Ductile Iron Pipe Dimensions

Written by Anup Kumar Dey in Engineering Materials,Pipeline,Piping Design Basics,Piping Interface

Ductile iron pipes are are mode of ductile cast iron and hence the name. They find extensive applications for potable water transmission and distribution. Ductile iron pipes are produced by the centrifugal casting method. Internal linings and external coatings are applied to prevent the corrosion of ductile iron pipes.

Nominal Diameter or DN, a dimensionless term is used to specify ductile iron pipe dimensions. Similar to steel pipes, the outside diameter of ductile iron pipes is kept constant, and depending on the pipe thickness the inner diameter varies. Ductile iron pipe dimensions vary from region to region. The dimension also varies according to the design code used. In the following paragraphs, the dimensions of ductile iron pipes are provided according to the design codes and regions.

Ductile Iron Pipe Dimensions in North America

AWWA C-151 governs the dimensions of ductile iron pipes in North America. Typical dimensions of centrifugally cast ductile-iron pipes according to AWWA C151/A.21.51 is provided below in a chart format:

Nominal Size Outside Diameter Pressure Class Outside Diameter Pressure Class
(inches) (inches) 150 200 250 300 350 (mm) 150 200 250 300 350
    Wall Thickness (inches)   Wall Thickness (mm) 
3 3.96 0.25 0.25 0.25 0.25 0.25 101 6.35 6.35 6.35 6.35 6.35
4 4.8 0.26 0.26 0.26 0.26 0.26 122 6.6 6.6 6.6 6.6 6.6
6 6.9 0.25 0.25 0.25 0.25 0.25 175 6.35 6.35 6.35 6.35 6.35
8 9.05 0.27 0.27 0.27 0.27 0.27 230 6.86 6.86 6.86 6.86 6.86
10 11.1 0.29 0.29 0.29 0.29 0.29 282 7.37 7.37 7.37 7.37 7.37
12 13.2 0.31 0.31 0.31 0.31 0.31 335 7.87 7.87 7.87 7.87 7.87
14 15.3 0.33 0.33 0.33 0.33 0.33 389 8.38 8.38 8.38 8.38 8.38
16 17.4 0.34 0.34 0.34 0.34 0.34 442 8.64 8.64 8.64 8.64 8.64
18 19.5 0.35 0.35 0.35 0.35 0.35 495 8.89 8.89 8.89 8.89 8.89
20 21.6 0.36 0.36 0.36 0.36 0.39 549 9.14 9.14 9.14 9.14 9.14
24 25.8 0.38 0.38 0.38 0.41 0.44 655 9.65 9.65 9.65 10.4 11.2
30 32 0.39 0.39 0.43 0.47 0.51 813 9.91 9.91 10.9 11.9 13
36 38.3 0.43 0.43 0.48 0.53 0.58 973 10.9 10.9 12.2 13.5 14.7
42 44.5 0.47 0.47 0.53 0.59 0.65 1130 11.9 11.9 13.5 15 16.5
48 50.8 0.51 0.51 0.58 0.65 0.72 1290 13 13 14.7 16.5 18.3
54 57.56 0.57 0.57 0.65 0.73 0.81 1462 14.5 14.5 16.5 18.5 20.6
60 61.61 0.54 0.61 0.68 0.76 0.83 1565 13.7 15.5 17.3 19.3 21.1
64 65.67 0.56 0.64 0.72 0.80 0.87 1668 14.2 16.3 18.3 20.3