Definition - What does Nominal Diameter (DN) mean?
Nominal
Diameter (DN), in the context of trenchless technology, refers to the
internal diameter of a pipe that has to be laid in a horizontally
drilled bore hole. DN is of paramount importance in the process of
pipeline laying, as this is what determines the size of pipe fittings
such as bends, tees and elbows that are used for connecting pipes.
Trenchlesspedia explains Nominal Diameter (DN)
Any
standard pipe is characterized by two numbers that are dimensionless.
1. Nominal Diameter (DN) in inches (USA) or mm (UK); 2. Schedule.
Reference tables are used to arrive at the outside diameter and pipe
thickness based on the nominal pipe size and schedule. Pipes are
available in different DN sizes. DN does not necessarily indicate the
exact internal diameter. The DN is used to arrive at the pipe dimensions
using standard tables and schedules.
