Protective coatings reduce and irregularly reshape tower-internal holes, slots, mesh openings, sliding clearances, and bolt fits. Reliable design specifies finished dimensions, accounts for maximum coating buildup and stripe coats, prepares edges correctly, controls application and curing, and verifies critical openings after coating. Flat-surface thickness readings alone cannot prove hydraulic suitability; final dimensional inspection and post-coating performance testing are often required.

Caustic stress corrosion cracking can damage carbon-steel, stainless-steel, or other tower internals without major uniform metal loss. Risk depends on material condition, tensile stress, local caustic concentration, temperature, contaminants, and transient mixing or evaporation. Reliable prevention combines service-specific material selection, drainable geometry, controlled injection, low-restraint fabrication, qualified welding, targeted crack inspection, and formal review of every chemical or temperature excursion.

Elemental mercury can penetrate damaged oxide films, amalgamate with aluminum, and promote localized corrosion or liquid-metal embrittlement-related cracking of aluminum tower internals. Ordinary corrosion allowance does not control the risk. Prevention requires effective upstream mercury removal, representative monitoring, low-stress and damage-resistant internal details, controlled handling, and a defined response to breakthrough. Confirmed exposure demands specialist safety, inspection, and fitness-for-service assessment.

Bolt-hole tear-out in tower internals results from bearing, shear-out, net-section rupture, pull-through, prying, or joint slip in thin sheet. Prevention requires realistic load distribution, adequate edge distance and spacing, controlled hole geometry, suitable washers or backing plates, minimum-thickness checks, compatible tightening, and strict field-modification limits. Bolt strength alone cannot demonstrate joint adequacy, and a deformed hole requires evaluation of the entire connection.

Tower-internal perforated plates must satisfy hydraulic free-area requirements without losing the ligament network needed for strength and stiffness. Hole size, pitch, pattern, orientation, edge distance, manufacturing tolerance, cutouts, and support locations determine net-section strength, buckling, deflection, and fatigue resistance. Procurement drawings and inspections should specify minimum ligaments and final as-built geometry, not only nominal open area and plate thickness.