Thank you to everyone who's offered feedback on my recent columns about Firefighter 1, the training course I've been taking after joining the volunteer fire department. Since people seem interested, I'm happy to keep writing about it.
Last week I mentioned that we were about to cover ground ladders and ventilation, which we got lectures on when it was dry outside and did practicals on when it was raining. As the instructor said, "If it ain't raining, it ain't training!" It took a couple of days for my turn-out gear to dry.
But it was worth it. Ventilation is the fine art of removing smoke and other bad stuff in the air from a building. This is why you see firefighters chopping holes in a roof or breaking out windows. It's not just random mayhem, but a carefully planned element in attacking a structure fire. The planning comes in because if you ventilate too early, you risk spreading the fire, and if you ventilate too late it's, well, too late.
The basic idea is to ventilate at the same time that you enter the building with a hose team, so that you can clear the air and put out the fire all at once. I was especially interested to learn that if you put water on a fire without ventilating, you can actually make things worse-and endanger the firefighters handling the hose. Superheated steam from the heat and water, if it has nowhere to go, can roll over the firefighters and cut them off, so ideally you ventilate behind the fire and push the smoke and steam out of the structure through the opening (a broken window, typically).
One of the most dangerous jobs is roof ventilation, and so we've been working hard on learning how to do it properly. Here the idea is to create an upward draft that clears smoke out through the opening, which acts as a chimney. The most common tools for doing this are a rotary saw or a chainsaw.