# What is Meant by OD, ID, NB, NPS, T , ERW, EFW in Piping System ?

In these Article we will learn about the term like :-

• OD - Outer Diameter ,
• ID - Inner Diameter ,
• NB - Nominal Bore ,
• NPS - Nominal Pipe Size ,
• T - Thickness ,
• ERW - Electric resistance welded,
• EFW - Electric Fusion Welding

What is Meant by OD of a Pipe ?
OD is the abbreviation of Outer diameter .
The outer diameter (OD) of a hollow circular pipe is the measurement of the outside edges of the pipe passing through its center. The outer diameter of a pipe, together with its wall thickness, are essential to inside diameter calculations.
Outer diameter is also known as outside diameter or external diameter.

What is Meant by ID of a Pipe ?

ID is the abbreviation of Inner diameter.

The inside diameter (ID) of a hollow circular object, like a pipe, is a measurement of the distance of a straight line from one point on the inner wall of the object, through its center, to an opposite point also on the inside. The inside diameter is dependent on the outside diameter of the object and its wall thickness.
Inside diameter is also known as inner diameter or internal diameter.

Note :- Some pipes are measured base on their outside diameter, or O.D. Others are measured by their interior diameter, or I.D.

What is Meant by SCH ?

Wall thickness of Pipe is expressed by “schedules or Schedule numbers“, referred to as pipe schedules or Piping Schedules. The pipe Schedule describes the pipe wall thickness. With an increase in pipe schedule number pipe thickness increases.

What is Meant by NB  ?

NB means Nominal Bore
For pipes, the bore is the hollow center, and Nominal is used in the sense of “in name only” or approximate. Nominal bore is actually the approximate internal measurement across the diameter of the mouth of a pipe.
In the inch system, nominal bore is abbreviated as NB; in metric systems, it is “diameter nominal” (DN), or Nominal Pipe Size (NPS) in North America.

What is Meant by T of Pipe ?

T indicate the Thickness of a Pipe . Pipe thickness calculation is a very important activity for every piping engineer. As it required to calculate numerous pipe wall thickness calculations for different design conditions.

What is Meant by NPS ?
NPS Means Nominal Pipe Size.
Nominal pipe size (NPS) is a set of standard North American sizes to designate pipe diameter and thickness for pipes that are used for low and high pressures and temperatures. Nominal means something that is not specified, and in terms of pipe sizes, it refers to the diameter of the pipe hole with a dimensionless number.
NPS is used for calculating the required pipe strength and outer diameter (OD) required for installing pipelines using trenchless methods since these methods require pulling the pipes through boreholes.

What is Meant by ERW ?

ERW is the abbreviation of Electric Resistance Welding.
Electric resistance welding (ERW) refers to a group of welding processes such as spot and seam welding that produce coalescence of faying surfaces where heat to form the weld is generated by the electrical resistance of material combined with the time and the force used to hold the materials together during welding.

What is Meant by EFW ?

EFW is the abbreviation of Electric Fusion Welding. Electric Fusion Welding (EFW) steel pipe refers to an electron beam welding, the use of high-speed movement of the electron beam directed impact kinetic energy is converted to heat the work piece so that the work piece leaving the melt, the formation of the weld.