API 5L X42 Pipe Calculator
ASME B31.8 — design pressure, minimum wall thickness and MAOP. SMYS is locked to the grade value.
API 5L X42 has a minimum yield of 290 MPa (42 ksi) and is produced in seamless or ERW form. It is used for low-pressure gathering systems and distribution pipelines where moderate strength is sufficient.
When to use this calculator: Size minimum wall thickness for low-pressure gathering lines and check design pressure compliance under ASME B31.8.
Example (API 5L X42)
| OD (mm) | Wall (mm) | Result |
|---|---|---|
| 273.1 | 9.27 | 14.2 MPa | 142 bar design pressure (F=0.72) |
Results are reference values — verify against API TR 5C3 (OCTG) or ASME B31.8 (line pipe) before use in final design.
Design Pressure
P = (2 × t × SMYS × F × E × T) / OD | ASME B31.8 §841.11
E = 1.0 (seamless / full-NDE ERW / LSAW), T = 1.0 (≤120 °C). Adjust per B31.8 Tables 841.115A/B for temperature derating or reduced joint efficiency.
Minimum Wall Thickness
t = (P × OD) / (2 × SMYS × F × E × T) | Rearranged ASME B31.8
Maximum Allowable Operating Pressure (MAOP)
MAOP = (2 × t_actual × SMYS × F × E × T) / OD
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