ASME 31.3 - Skillet Flange for Hydro testing
ASME 31.3 - Skillet Flange for Hydro testing
(OP)
The application is to insert a flange skillet temporarily on two ends to hydrostatic test a 24" line. I am using the equation found in ASME 304.5.3 for determing the thickness "t" of Blanks. Namely, equation 15, where t= d(3P/16SE)^.5 + c. I am unable to verify the customers thickness requirements using the given information:
Skillet material = SA-514 GR 100, d = 23 in, t = 1/2 in, E = 1, S = 90,000 psi (90% yield for temporary use), and c = 0. Solving for P, I get 227 psi.
Apparently, they claim that one can test up to 341 psi. I am getting a much lower number and think you will need a thicker plate to reach this test pressure. Is there an exception that I am missing when you are using a skillet for testing only? I don't have API 590 handy, but is there a different equation in there? The goal here is minimizing the spreading distance due to field conditions.
Thanks for your help
Skillet material = SA-514 GR 100, d = 23 in, t = 1/2 in, E = 1, S = 90,000 psi (90% yield for temporary use), and c = 0. Solving for P, I get 227 psi.
Apparently, they claim that one can test up to 341 psi. I am getting a much lower number and think you will need a thicker plate to reach this test pressure. Is there an exception that I am missing when you are using a skillet for testing only? I don't have API 590 handy, but is there a different equation in there? The goal here is minimizing the spreading distance due to field conditions.
Thanks for your help





RE: ASME 31.3 - Skillet Flange for Hydro testing
Think I would go to 1" and use some banana wedges to get it in.
RE: ASME 31.3 - Skillet Flange for Hydro testing
I think that your concern is the risk we are trying to minimize. Most cases if it bulges out, you need to cut back on the pipe and weld in a new pup piece, which kills you in cost. My concern is that we may not be able to spread a few of the flanges to get that 1".
Any other thoughts regarding the calculations?
RE: ASME 31.3 - Skillet Flange for Hydro testing
I think you'd find this paper http://sto
I'm not too sure you're bound by any code on this (check local laws and regulations etc). Components which exist only to support a hydrotest and are removed from the system prior to placing the system into service don't fall into code jurisdiction. As long as they are fit for purpose i.e. they hold the hydro pressure they are acceptable. Just be sure you can pull 'em out if they dish a bit.
Keep us posted as to how this project proceeds. My guess is that if they use 1/2" blinds they will see dishing of less than 1/4".
jt
RE: ASME 31.3 - Skillet Flange for Hydro testing
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RE: ASME 31.3 - Skillet Flange for Hydro testing
Regards, BCG1