This is not an easy question to answer, due to the numerous variables involved. The first major item is the size of the fire pit to be installed- or BTU input requirements for the appliance. Other factors such as gas pressure, the length of run, elbows, or other hardware that may affect gas flow, and must be figured into the calculation. Also, what is commonly forgotten are other appliances connected to the gas line that will take away gas from the fire pit. We at Starfire Direct strongly recommend working with your contractor or plumber, so they can account for all the factors to ensure proper gas delivery.