A fire pit (or firepit) is the general term for any open vessel that contains a fire. Fire pits range from simple holes in the ground, to rings of steel or of rocks set on the ground, to steel kettles or basins, to permanently installed brick- or stone-built structures, to decorative reinforced concrete structures.
The consumer may run into some confusion about the terminology, too, since fire pits are often referred to as “outdoor fireplaces” or “patio heaters.” But not all “outdoor fireplaces” or “patio heaters” are fire pits. (A fire pit is an open system, where a great number of “outdoor fireplaces” are enclosed with steel mesh or with glass, or have solid outer walls of steel or clay. And most devices referred to as “patio heaters” are more industrial than decorative in appearance and show little to no flame during operation.
Generally speaking, fire pits can be used for cooking, for warmth, or for beauty and atmosphere — though rarely is a model suitable for all of these uses. For instance, most will prefer a typical barbecue grill for cooking, but few will want to have a barbecue grill as the decorative centerpiece for their patio parties!
Fire pit fuels vary, but are generally either wood, liquid petroleum (LP gas) or natural gas. While there’s no matching the beauty and crackling of a natural wood fire, there are certainly disadvantages with how long it takes to extinguish a wood fire, and in dealing with the heavy fuel and the messy ashes it leaves. A gas fire over lava rocks or natural-looking synthetic fire logs, on the other hand, makes for a clean and natural fire that can be extinguished immediately when you’re ready to leave the patio. Further, a gas fire burns at roughly half the temperature of a wood fire, making it considerably less dangerous near combustible structures such as houses and decks. And a gas fire won’t spit out burning embers like a wood fire will do from time to time!
Most gas fire pits (ours included) have a variable gas valve, with which the user can adjust the rate of fuel flow, and thus, the height of the flames. With finer gas fire pits, the fuel sources can be hidden so that there are no unsightly hoses or tanks to be seen. Gas lines can be stubbed out from under the deck, patio, or lawn, and if those lines go to an LP tank (instead of a natural gas supply line), the tank can be hidden behind shrubbery, or even buried in the ground. When using LP as a fuel source, a larger tank is required than for a barbecue grill. The reason for this is that a fire pit’s valve allows for a much greater range of fuel consumption than does the valve on a gas grill. Where a typical gas grill will burn fuel at a rate of 15 to 40 BTUs, a gas firepit can go as high as 90,000 BTUs if the user wants the flames at their highest level. (A gas grill’s flames don’t have to be beautiful and they don’t have to look like the flames from a natural wood fire.) But the small LP bottle used on most barbecue grills has a regulator that is not configured to allow gas flow at this rate. When such a bottle is attached to a 90,000 BTU fire pit, the regulator assumes that the extra gas flow must be the result of a gas leak, and it shuts down the valve automatically.