Ductile Iron Pipe Dimensions

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:

The pressure class in the above table for ductile iron pipe dimension is the rated water pressure that the pipe can withstand in psi. The pipe thicknesses shown in the above table are adequate for the rated water working pressure plus a surge allowance of 100 psi. Thickness calculations are based on the minimum yield strength of 42,000 psi and a safety factor of 2.0 times the sum of the working pressure and 100 psi surge allowance.

Note that the above ductile iron pipe dimensions chart is based on standard pressure classes as specified in AWWA C151. However, there are special thickness classes as well based on AWWA C150 for which the dimensions for ductile iron pipes are provided in Fig. 1:

Ductile Iron Pipe Dimensions in Europe

European ductile iron pipe industry follows ISO 2531-Ductile iron pipes, fittings, accessories, and their joints for water applications. Accordingly, the dimensions of ductile iron pipes in Europe are governed by ISO 2531. Typical Dimensions are provided below:

There are other European Standards that are dedicated to a specific type of ductile iron piping as follows EN 15655, EN 877, EN 598, EN 12842, EN 14628, EN 15189, EN 14901, EN 969, EN 15542, EN 545, EN 14525, etc.

Ductile Iron Pipe Dimensions in Australia and New Zealand

The ductile iron piping industry in Australia and New Zealand follows an independent specification AS/NZS 2280- Ductile iron pipes and fittings. Typical dimensions for ductile iron pipes for Australia and New Zealand are provided below: