Hydrotest & burst pressure calculator
Hydrostatic test pressure per ASME B31.3 §345.4.2 and Barlow's formula for burst and yield pressure of a pipe.
Hydrotest pressure (B31.3)—
Barlow yield pressure—
Barlow burst pressure—
Defaults are A106 Gr B (SMYS 240 MPa, SMTS 415 MPa). B31.3: PT = 1.5 × P × ST/S, with ST/S not more than 6.5. Barlow: P = 2·S·t / D using nominal wall.
Frequently asked questions
What is the hydrotest pressure under ASME B31.3?
At least 1.5 × design pressure, increased by the ratio of allowable stress at test temperature to that at design temperature (ratio capped at 6.5).
What is Barlow's formula?
P = 2·S·t/D — the pressure at which hoop stress in a thin pipe reaches stress S, using wall t and outside diameter D.
Last updated 2026-11-02