PTFE gaskets can lose thickness and bolt preload through cold flow, causing internal leakage even when the initial test was satisfactory. Reliable sealing requires rigid and aligned flange geometry, controlled gasket stress, adequate bolt spacing, extrusion resistance, staged tightening, temperature evaluation, and inspection after relaxation or thermal cycling.

Rapid depressurization can create temporary pressure differences between tower sections because gas inventories do not equalize instantly through packing and internals. These transient loads may act opposite to normal operation and can lift, buckle, or unseat panels. Safe design requires dynamic pressure evaluation, bidirectional structural checks, verified equalization paths, and targeted inspection after any abnormal depressurization event.

When liquid viscosity changes strongly with temperature, local temperature gradients inside a distributor can create major flow differences between outlets. The imbalance may reinforce itself through residence time and cooling. Reliable design requires evaluation of cold startup, normal operation, turndown, heat loss, header residence time, outlet Reynolds number, mixing, insulation, and representative testing—not a single nominal viscosity value.

Trough distributors can develop liquid-level oscillations caused by inlet momentum, control cycling, slug flow, gas release, surface waves, and unstable compartment overflow. Correct average flow does not guarantee stable packing irrigation. Dynamic testing, multi-point level observation, controlled inlet momentum, proper equalization, and coordinated control-system design are required.

Weld root oxidation forms when the inside surface of stainless-steel piping is not adequately protected during welding. Severe heat tint or sugaring reduces corrosion resistance, increases roughness, traps deposits, and can disturb distributor hydraulics. Reliable acceptance requires controlled backing-gas purging, oxygen measurement, protected tack welds, internal inspection, and defined rejection and repair criteria.