum storage tanks in 1987. Examples of fires and explosions, pp.138-146 (2002).
High Pressure Gas Safety Inst. of Japan able 4-1. Major examples of accidents related to High Pressure Gas Control Law in Japan. High-pressure gas protection overview. pp.138-141 (1988).
National dangerous material safe association. Explosion in crude oil relay tank. 100 cases of accidents at dangerous facilities. pp.53-54 (1991).
Kawasaki City dangerous material safety research association, Accident case Examples of accidents at dangerous material facilities with FTA. pp.47-49 (1997).
|
| Number of Deaths |
4 |
| Number of Injuries |
1 |
| Physical Damage |
A 200 kL cone roof-type tank containing 164.08 kL of an oil blend of crude oil and gas oil exploded. The roof was blown about 15 m away and the main body collapsed. The blend oil leaked into the oil retaining wall and burned. About 100 kL was lost by the fire. |
| Multimedia Files |
Fig2.Isometric view of the accident site
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| Field |
Chemicals and Plants
|
| Author |
KOSEKI, Hirosi (National Research Institute of Fire and Disaster)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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