Thickness compliance
t_nom at or above t_min, and MAOP at or above design pressure
COMPLIANT
Home / ASME B31.4 Wall & MAOP
Live calculator
ASME B31.4 Wall Thickness & MAOP Sizer
A dedicated sizer for ASME B31.4 liquid pipelines. Choose a mode, enter pipe and design data, and get the pressure design result for that mode. Design factor F is fixed at 0.72 for B31.4 liquid service. Switch to US Customary to convert the inputs already in the form.
Section 1
Units & Sizing Mode
Unit system
Sizing mode
Design factor F is fixed at 0.72 for ASME B31.4 liquid pipelines.
Section 2
Pipe & Design Parameters
mm
MPa
kPa
mm
mm
factor
1.00 for Seamless or ERW. Use a lower value for EFW or lap weld.
factor
T stays 1.00 at or below 121 C. This tool does not apply a full temperature table.
Section 3
Minimum required wall (t_min)
Allowable hoop stress S
347.76 MPa
S = F x SMYS, F = 0.72 for ASME B31.4
Pressure design thickness t_p
7.25 mm
t_p = (P x D) / (2 x S x E x T)
Minimum required wall t_min
8.85 mm
t_min = t_p + corrosion allowance
Design pressure capacity (MAOP)
9,930 kPa
MAOP = 2 x (t_nom - A) x S x E x T / D
D/t slenderness
57.4 nom / 57.4 min
Limit is D/t of 140 or less for both checks
Slenderness D/t
D/t_nom and D/t_min at or below 140
PASS
What this tool calculates
Allowable hoop stress is S = F times SMYS, with F fixed at 0.72 for ASME B31.4 liquid pipelines. Pressure design thickness is t_p = (P x D) / (2 x S x E x T). Minimum required wall is t_min = t_p plus the corrosion allowance. MAOP is 2 x (t_nom minus A) x S x E x T / D.
In Required wall mode, enter the design pressure and the tool solves for t_min. The nominal wall field is optional in this mode and is used only to check slenderness and compliance if entered. In MAOP mode, enter the selected nominal wall thickness and the tool solves for MAOP. The design pressure field is optional in this mode and, if entered, is used only to show a compliance check against that target.
Slenderness checks are D/t_nom and D/t_min. Either ratio above 140 fails that check.
Metric uses mm, kPa, and MPa, with SMYS converted from MPa to kPa inside the hoop stress term. US Customary uses inches and PSI, including SMYS in PSI. Switching the unit toggle converts values already in the form, length and thickness by 25.4, SMYS by 145.038, and pressure by 0.145038. E and T are dimensionless and do not convert.
This page uses the same pressure design math as the suite wide Wall Thickness calculator, locked to the ASME B31.4 design factor. It does not apply location class factors, since ASME B31.4 does not use location classes. Default E is 1.00 for Seamless or ERW. Default T is 1.00 at or below 121 degrees C or 250 degrees F. This tool does not apply a full temperature derating table or a mill tolerance adjustment.