Dn NPS Sch5S Sch1OS Sch40S Sch80S Sch1O Sch20 Sch30 STD Sch40 Sch60 XS Sch80 Schl00 Schl20 Schl40 Sch160 6 1/8 10.3 1.24 1.73 2.41 1.73 1.73 2.41 2.41 8 1/4 13.7 1.65 2.24 302 2.24 2.24 3.02 3.02 10 3/8 171 1.65 2.31 3.2 2.31 2.31 3.2 3.2 15 1/2 21.3 1.65 2.11 2.77 3.73 2.77 2.77 3.73 3.73 4.78 20 3/4 26.7 1.65 2.11 2.87 3.91 2.87 2.87 3.91 3.91 5.56 25 1 33.4 1.65 2.77 3.38 455 3.38 3.38 4.55 4.5