Fire Fighting 101:
Fires are classified into 4 catagories lables A,B,C,and D.
Alpha class fires are anything that will leave an ash. People fall under this catagory and are fondly called "screaming Alpha". Paper, wood, coal, fabric would all be examples of an Alpha class fire. They will also initially give off a white steam type looking smoke. My tent was an alpha.
Brovo class Fires are "usually" a liquid, and some may leave an ash. Solvents, paint, thinners, and the gas that Justin demo'd for us all fall under this class of fire. Thanks again to Justin for brining this to our attention.
Charlie class fires are electrical fire. These don't need much explanation. However, there are a whole new set of rules for dealing with this type of fire.
Delta class fires are exotic matirial fires. These again require a whole new approach to put out. For those who camped out Friday night and seen me ignite that magnesium (sp?) seen that applying water to that type of fire is a VERY bad idea. There are several materials that fall under this class, but for several reasons I doubt that the 4wheel types will not come in contact with. Unexploded boms for example.
How to put them out:
A class: water, sand, pouder style extinguisher all work fine. Thise is where those letters on the side of a extinguiisher mean something. Those ABCD's are all referign to the class of fire they are intended for.
B class fires: The same extinguishers work on this fire but you MUST remember that unlike an A class, a high pressure extinguisher can spread this type of fire. Since its a liquid fire. Also remember that the liquid will usually be absorbed into the enviroment, such as sand. You may think the fire is out, but there will be fresh fuel waiting to be lit as it becomes a vapor. Reflash is a HUGE issue with these fires. The most effective type of extinguisher here is a foam type. After the fire is out, the foam stays in place and acts as a barrier between the fuel and the air. Thes types will have a very dense black smoke. Think of tires on fire. Tires are a class B because they will liquify as they burn.
C class fires are electrical and although you have been taught not to use water on these type you in fact can. However, you can't use a solid stream, btu you can use a spray style or a mist. Obviouly this is NOT your first choice. HALON was developed for these types of fires. Be VERY careful with HALON. It operates by displacing the oxygen from the enviroment. If it were to bo sprayed into a persons face it "could" be fatal. NEVER USE HALON IN AN ENCLOSED SPACE UNLESS YOU HAVE A SELF CONTAINED AIR SUPLY.
Also, like a class B, reflash is a problem with these. Once its out, post a fire watch until teh power supply has been cut off and the fire site is cool to teh touch. Obviously your first priority here should be to kill the power supply, but sometimes this is not an option and are forced to deal with the fire aspect first. These will have either a light black, or white smoke.
D class fires are a bit tricky and this why ABC type extinguishers are more common than ABCD types. I doubt if you will ever see a class D. I would suggest that if you think its a D class that you simply evac and call 911. These types of fire are usually very toxic so don't try to be a hera with them. RUN.
I would say that a ABC extiguisher is all that most of us will ever need. As some of you have found out, the small extinguishers have only about 10-15 seconds of life to them.
When trying to put out a fire, aim for the base of it and use a left right sweeping motion. BE VARY AWARE OF WIND DIRECTION AND DO NOT GET IN THE FIRES PATH OR SMOKE. Most some is very toxic.
That concludes todays lesson. You can that the USN for this lesson.
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