Environmental stress cracking occurs when a susceptible thermoplastic, damaging chemical, and tensile stress combine, often below short-term yield strength. Reliable tower-internal design requires exact resin-grade selection, service-specific long-term testing, low-stress geometry, thermal-movement allowance, controlled welding and tightening, and inspection of notches, holes, welds, and restrained connections. It is a distinct mechanism from ordinary corrosion, swelling, or thermal creep.

Ship and offshore motion repeatedly tilts liquid surfaces, redistributes tray and packed-bed flow, changes downcomer seals, creates sloshing loads, and applies cyclic forces to tower internals. Reliable FPSO and FLNG design requires a defined six-degree-of-freedom motion basis, orientation-sensitive hydraulic analysis, adequate distributor head and freeboard, controlled compartmentation, packing restraint, and fatigue-resistant supports. Stationary performance tests alone cannot demonstrate suitability at sea.

Duplex stainless-steel tower internals obtain their performance from controlled ferrite–austenite balance and freedom from harmful intermetallic phases. Alloy chemistry verified by PMI is not enough. Reliable procurement defines product form, forming limits, filler metal, heat input, interpass temperature, shielding, repair limits, phase-balance verification, corrosion testing where required, surface restoration, and controlled field modification.

Gas binding occurs when entrained, evolved, or displaced gas becomes trapped in distributor headers, laterals, troughs, or submerged inlets. It causes delayed filling, pressure oscillation, intermittent discharge, branch maldistribution, and dynamic loading. Prevention requires mapping true high points, providing safe and cleanable vent paths, controlling feed aeration and flashing, testing from an empty condition, and verifying installed orientation and slope.

Vacuum-truck hoses can create concentrated differential pressure or depressurize enclosed internal compartments when a nozzle seals against thin tower components. Prevention requires suitable stand-off nozzles, vacuum relief, verified vent paths, component-specific limits, controlled hose routing, and structural review of corroded internals. Any seal or movement event should trigger inspection because small deformation can impair tray, distributor, demister, or packing performance.