Wednesday, April 29, 2009

Cold Water Rescue

Training was not too tasking last night. Mostly what we're focusing on right now is knots and ropes. This should have worked out well for me as I'm an avid amateur rock climber, but it turns out that tying knots in fire gloves while under pressure is just a bit different from tying knots on a cool breezy day at the base of a rock face. I'll get there, though.

One of the more interesting things we got to play with was the cold water rescue suit. This is the piece of equipment that a firefighter dons when they need to go pull somebody up who has fallen through an iced over body of water. It's this big red piece of rubber that fits your body like a glove, stretching to fit all the way over your head, reminding me of a kid's onesie with a hood, entirely made out of 1-inch-thick-waterproof-thermal-insulating-material. Attached to the back is a large D-ring that a rescue rope is tied to so you are tethered to shore by your crewmates who are manning the rope, and in your pocket you carry an extension of that rope with a carabiner at the end to clip around your patient before pulling them out.

Once you're in, you have to start moving over the ice so that your weight is as spread out as possible, otherwise you'll just break through the ice in another spot, making it hard to get to the victim. In essence, they've found one of the better ways to do this is to lay flat on your side gripping your tether over your head and just to roll out to your victim like a bakers rolling pin. We practiced this in a grassy area, rolling out to rescue each other from the middle of a field, and it's a bizarre feeling. The suit holds air well, so as you roll from one side to the other, the pressure can change in the area around your head causing your ears to pop; your fingers don't move right because of the thickness of the material. I can only imagine how much tougher this would be on a cold day, moving over slippery ice, into a freezing hole in the center, all under the pressure of getting to a person who only will last mere minutes in that sort of environment.

Another interesting fact: we are taught a hand signal that means "I need help!". Sticking one arm straight up in the air means that you are in trouble and require assistance. My thought is, how is anybody going to help you? There's only one suit on the truck. You'd at least have to wait until the next due engine arrived for anyone else to get out there and lend a hand.

Firefighting is not always about fire, but it sure does seem to involve a lot of running straight into places most people should never go and doing things most people would be crazy to attempt.

What a cool job.

Saturday, April 25, 2009

Water Supply for the layman

Without water, it's going to be pretty hard to knock down a fire; that's why you need so many more people to fight a fire than just the few people running into the building with hoses. Where does all that water come from?

Well, you might say, the fire engine of course! That's where the hoses are coming from, so that's where the water is. Great job, you'd make an excellent detective! But consider this: each one of our fire engines contains 750 gallons of water. That sounds like a lot, but it actually won't last as long as you thing. One regular hand line (a hose carried into a building) is usually configured to spray 125 gallons per minute. That's about 6 minutes of water for 1 hose; that's not that long, and it's not likely that you're fighting a large fire with just one hose. On anything larger than a regular room-and-contents fire, you're going to need a little more than that 750 gallons showing up in the first engine.

That's one of the reasons you send more than 1 fire engine to a fire: you need to be getting your water somewhere, and the engine pumping water into the house (the "attack" engine) doesn't have time to find out where the best place to get water is. So the next engine to show up (the "supply" engine) hooks up a large supply hose to the intake of the 1st engine and sends all the water in it's tank shooting into the tank of the attack engine. Alright, now you have about 1500 gallons of water, that's pretty good. Except you might have 3 hoses being used by this point, so you could possibly be using somewhere around 500 gallons a minute. In fact, some of the larger deck guns can shoot up to 1000 gallons per minute just by themselves. If you have a hydrant around, that's super, and in most metro areas you do. A good hydrant can flow over 1500 gallons every minute by itself, which is pretty good. However, not all hydrants have that level of pressure, and if you're in a more rural area you may not have a hydrant near enough to hook the supply engine into. Now what?

Here's where the well-oiled machine of teamwork comes into play, and it's a pretty impressive operation when it's running smoothly. Picture this:

The attack engine is pumping water onto the house as fast as it can. The supply engine is sending every drop it has available into the tank of the attack engine. By the supply engine are 2 large "fold-a-tanks", big steel frames with tarps inside of them that basically form a small pool that can hold over 2000 gallons of water. The supply engine has a suction hose dipped into the nearest tank and is sucking water in from it, but how is the water getting into the fold-a-tank?

From the tankers. Tankers are big firetrucks who's main job is to shuttle large amounts of water from one place to another. Each one (on our department) holds about 1500 gallons of water, and can dump it all into one of these tanks in about 30 seconds. So you get 2-3 of these tankers that are driving a circuit to the nearest hydrant or other water source: Fill up the truck, drive to the supply engine, dumpt the water, drive back to the water source. As long your water source doesn't go dry and your trucks don't break down, you can now put water on the fire all day if you need to. It's a marvel to watch when it goes right and this system is clicking like an oversized bucket brigade.

So you see, the heros running into the building are depending upon a large team on the outside to keep them in action. Pretty cool, huh?

Friday, April 24, 2009

New Article on Firelink

I have a new article that's been posted on firelink.com, this one regarding integrating into the crew as the new guy. Check it out at the following link:

The Brotherhood

Thursday, April 16, 2009

My kind of firefighting

This week is all about pumps. Maybe that doesn't sound that exciting to you, but for me this is a great week. You see, most of the necessary skills for firefighting have to do with physical ability. You need strength to move a victim, balance to climb and work from a ladder, endurance to spend time working in the heat of a fire environment without collapsing. I'm not BAD at that kind of thing; in fact, I'm in pretty good shape. But working the pump on a firetruck is mostly about simple math and abstract thought -- yes!

For those who are not part of the fire service, you should know that using the pump on a firetruck is more than just turning it on and letting the water flow. There are at least 8 points from where an engine can be discharging water, and each one of them has to have their pressure adjusted properly for the task at hand. Let me give you a simple example:

For a house fire, you might have 2 lines deployed off of the truck, both 1 3/4 inches in diameter. One might be 150 feet long because it's going in through the front door, the other might be 200 feet long because it's being taken in through the side of the house. Each one needs water pressure of 100 PSI (pounds per square inch) at the nozzle, and they each are running 125 gallons per minute of water through the hose. How much pressure does the pump need to be discharging at?

Well, when you push water through a 50ft stick of 1 3/4 inch hose at 125 GPM, it loses 12 PSI. So if you are pumping 112 PSI, by the time it reaches the end of that 50 foot length, it's down to 100. The longer of the 2 hoses deployed off the truck is 200 feet, which is 4 50 foot lengths, so the pump will have to be discharging 148 PSI to make sure that the longer hose has enough pressure. However, the shorter hose (the 150 foot one) only needs 136 PSI to have 100 PSI at the nozzle, so you would have the pump discharging at 148 PSI, and gate the shorter hose down to 136.

Now, there are many more complicated scenarios than that when you get into having multiple hoses of different sizes at different flow rates, and when you start incorporating things like standpipes to raise water up to a higher story in a building, and managing the intake into the truck at the same time from the water supply operations. This is the kind of material a geek can really get into.

Moral of the story: don't go thinking that firefighters are just brute muscle, they need some brains to get things done as well.