| Case Name |
Fire due to accumulated material in an exhaust gas duct at a finishing section of a synthetic rubber plant |
| Pictograph |
|
| Date |
December 3, 2000 |
| Place |
Kawasaki, Kanagawa, Japan |
| Location |
Chemical plant |
| Overview |
A fire broke out near a rotary wing of a fan installed in an exhaust gas duct of a dryer, which is in the finishing section of a synthetic rubber manufacturing plant, and the exhaust gas duct and the roof of the building which accommodates these facilities, etc. were damaged by fire. The rotary wing was damaged by metal fatigue due to long-term use, contacted a guide plate, generated heat, and rubber in the duct ignited. |
| Incident |
In a dryer of a finishing section of a synthetic rubber manufacturing plant, synthetic rubber powder near the duct ignited. |
| Processing |
Manufacture |
| Individual Process |
Drying and desiccation |
| Substance |
Styrene Butadiene Rubber |
| Type of Accident |
Fire |
| Sequence |
11:25 on December 2nd, 2000; continuous operation of C dryer started.
07:25 on December 3rd; there were no abnormalities in the plant. The shift changed. (Two shifts a day).
11:47; an operator at the first floor in the building heard a strange sound.
Around 11:50; another operator found black smoke coming from the roof of the building.
11:51; a fire alarm was actuated manually with a push button in the polymerization control room.
11:53; A smoke detector in C dryer exhaust gas duct sounded.
11:56; C dryer was stopped urgently, and automatic extinguishing facilities in the duct started. At that time, an intake air blower was stopped by an interlock.
11:57; the private fire brigade started spraying water (initial fire extinguishing using a fireplug on the roof)
11:58; an emergency call to the public fire station was made. (At Chidiri town branch office of Port fire-fighting station about 550 m from the plant, a fire-fighting staff member saw black smoke, which was reported to the command center. At the same time, it was reported from the security center of the office.) |
| Cause |
Revolutions of the exhaust fan installed in the duct became unstable due to damage to a rotary wing. The rotary wing contacted a guide plate in the duct. Friction was generated, rubber powder that adhered to the circumference was ignited by frictional heat, and a fire broke out. As rubber powder easily accumulates in the duct, it was cleaned periodically, but the powder seemed to have adhered after cleaning or was not taken off completely. |
| Countermeasures |
Replacement of the fan. Checks and overhauls of fans of the same type including undamaged ones. Preventing adhesion of combustibles such as rubber (cleaning work). |
| Knowledge Comment |
Accompanying oil and pitch, etc. adhere to the exhaust air duct and ignite unexpectedly. Periodic cleaning is desirable.
Various stresses with rotating are generated, even in small, light-load machines. It is necessary to take sufficient care. |
| Background |
Thirty years have passed since the exhaust fan was installed, but what maintenance was done is uncertain from the report. A bearing was changed in August 2000. However, there was no abnormal appearance at the time. Daily visual inspections were done, but nondestructive inspections, etc. were not carried out. Under such conditions, there seems to have been a fatigue failure caused by repeated starts and stops during 30 years, adjustment of a tie rod and small residual stress from welding, etc.
Basic measures were not taken because the equipment was not considered to be important equipment and there seemed to be no problems. |
| Reason for Adding to DB |
Example of fire due to adherence of liquid and solid materials to an exhaust gas duct |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Ignorance, Insufficient Knowledge, Convincement, Usage, Maintenance/Repair, No repair for 30 years, Failure, Fracture/Damage, Fatugue, Bad Event, Mechanical Event, Friction, Secondary Damage, External Damage, Fire, Loss to Organization, Economic Loss, Direct Monetary Damage 50 million yen
|
|
| Sources |
Kawasaki City Fire station, Fire prevention section, Peace division. Report on fire in exhaust gas duct of synthetic rubber finishing section. Material of the Kawasaki City Complex safety countermeasure committee. (2001)
|
| Physical Damage |
An exhaust air duct and about 300 square meters of the roof of a building were destroyed by fire. Electric devices and instruments in the building were damaged by water. |
| Financial Cost |
¥51 million. (Material of the Kawasaki City Complex safety countermeasure committee) |
| 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)
|
|
