Types :

Accumulators and dampeners, Bottom and Foot valves, Closures, Dehydrators,
Drains and cocks, Fill caps and adaptors, Flame /detonation arrestors, Floating
suctions (Aviation), Gage  and  inspection  hatches, Level indicators, Manholes,
Roof structures and seals, Sample ports, Sight windows, Surge tanks, Swing joints, Tank vents (Breather, Emergency, Pressure & Vacuum)