Site map|Online message

Home > Reference > Fittings standard data



times   2015-11-02


This Standard covers the standardization of dimensions of welded and seamless wrought stainless steel pipe for high or low temperatures and pressures.

The word pipe is used, as distinguished from tube, to apply to tubular products of dimensions commonly used for pipeline and piping systems. Pipes NPS 12 (DN 300) and smaller have outside diameters numerically larger than their corresponding sizes. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes.

The wall thicknesses for NPS 14 through 22, inclusive (DN 350–550, inclusive), of Schedule 10S; NPS 12 (DN300) of Schedule 40S; and NPS 10 and 12 (DN 250 and 300) of Schedule 80S are not the same as those of ASME B36.10M. The suffix “S” in the schedule number is used to differentiate B36.19M pipe from B36.10M pipe. ASME B36.10M includes other pipe thicknesses that are also commercially available with stainless steel material.


The size of all pipe in Table 1 is identified by the nominal pipe size. The manufacture of pipe NPS 1⁄8 (DN 6) through NPS 12 (DN 300), inclusive, is based on a standardized outside diameter (OD). This OD was originally selected so that pipe with a standard OD and having a wall thickness

that was typical of the period would have an inside diameter (ID) approximately equal to the nominal size. Although there is no such relation between the existing standard thicknesses — OD and nominal size — these nominal sizes and standard ODs continue in use as “standard.”

The manufacture of pipe NPS 14 (DN 350) and larger proceeds on the basis of an OD corresponding to the nominal size.


The dimensional standards for pipe described here are for products covered in ASTM specifications.

Copyright@Hebei HAIHAO high-pressure pipe flanges Group Co., Ltd.