Pipes are used for transporting fluids and gases in Chemical, Petrochemical, Power Plants, Refineries, Storage units, compressed air systems, plumbing systems, etc. They are circular in cross-section and specified by Nominal Pipe Size.
What is a Tube?
Tubes are used for mechanical applications (Heat Exchanger, Fired heater, Boiler, etc.), for instrumentation systems (used for measuring instruments); for structural applications, etc and could be rigid or flexible. They are specified by their outer diameter and tube wall thickness, in inches or in millimeters.
Differences between Pipe and Tube
From a layman’s viewpoint, Both Pipe and Tube seem to be the same as they have many similarities like both are hollow, made from metals, both can transfer fluids, etc. Many a time, these terms are used interchangeably. But in actual practice Tubes and Pipes are not the same as both possess different features. Through this article, we will try to investigate all such characteristics based on a few parameters like Size, Shape, Diameter, Thickness, Use, Availability, End Connection, Design Standard, etc.
Sr No
Parameter
Pipe Characteristics
Tube Characteristics
1
Shape
Always cylindrical or round in shape
In general, cylindrical. However, different other shapes like square, rectangular, etc. are available.
2
Size
Pipe is Specified by Nominal Pipe Size (NPS) or Nominal Bore (NB).
The size of Tubes are specified in millimeter or in inches by outside diameter.
3
Diameter
The outside diameter of pipe up to size 12” are numerically larger than corresponding pipe size
Outside diameter of tubes is numerically equal to the corresponding size.
4
Thickness
Pipe Wall thickness is expressed in schedule number that can be converted into mm or inches.
Tube Wall thickness is expressed in millimeter, or inches, or BWG (Birmingham wire gauge.)
5
Thickness Increment
Pipe thickness depends on the schedule, so there is no fixed increment
The thickness of tubes increases in standard increments such as 1 mm or 2 mm
Difference Between Pipe and Tube
Sr No
Parameter
Pipe Characteristics
Tube Characteristics
6
Application
Used in all Process, Power & Utility lines to carry fluids.
Generally used in tracing lines, tubes for heat exchanger & fired heater & in instrument connection. They are more prevalent in medical area, construction, structural or load bearing.
7
Availability
Available as the small bore and the big bore
Normally small-bore tube is used in process piping. For structural use, tubes are available in custom sizes.
8
Structural Rigidity
Always rigid and resistant to bending
Available as rigid as well as flexible depending on the application. Rigid tubes are normally used in structural applications whereas copper and brass tubes can be flexible.
9
Joining and Stability
Joining pipes is more labour intensive as it requires flanges, welding, threading, etc.
Tubes can be joined quickly and easily with flaring, brazing or couplings, but for this reason, they don’t offer the same stability
10
Tolerance
Pipe tolerances are not too restrictive.
Tolerances are very strict with tubes compared to pipes and tubes are often more expensive to produce than pipes
Pipes used in operating process plant
Sr No
Parameter
Pipe Characteristics
Tube Characteristics
11
Manufacturing
Pipe manufacturing is easier as compared to tubes
Tubes need cumbersome tests, inspection and quality control than pipes.
12
Cost
Cheaper
Costlier
13
Packing & Delivery
Delivered in bundle as bulk item. Delivery time is short.
Tubes are usually wrapped with wooden box or thin film and delivered with much care. Delivery time is longer.
14
Production Quantity
Produced in mass quantity and for long distance applications.
Produced in small quantity depending on requirement.
Tubes used inside a Fired Heater
Sr No
Parameters
Pipe Characteristics
Tube Characteristics
15
End Connection
Normally plain or bevelled for welding purposes
With coupling ends, irregular ends, special screw thread etc.
16
Surface Finish
Inner and Outer surface is rough with comparison to tube
Normally, both inner and outer surface are smooth
17
Common material
Carbon Steel
Alloy Steel
18
Design Codes & Standards
Thickness is decided as per governing codes like ASME B 31.3/ B31.1/ B 31.4/ B31.8 or IBR Codes
Depending on use thickness is decided.
I am sure there will be many more differences, I invite the readers to list out those in the comments section.
I am a Mechanical Engineer turned into a Piping Engineer. Currently, I work in a reputed MNC as a Senior Piping Stress Engineer. I am very much passionate about blogging and always tried to do unique things. This website is my first venture into the world of blogging with the aim of connecting with other piping engineers around the world.
5 thoughts on “Comparison of Pipe and Tube (Pipe Vs Tube)”
Hi, very useful & detail difference has given between tube & pipe. It’s really helpful, which added few new point in knowledge.
Thanks
Dear Anup thanks, I am Noor ul Arefeen from Pakistan. Your above subject is very informative and you have tried to contain very big topic in short spain. I am running my own business in mechanical fabricaion. I will keep in touch with for further knowledge. Thanks once again.
HI ANUP SIR,
IAM ALSO A MECHANICAL ENGINEER GRADUATE AND WORKING AS PROCESS DESIGNER. AND I HAVE ALSO INTEREST TO BECOME A PIPING ENGINEER, CAN YOU PLEASE SUGGEST HOW I BECOME THE PIPING ENGINEER.
AND YOURS ARTICLES ALSO VERY USEFUL TO GAIN THE KNOWLEDGE ABOUT THIS FIELD THANK YOU VERY MUCH
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The stress analysis methodology of air cooler piping is quite different from other types of heat exchangers. This is mainly due to its different construction and supporting arrangements. The...
Hi, very useful & detail difference has given between tube & pipe. It’s really helpful, which added few new point in knowledge.
Thanks
Dear Anup thanks, I am Noor ul Arefeen from Pakistan. Your above subject is very informative and you have tried to contain very big topic in short spain. I am running my own business in mechanical fabricaion. I will keep in touch with for further knowledge. Thanks once again.
I’m also a MECHANICAL ENGINEER From
INDIA…
HI ANUP SIR,
IAM ALSO A MECHANICAL ENGINEER GRADUATE AND WORKING AS PROCESS DESIGNER. AND I HAVE ALSO INTEREST TO BECOME A PIPING ENGINEER, CAN YOU PLEASE SUGGEST HOW I BECOME THE PIPING ENGINEER.
AND YOURS ARTICLES ALSO VERY USEFUL TO GAIN THE KNOWLEDGE ABOUT THIS FIELD THANK YOU VERY MUCH
Sir so many piping draftsmans are hired on temporary or contract basis. What is their future ?