Category
Piping & Fittings
Subcategory
Specialty Piping
Applicable standards
3
Issuing bodies
1
Description
ASME B31.12 piping & pipelines for hydrogen service (gaseous, liquid).
Applicable Standards (3)
ASME — 3 standards
ASME B31.12
Hydrogen Piping and Pipelines
Industrial piping (Part IP) and pipelines (Part PL) for gaseous and liquid hydrogen, including hydrogen embrittlement controls.
ASME B31.3
Process Piping
Piping in petroleum refineries; chemical, pharmaceutical, textile, paper, ore-processing plants and related processing facilities. Default process piping code worldwide.
Key requirements (10)
- Process piping — refining, chemical, pharmaceutical, semiconductor.
- Categories: Normal Fluid Service (default), Category D (low pressure < 150 psig & temp 38–186 °C), Category M (lethal), High Pressure, Severe Cyclic, High Purity.
- Allowable stress: lower of UTS/3, Yield/1.5, etc., from Table A-1.
- Wall thickness: t = P·D / (2·(S·E·W + P·Y)) where Y = 0.4 for ductile under 482 °C.
- Joint efficiency E: 1.0 (seamless), 0.85–0.95 (welded depending on RT).
- Hydrotest: 1.5 × design pressure × (S_test/S_design) — ≥ 10 minutes hold.
- Pneumatic test (when hydro impractical): 1.1 × design pressure with safety analysis.
- Examination: 5% RT for Normal service; 100% RT for Category M and Severe Cyclic.
- Flexibility analysis required when temperature differential > 28 °C and complex routing.
- Stress range allowable SA = f·(1.25·Sc + 0.25·Sh) with f = cyclic reduction factor.
ASME B31.8
Gas Transmission and Distribution Piping Systems
Pipelines transporting natural and other gases.
Key requirements (7)
- Gas transmission and distribution piping.
- Class locations 1–4 based on population density within 1/4-mile (200 ft typical x 1 mi each side of pipeline).
- Design factor F: 0.72 (Class 1 Div 2), 0.60 (Class 2), 0.50 (Class 3), 0.40 (Class 4).
- Hydrotest: typical 1.25 × MAOP for 8 hours minimum.
- MAOP = 2·S·t·F·E·T/D — basis for design.
- Compressor stations covered per Chapter VIII (B31.8); offshore per B31.8.S.
- Pipeline integrity management per ASME B31.8S (gas) — covers HCAs (high consequence areas).