| Case Name |
Fire of an outdoor storage tank caused due to sloshing from an earthquake |
| Pictograph |
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| Date |
May 26, 1983 |
| Place |
Akita, Akita, Japan |
| Location |
Power plant |
| Overview |
A vertical motion (sloshing) of the oil level in the tank following the earthquake shock caused a vertical motion of the floating roof, and combustible gas leaked from the seal. Metal friction between attached facilities (a fixed foam ejection nozzle or water sprinkling pipe) mounted in the tank and the floating roof caused ignition and a fire. There was a problem in the design of the tank which might have caused a leak of combustible gas when an earthquake occurred, and also ignition due to friction. The periodic overhaul of the foam extinguishing facilities delayed extinguishing of the fire. If there had been stand-by facilities etc. prepared, the fire could have been extinguished earlier. |
| Incident |
The Mid-Japan Sea Earthquake with a magnitude of 7.7 caused a vertical motion (sloshing) of the oil level in a tank, resulting in a fire at the seal of a floating roof. Form extinguishing facilities of the tank was under an overhaul and needed a long time to be actuated, and the fire burned for about two hours. |
| Processing |
Storage |
| Substance |
Crude oil |
| Type of Accident |
Fire |
| Sequence |
About 12:01 on May 26th, 1983, the Mid-Japan Sea Earthquake with a magnitude of 7.7 occurred. Soon after the earthquake, a fire alarm on the control panel in the central control room (CCR) was actuated. A fire was detected in the tank yard of tanks No.7-10. When a staff of the CCR rushed immediately to the site, black smoke was rising from a peripheral part of the floating roof of No.10 tank (35,000 kL), and flames were sometimes visible. With turning out of the private fire brigade, public fire fighters and a cooperative disaster prevention team were called out immediately. Public, private, and cooperative disaster prevention teams sprayed water for cooling, and the sprinkling facilities of the burning tank (No.10) and adjoining No .8, 9 tanks were operated. Foam extinguishing facilities were under periodic maintenance, and the pump power supply was disconnected.
Then, the power supply under periodic maintenance restarted, and the fixed foam extinguishment facilities of the tank started to work at about 12:25. At about 13:15, foam spraying was stopped, and fire extinguishing was switched to water.
About 13:30, water-spraying was stopped.
14:29, The fire was confirmed to have been extinguished. |
| Cause |
1. The vertical motion (sloshing) of the oil level in the tank following an earthquake shock caused a vertical motion of the floating roof, and combustible gas leaked from the seal.
2. Metal friction between attached facilities (a fixed foam ejection hole or water sprinkling pipe) mounted in the tank and the floating roof caused ignition and a fire. |
| Response |
With turning out of the private fire brigade, public fire fighters and the cooperative disaster prevention team were called out soon after the fire was detected. Public, private, and cooperative disaster prevention teams sprayed water for cooling, and the sprinkling facilities of the burning tank (No.10) and adjoining No. 8, 9 tanks were operated. The power supply under a periodic check restarted afterwards, and fixed foam extinguishing facilities of the disaster tank started to work. |
| Countermeasures |
Removing attached facilities mounted inside the tank and material of protruding parts were considered. The fixed foam ejection nozzle and water-sprinkling pipe were attached to the outside of the tank. In addition, the clamp of the Halon extinguishing facilities was changed to a copper one. |
| Knowledge Comment |
As an earthquake hazard was insufficiently considered in the tank design and extinguishing facilities inspection, a fire occurred and extinguishing took a long time. It was proved that an earthquake hazard is a very important factor in safety design and management. |
| Background |
Taking the two accident causes, that is, leakage of combustible gas caused by sloshing and ignition caused by facilities mounted in the tank, into consideration, a basic factor seems to be that attention to safety was insufficient in the design of the tank. |
| Incidental Discussion |
There have been some rupture and fire accidents of oil tanks caused by an earthquake. In these accidents, resonances related to sloshing and bulging are problems. In the factory, special tools that do not emit sparks when they are struck are used. The fact that materials that could emit sparks were used was also a problem. |
| Reason for Adding to DB |
Example of fire of a tank caused due to sloshing from an earthquake |
| Scenario |
| Primary Scenario
|
Insufficient Analysis or Research, Insufficient Practice, Tank Behavior at the Earth-Quake, Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Planning and Design, Poor Planning, Poor Design, Bad Event, Mechanical Event, Sloshing by Warth-Quake, Bad Event, Mechanical Event, Friction, Secondary Damage, External Damage, Leakage/Fire, Loss to Organization, Economic Loss, Manetary Damage 300 million yen
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| Sources |
Fire and Disaster Management Agency. Outdoor tank fire caused by earthquake motion. Examples of accidents at dangerous material manufacturers. 1983. pp.94-95.
Dangerous object safety research association of Kawasaki City. Fire at outdoor tank storage area caused by earthquake motion. Examples of accidents at dangerous facilities (with FTA). pp.119-121(1997).
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| Physical Damage |
Sealing of a floating roof was totally destroyed by fire. A weather shield was totally lost. Side walls were partially deformed. Foam extinguishing facilities were damaged by fire. Halon extinguishing piping and a head were destroyed by fire. The water sprinkling piping, a rolling ladder, and a foam dam were deformed. A fire alarm system and meters were damaged. |
| Financial Cost |
¥ 35 million (Fire and Disaster Management Agency) |
| Field |
Chemicals and Plants
|
| Author |
DOBASHI, Ritsu (School of Engineering, The University of Tokyo)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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