SAMPLE
Piping Toolset — Calculation Report
generated by calc-core · 2026-07-21
ProjectSample Project — Demonstration Only Job No.SAMPLE-001 Client—
CalculationASME B31.3 Allowable Working Pressure Calculator Calc byPiping Toolset (calc-core) Checked byUNCHECKED — sample
Date2026-07-21 Rev0 BasisASME B31.3 ¶304.1.2 Eq. (3a), solved for P (B31.12 Mf supported)

1 · Design inputs

NPS 8 Sch 40 (8.625 in OD × 0.322 in wall), S = 17,500 psi, E = 1.0, y = 0.4, corrosion allowance 0.065 in, 12.5% mill tolerance.

Outside diameter D8.625in
Nominal wall t0.322in
Mill tolerance12.5%
Allowance A0.065in
Allowable stress S17,500psi
Quality factor E1.0—
Coefficient y0.4—

2 · Method

Thickness available for pressure, then Eq. (3a) inverted:

tp = t·(1 − mill tol) − A

P = 2·S·E·tp / ( D − 2·y·tp )

The hydrogen line applies the same form with the B31.12 material performance factor Mf multiplying S·E.

3 · Calculation

  1. Thickness available for pressure: tp = 0.322·0.875 − 0.065 = 0.28175 − 0.065 = 0.21675 in.
  2. Allowable pressure: P = 2·17,500·0.21675 / (8.625 − 2·0.4·0.21675) = 7,586.25 / (8.625 − 0.17340) = 7,586.25 / 8.45160 = 897.6 psi.

4 · Results COMPUTED

tp — thickness available0.21675in
Allowable pressure897.6psi

5 · Verification statement

The result values above are locked as fixture b31-allowable-pressure.json, case “NPS 8 sch 40, S=17500, E=1, y=0.4, Mf=1”, tolerance 0.001, in the calc-core continuous verification gate (see https://pipingtoolset.com/trust/validation.html). Allowable-stress and factor data are user-supplied inputs; citations: ASME B31.3, Process Piping — ¶304.1.2 Eq. (3a), solved for internal pressure. · ASME B31.12, Hydrogen Piping — Part IP material performance factor Mf (applied multiplicatively when used from the Hydrogen line).

SAMPLE REPORT — auto-generated from a verification fixture to show the report format. Not a project calculation. ⚠ Engineering-aid tool. Public code equations; allowable-stress and factor data are user-supplied. Results MUST be independently verified and reviewed by a qualified/licensed engineer before any design, fabrication, or operation decision.