Last Thursday we had our Compartment Fire Behaviour Training session at Halesworth Fire Station, courtesy of the Training Department.
The whole point of this training is to let us see, first hand, how a fire develops and then practice how to cool some very hot gases from within the compartment and then advance to extinguish the fire.
And the compartment we use is basically a 40 foot shipping container that has been modified to withstand hundreds of very hot fires.
So what's the point of all this? Well, any room in a house that has its doors and windows closed and also contains a fire is a compartment fire and should be treated with a great deal of respect.
If a room is all shut up the fire starts to starve itself of Oxygen and seemingly goes out. The Triangle of Fire has lost one of its three elements – Heat, Fuel or Oxygen. But the room is quite possibly full with superheated gases just waiting to be fed with Oxygen. Open the door and you have a good chance of creating a backdraught and we're not too keen on them!
On to our first practical exercise with full fire kit and BA sets… We entered the 'hotbox' and knelt down near the front as the doors were shut behind us. A small fire was then lit in one corner, just like a bin fire and we watched it rapidly develop, firstly pyrolysing the nearby wooden walls before they flashed over.
You then start to see the gas layer forming near the ceiling and then move down towards you.
We then repositioned ourselves a bit further away from the fire to see the effects of increasing and decreasing the supply of Oxygen to the compartment.
It was interesting to witness close up how quickly a plastic bottle melted and pyrolysis of a cardboard box then rapidly changed to flashover. A plastic bottle full of water faired slightly better because the water was able to absorb some of the heat.
After our Fire Service picnic it was our turn to practice entering the compartment, advancing on the fire and 'extinguishing' it. For practical purposes we couldn't extinguish the fire completely as other teams had to follow on and repeat the exercise.
After cooling the outside of the door and giving a cooling spray to any hot gases escaping at the top of the door, we made our entry. Richard Belsey opens the door and I crouched down in the doorway giving an 'umbrella' pulse on the the hosereel branch to cool gases right above our heads. We both have a quick look in the immediate vicinity in case there are any casualities within easy reach. Take a look at the fire and assess whether to fight the fire from the doorway or whether to enter and approach the seat of the fire.
We decide to enter the compartment and so I give another 'umbrella' pulse to cool the unburnt gases. Straightaway we move forward on our knees and I give another protective pulse above our heads. Just this small pulse of water is enough to dramatically reduce the temperature in our immediate vicinity. The water goes up but it doesn't come down… If too much water is sprayed above our heads it will turn to steam and start to poach us like 'boil in the bag' firefighters!
We're now near enough to the fire to attack it – about 4 metres away from the raging fire which is reaching temperatures of 600oC. I point the hosereel branch at the burning gases above the fire as if I'm about to fire a pistol. A well aimed 2 second 'squirt' and the interior of the container goes dark. The gases have been cooled enough to knock the fire right down. In a real fire we would now give ourselves another cooling 'umbrella' then rapidly advance to the seat of the fire and put it out. But for the exercise we wait a few seconds and see the flames start to lick across the ceiling again, rolling towards us.
Job done and we withdraw to allow another team in.
As the BA teams rotate the fire is allowed to grow and you can really start to feel the increased temperatures. The instructors then show us the old way of hitting the fire – lots and lots of water. That really is 'boil in the bag' time and not a very pleasant place to be.
After four turns at attacking the fire it feel like it's time to call it a day… Time to take on more water and food, make up all the equipment and head off back to Lowestoft.
An excellent days training especially borne out of the fact there were no moans and groans from any of us. So a big thank you to Training Department and our three instructors – Darren, Roy and Phil.
There were still areas of the fire that we couldn’t easily reach. No crews were going to be committed to the building due to the possibility of collapse. The best we could do was to position ground monitors to send jets of water into the interior of the cold stores. Every so often we would venture back to see the effect of the water or to shut the water off and reposition the monitor. 
And that was about it for us. White Watch from Lowestoft South relieved us at around 12.30, home, shower and now try to get on with some of my own work…
