Experts: What does a safety valve with 100% redundancy capacity mean? It would be better with illustrations.

The rated discharge capacity of the safety valve is twice the actual exhaust volume

The safe discharge volume of a pressure vessel refers to the amount of gas that must be discharged per unit time when the vessel is under overpressure, in order to prevent its pressure from rising any further. The discharge capacity of a safety valve refers to the amount of fluid discharged per unit time under the discharge pressure when the valve is in its fully open position. For boilers, it is required that the total discharge capacity of the safety valves be greater than the boiler’s maximum continuous evaporation rate, and that the steam pressure inside the drum shall not exceed 1.1 times the design pressure once all safety valves on the drum and superheater have opened. For pressure vessels, it is required that the discharge capacity of the safety valve must be greater than or equal to the safe venting capacity of the pressure vessel. When selecting a safety valve, the following aspects should be considered: (2) Pressure range. Safety valves are designed and manufactured according to nominal pressure standard series, and each type of safety valve has a specific operating pressure range. When selecting, a suitable safety valve should be chosen based on the maximum allowable operating pressure of the boiler and pressure vessel. (3) The discharge capacity of the safety valve selected for emissions must be greater than the safe discharge capacity of the equipment; this ensures that when the boiler or pressure vessel is under overpressure, the safety valve can open to discharge a portion of the fluid in a timely manner, preventing the pressure inside from rising further. Redundancy refers to the portion of the safety valve’s exhaust volume that exceeds the safe venting volume. I can’t remember how to calculate the standard for myself; I need to ask the manufacturer for the parameters when selecting a safety valve

You need a 100% safety valve; by installing two of them, you achieve 100% redundancy as a backup