Adding stiffening ring due to change of service
Adding stiffening ring due to change of service
(OP)
Is is possible to add a stiffening ring/s to increase the fill height of a change of service tank? I would like to change service of a storage tank, but based on API653 calcs and the new specific gravity, the tank level will have to be significantly reduced (original S.G.=1.0, new S.G.=1.21). Is there any option to increase the fill height allowed by 653?





RE: Adding stiffening ring due to change of service
Theoretically, you could add hoops to a tank and increase the strength of it and thus the fill level. However, it's not normally done, and so is not included in the design codes. (The hoops don't actually have to be stiffeners, they just need to act in tension.)
RE: Adding stiffening ring due to change of service
RE: Adding stiffening ring due to change of service
If you start using excess thickness from the shell due to higher specific gravity, you'd also need to recheck reinforcing area at repads. And there might be some increase in manway flange and cover thicknesses.
RE: Adding stiffening ring due to change of service
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Adding stiffening ring due to change of service
The other ideas presented (corrosion allowance, temperature, actual vs. calculated thickness, tank jacking, etc.) are all excellent, but only within the restrictions of the foundation and soil as LittleInch mentioned. There are ways to increase the foundation if necessary, but the added expense may be out of your budget.
RE: Adding stiffening ring due to change of service
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way