I’d agree that fires should go through stages. Starting one without an accelerant should take time, and be very prone to failure in the wind and rain, then it would be a small fire as it begins to consume the available fuel and gradually swell to a level moderated by the amount of fuel available and what kind was available. This would definitely help with the ‘Instant tactical shrub fire’ scenario, requiring a bit of preparation to execute or the proper starting materials.
On the subject of destroying bodies with fire, I found a neat discussion about a forensic research group that burns bodies for science: http://www.sott.net/article/185067-Body-burners-The-forensics-of-fire :
"So what happens after they light the fire? “A human limb burns a little like a tree branch,” says John DeHaan, a fire investigator at Fire-Ex Forensics in Vallejo, California, who works with Pope. First, he says, the thin outer layers of skin fry and begin to peel off as the flames dance across their surface. Then, after around 5 minutes, the thicker dermal layer of skin shrinks and begins to split, allowing the underlying yellow fat to leak out.
“That’s when the fire gets most interesting,” says DeHaan. Body fat can make a good fuel source, but it needs material such as clothing or charred wood to act as a wick. Like that in a wax candle, a wick absorbs the fat and pulls it into the flame, where it is vapourised, so enabling it to burn.
Assuming there is sufficient wick material, the body can sustain its own fire for around 7 hours. During this time, the heat causes muscles to dry out and contract, making the limbs move and sometimes adopt characteristic postures. Bone takes longer to burn, so by the end the skeleton is usually laid bare like a charred anatomical model, coated in the greasy residue of burned flesh. "
So given the right conditions, it seems a body can provide it’s own fuel, read the last few paragraphs for some expansion on the topic. However, the article has this to say about using gasoline:
“A related misconception is that flammable liquids alone are sufficient to destroy a body. “If you dump gasoline on someone, it will burn for about a minute,” says Pope’s colleague John DeHaan of Fire-Ex Forensics in Vallejo, California. “That’s enough to cause localised burns, but not enough that the skin will split and the body fat gets involved.” The body needs to be exposed to fire for about 5 minutes for that to happen.”
It’s an interesting read and gives a lot of food for thought.
