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A fire pit or a fire hole can vary from a pit dug in the ground to an elaborate gas burning structure of stone, brick, and metal. The common feature of fire pits is that they are designed to contain fire and prevent it from spreading.
Pre-made fire pits are the most common form of fire pits and can be purchased from a store. These are commonly made of pre cast concrete or metal and/or a combination of metal table and stone. They are usually natural gas, propane ( LP ) or bio ethanol. Wood burning fire pits made of metal are also quite common but under increasing scrutiny due to fire bans and air particulate emissions. Natural gas and propane burners in these sort of pre fabricated vessels are certified under ANSI ( American ),CSA ( Canadian ) and CE ( European ) standards. Unregulated and uncertified fire pit burners are increasingly being scrutinized by regulatory authorities and being denied permits. Fire pits have recommended clearance to combustibles and require at least 5 feet above the flame and 16" circumference from the exterior perimeter of the vessel.
Essentially, to make a fire pit only a hole is required in order to safely contain a fire. This can be as simple as digging a hole in the ground, or as complex as hollowing out a brick or rock pillar. A wood burning fire pit should be located at least ten feet (three metres) away from structures for safety. Use of a fire pit in adverse conditions should be avoided, and basic fire safety precautions apply.
The Dakota smokeless fire pit
The Dakota fire pit is an efficient, simple fire design that produces little to no smoke. As depicted in the illustration, two small holes are dug in the ground: one for the firewood and the other to provide a draft of air. Small twigs are packed into the fire hole and readily combustible material is set on top and lit. The fire burns from the top downward, drawing a steady, laminar stream of fresh air from the air hole as it burns. Because the air passes freely around the fuel, near complete combustion is achieved, the result being a fire that burns strongly and brightly and with little or no seen smoke. The Dakota fire pit is a tactical fire used by the United States military as the flame produces a low light signature, reduced smoke, and is easier to ignite under strong wind conditions.
Fire pits in history
Many cultures, particularly nomadic ones would cut the turf above the fire-pit in a turf cutting ceremony, replacing the turf afterwards to hide any evidence of the fire. Elements of this ceremony remain in traditional youth organisations such as the Woodcraft Folk.
The remains of fire pits preserve information about past cultures. Radiocarbon dating from charcoal found in old fire pits can estimate when regions were first populated or when civilizations died out. Bones and seeds found in fire pits indicate the diet of that area.
In archaeological terms fire pits are referred to as features because they can be seen and recorded as part of the site but cannot be moved without being destroyed.