Pipe & Flange Reference — validation & limitations

What it calculates

• Pipe dimensions and section properties with ASME B36.10M / B36.19M wall schedules on EN 10220 outside diameters — 5S, 10S, Sch 10, 20, 40, 60, 100, 120, 160, STD, XS and XXS, each offered only at sizes where the standard defines that wall
• Barlow allowable pressure with ASME B31 design factor, SMYS material presets and utilisation check
• Darcy-Weisbach flow velocity and pressure drop with Swamee-Jain friction factor, Reynolds number and flow-regime classification
• Pipe section properties — flow area, moment of inertia, section modulus, radius of gyration and mass per metre

Standards this tool applies

• ASME B31.3 — ASME B36.10M / B36.19M pipe dimensions and a Barlow allowable-pressure screen with a selectable design factor (not a B31.3 factor) — feeds the B31.3 wall-thickness inputs.
• ASME B36.10M — Pipe dimension lookup for DN 6 to DN 600 — OD, wall thickness by schedule, ID, flow area, section properties and pipe mass, plus a Barlow allowable-pressure screen (user-entered design factor, no mill-tolerance deduction) and Darcy-Weisbach pressure drop. ⚠️ The WALL SCHEDULES follow ASME B36.10M / B36.19M, but the OUTSIDE DIAMETERS are the EN 10220 metric DN series, which differs from B36.10M at several sizes — most significantly DN 65 (EN 76.1 mm vs NPS 2-1/2 at 73.0 mm). Use the ASME OD from B36.10M if you are working to an ASME line class.

Validation evidence — independent reference cases (3)

Each case runs the tool's engine on a worked example whose values come from a published source or a hand derivation from the cited equations, and an automated regression test asserts the engine against those values within the stated tolerance. "Conservative" means the engine is known to sit on the safe side of the reference and the test asserts that side. Sources are cited; their text is not reproduced.

• Barlow allowable pressure and utilisation verdict, API 5L X52 pipe

  Agrees

  Source: ASME B31.8 §841.11 design formula P = (2·S·t/D)·F·E·T; ASME B31.4 §403.2.1 (same Barlow form); API 5L X52 SMYS 52 000 psi

  Inputs: NPS 12 OD 12.750 in, wall 0.375 in, SMYS 52000 psi, F 0.72, E = T = 1; test pressures 1500 / 2000 / 2300 psi

  Quantity	Reference value	Tolerance
  Allowable pressure	2202.35 psi (151.847 bar)	1e-5 relative
  Utilisation at 1500 psi	0.68109 (OK)	1e-5 relative
  Utilisation at 2000 psi	0.90812 (CHECK)	1e-5 relative
  Utilisation at 2300 psi	1.04434 (FAIL)	1e-5 relative

  tests/golden/REF-dn-barlow.golden.test.ts

• Pipe velocity, Reynolds number and Darcy-Weisbach pressure drop

  Agrees

  Source: Darcy-Weisbach with implicit Colebrook-White friction factor (Colebrook 1939; Crane TP-410 Ch. 1 / Moody chart; Munson, Fundamentals of Fluid Mechanics, Ch. 8); laminar f = 64/Re; Moody roughness 0.046 mm

  Inputs: NPS 4 Sch 40 (OD 114.3 mm, t 6.02 mm), water 998.2 kg/m³, 1.002e-3 Pa·s, Q 50 and 150 m³/h; oil 870 kg/m³, 0.046 Pa·s, Q 10 m³/h

  Quantity	Reference value	Tolerance
  Velocity (50 m³/h)	1.691087 m/s	1e-6 relative
  Reynolds number (50 m³/h)	172 274.8	1e-6 relative
  Pressure drop (50 m³/h, turbulent)	262.985 Pa/m	1.5 % relative; engine not below Colebrook by more than 0.5 %
  Pressure drop (oil, laminar)	47.60935 Pa/m	1e-6 relative

  Conservative simplification: The engine uses the explicit Swamee-Jain friction factor, which sits about 0.53 % above implicit Colebrook-White on this case, i.e. on the conservative side.

  tests/golden/REF-dn-pressure-drop.golden.test.ts

• Pipe section properties and mass vs ASME B36.10M, NPS 4 Sch 40

  Agrees

  Source: ASME B36.10M dimension table, NPS 4 / DN 100 Sch 40 (STD): I 7.23 in⁴, Z 3.21 in³, 16.07 kg/m (property columns as in Crane TP-410 Appendix B); B36.10M mass formula w = 0.0246615·(D − t)·t; hand derivation from I = π/64·(D⁴ − d⁴)

  Inputs: OD 114.3 mm, wall 6.02 mm (ID 102.26 mm)

  Quantity	Reference value	Tolerance
  Moment of inertia I	301.052 cm⁴ (table 7.23 in⁴)	1e-6 vs formula; 0.15 % vs published table
  Section modulus Z	52.6775 cm³ (table 3.21 in³)	1e-6 vs formula; 0.25 % vs published table
  Mass per metre	16.0755 kg/m (table 16.07)	1e-4 vs formula; 0.1 % vs published table
  Radius of gyration	38.342 mm	1e-6 relative

  tests/golden/REF-dn-section-properties.golden.test.ts

Limitations

Conservative simplifications

• Pipe velocity, Reynolds number and Darcy-Weisbach pressure drop — The engine uses the explicit Swamee-Jain friction factor, which sits about 0.53 % above implicit Colebrook-White on this case, i.e. on the conservative side.

Not checked by this tool

• Code wall-thickness design with mill tolerance and corrosion allowance — The Barlow figure is a screen; check the wall with /pipestress (ASME B31.3 section 304) or the governing code
• Temperature derating of the allowable stress and the weld-joint factor — SMYS at room temperature; apply the code's temperature and weld factors
• Flange pressure-temperature rating — Flanges are a dimension lookup; check the P-T rating for the material group (EN 1092-1 / ASME B16.5)
• Gasket selection and flange bolt load / torque — Check the bolting with the /seals gasket module or EN 1591-1
• Fittings, valves and the system pressure drop — A straight run only; use /pipeflow for a system