What materials maintain toughness at cryogenic temperatures?
9% nickel steel for storage tanks. Aluminum 5083 for transfer piping. Austenitic stainless steels for process lines. INVAR alloys for special applications. All materials certified for -165°C service.
How are LNG pipe welds qualified for cryogenic service?
Charpy testing at -196°C demonstrates toughness. CTOD testing validates fracture resistance. Macroetching verifies weld penetration. Bend testing confirms ductility. Production test coupons accompany each weld procedure.
What insulation systems prevent boil-off?
Vacuum-insulated piping for transfer lines. Polyurethane foam with vapor barrier. Perlite-filled annular spaces. Multi-layer superinsulation. All systems include moisture monitoring.
How are LNG pipes commissioned?
Nitrogen purging to <1% oxygen content. Cool-down procedures with liquid nitrogen. Thermal contraction monitoring. Pressure testing with instrumented monitoring. Final leak testing with methane detectors.
What safety systems protect LNG piping?
Emergency shutdown valves every 200m. Leak detection with infrared cameras. Fire protection deluge systems. Vapor dispersion modeling. Regular emergency response drills.
