⚠ Safety-critical — screening ECA only. Single axial surface flaw, deepest point, fw=1, ρ=0 unless supplied. Includes an axial-flaw Folias bulging magnification and the Newman-Raju bending term (for high c²/Rt confirm K with the full BS 7910 Annex M / API 579 Part 9 cylinder solution); excludes fatigue growth, embedded/circumferential flaws, and weld mismatch. Not for safety case submission, regulatory filing, or formal engineering critical assessment without SME review — use Crackwise / API 579 software for ECA of record.

Geometry & Loading

Pipe outer diameter

Wall thickness

Internal pressure (or use membrane below)

MPa

Membrane stress (optional, overrides pressure)

MPa

Bending stress (optional)

MPa

Flaw & Material

Crack depth a

Crack length 2c

Yield strength σ_Y

MPa

Ultimate tensile σ_U

MPa

Fracture toughness K_mat

MPa√m

ρ secondary/residual (optional)

—

Engineering Basis

K_I = P_m·F·√(πa/Q) — Newman-Raju (1981) semi-elliptical surface crack, deepest point (φ=90°), Q = 1+1.464(a/c)^1.65.
Reference stress σ_ref = [P_b+√(P_b²+9P_m²(1−α)²)]/[3(1−α)²], α = (a/t)/(1+t/c) — BS 7910:2019 surface flaw.
FAD Level-2A: K_r = (1−0.14L_r²)(0.3+0.7e^−0.65Lr⁶); L_r,max = (σ_Y+σ_U)/(2σ_Y).
Point: L_r = σ_ref/σ_Y, K_r = K_I/K_mat + ρ. Acceptable if on/under the curve and L_r ≤ L_r,max.
Reserve factor = radial load multiplier to the FAD envelope (collapse-capped).
Standards: BS 7910:2019, API 579-1/ASME FFS-1 (2021) Part 9, Newman-Raju 1981, 49 CFR 192.624(c)(3)/192.632/192.712.

Engineering Critical Assessment (ECA)

Geometry & Loading

Flaw & Material

Engineering Basis

FAD Assessment

Assessment Point

Drivers

Compliance Checks

Engineering Critical Assessment (ECA)

Geometry & Loading

Flaw & Material

Engineering Basis

FAD Assessment

Assessment Point

Drivers

Compliance Checks

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