Standard Pipe Size
Standard Pipe Size is the given set of values for pipes using specific standards. It used to connect with SAE Flange to build a piping line that allows fluid to run through. Generally, the standard pipe size signifies two designations which are Nominal Pipe Size (NPS) and pipe schedule. Before production, there are a set of standards that manufacturers follow to ensure the standard of the materials is in line with the given specifications. Nominal Pipe Size (NPS) is the standard given by the North American body for pipes applied for high and low pressures and temperatures. Pipe Schedule is used to explain the thickness of the pipe wall and is often abbreviated as SCH.
1. What is Standard Pipe Size ?
Standard Pipe Size is a set of values used to differentiate pipes. Pipes are produced in different sizes, weights, and thicknesses. The same is applicable to SAE Flanges. These pipes and SAE Flanges are applied in different hydraulic systems based on the pressures they can bear. The standard for pipe and SAE Flange sizes is given by the Nominal Pipe Size (NPS).
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Nominal Pipe Size (NPS) is a North American size standard for pipes of high/low pressure and temperatures. Nominal Pipe Size signifies the outside diameter (OD) of the pipe. For example, a pipe with an NPS value only explains the measurement of the outside diameter irrespective of inner diameter or wall thickness. Sometimes, the National Pipes Size is referred to as Nominal Diameter (DN) or Nominal Bore (NB).
Nominal Bore: as stated above, the nominal bore is an alternative term for the Nominal Pipe Size. It is the American method of showing pipe dimensions. The only difference between NPS and NB is that the latter has dimensions in mm.
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Nominal Diameter (DN): Nominal Diameter (DN) is another alternative term for Nominal Pipe Size (NPS). However, the DN value is different from NPS. To change an NPS value to DN, simply multiply by 25.
The table below shows the different values for NPS, NB, and DN:
2. What are the dimensions for Standard Pipe Size ?
Please refer to the table below for the dimensions of pipes in mm:
3. What are the uses of Standard Pipe Size with SAE Flange?
When it comes to weld-in connection, the size of SAE Flanges outer diameter is bigger than pipe outer diameter. The reason is that the SAE Flanges outer diameter is made with tolerance and this tolerance allows the pipe to insert into SAE Flanges inner diameter before welding. SAE Flange threaded connection comes with female or internal thread. It used to connect with an externally threaded pipe to form a tightened-up connection.
Both pipes and SAE flange are connected in a welding or threaded way. There are two different types of connection as below:
4. What are Pipe Schedule and Wall Thickness ?
Pipe Schedule is the value for a pipe wall thickness.
The schedule number of a pipe is the exact value of the illustration:
1000 x P/S where S = allowable stress (PSI) and P = service pressure (PSI).
Pipe wall thickness explains the chunkiness of the pipe.
The measurement of the pipe wall thickness can be measured using this formula:
The diameter of the Outer Wall – Diameter of Internal Wall / 2.
It is an important factor to consider because a pipe with a very thin wall may explode when exposed to high pressure. Selection of the right SAE Flange with the allowable working pressure is critical to ensure a safe connection. The major use of standard pipe size is to give the specific dimension for the various pipes used in the industry. It helps to know the specific pipe fit for an application which in turn prevents any fault that may develop from the use of wrong pipes or SAE Flange.