Maximum Design Pressure for API 650 Tank
Maximum Design Pressure for API 650 Tank
(OP)
Dear Fellow Members,
We are ordering an API 650 tank for storing Hydrocarbons.
Please confirma the maximum design pressure a dome roof tank can be designed ?
API 650 describes at page 5-5 under the deisgn considerations for loads that maximum internal deisgn pressure is 2.5 psi. but does not specify the type of roof.
Is it the maximum pressure a tank can be designed as per API650 irrespective of the type of roof?
We are ordering an API 650 tank for storing Hydrocarbons.
Please confirma the maximum design pressure a dome roof tank can be designed ?
API 650 describes at page 5-5 under the deisgn considerations for loads that maximum internal deisgn pressure is 2.5 psi. but does not specify the type of roof.
Is it the maximum pressure a tank can be designed as per API650 irrespective of the type of roof?





RE: Maximum Design Pressure for API 650 Tank
Theoretically, any roof can be designed for pressure, but steep self-supporting cones or domes lend themselves to pressurized use better. Before specifying domes, check with your tank suppliers for availability.
RE: Maximum Design Pressure for API 650 Tank
That is what I also thought....however, in the mean time. I referred API 620 as well for Tank design pressure.
It dictates in the scope itslef i.e. page 1-1 point no.1.2.2
Quote:
"The tanks described in this standard are designed for metal temperature not greater than 250 DegF and with pressures in their gas or spaces not more than 15 lbf/in.2"
How do u signify this pressure stated by API 620 which is almost 06 times of pressure in tanks as guided by API 650?
This is very cruicial to understand as it has a severe impact on deciding the design pressure.
See the attachments of excerpts from standards
RE: Maximum Design Pressure for API 650 Tank
Joe Tank
RE: Maximum Design Pressure for API 650 Tank
If API-620 has always been the primary Code for pressurized tanks. Why the title of API620 appears as:-
"Design and Construction of Large, Welded, Low Pressure Storage Tanks"
I wonder the versatility of standards sometimes confusing too.
RE: Maximum Design Pressure for API 650 Tank
Joe Tank
RE: Maximum Design Pressure for API 650 Tank
It is all relative......drawing a bigger line in front of a small line.......2nd line automatcially becomes larger...and hence happened to my thoughts....!!
Thanks any ways...!!
RE: Maximum Design Pressure for API 650 Tank
Anything less can be designed to any code you wish, unless in your locale there is a law against it. API-650 just helps to make more economic choices. If you wanted I could design you up a tank with a design pressure of 14.9 psi with a flat roof. It would just be fairly expensive.
RE: Maximum Design Pressure for API 650 Tank
My sincere apologies if I sounded rude in my response. I did not intend to be so rude.
Joe Tank
RE: Maximum Design Pressure for API 650 Tank
Anything below 15psi (in this part of the world) is considered low pressure. High pressure above.
So, 620 allow for building tanks to withstand the low-high pressures, 650 for closer to ambient.
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Maximum Design Pressure for API 650 Tank
For example, in API-12F, the tank designs are stated to be good for 1.0 PSI, so the assumption is that any API-12F tank is adequate for that pressure, whether required for a particular application or not.
In contrast, most API-650 tanks are not designed for any pressure. Of those that are designed for pressure, it is very seldom the full 2.5 PSI that is designed for.
If you have a small vessel, the difference between a 20 psi and a 40 psi design may be negligible, and it's not unreasonable to specify a 50 psi pressure when you only really need 20 psi. But if you have a large tank (say 150' diameter), raising the pressure from atmospheric to 2.0 PSI may cost thousands and thousands of dollars.
RE: Maximum Design Pressure for API 650 Tank
What is the capacity of the tanks you are considering?
Joe Tank
RE: Maximum Design Pressure for API 650 Tank
RE: Maximum Design Pressure for API 650 Tank
JoeTank,
we are planning for a 400m3 tank.
RE: Maximum Design Pressure for API 650 Tank
Joe Tank
RE: Maximum Design Pressure for API 650 Tank
My query was raised at very initial stage.
Thanks for the suggestions and advice.
RE: Maximum Design Pressure for API 650 Tank
RE: Maximum Design Pressure for API 650 Tank
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>