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Classes of Fire

In Europe and Australasia 6 groups are used:

* Class A: Fires that involve flammable solids such as wood, cloth, rubber, paper, and some types of plastics.
* Class B: Fires that involve flammable liquids or liquifiable solids such as petrol/gasoline, oil, paint,some waxes & plastics, but NOT cooking fats or oils.
* Class C: Fires that involve flammable gases, such as natural gas, hydrogen, propane, butane
* Class D: Fires that involve combustible metals, such as sodium, magnesium, and potassium.
* Shock Risk (formerly known as Class E): Fires that involve any of the materials found in Class A and B fires, but with the introduction of an electrical appliances, wiring, or other electrically energized objects in the vicinity of the fire, with a resultant electrical shock risk if a conductive agent is used.
* Class F: Fires involving cooking fats and oils. The high temperature of the oils when on fire far exceeds that of other flammable liquids making normal extinguishing agents ineffective

In the U.S., fires are generally classifed into four groups: A, B, C, and D.

* Class A: Fires that involve wood, cloth, rubber, paper, and some types of plastics.
* Class B: Fires that involve gasoline, oil, paint, natural and propane gases, and flammable liquids, gases, and greases.
* Class C: Fires that involve any of the materials found in Class A and B fires, but with the introduction of an electrical appliances, wiring, or other electrically energized objects in the vicinity of the fire.
* Class D: Fires that involve combustible metals, such as sodium, magnesium, and potassium.

A fifth group, Class K, is sometimes added. It refers to fires involving large amounts of grease or oil. Although, by definition, Class K is a subclass of Class B, the special characteristics of these types of fires are considered important enough to recognize.
 
/grabs oxyacetylene torch

/grabs 12" magnesium rod

/lights end of magnesium rod

....

/throws magnesium rod into thread

/runs
 
There are other hazardous combinations one must remember.

For example a fire near switchgear can cause a fault as a flame is conductive. Fires cause power outages near transmission lines for this reason.

Fires near vessels containing flammable liquids (propane tank, for example) can cause a dangerous condition. Normally a relief valve will vent the excessive pressure. The venting fuel may ignite or it may not. If there is sufficient heating, the rate of expansion in the vessel can actually exceed the escape capacity of the relief system and the vessel can rupture. This is known as a BLEVE and is extremely dangerous.

 
Originally posted by: sharkeeper
There are other hazardous combinations one must remember.

For example a fire near switchgear can cause a fault as a flame is conductive. Fires cause power outages near transmission lines for this reason.

Fires near vessels containing flammable liquids (propane tank, for example) can cause a dangerous condition. Normally a relief valve will vent the excessive pressure. The venting fuel may ignite or it may not. If there is sufficient heating, the rate of expansion in the vessel can actually exceed the escape capacity of the relief system and the vessel can rupture. This is known as a BLEVE and is extremely dangerous.
Click to expand...
I've always wanted to put one of those small Coleman propane canisters into the fire...

But a closed bottle of beer is big/loud enough. I'd be afraid.

What would one expect? 😉
 
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