| Case Name |
Fire caused due to a flange loosened from vibrations at a synthetic rubber plant |
| Pictograph |
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| Date |
December 1, 2000 |
| Place |
Sodegaura, Chiba, Japan |
| Location |
Chemical factory |
| Overview |
At a special rubber manufacturing plant, leakage and a fire occurred from a pump discharge flange during use. The flange was loosened by vibrations from a pump, and a hexane solution leaked. Generated hexane vapor was ignited by a static electricity spark and a fire occurred. Piping vibrations should be suppressed. |
| Incident |
Hexane solution leaked from a transfer pump to an unreacted raw material recovery tank in an ethylene propylene rubber (EP-rubber) manufacturing plant, and a fire occurred. |
| Processing |
Manufacture |
| Individual Process |
Transfer |
| Process Flow |
Fig2.Unit process flow
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| Substance |
Hexane, Fig3 |
| Ethylene, Fig4 |
| Propylene, Fig5 |
| Type of Accident |
Leakage, fire |
| Sequence |
About 15:35 on December 1st, 2000. Routine operation was being carried out. From the outlet first flange of a pump (P-103B), which transferred a hexane solution from an un-reacted raw material recovery tank to the washing process, the hexane solution leaked, ignited, and burned. The initial stage of fire-fighting was carried out immediately, and the EP-rubber manufacturing plant performed an emergency shut-down. The fire spread. Fire-extinguishing with foam extinguishers and cooling of adjacent facilities by spraying water was carried out.
19:40. The fire was suppressed.
20:42. The fire was confirmed to have been extinguished. |
| Cause |
The cause was a loose flange and leakage. Vibration that originated from unexpected cavitation was generated when the pump P-103G, which used the same discharge piping as the pump P-103B, was used before the accident. This vibration loosened the flange of the pump. The vibration might also have been accelerated due to passage of an insoluble polymer lump through the pump, which was created on the piping wall. In addition, a 3-inch flange of pump discharge was connected by a reducer to 6-inch piping. The looseness of this flange might have been accelerated when the force of vibration was added on the piping.
The cause of ignition: A hexane solution, which leaked, is easily charged. It is considered that hexane was charged when it spouted from the flange, and static electricity was discharged; then hexane vapor ignited and a fire occurred. |
| Response |
An emergency shutdown of the plant was performed. The feed of raw material was cut off, and rotating machines were stopped. Fire extinguishing was performed with fire foam, and water was sprayed for cooling at peripheral equipment. |
| Countermeasures |
Pump vibration control and inspection: Installation of a vibration monitor and change of the suction piping shape in the pump were carried out. The suction piping was changed to prevent cavitation. Throughout the factory, the shapes of piping were changed where the connection piping caliber greatly differed from that of the flange outlet, and piping support was corrected.
The disaster prevention system of the district was improved. |
| Knowledge Comment |
Piping vibrations can cause a leakage accident. It is necessary to pay sufficient attention to pump vibrations. |
| Background |
It is a basic factor that a flange is loosened by pump vibrations. It is still unclear why cavitation occurred. Besides, it is difficult to understand why the vibration, which was strong enough to loosen the flange, was neglected. |
| Reason for Adding to DB |
Example of leakage and fire caused due to vibration of a pump |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Organizational Problems, Poor Management, Slackness of Management, Carelessness, Insufficient Understanding, Insufficient Recognition of Risk, Planning and Design, Poor Planning, Poor Design, Malicious Act, Rule Violation, Safety Rule Violation, Bad Event, Mechanical Event, Vibration, Secondary Damage, External Damage, Leakage/Fire, Loss to Organization, Economic Loss, Manetary Damage 150 million yen
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| Sources |
Fire and Disaster Management Agency. Leakage near transfer pump outlet in EP-rubber manufacturing plant. Accident cases of dangerous materials. 2000. pp.1348-1349.
The S chemistry C factory. EP-rubber manufacturing plant. Issue of the fire accident in the first series. S Chemistry Co. home page. (2000).
The S chemistry C factory. Report on fire that occurred in S district EP-rubber manufacturing plant No.1 un-reacting raw material recovery process. (2000).
|
| Physical Damage |
Damage to piping and cables in the plant. About 30 cubic meters of a solvent burned. 150 square meters of a plant burned. (Sankei Shimbun) |
| Financial Cost |
About ¥ 10 million. (Fire and Disaster Management Agency).
About ¥ 10 million at book value for damaged facilities. About ¥ 150 million for restoration. (By company concerned).
¥ 21 million (S city fire defense headquarters) |
| Multimedia Files |
Fig3.Chemical formula
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Fig4.Chemical formula
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Fig5.Chemical formula
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| Field |
Chemicals and Plants
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| 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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