The Aluminium
Association classifies molten aluminium explosions in three categories, Force
1, Force 2, Force 3. A force 1 explosion is the least severe in regards to
equipment damage and workers being injured. These explosions are
characterized by metal thrown a short distance, usually up to about 4.5 meters
and often less than 4.5 kilograms, with minimal or no property damage. Force 1 explosions are
sometimes referred to as "pops". It is important for the industry to acknowledge
that small molten metal explosions are dangerous. History has shown time and
time again that a smaller explosion can lead to larger more severe explosion. This
is a story of a force 1 explosion that resulted in molten metal being sprayed/splashed
upwards igniting on fire whatever the molten metal came into contact with. This
incident illustrates how a force 1 explosion can result in a building being
caught on fire.
The Doncasters
Paralloy factory in Northeast England, was badly damaged by the fire during the
night of Tuesday, March 6, which broke out just after 8pm.
Three different areas
of the building caught fire when machinery malfunctioned, causing molten metal
to escape.
The watch manager at
Stockton Fire Station, said "The metal splashed upwards when it hit the
floor, igniting everything a 50 tonne molten metal ladle, an overhead crane and
the roof space. It was quite a difficult job
because you can’t put water on molten metal, and the crane had nine kilovolts
going through it, so we couldn’t put water on that either.
“We had to isolate the entire power supply before we could get
some water onto it.”
The electricity supply
to the whole plant had to be cut off before the fires could be tackled using
high-powered water jets, and it took an hour for the blaze to be brought under
control.
The Stockton Fire
Station watch manager said no-one was injured due to the diligence of the staff
at the site and the fire service. About 20
production workers were sent home and an inspection was carried out the
following day. The area where the fires started remained closed, but most of
the factory was reopened.
Please comment.
5 comments:
I couldn't find the details of the explosion such as ignition sources and explosive environment leadin to the explosion. Could you help?
Thank you for commenting, the ignition source may have been moisture on the concrete or steel substrate.
The below link dates back to 2005, yet provides timeless advice as to how to operate more safely. Often, it is the combination of multiple unsafe practices with poor housekeeping that starts a countdown to disaster.
http://www.csb.gov/newsroom/detail.aspx?nid=264
"This accident followed a classic syndrome we call 'NORMALIZATION OF DEVIATION,' in which organizations come to accept as 'normal' fires, leaks or so-called small explosions. The company failed to investigate the smaller fires as abnormal situations needing correction or as warnings of potentially larger more destructive events. The CSB almost always finds that this behavior precedes a tragedy."
A presentation was given in Sao Paulo last week and included a 30 second video clip of the world's largest dominoes in a line, then falling down. That clip emphasized that small incidents lead to larger incidents. In the case of the aluminium industry, small molten metal explosion always lead to larger explosions.Proper investigation of the root cause of an incident is necessary to eliminate re-occurrence.
Agreed -- as well as root cause analysis of "near misses," since these indicate the risks that eventually precipitate an incident. The ideal time to deal with an accident is before it happens.
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