On the 25th November 2010 DoseTech Special Risk Fire Protection met with the Milnerton Fire Department, Chevron Refinery Fire Team, Koeberg Nuclear power station fire team and various fire protection consultants and installers at the Koeberg power station fire training centre to demonstrate a crude oil boil over.
For those of you who are not familiar with a boil over, it's pretty scary if you're not prepared for it.
The theory behind a boil over is that, when water enters a fuel storage tank, after some time it sinks to the bottom of the tank. The majority of fuel storage tanks have drainage points to remove this water but if too much water accumulates and a tank surface fire breaks out the water can be heated to the point of changing to steam. Once water turns to steam it expands 1600 times and the level of the fuel or oil in the storage tank is raised.
If the fuel level in the tank was high to start with the expanding steam can cause the tank to over flow and your surface fire quickly becomes a running fire. Not nice.
Our demonstration at Koeberg was a controlled boil over and as such we were well prepared for the expected results.
A 200L drum containing crude oil run off/slop was placed into a steel bund, approximately 2m x 2m, which was itself contained in a bricked bund area of 4m x 7m. 25L of water was added to the crude oil drum to form a layer of water in the bottom of the oil drum.
At 1PM on Thursday the 25th the surface of the oil drum was lit, with the help of some diesel poured on top of the oil, and the surface of the drum was allowed to burn. And for 40 minutes that's all it did.
At 42 minutes a crackling noise could be heard as the steam started to form and within a few seconds the crude oil started to boil over the side of the drum with spectacular efficiency. A roar of applause erupted from the gathered crowd as the fire continued to spread at a rate of knots.
Fortunately the Chevron Fire Department had matters well in hand and were prepared to extinguish.
We allowed the fire to burn for about another 2 minutes before starting to extinguish with a 1% AFFF Sthamex foam concentrate dosed into the water supply by our FD1000 adjustable FireDos foam pump. End of line the Firemen made use of our Akron Turbojet hand held nozzle complete with foam aeration tube. Water flow was set at 115 L/min.
Within 2 minutes 23 seconds the fire was out and we could breath a sigh of relief for a job well done.
Below are some photos of the boil over.
DoseTech (Pty) Ltd Managing Director
083 251 9346
mgf@dosetech.co.za
Keep an extinguisher in every part of your home where fire might occur-especially in the kitchen, living room and laundry room.
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