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Wall
Thickness Calculation of Straight Pipes Under Internal Pressure
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Calculation as per par. 841.1 Steel Piping Systems Design
Requirements by ASME B31.8
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(Enter values in yellow cells for calculations and
in blue cells as information)
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DATA INPUT
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Nominal Pipe Size, NPS =
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in.
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Longitudinal
Weld Joints =
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External
Diameter, D =
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in.
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Material =
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Internal Design Pressure (gauge), Pi =
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psig
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Design
Temperature =
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ᵒF
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Design temp. between −20°F* and 450°F
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* For temp. below of -20ᵒF see parag. 812
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Location Class =
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Long. joint factor, E =
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Table 841.1.6-1
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See table 841.1.7-1
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Design factor, F =
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Spec. min. yield strength, S =
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psi
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See table 841.1.6-1 o 841.1.6-2
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Temperature derating factor, T =
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It's
optional for the designer to include it in the calculation.
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See table 841.1.8-1
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Allow. for corrosion, CA =
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in.
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After
Nominal thickness calculation, t as per 841.1.1,
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it's must be selected
T̅ ≥ tn from ASME B36.10M.
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CALCULATIONS
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Nominal thickness as per 841.1.1, t =
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in.
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t =
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PD
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Minimum thickness required
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2SFET
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Nominal thickness + Corr. Allow., tn =
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in.
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tn = t + CA
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Nom. pipe wall
thickness T̅ ≥ tn =
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in.
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From ASME B36.10M (Thickness most commonly used)
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SCH =
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(Minimum acceptable when applicable)
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