Nominal Pipe Size O.D. Average I.D. Min. Wall Nominal wt./ft. Maximum W.P PSI 1/8" .405 .249 .068 .051 810 1/4" .540 .344 .088 .086 780 3/8" .675 .473 .091 .115 620 1/2" .840 .602 .109 .170 600 3/4" 1.050 .804 .113 .226 480 1" 1.315 1.029 .133 .333 450 1-1/4" 1.660 1.360 .140 .450 370 1-1/2" 1.900 1.590 .145 .537 330 2" 2.375 2.047 .154 .720 280 2-1/2" 2.875 2.445 .203 1.136 300 3" 3.500 3.042 .216 1.488 260 3-1/2" 4.000 3.521 .226 1.789 240 4" 4.500 3.998 .237 2.188 220 5" 5.563 5.016 .258 2.874 190 6" 6.625 6.031 .280 3.733 180 8" 8.625 7.942 .322 5.619 160 10" 10.750 9.976 .365 7.966 140 12" 12.750 11.889 ..406 10.534 130 14" 14.000 13.073 .437 12.462 130 16" 16.000 14.940 .500 16.286 130 18" 18.000 16.809 .562 20.587 130 20" 20.000 18.743 .593 24.183 120 24" 24.000 22.544 .687 33.652 120