Length(ft) Capacity in Cubic Feet of Gas Per Hour 10 172 360 678 1,390 2,090 4,020 6,400 11,300 20 118 247 466 957 1,430 2,760 4,400 7,780 30 95 199 374 768 1,150 2,220 3,530 6,250 40 81 170 320 657 985 1,900 3,020 5,350 50 72 151 284 583 873 1,680 2,680 4,740