continuing the previous article about pipe wall thickness calculation based on ASME B31.8 (http://pipelineworld.blogspot.com/2015/08/pipe-wall-thickness-calculations-asme.html, now i'm going to discuss about calculating pipe wall thickness using another code (ASME B31.3).
ASME B31.3 is a code used for process piping. This standard appointed requirements for materials and components, design, fabrication, assembly, erection, examination, inspection, and testing of piping. This code includes the following fluids :
- raw, intermediate, and finished chemicals
- petroleum products
- gas, steam, air and water
- fluidized solids
- refrigerants
- cryogenic fluids
Pipe wall thickness calculation in ASME B31.3 mainly divided into two main part as follow :
- Straight Pipe
- Curved and Mitered Segments of Pipe
in this page we will discuss about pipe wall thickness calculation in a straight pipe based on ASME B31.3.
Pipe wall thickness determined in this following equation :
tm = t
+ c
where :
tm = minimum required thickness, including mechanical, corrosion, and erosion allowances
t = pressure design thickness, as calculated in accordance with para. 304.1.2 for internal pressure or as determined in accordance with para. 304.1.3 for external pressure
c = the sum of the mechanical allowances (thread or groove depth) plus corrosion and erosion allowances. For threaded components, the nominal thread depth (dimension h of ASME B1.20.1, or equivalent) shall apply. For machined surfaces or grooves where the tolerance is not specified, the tolerance shall be assumed to be 0.5 mm (0.02 in.) in addition to the specified depth of the cut.
T = pipe wall thickness (measured or minimum per purchase specification)
d = inside diameter of pipe. For pressure design calculation, the inside diameter of the pipe is the maximum value allowable under the purchase specification.
P = internal design gage pressure
D = outside diameter of pipe as listed in tables of standards or specifications or as measured
E = quality factor from Table A-1A or A-1B
S = stress value for material from Table A-1
Y = coefficient from Table 304.1.1, valid for t < D/6 and for materials shown. The value of Y may be interpolated for intermediate temperatures.
The pipe wall thickness shouldn't less than the value that calculated from the following equations :
T = pipe wall thickness (measured or minimum per purchase specification)
d = inside diameter of pipe. For pressure design calculation, the inside diameter of the pipe is the maximum value allowable under the purchase specification.
P = internal design gage pressure
D = outside diameter of pipe as listed in tables of standards or specifications or as measured
E = quality factor from Table A-1A or A-1B
S = stress value for material from Table A-1
Y = coefficient from Table 304.1.1, valid for t < D/6 and for materials shown. The value of Y may be interpolated for intermediate temperatures.
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| Y Coefficient Values for t < D/6 |
The pipe wall thickness shouldn't less than the value that calculated from the following equations :
 |
| wall thickness value for Under Internal Pressure Pipe |
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| wall thickness value for Under Internal Pressure Pipe |
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