Spar Steel is a leading and trusted scaffolding company across Dubai,UAE,
and Middle East countries and known for manufacturing with the latest
advanced technology a wide range of high quality steel pipes and tubes such as MS ERW Pipes/Black Pipes /PG/GI Pipes/GIS Tubes/Galvanised
Pipes/Galvanised Tubes/Scaffolding Pipe/Scaffolding Tubes/ARAMCO Seamless Pipes & Tubes, etc. based on international parameters. In this article, we
will discuss know the difference between steel pipe and tube.
We often use the words pipe and tube for one another, and think that both are the same. But we should know what are differences between pipe and tube.
Pipe is a round hollow cross section used
to distribute fluids, gases, pellets, powders, such as oil
& gas, propane, steam, acids, and water. Pipe is designated
by a nominal pipe size (NPS) that represents a rough indication of the pipe
conveyance capacity. The most important dimension for a steel
pipe is the inside diameter (ID), which
indicates the rough (not the exact) fluid conveyance capacity of the tubular.
The ID is expressed in nominal pipe size (NPS) in inch or diameter
nominal (DN) i.e. bore size (BS) in
outside diameter (OD) does not match the nominal pipe size (NPS)
below NPS 14 inches (a 2 inches pipe, for instance, has an internal flow
capacity (ID) of approximately 2 inches, but has an outside diameter of 2.375
of a given NPS, the pipe outside diameter is fixed, whereas the pipe inside
diameter decreases by increasing schedule values (pipe wall thickness
most important mechanical parameters for pipes are the pressure rating,
the yield strength, and the ductility.
The standard combinations of pipe nominal diameter and wall thickness (schedule) are covered by the ASME* B36.10 and ASME B36.19 specifications (carbon & alloy pipes, and stainless steel pipes respectively). ASME*—American Society of Mechanical Engineers
Pipe Inside Diameter (ID) Calculator
ID can be calculated by deducting from the pipe NPS the pipe wall thickness
(WT) multiplied by 2 (the pipe WT can be taken from the
ID = NPS – 2 x WT
For example: for a 12
NPS pipe (DN 300 mm), schedule 40, the pipe outside diameter and the wall
thickness are 12.75 inches (324 mm) and 0.406 inches (10.4 mm). Then Pipe ID
calculation in inch and millimeter will be
1. Pipe ID in inch
(”) = NPS – 2 x WT i.e. 12.75” – 2 x 0. 406”
– 0.812 = 11.94”
2. Pipe ID in millimeter
(mm) = NPS – 2 x WT i.e. 324 – 2 x 10.4
= 324 – 20.4 = 303.2 mm
However, this calculation is just theoretical, as pipes have a wall thickness tolerance which is generally +/-12.5% for American Society of Mechanical Engineers (ASME) pipes. Hence the actual ID of a given pipe may differ by +/- 12.5% from the theoretical value.
Whereas, Steel Tube is a round, rectangular, squared or oval hollow section used for pressure equipment, for mechanical applications, and for instrumentation systems.
Steel tube often incorporates
different alloys such as aluminum, manganese, titanium and
tungsten. Steel tube can be Electric Resistant welded (ERW)
or seamless. Seamless tubes
are made by passing the
molten steel over a piercing rod to create a hollow tube.
Steel tubes or pipes are produced by two distinct methods
which result in either a welded or seamless pipe. In both methods,
raw steel is first cast into a molten workable starting form. It is
then made into a tube or pipe by stretching
the steel out into a seamless tube or forcing the edges
together and sealing them with a weld.
Due to a variety of factors, tubes are
inherently stronger than pipes. This means that
steel tubes perform better overall in applications that require durability and
Tubes are designated by their outside
diameter (OD) and wall thickness (WT), which are
exact measures in inches or millimeters. For tubes, the
difference between the outside diameter and the wall thickness, multiplied by two,
defines the inside diameter (ID) of the tube.
The dimensions for a pipe is the outer diameter (OD) together with the wall thickness (WT) decide inside diameter (ID) of a pipe.
Pipe’s ID = OD – 2 x WT.
The inside diameter (ID) determines the liquid capacity of the pipe approximately.
The dimensions for a steel tube are the outside diameter (OD) and the wall thickness (WT).
These parameters are marked in inches or millimeters and determines dimensional value of the hollow section of the tube.
Pipe Wall Thickness
The wall thickness of a steel pipe is denoted with a " schedule1" value (the most common are Sch. 40). Two pipes of different NPS2and same schedule have different wall thicknesses in inches or millimeters.
The wall thickness of a steel tube is expressed in inches or
millimeters. For tubing, the wall thickness is measured also
with a gage nomenclature.
Round, rectangular, square, oval
Extensive (up to 80 inches and above)
A narrower range for tubing (up to 5 inches), larger for steel
tubes for mechanical applications
Tolerances and strength
Tolerances are set, but rather loose. Strength is not the major concern.
Steel tubes are produced to very strict tolerances. Tubes undergo several dimensional quality checks i.e. straightness, roundness, wall thickness, surface, during the
manufacturing process. Mechanical strength is a major concern for tubes.
Pipes are generally made to stock with highly automated and efficient processes, i.e. pipe mills produce on a continuous basis and feed distributors stock around the world.
Tubes manufacturing is more lengthy and labor intensive.
Can be shorter
Relatively lower price per ton than steel tubes
Higher due to lower mills productivity per hour, and due to
the stricter requirements in terms of tolerances and inspections
A wide range of materials is available
Tubing is available in carbon steel, low alloy, stainless steel,
and nickel-alloys; steel tubes for mechanical applications are
mostly of carbon steel.
The most common are beveled, plain and screwed ends
Threaded and grooved ends are available for quicker connections on site
WHAT IS PIPE SCHEDULE1?
Pipe Schedule is the term used to
describe the wall thickness (WT) of a pipe. The outside diameter of a
pipe is the same for all Schedules in a particular nominal pipe diameter.
Standard pipe schedules or schedule
number or pipes sizes as given by ANSI / ASME
B36.10M and API 5L are 11 schedule numbers — 5, 10, 20, 30, 40, 60, 80, 100,
120, 140, & 160.
The most popular pipe schedule is 40.
For pipe 8-inches and under, Schedule 40 and Standard Weight pipe wall
thicknesses are the same. Schedules 5, 60, 100, 120, & 140 are rarely used.
This should be considered when piping is specified for a particular project.
Schedule Number = 1,000 x(P/S)
P = the internal working pressure, psig
S = the allowable stress (psi) for the
material of construction at the conditions of use.
For example, the schedule number of
ordinary steel pipe having an allowable stress of 10,000 psi for use at a
working pressure of 350 psig would be:
Schedule Number = 1,000 x (350/10,000) = 35 (approx. 40)
Which is better pipe schedule 40 or 80?
Schedule 40 pipe has thinner walls, so it is best for applications involving relatively low water pressure. Schedule 80 pipe has thicker walls and is able to withstand higher PSI (pounds per square inch). That means with an increase in service pressure schedule number will increase its pipe wall thickness designator.
What is Nominal Pipe Size (NPS2)?
Nominal Pipe Size is a North American set of standard sizes for pipes used for high or low pressures and temperatures. “Nominal” refers to pipe in non-specific terms and identifies the diameter of the hole with a non-dimensional number.
What is Diameter Nominal (DN)?
Diameter Nominal (DN) is International designation (SI or Matric Designator) and also a European equivalent of NPS to show pipe sizes. It refers to the internal diameter (ID) of a pipe generally mentioned in millimeter. NPS can be converted into DN by multiplying it with 25. For example, 2” NPS pipe is simply mentioned as DN 50 mm.
What is Nominal Bore (NB) Pipe?
The nominal bore (NB)is the hollow section of the pipe. NB (nominal bore) is the European designation equivalent to NPS in DN i.e. mm value. As, there is no difference between NB and NPS. NB is also an American way to refer pipe dimensions. It is seen that when pipe dimensions are shown in mm (DN) people refer pipe sizes in NB. So, when someone says 25nb pipe or 50nb pipe basically they are talking about DN. For example, 100nb pipe works out to be exactly 4.5 inches = 4.5 inches x 25.4 mm = 114.3 mm.
Spar Steel is supported by its qualified
and experienced R&D team having the expertise in the application of the
advanced technology of construction field used in the USA, European Union,
Japan, Australia, etc. for scaffoldings production to ensure the scaffolding
standard quality of SGS, JIS, ASTM, BS, and others.
Spar Steel standard quality product materials and scaffolding services which meet OSHA, ARAMCO, Adnoc, Enoc, UAE and SABIC specification, and testing are:
Tube And Fittings: Galvanised Iron Scaffolding Tubes, Double Coupler, Swivel
Coupler, Putlog Coupler, Grider-Coupler, Board Retaining Clamp, Toe Board
Couplers, Sleeve Coupler, Ladder Clamp, Rocking Or Swivel Base Plate,
Adjustable U Head Jack, Scaffolding Ladder Beams, Scaffolding Ladders, Heavy
Duty Self-Closing Scaffolding Gate, Scaffolding Base Plate, Adjustable Base
by keeping the safety and security of scaffolds structure and workers, scaffolding customers should not compromise with
the kinds and quality of scaffolding products
and services used in scaffolding works.
Locations for Spar Group Scaffolding Products & Services [H1]
For Spar Steelquality scaffolding products and services based on OSHA, Saudi Aramco, and Adnoc, Enoc, UAE safety standard and rules, clients can contact on the following addresses given below:
RAK – UAE
SPAR STEEL INDUSTRIES LLC
PO Box 37374, Plot No. P111,
Al Ghail Industrial Park,
Ras Al Khaimah, UAE
ARABIAN SPAR CO. LTD
King Abdullah Road, After Flyover, Behind KPS 33
Post Box -1396, Al- Jubail – 31951,
Kingdom of Saudi Arabia Tel : +966 (13) 3619096, +966 (13) 3627320 Fax: 966 (13) 3618032 Email:firstname.lastname@example.org
ARABIAN SPAR CO. LTD
PO Box 4424, Ring Road, Exit-22,
Faryan Street, Riyadh-14515
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