Plasma Generators

An Emergency Fire Extinguisher being developed by the Defense Advanced Research Projects Agency (DARPA) works using generated plasma fields to actually bend flames to create an escape pathway. In order to understand this concept, you need to know that flames are a form of partially ionized plasma and can be manipulated using electrical fields. Researchers are working on creating devices based on this principle and as mentioned, may be able to actually bend the flames to create escape corridors for a safe path of egress in the event of fire. Researchers have already shown that electrical fields can extinguish methane fires.

DARPA's next step is building a prototype electric fire-suppression system for the compartment of a Humvee-size vehicle.

Source: July 2010 Popular Mechanics, Page 18

Background Information to Understand Fire

Firefighters have always depended on water to extinguish fires, but technology and science may provide us with better and more efficient tools to mitigate incidents involving fire. It's probably an important thing for folks to fully understand the thing that we fight and are named after...

Mankind has been battling and learning how to harness and control fire since the beginning of time. The ancient Greeks believed that fire – along with earth, water, and air – was one of the four essential elements that made up the world. We now know that the world's a lot more complicated, with over a hundred elements of matter which can be combined in a tremendous variety of ways. This might leave you wondering where fire fits in to the big picture...

What exactly is fire? 

Watching a flame dance through the air, you might conclude that fire's a gas, like oxygen or carbon dioxide. It's not. Fire can burn fuel that's a gas, or a liquid, or even a solid – as in the case of glowing charcoal. But the fire itself isn't any of these things. In fact, fire isn't anything at all. It's not its own type of matter; it's something that matter can do. Fire is a chemical reaction. 

A fire needs oxygen and some kind of fuel. This fuel – whether it's candle wax, wood, or gasoline – usually contains big molecules that have carbon atoms inside them. You can think of these molecules as little containers of energy. When they're allowed to combine with oxygen, this energy is released as heat and light. 

Fire is a rapid chemical reaction known as oxidation. Inside a fire, oxygen molecules break bigger molecules apart into carbon dioxide and water vapor. All the heat and light of a fire comes from big, carbon-based molecules combining with oxygen. 

So what is fire?

It's not the fuel or the oxygen or the heat or the light. Fire is what happens between all these things! 

The Fire Tetrahedron 

There are four elements that maintain the combustion process, and the absence of any one of them will prevent a fire. The removal of these elements is what firefighters understand better than anyone. We have all memorized the following: 

* The reducing agent (fuel) may be removed from the site of a fire to curb its spread. In forestry, controlled burns are used to keep the available fuel supply low, so that intense fires do not occur. Sometimes you can stop the flow of a liquid or gas fuel. In the case of a burning pipeline, the flow of fuel can simply be turned off. 
* An oxidizer (usually oxygen) is needed to react with the fuel. Sand, foam, or gases which do not support combustion (such as carbon dioxide) may be used to stop the flow of oxygen to a fire (smother the flames). In particularly violent fires, such as those of the Kuwaiti oil wells during the Gulf War, explosions may be used instead. 
* Heat is what allows liquid fuels to be vaporized, and solid fuels to undergo pyrolysis. Solids and liquids do not burn directly, they must first be converted into a gas through pyrolysis or vaporization. Removal of enough heat prevents fuels from burning. Water is uniquely effective at removing heat due to its high specific heat capacity. 
* The chemical chain reaction is what perpetuates combustion; compounds such as halon extinguishing agents cause the chain reaction to be broken. The precise mechanism is not known, but it is thought that the halogen radicals end the reactions that support combustion.

Technology is dominated by two types of people: those who understand what they do not manage, and those who manage what they do not understand. - Archibald Putt