Block valves in Relief Systems

I am a process engineering coming from Refinery and Petrochemical environment now working with LNG in Norway (so I don’t now al the American codes and guidelines, but we are used to API 520 and 521.
One of our suppliers is planning to install butterfly valves as block valves in a relief system. The valves will be located up and down stream relief valves on double installations and on battery limit from a skid unit, al the valves will be equipped with interlock equipment to avoid closing when the system should be in operations.
My (our) worries is to install butterfly valves in a relief system where the gas velocities can be very high. My experience from my previous projects is that we have used ball or gate valves. Is there anyone with experience or an opinion on this matter?

 

[zerosum]

There are high performance butterfly valves that probably could take this service. Vanessa is one such, but you will need a writen committment that the application is valid.