Rupture Disc - Vacuum Vessel - Pressure Relief Valve

[usmcmcc]

I'm using a 24"dia by 48" long steel vessel which is 75% jacketed for 50psig steam in the jacket and full vacuum in the vessel. The steam heats the liquid inside the vessel to just under atmospheric pressure in normal operations. The vessel and jacket are seperatll code to ASME "U" stamp.
Do I use a rupture disc alone to protect the liquid vessel? Or do I use a pressure relief valve? Or both?

 

[TD2K]

Rupture disks are commonly used where the equipment can be taken out of service and isolated to allow you to replace the rupture disk.

Pressure safety valves will close once the pressure drops sufficiently below the set pressure.

Rupture disks are less expensive than safety valves and have a higher capacity. However, they are prone to early failure due to fatigue and should not be operated close to the set pressure (that limit can vary between 70% to 90% of set pressure depending on the type of rupture disk).

You might also want to consider a buckling pin device. They have a lot of the advantages of a rupture disk but avoid a lot of the problems.