What is the difference between American standard fittings and national standard fittings?
The biggest difference between the American standard
pipe fittings and the national standard pipe fittings is the calibre. The American standard is the A series national standard often referred to as the B series.
For example, the elbow: DN100*6, the nominal diameter is DN100, the national standard DN100's outer diameter is 108MM, the thickness is 6MM, the American standard DN100 refers to the inch is 4'', the outer diameter is 114.3MM, the thickness is also 6MM , And the length of the American standard's elbow is slightly longer than the national standard.
It is also said that the pipe with the same nominal diameter (including elbows, tees, heads, caps), the caliber of the American standard and the national standard are not the same size.
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