A new industrial plant requires a supply of water at a rate of 5.7 m3/min. The pressure in the water main 800 kPa, and it is 50 m from the plant. The line from the main to the plant will have 65 m of galvanized iron pipe, four standard elbows, and two gate valves. If the water pressure at the plant must be no less than 500 kPa, what diameter pipe must be used