SAMPLE
Piping Toolset — Calculation Report
generated by calc-core · 2026-07-21
ProjectSample Project — Demonstration Only Job No.SAMPLE-001 Client—
CalculationPipe Bend Minimum Wall Thickness Calculator (B31.3 ¶304.2.1) Calc byPiping Toolset (calc-core) Checked byUNCHECKED — sample
Date2026-07-21 Rev0 BasisASME B31.3 ¶304.2.1 / B31.1 ¶102.4.5 (I-factor)

1 · Design inputs

NPS 8 (8.625 in OD) bent at R = 12 in (≈1.4D), P = 1,000 psi, S = 20,000 psi, E = 1, y = 0.4, allowance 0.065 in.

Pressure P1,000psi
OD D8.625in
Bend radius R12in
S / E / y20,000 / 1 / 0.4psi, —, —
Allowance A0.065in

2 · Method

With R the bend radius to centerline and D the OD:

Iintrados = (4(R/D) − 1) / (4(R/D) − 2)   Iextrados = (4(R/D) + 1) / (4(R/D) + 2)

tm(I) = P·D / ( 2( S·E/I + P·y ) ) + A

The same form is referenced by B31.1 ¶102.4.5 and the B31.4/B31.12 bend rules; the centerline case (I = 1) reproduces straight pipe.

3 · Calculation

  1. R/D = 12/8.625 = 1.39130 → 4(R/D) = 5.56522.
  2. Iintrados = (5.56522−1)/(5.56522−2) = 4.56522/3.56522 = 1.28049; Iextrados = 6.56522/7.56522 = 0.86782.
  3. Intrados: tm = 1,000·8.625 / (2·(20,000/1.28049 + 400)) + 0.065 = 8,625/32,038 + 0.065 = 0.33421 in.
  4. Extrados: 8,625/46,893 + 0.065 = 0.24893 in; centerline: 8,625/40,800 + 0.065 = 0.27640 in.

4 · Results COMPUTED

I intrados / extrados1.28049 / 0.86782—
tm — intrados (governs)0.33421in
tm — extrados0.24893in
tm — centerline0.27640in

5 · Verification statement

The result values above are locked as fixture bend-thickness.json, case “NPS 8, R=12 in, P=1000, S=20000, E=1, y=0.4, A=0.065”, tolerance 0.0001, 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 — ¶304.2.1, pressure design of bends. · ASME B31.1, Power Piping — ¶102.4.5 (same I-factor form on the Power line card).

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.