| Case Name |
Fire of ethylene oxide adducts at a manufacturing plant not in operation |
| Pictograph |
|
| Date |
December 10, 1987 |
| Place |
Kawasaki, Kanagawa, Japan |
| Location |
Chemical factory |
| Overview |
Xylene flowed into a waste water drum from a chemical drum at a plant manufacturing ethylene oxide adducts, which was under shutdown due to a leakage of a control valve. Xylene overflowed the waste water drum, and flowed into a gutter. Steam used in another tank for purging and its drain also flowed into the same gutter. Xylene evaporated due to high temperature of steam and steam drain, and was ignited by welding sparks. Separation by only one control valve caused a leakage, and different sizes of vessels caused an overflow. Besides, there was insufficient safety management at the site of hot work. |
| Incident |
Receiving piping from the waste water tank of another plant was tried to install in the waste water tank (D-7303B of Fig2) of the plant stopping operation to control production. Before electric welding, a welding rod was set at the holder of the welder, being made contact with the brace of a nearby column to confirm grounding. Vapor of leaked xylene was ignited by a spark. |
| Processing |
Manufacture |
| Individual Process |
Maintenance |
| Process Flow |
Fig2.Unit process flow
|
| Substance |
Xylene, Fig3 |
| Type of Accident |
Leakage, fire |
| Sequence |
The plant named CP-2 had not been in operation since November 7th, 1987 to control production.
On December 10th, 1987. Waste water draw-off piping of another plant was planned to be connected to D-7303B tank.
About 08:30. The operation staff checked the site and found no abnormalities.
13:00 ~ 13:20. Employees of a subcontractor set the grounding of a welding machine.
13:25. A fire occurred as soon as the welding rod was set to the holder of the welding machine to mount piping and do other preparatory work for welding. |
| Cause |
1. No safety check was carried out before hot work. A safety check is mandatory for a plant close to flammables, even if it is not in operation.
2. Xylene remained in a drum, (D-7303A) upstream of the waste water tank (D-7303B), when the plant stopped. The control valve (LKICV-7303) used to stop it caused leakage of xylene. It flowed into the waste water tank, and overflowed from the waste water tank vent. Refer to Fig2.
3. Xylene overflowed into a gutter where the existence of dangerous materials was not assumed.
4. Steam and steam drain used for steam-purging of another tank flowed into the gutter. Xylene vaporized by the high temperature of steam.
5. Welding was being done at the adjacent area. |
| Response |
Extinguishing with water |
| Countermeasures |
1. Safety education will be provided to employees of the subcontractor who are going to work at the site.
2. Gas detection in hot work will be ensured.
3. The facility will be modified to make level management of a waste water tank possible. |
| Knowledge Comment |
It is not possible to stop a flow completely, even if an automatic control valve (CV) is shut perfectly. We should not consider that only one control valve can stop a flow. It is a fundamental principle in stopping such a flow. The possibility of leakage and mistaken inflow should be recognized when multiple vessels are connected. |
| Background |
1. It was considered possible to stop the flow simply by closing a control valve. The operation stopped, leaving xylene in the drum (D-7303A). In addition, the connection piping from the drum D-7303A to the tank D-7303B was closed only with the control valve. As a result, xylene leaked. Generally, a control valve is not designed to be shut completely.
2. As drum D-7303A is bigger than tank D-7303B, it is predictable that a leakage quantity of xylene from drum D7303A will overflow drum D-7303B. There was no quantitative consideration or level management.
3. There was a lack of awareness of the risks of hot work. Even at a plant not in operation, the level of danger during hot work is the same as that in operation if flammables remain in it.
4. The subcontractor in charge of repair work was not informed of the existence of dangerous materials. There was a total lack of awareness of the dangers, which is considered to be a major cause. |
| Incidental Discussion |
Valves are not leak-free instruments. To eliminate leakages, it is not a wise idea to rely on the valves only. |
| Reason for Adding to DB |
A typical accident caused due to hot work near flammables |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Insufficient Safety Measure, Organizational Problems, Poor Management, Inadequate Operation Management, Carelessness, Insufficient Precaution, Carelessness of Operator, Planning and Design, Poor Planning, Poor Design, Malicious Act, Rule Violation, Safety Rule Violation, Bad Event, Chemical Phenomenon, Evaporation, Secondary Damage, External Damage, Fire, Bodily Harm, Injury, I person injured
|
|
| Sources |
National dangerous object safety association of Japan. Fire accident involving leaked xylene in non-polymer manufacturing plant. One hundred cases of accidents at dangerous facilities. pp.14-15(1991).
High Pressure Gas Safety Inst. Ethylene oxide adducts manufacturing plant. Fire in an ethylene oxide adducts manufacturing plant. Accident examples of Petroleum refinery and Petrochemical units. pp.169-174(1995)
|
| Number of Injuries |
1 |
| Physical Damage |
A motor, some parts of an attic, and plastic sheets were damaged by fire. About 480 liters of xylene were burned. |
| Financial Cost |
¥ 8 million. (Accident examples of Petroleum refinery and Petrochemical unit) |
| Multimedia Files |
Fig3.Chemical formula
|
| Field |
Chemicals and Plants
|
| Author |
WAKAKURA, Masahide (Kanagawa Industrial Technology Research Institute)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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