|Professional Services||Second Signal||Presentations||Andrew's Blog||Support|
CAFS (Compressed Air Foam System) is a fairly new technology for the fire service. Some people swear by it, and other people don't like it at all. Until today I held no real opinion as I hadn't used it, though I'd expressed some trepidation.
At just after 4 this afternoon, Cumberland toned out for our RIT to respond to the next town over, Yarmouth, for a possible structure fire. By the time we were on the road, Yarmouth had gone to the All hands, and about the time we got there they went to a 2nd Alarm. Most of the reason for those escalations were manpower related. This was an old New England residential home with lots of additions, very little fire control, plaster and lathe walls and ceilings, and a fuel load inside that was pretty amazing.
Although we'd responded as RIT, on arrival they were so short staffed that we were redirected to the attack line. That's a really big no-no usually, but I wasn't in change and half dozen chiefs on site had already called for a replacement RIT which was due very shortly. In any case, the four of us took a line that was already in place to the front door connected to one of Yarmouth's engine companies and after checking our gear and making sure we were "fully encapsulated", snapped in our regulators and entered the building.
The firefighting wasn't terribly glamorous. Most of the first few minutes I spent just a few feet into the structure hauling line from outside and pushing it through to the guys on the nozzle so they wouldn't get caught short as they went around corners or stairs. After a bit I was in what I guess was a living room or front room when I was handed a line that was being manned by another group who was exiting the building for new air bottles. I had one guy with me who was an officer of one kind or another from Yarmouth, and together we went through a door (and I mean we went through the door, not just the doorway) and into a room with a bit of fire still in it.
Here's where the CAFS comes into play. The line I was handed was a CAFS line. Instead of water or solution of 3% class A foam in water what was coming out the end of that nozzle when I pulled it open was mostly air. It should have been a well mixed air-foam mixture but it wasn't. There was some foam but mostly it was air. I don't know if it wasn't set right on the engine, if someone hadn't opened a valve or whatever. Maybe nothing was wrong with it at all, and its just the way the stuff behaves. All I can say is that what came out of that nozzle didn't come close to making me happy. When you put water on fire it turns into steam. In the process it expands to thousands of times its volume and takes away a huge amount of heat in the conversion. CAFS, in theory, traps the heat in the structure of the foam, releasing it slowly as the foam dissipates.
What has always worried me about CAFS is what happens if you don't get the mix right. I know those guys are trained on it. Its all they use. I also know that when you're short water CAFS can be a real gift. In Cumberland, we practice tanker shuttles. We do it a lot. At least once and often twice a year we practice a big multi-town tanker shuttle. We do the practice because we don't want to be in a situation where we're short on water. People will also tell you that CAFS gives you a lighter and easier to handle hose line. I don't really find that to be the case.
The long and short of it is that when I opened that nozzle up and took aim at a hot spot the effect was as much like blowing air on the fire as anything else until the mix was better and then the foam got a little better. At no time did I get the rich, thick foam I get with the Class A off our units. I know those who swear by the stuff will tell me the line needed to be bled before we entered the building. To them I answer that this line was already in the building and had already been used. Water would have instantly knocked out what little fire was left there in that room. It would have converted to steam and that would have been it. The foam sort of worked too -- but it also blew the fire around a great deal and didn't so much "extinguish" as it just "went away" in a way that left me very little confidence that it would stay gone. It left things hot and dry with a little bit of foam around. It didn't leave things saturated and cool.
I haven't been doing this long enough to be one of those crusty old leatherheads who say things like "water puts out fire, not foam". I think any reader of this site nights I'm not resistant to new technology. Still, here's a case where I'll stick with what works -- which is water -- for as long as I can.
Please wait while your document is saved.