Piping & tube specifications

[Freeman]

PIPING & TUBE SPECIFICATIONS

All pipe is to be made of a long hole, surrounded by metal centered around the hole.
All pipe is to be hollow throughout the entire length.
All pipe is to be of the very best quality, preferably tubular or pipular.
All acid-proof pipe is to be made of acid proof metal.
Outer-diameter of all pipes must exceed the inner-diameter. Otherwise, the hole will be on the outside of the pipe.
All pipe is to be supplied with nothing in the hole so that water, steam, or other stuff can be put inside at a later date.
All pipe is to be supplied without rust, as this can be more readily put on at the jobsites.
All pipe is to be cleaned free of any covering such as mud, tar, barnacles or any form of manure before putting up, otherwise it will make lumps under the paint.
All pipe over 500 feet in length must have the words "Long Pipe" clearly painted on each end so that the fitter will know that it is a long pipe.
All pipe over two miles in length must also have these words painted on the middle so that the fitter will not have to walk the full length of the pipe to determine if it is long pipe or not.
All pipe over six inches in diameter is to have the words "Large Pipe" painted on it, so that the fitter will not use it for small pipe.
All pipe fittings are to be made of the same stuff as the pipe.
All pipe closers are to be open on one end.
No fittings are to be put on pipe unless specified. If you do, straight pipes become crooked pipes.
Pipe is a pressure tight cyclinder used to convey fluid (,liquids,gases,semi-solids etc) under pressure made of materials commercially availabe designations.

Since the purpose with a pipe is the transport of fluids like water, oil and many other products, the most import pipe property is the capacity, or in reality, the inside diameter of the pipe. The nominal diameter of a pipe is therefore related to the inside diameter.
In reference to ASME/ANSI B 36.10 Welded and Seamless Wrought Steel Pipe, the inside diameter of a 2'' pipe schedule 40 is 2.067". The inside diameter of a schedule 80 pipe is 1.939". Both inside diameters are close to 2". The outside diameters for both schedules are 2.375".

Since the outside diameter of a single nominal pipe size is kept constant, the inside diameter of a pipe will depend on the "schedule", or the thickness, of the pipe. The schedule and the actual thickness of a pipe will vary with size of pipe.

It is common to identify pipes in inches by using NPS or "Nominal Pipe Size". The metric equivalent is called DN or "diametre nominel". The metric designations conform to International Standards Organization (ISO) usage and apply to all plumbing, natural gas, heating oil, and miscellaneous piping used in buildings. The use of NPS does not conform to American Standard pipe designations where the term NPS means "National Pipe Thread Straight".

Nominal Bore (NB) may be specified under British standards classifications along with schedule (wall thickness).

The tolerances are looser to pipes compared with tubes and they are often less expensive to produce.

[Freeman]

Tubes


The nominal dimensions of tubes are based on the outside diameter. In reference to Copper Tubes - ASTM B88 the outside diameter of a 2" pipe is 2.125", relatively close to 2".

The inside diameter of a tube will depend on the thickness of the tube. The thickness is often specified as a gauge. In reference to Copper Tubes - ASTM B88 the wall thickness of 0.083"of a 2" pipe is gauge 14.
What's the difference between a pipe and a tube?


More often than not, people guess it has something to do with the quality of the materials, but that's got nothing to do with it. The difference between a pipe and a tube is how they are measured, and ultimately what they are used for.

A pipe is a vessel - a tube is structural.

A pipe is measured ID - a tube is measured OD. From the size 14" and above NB=OD of pipe.

How they are measured... Pipes are measured ID or inside diameter because they are vessels. Tubes are measured OD or outside diameter because they are structural.
Pipes have a consistent ID regardless of wall thickness. In other words, a 1/2" high pressure pipe may need a 2" thick wall, but the ID will still only be 1/2" even tho the OD is 4.5".

Generally speaking, a tube will have a consistent OD and it's ID will change. Engineers see tubes and pipes with different eyes.

A tube is structural.

By having a consistent OD they can vary wall thickness, changing the ID, to increase strength. Because they are consistent OD, they have predictable characteristics.
Again, the difference is simple, it's how they are measured and what their intended uses are.

[deepak_gharpure1]

But sir pipes have a fixed od as schedule changes id changes i mean to say od of the pipe is always fixed a 3 inch pipe will always have same od