Hello,
I am searching for guidance on best practice for considering the wetted surface area for the tube side of a shell and tube heat exchanger. I have read in some engineering manuals that if the shellside material bubble point at relieving temperature is higher than the tubeside, then the shell surface area should be considered in the tube side wetted surface area because heat will transfer through the shell fluid into the material in the tubes and tube side and contribute heat through that.
My question is what is the best practice to consider for if the material in the shell and tube side is the same? I think the conservative answer is to include both the shell and tube area in the interest of increased safety. I also think that the shell side relief will open and if sized properly will be able to handle the heat input from the shell side fire exposure. And logically I think the tube side will see some increased heat input albeit likely less than the full heat input to the shell as vaporizing liquid removes heat input from the shell. I have internal resources I can consult for this question but I am validating an old contingency that used only the tube side head area in the exchanger in question with the same material on both sides. Any guidance is appreciated even if you are able to direct me to resources to read (I have read and can consult further API520/521 if I am misremembering a section that deals with this question in particular, etc)
I can provide more information if necessary about the exchanger in question but I'm more interested in a general guidance on what surface area to consider for a shell and tube heat exchanger with the same material on both sides.
Thank you for your time.