Storage tank design with special focus on Cryogenic fluids

A: A: Full containment means exactly that — credible inner tank rupture with liquid retained. That's the safety logic. B: NFPA 59A distances don't replace containment philosophy. C: Structural-only thinking ignores why prestressing and crack control exist. D: Procedural overfill controls aren't accepted as a primary barrier in hazard analysis.

A: A: At cryogenic service, cold spring and vapor density matter; 0.15 barg vs 0.2 barg leaves no operating margin. B: Parallel PSVs are common when sized correctly and manifolded. C: Nozzle size depends on relieving case, not tank volume alone. D: MAWP vs design pressure mismatch often hides a real assumption gap.

A: A: This is the industry workhorse for large LNG tanks and behaves predictably at −162 °C. B: Carbon steel hits brittle transition well above LNG temperature. C: Duplex loses toughness and isn't qualified for this service. D: Aluminum works cryogenically, but dismissing it purely on seismic grounds mixes material and structural issues.

A: A: Stress from temperature gradients cracks steel long before steady cold does. B: BOG can be managed; cracked welds can't. C: Annular gas composition is a secondary concern. D: Logistics don't dictate metallurgical limits.

A: A: Slow, uneven heave is the classic long-tail failure mode that shows up in trends, not trips. B: Bearing failures are rare without massive leakage. C: Cryogenic exposure is localized and short-lived in credible cases. D: Prestress loss is temperature-compensated in design.

A: A: Carbon steel goes brittle; transitions exist to manage that exact problem. B: Heat leak is secondary to fracture risk here. C: Penetrations are allowed when detailed correctly. D: Insulation doesn't change weld metal behavior.

A: A: Convective mode sloshing produces meter-scale waves in large tanks. B: Density doesn't kill free-surface motion. C: Linear scaling overshoots real response. D: Containment philosophy doesn't cancel physics.

A: A: Codes assume leaks beyond catastrophic rupture; piping failures still spill LNG. B: No such waiver exists. C: Roof volume isn't the governing spill source. D: Construction-phase controls don't define permanent safety features.

A: A: Small inventory, tight space, frequent cycling — this is what these vessels are built for. B: Massive overkill for volume and duty. C: Carbon steel fails at −196 °C. D: Inertness doesn't fix heat leak or material limits.