Stainless steel manholes are safety emergency venting devices installed on the top of storage tanks. They are usually used in conjunction with fire extinguishers and mechanical breathing valves to prevent accidents caused by sudden overpressure or vacuum inside the tank due to unexpected reasons. They also serve as a safety fire barrier, acting as a protective device for the storage tank, particularly suitable for dome-shaped atmospheric tanks sealed with nitrogen. They offer features such as pressure-regulated discharge and intake, flexible operation, safety fire prevention, compact structure, good sealing performance, and reliability.

Stainless steel manholes are generally made using steel plates of grade 304 or 316L as raw materials.

Manholes are categorized into emergency relief, explosion-proof fire-retardant breathing, canopy, wall, and core manholes, among others.