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Based on the NPS and schedule of a pipe, the pipe outside diameter (OD) and wall thickness can be obtained from reference tables such as those below, which are based on ASME standards B36.10M and B36.19M. For example, NPS 14 Sch 40 has an OD of 14 inches and a wall thickness of 0.437 inches. However the NPS and OD values are not always equal, which can create confusion.

- For NPS â…› to 12 inches, the NPS and OD values are different. For example, the OD of an NPS 12 pipe is actually 12.75 inches. To find the actual OD for each NPS value, refer to the tables below. (Note that for tubing, the size is always the actual OD.)
- For NPS 14 inches and up, the NPS and OD values are equal. In other words, an NPS 14 pipe is actually 14 inches OD.

The reason for the discrepancy for NPS â…› to 12 inches is that these NPS values were originally set to give the same insidediameter (ID) based on wall thicknesses standard at the time. However, as the set of available wall thicknesses evolved, the ID changed and NPS became only indirectly related to ID and OD.

For a given NPS, the OD stays fixed and the wall thickness increases with schedule. For a given schedule, the OD increases with NPS while the wall thickness stays constant or increases. Using equations and rules in ASME B31.3 Process Piping, it can be shown that pressure rating decreases with increasing NPS and constant schedule.[note 1]

Q: Why pipe NB is different with OD up to 12 inches?

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YES

1.6 inches

The thickness of 40mm NB MS Pipe is 4mm Regards, ZAFFAR EKBAL +91-9001798487

5.5 feet = 1.68 metres. NB: 5.5 feet is 5 ft 6 inches, not 5 ft 5 inches.

3 dozen = 36 Remember the medieval word French word for '12' is 'douze'. Hence 'dozen'. So 1 dozen is 12 units. Hence 3 doz. = 36 units. NB 'doz' is short for 'dozen'.

Related questions

A 250 NP pipe is a pipe that is 250 millimeters in diameter and is 10 inches long. It comes in a variety of thicknesses. NB stands for nominal bore. Sometimes this is referred to as NPS which stands for nominal pipe size. NB is a standard for pipe sizes in North America.

NB is nominal bore of that pipe, that doesn't mean that the pipe diameter (Inner or Outer)will be equal to the NB, but it is an digit nearest to the out side diameter of the pipe. That digit will be an easily memorable one like 25, 20, 32, 40 etc (Not like 23.25, 27.5, 41.8 etc). In standard pipes, the NB and the outside diameter will be same from 14 inches and above...

27.2 kg/meter for 100 NB Simless pipe

the inner diameter of the pipe Nominal bore (NB) is 40 mm

14" and above

Nominal bore which is designation for pipe size.

YES

NB = inside diameter of the tube. OD = outside diameter of the tube.

150nb

1.6 inches

what is difference between NB & OD in pipe size

4.8 kg/mtr