Pipe fitting inch - mm dimensions

 

    Tube based on the use of environment and pressure on the nominal pressure of the same nominal diameter of the tube may have a different diameter, would like to clarify the conditions of use and nominal pressure PN, and the temperature - pressure ratings (Pressure / temperature Ratings)

And the possession of different materials in the same nominal pressure, may also have a different outer diameter

Nominal diameter (nominal diameter), also known as the average outer diameter (mean outside diameter).

This is the edge of the tube from the metal tube Bi thin, tube diameter and tube diameter is almost the same, so take the tube diameter and tube inner diameter of the average as diameter called.

 

Because the units are metric (mm) and imperial (inch) distinguish the following call.

 

(1) Metric (mm) as the base, said DN (metric unit)

To Imperial (inch) as the base, said of NB (inch unit)

3. DN (nominal diameter)

NB (nominal bore)

OD (outside diameter)

4 [Example]

Galvanized steel pipe DN50, sch 20

Galvanized steel NB2 ", sch 20

Diameter and DN NB relationship as follows:

------ DN (mm) -------- NB (inch) ------- OD (mm)

15----------- --- 1/2--------------21.3

20----------- --- 3/4 -------------- 26.7

25----------- --- 1 ---------------- 33.4

32----------- --- 1 1/4 ----------- 42.2

40----------- --- 1 1/2 ----------- 48.3

50----------- --- 2 ---------------- 60.3

65----------- --- 2 1/2 ----------- 73.0

80----------- --- 3 ---------------- 88.9

100----------- --- 4 ------------ 114.3

125----------- --- 5 ------------ 139.8

150----------- --- 6 ------------ 168.3

200----------- ---- 8 ------------ 219.1