Vertical and Horizontal Hydrotest Position

Hi Faizol,

I assume that you are talking about vessels that are fairly tall. If so, then the only difference when hydrotesting the vessel in the vertical position is that you must take the static head of the water into account. The top of the vessel must obviously experince the full hydrotest pressure, so the bottom of the vessel will experince this pressure plus the static head. The pressure guage is usually at the bottom of the vessel, so when testing ensure that the guage reads the total pressure (test pressure plus static head).

I would think that the better position would be the one the vessel will be used in. As stated above, a tall vertical vessel will have a higher pressure at the bottom that at the top, while a horizontal vessel will have the same pressure throughout.

Dear Members,

anybody know how to calculate stress for every parts like bottom head, shell and top head using manual calculation. Could someone guide me and provide a stress formula.

Thank you.

For vertical vessels tested horizontally, we have always added the static head to the required hydro pressure. Per interpretation VIII-1-95-27, this is not required. The test pressure regardless of position is 1.3P times the materials stress ratio. Interpretation: VIII-1-95-27 Subject: Section VIII, Division 1 (1992 Edition, 1993 Addenda); UG-99(b) Date Issued: January 12, 1995 File Number: BC94-414 Related Documents: Question (1): Does the last sentence of UG-99(b) of Section VIII, Division 1, "All loadings that may exist during this test shall be given consideration," require that the static head that exists in a tower in the vertical position must be considered when determining the test pressure in the horizontal position? Reply (1): No. Question (2): Does UG-99 specify in which position a vertical tower must be hydrotested? Reply (2): No.