/// material properties reference - click to load
| Material | Grade | SMYS (MPa) | SMTS (MPa) | Allow. S (MPa) | Max T (°C) | Application |
|---|
/// key formulas - ASME B31.3 and B31.8
ASME B31.3 - Required wall thickness:
t_min = (P x OD) / (2 x S x E x W + 2 x P x Y) + c + mill_allowance
where: P = design pressure (MPa) | OD = outside diameter (mm)
S = allowable stress (MPa) | E = quality factor | W = weld joint factor
Y = temperature derating factor | c = corrosion allowance (mm)
MAOP from existing pipe (B31.3):
P_max = (2 x S x E x (t_nom x (1 - mill/100) - c)) / (OD - 2 x Y x (t - c))
Hoop stress (Barlow - thin wall, D/t > 20):
sigma_h = P x D / (2 x t) [MPa, with P in MPa and D,t in same unit]
Hoop stress (Lame - thick wall, D/t ≤ 20):
sigma_h = P x (ri^2 + ro^2) / (ro^2 - ri^2) [at inner wall]
sigma_h_outer = 2 x P x ri^2 / (ro^2 - ri^2) [at outer wall]
Longitudinal stress: sigma_L = P x ri^2 / (ro^2 - ri^2) + F / A
Radial stress (inner): sigma_r = -P (compressive)
Von Mises: sigma_vm = sqrt(sigma_h^2 - sigma_h x sigma_L + sigma_L^2 + 3 x tau^2)
Design factor B31.8: t = P x D / (2 x SMYS x F x E x T)
F = 0.72 (Class 1 Div 2) | 0.60 (Class 2) | 0.50 (Class 3) | 0.40 (Class 4)
/// API 5L pipe grades quick reference
| Grade | SMYS min (MPa) | SMTS min (MPa) | C max (%) | Typical application |
|---|
| A25 | 172 | 310 | 0.29 | Low pressure gas gathering |
| A | 207 | 331 | 0.22 | Low pressure distribution |
| B | 241 | 414 | 0.22 | Standard oil and gas pipelines |
| X42 | 290 | 414 | 0.26 | Cross-country pipelines |
| X46 | 317 | 434 | 0.26 | Cross-country pipelines |
| X52 | 358 | 455 | 0.26 | High pressure oil/gas pipelines |
| X56 | 386 | 490 | 0.26 | High pressure transmission |
| X60 | 413 | 517 | 0.12 | Long distance transmission |
| X65 | 448 | 531 | 0.12 | Offshore and deepwater |
| X70 | 482 | 565 | 0.12 | HPHT and subsea |
| X80 | 551 | 621 | 0.10 | Ultra-high pressure |