Hi all

Could we do hydrotest check on the half pipe jacket in PVElite?

If not, any method to verify the half pipe jacket will not fail under user defined hydrotest pressure?

For nozzle calculation on half pipe jacket (eg. 3"), could we assume the pipe jacket as a vessel with random length with 2 nos. pipe cap and nozzles to be attached?

Hello CW

If you have performed the calculation in accordance withe ASME VIII, Division 1, the jacket should not fail under the hydrostatic test pressure. Provided you nave used the correct design pressure for the jacket, the hydrotest pressure has already been accounted for.

For nozzles in a half pipe jacket, you can consider the half pipe jacket to be a cylinder with a nozzle installed. The code makes no special case of a half pipe jacket. For the pipe cap, you consider this as an elliptical head with nozzle installed.

Hi Ray Delaforce

With regards the half-pipe jacket thickness calculation in PVElite, we noticed the joint effiency used is 0.85 which is based on the sample calculation as per ASME code sample calculation. However, we will only go for PT instead of spot radiography. There is no option to fill in user defined joint efficiency for this calculation.

In view of this, we have to verify using manual calculation to show the used pipe schedule is able to withstand the design pressure.

Hello CW

According to Appendix EE, the 0.85 joint factor is built into formula (2). We just accommodated that in our software. Whether you employ PT or RT is not addressed specifically. There seems to be no discretion it using a joint factor other than 0.85 as far as we can see.

Hi Ray Delaforce,
I have a Vertical skirt mounted PRessure vessel design case as below

Shell:-
Shell ID 3400mm X4500mm Tl-TL length ,Int.Design pressure -2bar, Ext Design pressure- 0.1bar

Half pipe limped jacked- Int.Design pressure -4 bar, Ext Design pressure- full vacuum.

I am calculating above case in PV elite-2013 and using appendix EE
But where to account and design for Full vacuum in Jacket?
I have designed 114mmOD X 3mm thick half pipe . Will it fail under Full vacuum?

Please help.
Tushar Deshmukh

Hello tndeshmukh,

Please refer TABLE 9.3 Reaction and deformation formulas for circular arches Case No: 1J in Roarks Stress and strain handbook.

Also lets say if your limpet pipe is welded on a plane instead on a cylinder, you can refer TABLE 15.2 Formulas for elastic stability of plates and shells case no: 21 and TABLE 15.1 Formulas for elastic stability of bars, rings, and beams case no:09 and 10.

Regards
ASD23789

tndeshmukh,

For FV design consideration of limpet coils, you can refer PD:5500.

Thanks.

Mukesh B. Chopra
theculminates@yahoo.com
+91-9428500192

USING PV ELITE HOW CAN WE JUSTIFY THICKNESS OF DISHEND HAVING HALF LIMPET PIPE ON IT.
ALSO DESIGN PRESSURE OR HYDROTEST PRESSURE FOR LIMPET IS TO BE USED.