Setting PV and EV HELP

[lpfaustini]

Dear Community,

I would like to ask a question about Emergency Relief Valve & Pressure/Vacuum Relief.

Following API-650 appendix F, I calculated a max design pressure of 9,6 kPa. I suppose I’ll have to limit our PV at 9,6 kPa or less.

But, I do not want to use anchorage, and if I use this limit, I’ll have to use it. So, calculating the overturning stability, I found that an internal pressure of 3 kPa is enough to avoid anchorage.

According to the information above, am I correct to request our VALVE SUPPLIER to specify PV limit at 3 kPa and EV limit at 9,6 kPa?

Thanks in advance,
Luiz

 

[LittleInch]

You've managed to answer your own question. No anchoring = 3kPa, therefore this is your design pressure and you set your vent pressures accordingly. See other recent threads on this page about set points for Pv and ev. You really need to set pv below ev, but neither should allow the internal preassure to exceed your design pressure.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[LittleInch]

See the post below called emergency relief venting which covers this in more depth.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way