fire questions

[tyr567]

1. What class of fire is a light yellow color?

2. What class of fire is a darker yellow/orange color?

3. What type of hose would you use to extinguish a Class B fire?

[Rolig Loon]

The more fuel-rich a flame is, the yellower (or oranger) it is.    An orange flame also contains a lot of very fine carbon particles, which radiate in the yellow-red end of the spectrum.  The more oxygen-rich it is, the clearer and (generally) the hotter the flame is.

The color of a fire is not related very closely to the class of the fire.  Fires are designated class A, B, C, or D on the basis of the type of fuel that sustains them.  The color of the flame depends on the fuel-air ratio and only weakly on the type of fuel.

A Class B fire is sustained by burning flammable gases or liquids like oil, paint, or grease.  You would never try to put out a Class B fire with water or another liquid that would tend to spread the fire, although you could cool and smother a Class B fire with a dense mist.  The proper way to stop a Class B fire is with carbon dioxide or a dry chemical extinguisher, not with most things that you would dispense with a hose.

[Griffin Ceawlin]

Are you cheating on your firefighter exam?

[Nyll Bergbahn]

Rolig, when he's talking about the hose here, I think he probably means the short fixed hose from the fire extinguisher trigger handle to the nozzle and not a typical fire engine or hose reel water hose but he should be asking what type of extinguisher not what type of hose.

I always recommend foam extinguishers (most are now AFFF) when faced with possible flammable liquids fires although you have to be careful to smother the fire and not push it out further and dry powder is also very effective but can have a scattering effect from the discharge. I would rarely if ever recommend CO2 for flammable liquid fires even though it can be effective and doesn't leave a residue. Foam and dry powder are just more effective and a fire will not reignite as it may do with CO2 once the gas disperses. Use of CO2 is also restricted. For example, CO2 is pretty useless on outdoor fires and while it will work on some internal flammable liquid fires, it should never be used in very confined spaces (risk of suffocation) or on flammable liquid fires in kitchens such as from deep fat fryers (the gas discharge is likely to spread the burning fat or oil). Foam, fire blanket or an Ansul auto wet chemical fire suppressant system are the ones to use in kitchens but these would be Class F fires anyway not Class B.

Strange question for SL though tyr567, unless you are building an airport or heliport and want realism. In that case you will want some fire engines as well carrying both water and AFFF for foam production to deal with aviation fuel fires.

Here is a useful website for you: http://a.cdn.fpaa.com.au/information/docs/safety_extinguishers.pdf

[Rolig Loon]

Thanks. Yes, this was one of the stranger questions to see in SL. I figured that the OP was asking more out of personal interest than for any in-world reason. I responded as a chemist, where I have expertise, rather than as a fireman. Your firefighter's knowledge is more appropriate here.

[Nyll Bergbahn]

hehe I'm not a firefighter and hopefully never near a flammable liquids fire but I do need some expertise in extinguishers for my job! You could be right, just a general question.