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hydro test for jacketed vessels

hydro test for jacketed vessels

hydro test for jacketed vessels

(OP)
I must design a jacketed vessel (Fig. 9-2, Type 1) acc. to Div. 1.
Design data for
shell : FV / 40 psi @ 284°F
jacket : 40 psi @ 284°F
So part of the schell must be designed for 55 psi.
As I understand UG-99 (e), we must hydrotest the jacket based on this differential pressure (1.3x55xstress ratio). This test-pressure will govern all design calculation for part of the shell and the jacket.
Now my question : I cann´t find any way in the code, to do this ´hydrotest calculations´. Do I have to assume an operating load case at ambient temperature or is there a way to consider lower safety margins for hydrotest condition ?
By this I have some headache to use the stress ratio for hydrotests of jackets, because buckling of the shell normally is governed by young´s modulus.
But I´m not so familiar with the code, so maybe I have missed something.

RE: hydro test for jacketed vessels

No, you don't need to test based on differential pressure. As said in UG-99(e)(1) each chamber is tested as a separate vessel, so the reference pressure is 40 psi for both.
Normally there should be no need for hydrotest calculations (except for instability: see below) under Div.1 coverage. There are exceptions though, e.g. tall columns tested horizontally: in such cases I take 90% of yield stress at test (room) temperature, as specified by Div.2.
Of course you need to check that the shell is stable under jacket hydrotest pressure: this should be done with the normal design procedure using test (room) temperature in place of design temperature.

prex
motori@xcalcsREMOVE.com
http://www.xcalcs.com
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