Underground Gas Polyethylene (PE) Piping Fitting Assembly Maximum Capacity of PE Pipe in Cubic Feet per Hour with a Gas Pressure of 6.0 in. WC and a Pressure Drop of 0.5 in. WC (based on a 0.60 specific gravity gas) Tubing Size Tubing Length (ft) 200 250 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1/2" CTS 13 2 0 9 8 7 6 5 4 3/4