Pipe is a hollow "tube" used for conveying products and pressure.
The products include fluids, gas, slurry, powders, pellets and more.
The pressure is hydraulic power. We usually designate the "tube" as pipe in the applicable line class but the definition includes any similar component designed as tubing, which is used for the same application.
One of the earliest methods of conveying fluids in the history of mankind was by pipe.
The earliest pipe on record was the use of bamboo for moving small quantities of water as a continues flow.
As man progressed, he began using hollow logs for his piping needs.
Probably the first recorded use of metal in piping systems was the use of lead or bronze during the "Bronze" age.
During the excavation at Pompeii, complete water distribution systems fabricated from lead have been uncovered.
These systems, include probably the first use of metal plug valves, are still workable.
Without piping our modern civilization and their attendant conveniences could not exist.
Today piping is used in almost every aspect of our lives.
Our drinking water is produced in plants full of piping and then comes to us through a vast network of pipes.
The waste from our homes and businesses flows away through another network of pipes and is then treated in a plant full of piping.
The fuel we use for travel or for heating was collected, processed and distributed using pipe.
No mater what you think about, power, food, paint, medicine, paper products, plastics, chemicals, and many more are all made in plants full of piping.
Our safety is also dependent on the piping in the fire water systems in our neighborhoods and buildings.
Materials of construction:
The various kinds of material from which pipe is, or can be, made is proved to be endless; among them are the more common carbon steel, along with chromes, stainless steel, iron, brass, copper, lead, aluminum, glass, rubber and various types of plastic material.
Over the years some of these materials have been combined to form lined pipe systems. These include carbon steel pipe lined with glass, carbon steel pipe that is lined with various plastics; carbon steel pipe lined with concrete.
Each one, plain or lined has certain advantages and disadvantages. Many things enter into making a choice of materials. Among the most important of these are commodity, pressure, temperature, size, ease of assembly availability and economics.
Many years ago pipe was sized by its true inside diameter. i.e., a 1" pipe was actually 1" inside diameter.
However, as time went on and the methods of manufacturing were improved and made more standard, and because it became necessary to increase wall thickness to accommodate higher pressures and temperatures, it became necessary to size pipe by "nominal" size rather than actual size.
Because it was deemed too expensive to have a set of thread dies for each wall thickness in the smaller sizes, the outside diameter (O.D.) was held constant.
Thus wall thickness changes affect the internal diameter only and leave the O. D. constant for standardized fitting engagements.
Nominal size refers to the name by which we call a particular size pipe.
Nominal size and actual outside diameter of a pipe differs for size 12" and under.
For sizes 14" and larger the actual outside diameter and the nominal size are identical.
Pipe comes in a very wide range of sizes.
It is not uncommon to see piping as small as ½" or as large as 66".
Pipe mills can and will make almost any size for a price.
This does not always prove to be the economical choice because odd size fittings may not be available.
It is best to stick to the closest and most commercially available or common size to meet the need.
The smaller common sizes in pipe include ½", ¾", 1", 2", 3", 4", 6", 8" 10" and 12".
The larger sizes, 14" and above increase in 2" increments.
The Nominal size pertains to calling the pipe size by name only.
The actual outside diameter or O. D. is different for the 12" and under sizes.
Nominal Size Actual O. D.
Methods of manufacture:
Determining wall thickness:
Three end preps are standard.
- There is plain end (PE). This would be the choice for small sizes where socket welded fittings will be used to join pipe to pipe or pipe to fittings. This is also the default end prep if no end prep is specified.
- There is threaded end (TE). This would be the choice for small sizes where the pipe to pipe or pipe to fitting assembly is to be threaded.
- There is also bevel end (BE). This would be the choice for most all 3" and larger steel pipe (or other metallic pipe) where "butt welding will be used to join pipe to pipe or pipe to fittings.
This pipe will also have a weight problem.
The span for both lines is 25'.
|Line A||Line B|
|Total weight of span||2857 lbs.||6170 lbs.|
However, it does indicate that there must be some close coordination with the structural department so they do not assume that all 14" lines are equal.
Do either or both of these lines need a pipe guide at this specific pipe support?
Does either of these lines need anchors at this specific pipe support?
If an anchor is required will the anchor forces on each side of the support be the same or will the anchor farces be unbalanced?
Both cases must be brought to the attention of the structural group.
With the hot line there is normally an insulation shoe required which is added material and which changes the dimensional reference point for the centerline of this line and can cause design errors if not understood and allowed for.
About the Author
James O. Pennock has more than forty-five years in the process plant design profession. He has been involved in both home office and job site assignments on refinery, chemical, petrochemical, power and other projects. His experience ranges from entry level designer to engineering manager. Much of this was with Fluor. He is also the author of the book "Piping Engineering Leadership for Process Plant Projects." He is now retired, living in Florida, USA and does only occasional consulting work.