Basic information about pipe, its important for mechanical engineer.

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BY - Nitesh Gangwar
GET - Mechanical
Sugar Unit - Loni
PPT ON PIPE

2. What is Pipe?
• Pipe are thin cylindrical shells which is used for transportation of fluid.
• Basically pipe is defined on the basis of NPS & wall thickness.
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3. What is NPS?
• Pipe size is mentioned as nominal pipe size (NPS).
• Nominal pipe size (NPS) is the number that defines the size of the pipe.
For example, when you say 6” pipe, the 6” is the nominal size of that pipe.
• NPS is in between of outer and inner diameter of pipe.
• For NPS 14” and above NPS is same as outer diameter.
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4. What is Schedule No?
• Thickness are expressed in Schedule number (5, 10, 20, 30, 40, 60,
80, 100, 120, 140, 160).
• Higher the schedule higher the thickness for same NPS.
• ID will changed with changed in Pipe schedule number.
• For same NPS as schedule number increases then decrease is in
inside diameter of pipe.
• Chart of Pipe on the basis of Schedule-
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5. Pipe Classification
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Pipe
Seamless
Welded
SAW
ERW

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• Seamless Pipe - Seamless Pipe is formed by forcing molten metal through a round die
with a plug in the center to form a long tube of continuous metal which
is then cut into appropriate lengths.
• Seamless Pipe can also, usually, withstand higher operating pressures & temp
than weld pipe so it is commonly preferred for use in higher pressure system.

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• ERW Pipe – These pipes are manufactured by cold-forming a sheet of steel into a
cylindrical shape. Current is then passed between the two edges of
the steel to heat the steel to a point at which the edges are forced
together to form a bond.

8. Seamless & ERW Pipe-
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ERW PipesSeamless Pipe

9. Class Pipe VS Schedule Pipe
• ERW Pipe available in class A, B & Class C pipe.
• Seamless pipe available in schedule class
• Seamless pipe can withstand more pressure than Class pipe.
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10. Pipe Classification on the basis of class-
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11. Design of Pipe :-
• Inside Diameter of Pipe - The inside diameter of the pipe depends
upon the quantity of fluid to be delivered.
Let, D = Inside diameter of the pipe,
v = Velocity of fluid flowing per minute, and
Q = Quantity of fluid carried per minute.
We know that the quantity of fluid flowing per minute,
Q = Area × Velocity = π x d² x v
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d = √ Q X 4
π X v
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12. Pipe Wall Thickness or Schedule No-
• Thickness of straight pipe under Internal pressure-
• For t < D/6
Tm = T + C
T = PD C = C1 + C2
2(SE+PY)
P = Internal Design Gauge Pr. C1 = Corrosion Allowance
D = Pipe OD = 1.6mm for carbon steel
S = Allowable stress = 0 mm for stainless steel
E = Joint quality factor C2 = Depth of Thread
= 1 for seamless pipe (used only up to 1.5 NB)
Y = Coefficient (0.4)
• For t ≥ D/6 - calculation of pressure design thickness for straight pipe requires
special consideration of factors such as theory of failure, effects of fatigue, and
thermal stress.
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13. Allowable tensile stress for pipes
of different materials-
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Basic Allowable Stress in Tension for Metals
Material Grade
Specified Min,
Strength Ksi
Basic Allowable stress S(Ksi) at Metal
Temp. (F*)
Tensile Yield 100 200 300 400
Carbon
Steel SMLS
& ERW
API 5L
A25
45 25 15 15 14.7 14.2
Carbon
Steel
A53 60 35 20 20 20 20
API 5L - American Petroleum Institute specification API 5L covers seamless and welded steel
line pipe
A53 - These Pipes are Hot Dipped or Zinc Coated manufactured by welding or seamless.

14. Pipe Specification-
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ASTM - American Society for Testing & Materials.
A53 - These Pipes are Hot Dipped or Zinc Coated manufactured by welding or seamless.
PSL - Product specification level (PSL-2 shows higher performance than PSL-1)
Grade Tensile Strength(psi) Yield Strength(psi)
A53 A 48,000 30,000
A53 B 60,000 35,000
A25 45,000 25,000
API 5L-B (PSL-1) 41,000 24,000
API 5L-B (PSL-2) 41,000 - 75,000 29,000 – 49,000

15. Calculate thickness of 12” Pipe-
• MOC of Pipe - A53 Grade B SMLS
• NPS - 12”(323.85mm)
• Design Pr. - 1500 psi
• Design Temp. - 400*F
• Allowable stress - 20,000 psi
• Corrosion Allowance – 1 mm
Tm = T + C
T = PD C = C1 + C2
2(SE+PY)
T = 1500 X 323.85 = 242887.5
2(20000X1 + 1500X0.4) 20600
= 11.79 mm & C = 1
Tm = 11.79 + 1 = 12.79 mm
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16. Color Coding of Pipeline-
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Fluid Service Background color Letter Color Color & Letter sample
Fire quenching fluid Safety Red White Letter
Toxic & Corrosive fluid Safety Orange Black Letter
Flammable & oxidizing
fluid
Safety Yellow Black Letter
Combustible fluid Safety Brown White Letter
Potable, cooling, boiler
feed & other water
Safety Green White Letter
Compressed air Safety Blue White Letter
To be defined by user Safety Purple White Letter
To be defined by user Safety White Black Letter
To be defined by user Safety Gray White Letter
To be defined by user Safety Black White Letter

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