What material properties are essential for LNG piping?
Special nickel steels maintain toughness at -162°C. Controlled thermal contraction characteristics. High purity to prevent brittle fracture. Excellent weldability for field construction. Proven performance in cryogenic cycling.
How are LNG pipe welds qualified for cryogenic service?
Impact testing at -196°C verifies toughness. CTOD testing validates fracture resistance. Strict control of welding heat input. 100% volumetric examination of all welds. Procedure qualifications for each position.
What insulation systems are used for LNG pipes?
Vacuum-insulated pipe for critical transfers. Polyurethane foam with vapor barrier. Perlite-filled annular spaces. Multi-layer superinsulation for small lines. All systems include moisture protection.
How are LNG transfer systems tested before commissioning?
Helium leak testing of all connections. Cryogenic proving runs with nitrogen. Pressure testing at operating conditions. Emergency shutdown system validation. Final cleanliness verification.
What safety features protect LNG piping systems?
Leak detection with gas analyzers. Emergency release systems. Fire protection coatings and deluge systems. Rapid isolation valves. Overpressure protection devices.
