 Wall Thickness Calculation of Straight Pipes Under Internal Pressure Calculation as per par. 841.1 Steel Piping Systems Design Requirements by ASME B31.8 (Enter values in yellow cells for calculations and in blue cells as information) DATA INPUT External Diameter,  D = mm Material = Internal design pressure (gauge), Pi = barg Design Temperature = ᵒC KPag Design temp. between −29°C* and 232°C * For temp. below of -29ᵒC see parag. 812 Design factor, F  = Long. joint factor, E = See table 841.1.6-1 o 841.1.6-2 See table 841.1.7-1 Temperature derating factor, T = Spec. min. yield strength, S = MPa See table 841.1.8-1 Allow. for corrosion, CA = mm It's optional for the designer to include it in the calculation. Select T̅ ≥ tn mm After Nominal thickness calculation, t as per 841.1.1, it's from ASME B36.10M or B36.19M must be selected T̅ ≥ tn from ASME B36.10M or ASME B36.19M. CALCULATIONS Nominal thickness as per 841.1.1, t = mm t = PD Minimum thickness required 2000SFET Nominal thickness + Corr. Allow., tn = mm tn = t + CA Nom. pipe wall thickness T̅ = mm from ASME B36.10M or ASME B36.19M Wall Thickness Calculation of Straight Pipes Under Internal Pressure Calculation as per par. 841.1 Steel Piping Systems Design Requirements by ASME B31.8 (Enter values in yellow cells for calculations and in blue cells as information) DATA INPUT External Diameter,  D = in. Material = Internal design pressure (gauge), Pi = psig Design Temperature = ᵒF Design temp. between −20°F* and 450°F * For temp. below of -20ᵒF see parag. 812 Design factor, F  = Long. joint factor, E = See table 841.1.6-1 o 841.1.6-2 See table 841.1.7-1 Temperature derating factor, T = Spec. min. yield strength, S = psi See table 841.1.8-1 Allow. for corrosion, CA = in. It's optional for the designer to include it in the calculation. Select T̅ ≥ t in. After Nominal thickness calculation, t as per 841.1.1, it's from ASME B36.10M or B36.19M must be selected T̅ ≥ tn from ASME B36.10M or ASME B36.19M. CALCULATIONS Nominal thickness as per 841.1.1, t = in. t = PD Minimum thickness required 2SFET Nominal thickness + Corr. Allow., tn = in. tn = t + CA Nom. pipe wall thickness T̅ = in. from ASME B36.10M or ASME B36.19M
 Discussion and References Information about Wall thickness calculation of straight pipes under internal pressure: ASME B31.8 Gas Transmission and Distribution Piping Systems, para. 841.1.1 Tables and Standards - Table D-1 Specified Minimum Yield Strength for Steel Pipe Commonly Used in Piping Systems - Table 841.1.6-1 Basic Design Factors - Table 841.1.6-2 Design Factors for Steel Pipe Construction - Table 841.1.7-1 Longitudinal Joint Factor, E - Table 841.1.8-1 Temperature Derating Factor, T, for Steel Pipe - ASME B36.10M-Welded and Seamless Wrought Steel Pipe - ASME B36.19M-Stainless Steel Pipe Equations for Wall thickness calculation of straight pipes under internal pressure (841.1.1): t = PD (U.S. Customary Units) 2SFET t = PD (SI Units) 2000SFET tn = t + CA Corrosion allowance is not included in the parra. 841.1.1 It is optional to the designer its inclusion in the calculation. The parameters in the wall thickness calculation of straight pipes under internal pressure equations above are: D = nominal outside diameter of pipe, in. (mm) E = longitudinal joint factor obtained from Table 841.1.7-1 [see also para. 817.1.3(d)] F = design factor obtained from Table 841.1.6-1. P = design pressure, psig (kPag) (see also para. 841.1.3) S = specified minimum yield strength, psi (MPa), from appendix D T = temperature derating factor obtained from Table 841.1.8-1 CA = Sum. of Allow. for Corrosion, in. (mm) t = nominal wall thickness, in. (mm)