How can i calibrate an security PV valve (Pressure & vacuum)

[ale_001]

Hi friends,

I hope you can help me, I am working as an instrumentation engineer, son a client want´s we calibrate his Security pressure & vacuum valve, its a Varec, i will attach an image. So whats my problem i have the idea of how calibrate the pressure relief and i have an scheme of what could by ma test table, but i don't have any idea how can i calibrate the vacuum relief. This valve works on a tank with gasoline.

As parameters i have:

Max Press inside allowed(MAWP): 2.5psi
Max Pres outside allowed(MAWV): 0.125psi

Also the client wants we verify the relief capacity allowed (SCFH - of air).
And we adjust the set point.