What is the difference between sch 40 and sch 40s

It is worth bearing in mind that wall thicknesses come within a specified tolerance, depending on the engineering standard used. A typical wall thickness tolerance is This means that the actual internal pipe diameter may vary slightly from that quoted above.

Download PDF File. Tags: nominal bore nominal diameter nominal pipe size schedule. This statement in the article should be For NPS 4 and larger. Initially there are only three pipe wall thicknesses in use — Standard STD Extra Strong XS Double Extra Strong XXS However with the advancement of industrial age and use of pipes in varying pressure and temperature conditions, these three sizes did not fit all applications.

For a given schedule number, the OD increases with NPS while the wall thickness either stays constant or increases. Charles Diestel says:. Are you an Engineering professional? Join Eng-Tips Forums! Join Us! By joining you are opting in to receive e-mail. Promoting, selling, recruiting, coursework and thesis posting is forbidden. Students Click Here. Related Projects. The manufacturers of different parts of the world asking me various question, which confusing me.

Sch 40S is a stainless steel designation. In smaller sizes the wall thickness is the same between e. Stainless steel pipes sizes by schedule and other "standard" wall thicknesses are listed in ASME B That IPS system was established to designate the pipe size. The size represented the approximate inside diameter of the pipe in inches. An IPS 6" pipe is one whose inside diameter is approximately 6 inches. Users started to call the pipe as 2inch, 4inch, 6inch pipe and so on.

To begin, each pipe size was produced to have one thickness, which later was termed as standard STD or standard weight STD. The outside diameter of the pipe was standardized. As the industrial requirements handling higher pressure fluids, pipes were manufactured with thicker walls, which has become known as an extra strong XS or extra heavy XH. The higher pressure requirements increased further, with thicker wall pipes.

Accordingly, pipes were made with double extra strong XXS or double extra heavy XXH walls, while the standardized outside diameters are unchanged. So, at the IPS time only three walltickness were in use. In March , the American Standards Association surveyed industry and created a system that designated wall thicknesses based on smaller steps between sizes. The designation known as nominal pipe size replaced iron pipe size, and the term schedule SCH was invented to specify the nominal wall thickness of pipe.

By adding schedule numbers to the IPS standards, today we know a range of wall thicknesses, namely:. Nominal pipe size NPS is a dimensionless designator of pipe size.

It indicates standard pipe size when followed by the specific size designation number without an inch symbol. For example, NPS 6 indicates a pipe whose outside diameter is The NPS is very loosely related to the inside diameter in inches, and NPS 12 and smaller pipe has outside diameter greater than the size designator.