A furnace rated at 120,000 Btuh is to be installed 50 feet from the gas meter. It will be supplied by natural gas at an 11 water column, .6 specific gravity, .5 pressure drop and a rated value of 1000 Btu per cu foot. What is the size of th gas line?

A furnace rated at 120,000 Btuh is to be installed 50 feet from the gas meter. It will be supplied by natural gas at an 11 water column, .6 specific gravity, .5 pressure drop and a rated value of 1000 Btu per cu foot. What is the size of th gas line?