Standpipes, Alternative Agents
STANDPIPES
Put simply, standpipes are plumbing strung throughout the inside of a building that provides outlets for firefighters to hook up to. You will find these in any building where pulling a hand line from the truck is not going to suffice, like tall office buildings. Just like everything else in building construction, there is more than one type:
Class I standpipe- This is for FD use only. The outlets on the standpipe are 2 1/2" male outlets and a valve to allow water to flow. Firefighters enter the building carrying a gated wye, and as much 1 3/4" attack line as they can (this is also called a High Rise Pack ). Double check with your local department about how they approach Class I standpipes, and how high rise situations are handled.
Class II standpipe- Designed for use by civilians. The outlets are usually preconnected to a 1 1/2" hose. This system is not intended to be used in an IDLH (Immediately Dangerous to Life and Health) environment and are only intended to put out small fires or to hold off a fire until the FD arrives.
Class III standpipe- Sort of a combination of Class I and II, the Class III standpipe have 2 1/2" outlet for the FD, and smaller outlets that occupants can hook into (usually 1 1/2"). The civilian outlets will often times have the flow reduced to ensure that they can control the hose.
STANDPIPE FLOW & SUPPLY
Many standpipe systems are set to run at 65psi, when the combination nozzles that most FDs use are effective at 100psi or more. There are a few ways to approach this problem. Some fire departments will carry special low-pressure nozzles for high rise fires just for this situation.
Similarly to pressurizing the sprinkler systems, the engine outside the building can (and will) hook into the FDC to provide pressure for the firefighters inside. If you get lucky, the building will have a pump that will provide extra pressure as well. You'll need all the help you can get when it comes to pumping water vertically- especially if you're more than a few stories high.
ALTERNATIVE EXTINGUISHING SYSTEMS
When water is a bad idea for fire protection, all sorts of innovative systems come into play. Situations with flammable liquids or tons of electronics are the last place you want to dump water, so they use other systems. Crazy, eh?
Wet & Dry Chemical Systems
You'll see these quite commonly (especially in restaurant kitchens and gas stations because they work wonderfully against flammable liquids). Dry chemical systems use the same agent as a dry chemical extinguisher (B:C-rated), and will be pressurized with nitrogen or CO2. Wet Chemical Systems are the more modern method for kitchen fires. They're more effective than dry chem, and easier to clean up. Both of these systems should have a way to shut down the appliances and fans in the area.
Clean Agents
There are plenty of "clean agent" extinguishing systems (also called Halogenated Agents), but the big name here is Halon. They're no longer implemented due to a government ban on chlorofluorocarbons (Freon), but are still very much in existence.
Halon actually breaks the chain reaction that fire needs to perpetuate itself. It works extremely well, even at low concentrations. It produces no residue, and has no lasting effects. Other than that whole o-zone destruction part, it's a freaking miracle. There is still Halon available for those who already have a system in place and need to recharge it, and alternatives to Halon have been developed in recent years.
Carbon Dioxide
Carbon Dioxide (CO2) acts a lot like a clean agent system. The true difference is that instead of breaking the chemical reaction like Halon does, it smothers the fire by displacing the oxygen. These systems require a large quantity of the gas because it has to flood a room completely.