Tuesday, October 14, 2008

Where to start when designing a gas fire pit



Build a fire pit (firepit)

It is my experience that many people building gas (natural gas NG or liquid propane LP) fire pits start at the end of the process and work backwards and are often disappointed with the results. Fire pit design must start with the fire ring (the burner). The final size and height of the pit depends on the proper selection of this one component. Fire rings generally come in 6 inch increments starting at 6 inches up to 48 inches. Burners are custom made above 48 inches. The rings are made of either black iron or stainless steel. Black iron is more susceptible to corrosion than stainless steel, but should still be serviceable for 2 to 4 years depending on the climate. Compare
Seattle, Washington to Flagstaff, Arizona, for instance.

First Rule: The bigger the fire ring the shorter the flame at the same gas pressure. An 18 inch ring will have a 22-24 inch flame at 150,000 BTU at the pit. A 24 inch ring will produce a flame about 18 inches tall at the same pressure.

The fire ring affects the design of the pit because of space and offset distance requirements. More about this later in a separate blog entry.

Next blog "Got gas?"