Expansion Joint Connection to storage tank

[Amir Sedieqy]

Hello,
In a piping system connected to the outlet of an crude oil tank, process man has located the expansion joint after the valve which is connected to tank's nozzle. Since this expansion joint is located after the valve, it must be able to withstand the design pressure of the piping system. However, if this expansion valve were located before the valve, and was connected to the tank's nozzle, it should have only withstand the pressure due to fluid height in the tank, which is one-twentieth of the piping design pressure. I was wondering whether it is practical to connect the expansion joint directly to the tank's nozzle. I appreciate it if could share your similar experience.

 

[jrmichler]

Your description is unclear. Why is the design pressure of the piping system 20 times higher than the static pressure in the tank when the piping is connected to the outlet of the tank? Is there a pump in there somewhere? Where are the nearest anchor points in the piping system? How is the piping supported near the expansion joint? What is the tank's nozzle, or are you referring to the tank outlet connection?

We need a sketch of the existing system, and a second sketch showing your proposed system.