What makes something flamable?

Question

I know it's considered flamable if it catches fire but what makes it catch on fire? Why are some things not flamable?

Answer 1

Different materials have different temperatures it takes for them to ignite. Think about how how you would need to get a piece of paper to catch fire versus...a piece or metal. I think some items can be treated with various chemicals that will decrease their flammability.

If you're really interested in learning about the science behind it, I suggest visiting your local library!

Answer 2

Three factors must co-exist for a material to be flammable:

1. A fuel. 2. An oxidant

(usually oxygen, O2), and an ignition source (a match, a spark, something that raises

the "local" temperature above a minimum value). Remove one of the three factors and a

material will not be flammable. Having made that generalization, sometimes some

component may serve as two of the functions. For example, there is a temperature,

called the "auto-ignition" temperature at which a substance will burn without the

requirement of some ignition source. And some combination of substances may use

another oxidant than O2 (for example, H2 + Cl2 ----> 2HCl) is explosive in the

presence of visible light.

The U.S. Department of Transportation (DOT) defines a flammable solid into three broad

classes of materials which are: desensitized explosives; self-reactive materials that

give of extreme heat when combined with oxygen; and readily combustible solids such as

matches.

The U.S. DOT defines a flammable gas as any material which is a gas at 68 degrees F or

less and at atmospheric pressure. It is ignitable when in a mixture of 13 percent or

less by volume with air.