In sizing multiple relief valves, should each valve be sized for full relief load? OR the Total relief load should be shared between the multiple valves.
The total relief load can be shared between multiple valves.
Typically, each valve has at least 25% of the total required area.
At least one valve should have set pressure less than or equal to the vessel MAWP.
The other safety valves may have set pressure less than or equal to 105% of MAWP.
120% of the Total flow or one spare
(if you have 5 PSV each will be 24% of the max flow)
One with a lower set-point is a nice trick to overcome small bumps, but you need to make sure that your vent line stay atmospheric (otherwise you will cause back pressure on the others)

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