Rating Day Tank w/ Stiffeners and conical bottom
Rating Day Tank w/ Stiffeners and conical bottom
(OP)
I have been asked to calculate the ratings (internal and external pressure) of two existing, UNSTAMPED day tanks.
I am trying to figure out which code to apply...but the tanks do not seem to fit any of them
they are small 100 gallon vessels....lug supported....have a conical bottom....welded plate top...supported by lugs welded to the vessel....and there are stiffener rings on the shell. There are actually 3 stiffener rings around the shell and then they are all connected on either side of the tank by a longitudinal stiffener.
oh and they are not atmospheric. At this point I do not know the pressure but they have conservation vents.
Everything in my gut tells me that I am going to have to analyze the vessel per ASME Section VIII Div 1
I am trying to figure out which code to apply...but the tanks do not seem to fit any of them
they are small 100 gallon vessels....lug supported....have a conical bottom....welded plate top...supported by lugs welded to the vessel....and there are stiffener rings on the shell. There are actually 3 stiffener rings around the shell and then they are all connected on either side of the tank by a longitudinal stiffener.
oh and they are not atmospheric. At this point I do not know the pressure but they have conservation vents.
Everything in my gut tells me that I am going to have to analyze the vessel per ASME Section VIII Div 1





RE: Rating Day Tank w/ Stiffeners and conical bottom
RE: Rating Day Tank w/ Stiffeners and conical bottom
This is a dangerous business that you are in...
I suggest that; despite whatever pressure that you calculate you should consider testing these unstamped vessels. (Can you test a few to destruction ?)
For smaller diameters, (say ...less than 48 inches) I would expect to see positive 3-8 psig as being reasonable.
(The deflection of the flat top head will probably control this)
For external pressures.....good luck perhaps minus 5-10 IWG.
Stand back.... be careful
-MJC
RE: Rating Day Tank w/ Stiffeners and conical bottom
In other words, I can input the existing vessel parameters and it will tell me the allowable pressures.....although it will warn me that it is out of compliance with the code.