|
Internal Design gage Pressure (P, Psig) |
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| Pipe Outside Dia. (D,inch) |
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Piping Table |
| Nominal Pipe Thickness (wt,inch) |
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| Allowable Stress of Pipe (S,Psig) |
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| Quality Factor (E) |
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| Weld Joint Strength Reduction Factor (W) |
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| Coefficient (Y) |
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| Corrosion Allowance (c, inch) |
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| Mill Tolerance (M, %) |
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Result |
| Cal_Min.Req. Thickness(tm_3a, inch) |
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| Cal_Min. Pipe Thickness(tm_3b, inch) |
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| Cal_Thickness inc. mill tolerance(tw, inch) |
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| Min. Actual Thickness taking into account Mill Tolerance (wtt, inch) |
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Sizing Equations, "ASME B31.3, 2012"
t m=
P * D
/
2 *( S * E * W + P * Y)
+ c (3a)
t m=
P * (d + 2* c)
/
2 *[ S * E * W - P * (1 - Y)]
+ c (3b)
Where:
tm = minimum required thickness, including mechanical, corrosion, and erosion allowances
c = Corrosion Allowance
D = outside diameter of pipe as listed in tables of standards or specifications or as measured
d = inside diameter of pipe (without allowance) = D - 2 * wt * m - 2 * c
E = Longitudinal Weld Joint quality factor from Table A-1A or A-1B
P = internal design gage pressure
S = stress value for material from Table A-1
W = weld joint strength reduction factor in accordance with para. 302.3.5(e)
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.
For t ≥ D/6,
Y=
d + 2*c
/
D+d+2*c
M = Mill Tolerance,Mill tolerance and Piping Stress Analysis
STEPs
1 ) tm=Max (tm_3a, tm_3b)
2 ) tw=
tm
/
(1-M/100)
3 ) wtt=wt * (1-M/100)
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