Case
No.40
Explosion
at surface treatment furnace for automobile
components
|
 Click Here |
[Circumstances of Incident]
This accident
occurred at a continuous-type furnace used to carbonize the surface of
steel plates in the automobile manufacturing factory.
In this
process, steel plates are heated up to around 900°C in a continuous-type
gas furnace and the steel plate surface is carbonized. The carbonized
steel plate is then hardened through a heat treatment process.
The
operation of the furnace where the accident occurred was totally stopped
on December 30 for the year-end and new-year holidays. As it was necessary
to increase the temperature inside the furnace to the prescribed
temperature on the previous day in preparation for the start of operations
on January 8 in the new year, some workers came to work. Victims A and B
ignited burners by using an ignition torch one by one from around 8:45 in
the morning. When they were about to ignite burners Nos. 26 and 27, they
stopped the ignition because of the smell of gas. When they resumed the
ignition after ventilating the area, there was a loud bang with flames and
hot air emitted from the door at the exit side of the
furnace.
Because of this, victims A and B suffered second to third
degree burns on their arms, legs, faces, etc.
|
[Causes]
The
following can be considered as the causes of this
accident.
- Combustible gas was contained in the nitrogen gas
that was injected in the system for replacement before suspending
continuous-type furnace operations for year-end and new-year
holidays.
- Although the standard work manual required opening
the furnace doors before ignition to exhaust the remaining gas, this was
not implemented.
- Although the standard work manual dealt with
furnace ignition, a decrease in furnace temperature, gas replacement,
etc., these specifications were not fully implemented by the workers
concerned.
|
[Caused by] |
Combustible
gas |
[Type of
accident] |
Explosion |
[Number of
victims] |
Two
injured (requiring an absence from
work) |
|