Max vacuum allowable for tank & PV-vent 1

[gelsi]

Hi
anyone can give me this valeu and fonts:
Max vacuum allowable for tank (fixed roof & PV-vent)

I have a PV-vent that open at -0.22 kPa
its full open is -0.242 kPa
i remember that a tank resists to -0.25 kPa but a think it can reach -0.35

 

[Latexman]

It depends on the tank. All tanks are not the same. Reference your tank nameplate, drawing, and/or spec. If not available, communicate with tank fabricator and/or designer.

Good luck,
Latexman

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[gelsi]

I'M AGGREE WITH YOU, FABRICATOR OR DESIGNER CAN GIVE THE REAL VALEU, BUT I HAVE SEEN THAT A FREE VENT TANK (ATMOSFERIC TANK)HAVE A MAX POSITIVE PRESSURE OF +0.75KPA, SO I SUPPOSED THERE IS A STANDARD VALUE FOR VACUUM.
THANKS

 

[LittleInch]

The max design external pressure for a "standard" API 650 tank is 0.25kPa. No mention of any variance, which I what I believe you are looking for.

Appendix V allows design of max external presusre to go up to 6.9kPa, but this would be stated on your tank nameplate, which all tanks shold have if you look closely enough somewher eon the lower shell. Max internal pressure is set by the weight and type of the roof up to a certain maximum.

My motto: Learn something new every day

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

 

[don1980]

By default, an API tank can tolerate 1 oz/in2 vacuum (0.43 kPa), even if no vacuum limit is listed. For old API tanks, it's pretty common to find that no vacuum limit is listed in the specification and vendor documents. It'll just say "atm".

For internal pressure, there is no safe default value.

 

[CMA010]

Design code usually specifies the maximum allowable pressure and vacuum, at least the European standards do (EN 14015 or the old BS 2654)