If I recall correctly, one of the pieces of advice that Gary Gygax gave about Dungeon Mastering was to read omnivorously, including non-fiction. Since I woke up this morning thinking about torches and flammable things, here are a couple of minor thought-offerings that, even if they don't directly affect your game, might give you some ideas. They concern the mundane and lowly torch.
Pitch is one of the substances used in making torches (I looked this up). This stuff can be derived from petroleum (in which case it is called "bitumen") or from resin. Heating wood without burning it causes tar pitch to drip away from the wood, and this is also, by the way, what causes wood to turn into charcoal. I never knew that -- I'm glad I stumbled across it.
In general, torches have been made not with a single stick of wood, but with a bundle of sticks (or reeds, or bamboo, etc), usually green rather than cured, tied together. Pitch or animal fat is used at the end (impregnated into cloth or moss) to slow down the rate of burning and keep it from blowing out too easily.