Here are two news items and one comment (unrelated) from a website:
[Picked up from the following site:
Injured witness speaks
Statesman News Service
KOLKATA, Aug 12: Mr Bijan Biswas (25), an employee of the McDonalds
Family Restaurant on Park Street, was a witness of the blast that took
place this morning due to a faulty air-conditioner. Mr Biswas while
speaking to the media, gave a first-hand account of the incident.
While lying on bed number 23 in the burns ward in SSKM Hospital, Mr
Biswas gave the following statement to the police. “I came as usual at
around 9.30 am today, alongwith Sanjib Biswal and Subhash Mani Roy. We
had just started with our daily routine and were making preparations of
opening the shop for the day. The manager, Mr Ravi Kumar asked me to
switch on the air-conditioner. All the doors and windows of the outlet
were yet to be opened. The moment I put on the switch, I was hit by a
deafening blast and the entire place was immediately filled with thick
smoke. Then there was darkness all around as I lost consciousness. I am
unable to recall anything which happened thereafter. After a while, I
regained my senses. The place was still engulfed in smoke. I became
aware of a burning sensation all over my body. I somehow got up and
tried to come out of the place when I saw my two associates also lying
unconscious at the other side of the floor. After that we were taken to
the hospital by some people in a car.”
The experts’ opinion
Statesman News Service
KOLKATA, Aug. 12: Police and forensic experts are investigating a
number of possibilities that may have triggered the blast in McDonald’s
Investigations so far have revealed that the blast was the result of a
heat wave of nearly 350 degrees centigrade travelling at high velocity
across the shop that forced its way out after blowing the iron
shutters. The heat wave was triggered when some explosive gases, that
accumulated in the restaurant throughout the night, came in contact
with a fire source.
Police commissioner, Mr Prasun Mukherjee said: “That the blast was a
result of an explosive material planted by an outsider can be safely
ruled out. It was a heat wave which was triggered off when a gas came
in contact with a fire source causing the blast. The heat wave forced
its way out through the weakest opening of the restaurant ~ the iron
shutters. The Closed Circuit Tv recordings reveal that the blast took
place exactly at 9.34 am. It was at this point in time the heat wave
destroyed the CC Tv and it went off”.
One probability is that an inert gas Freon, used as a cooling agent in
AC machines, had leaked from the AC machine. There are three AC
machines inside the restaurant having a total capacity of 41 tons to
keep the total restaurant spanning over an area of 2,000 sq ft, cool.
When the electrically operated gas burner was switched on a fire ball
was triggered in the kitchen which sparked off the heat wave. A senior
fire official opined that an ideal explosive mixture might have formed
in the AC ducts after some combustible material deposited in the filter
due to non-cleaning over a long period of time.
It may also be possible that Methane gas formed in the sewerage system
of the restaurant’s kitchen which was choked. Methane gas had
accumulated over the night and it exploded when it came in contact with
Mr Mukherjee said “If the accident would have taken place a few hours later or on a weekday it would have been a disaster”.
Check out this schematic picture from the Telegraph: [Story: Big Mac Blows up…]
How can that happen? Here’s an explanation:
One wonders what safety norms were adhered to?
Also how common are air conditioner blow ups in International brand chain restaurants such as McDonalds?
How unsafe are CFCs? Not just for environment, but also for potential hazards such as the one we faced at kolkata?