| Case Name |
Explosion and fire of a boiler for power generation on restarting operation |
| Pictograph |
|
| Date |
April 8, 1977 |
| Place |
Yokohama, Kanagawa, Japan |
| Location |
Refinery |
| Overview |
On start-up operation of a boiler for power generation, fuel gas was introduced into the fuel gas piping. An explosion occurred when the operator, due to a misunderstanding, put fuel gas into the furnace before it was ready for combustion. The accident was caused by a lack of knowledge on the handling of flammables, as well as an awareness of danger at the operator side. The education system that caused the lack of knowledge and misunderstanding of instructions should also be blamed. |
| Incident |
On start-up operation of a boiler for power generation, fuel gas was being introduced into the fuel gas piping after nitrogen-purging. An explosion occurred when an operator introduced fuel gas into the furnace by a misunderstanding about the operation procedure. |
| Processing |
Consumption and usage |
| Process Flow |
Fig2.Unit process flow
|
| Substance |
Fuel gas |
| Type of Accident |
Explosion, fire |
| Sequence |
09:50, on April 8th, 1977. Nitrogen purging in fuel gas piping started for the restarting operation of a boiler that had been stopped.
13:20. Fuel gas was introduced into a fuel gas header to replace nitrogen.
16:15. Fuel gas was introduced into branch piping to replace steam. The burner's main valve was opened slightly.
16:58. An explosion occurred.
17:21. The fire was extinguished. |
| Cause |
1. The valve for the burner was slightly opened due to a misunderstanding by one operator. As a result, fuel gas entered the furnace to form a combustible gas-air mixture.
2. Fuel gas accumulated in the furnace because the chimney effect was not available as the exhaust gas damper was closed. |
| Response |
Extinguishment with water |
| Countermeasures |
1. A safety check of the whole plant.
2. Strengthening safety education.
3. Improving operation guidance.
4. Improving facilities. |
| Knowledge Comment |
1. Improving awareness of danger and safety measures is required for gas combustion.
2. The explosion caused considerable damage to the area surrounding the factory. |
| Background |
The operator misunderstood the operation procedure. He thought that the operation had been changed to purging operation for introducing fuel gas into the furnace to control the odor generated from introducing of fuel gas. Lack of education seems to have been a major factor causing such a misunderstanding. Although the actions were contrary to the basics of handling flammable gas, he did not notice that. |
| Reason for Adding to DB |
Example of explosion and fire caused due to lack of awareness on the hazards of flammable gas |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Organizational Problems, Inflexible Management Structure, Insufficient Education/Training, Misjudgment, Misperception, Mis-Convincement, Planning and Design, Poor Planning, Poor Start-up Planning, Regular Operation, Erroneous Operation, Selfish Judgment, Secondary Damage, External Damage, Explosion, Bodily Harm, Injury, 3 person injured, Loss to Organization, Economic Loss, Direct Manetary Loss 210 million yen
|
|
| Sources |
Yokohama City Fire fighting station. Michio Igarashi. Explosion and Fire in a boiler for power generation. 27th national fire fighting engineering conference paper (1979)
High Pressure Gas Safety Inst. of Japan. Power generation water tube boiler. Explosion and fire accident inside furnace. Accident examples in Complexes. pp.180-181(1991)
|
| Number of Injuries |
3 |
| Physical Damage |
A large steam boiler for power generation was severely damaged. The external walls of the compressor room and the generator room were damaged. (Fire Res. Inst. conference paper). The boiler was completely destroyed. The adjacent boiler also suffered damage. Piping, electrical and instrumentation facilities burned out. Three buildings were damaged. (Case studies by the High Pressure Gas Safety Inst. of Japan). |
| Financial Cost |
¥ 218 million (Material of High Pressure Gas Safety Inst. Of Japan) |
| Notes |
It is considered that there was no residue because it was a gas explosion. |
| Field |
Chemicals and Plants
|
| Author |
WAKAKURA, Masahide (Kanagawa Industrial Technology Research Institute)
YOSHINAGA, Jun (Graduate School of New Frontier Sciences, The University of Tokyo)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
|
