What does code say about this?

Post by **ashfaqanwer** » 26 Apr 2010, 05:05

Raise directly code related queries under this thread.

sharjeel · Post by **sharjeel** » 19 May 2010, 17:12

I have a vessel that has to be hydrotested at 207 Psig, but its associated piping that has already been installed and welded is to be hydrotested at 235 psig. Does ASME code allow me to hydrotest the system at pressure equivalent to vessel hydrotest pressure?

sadia.shahab · Post by **sadia.shahab** » 20 May 2010, 04:20

As far as I know, we can hydrotest the vessel at 1.5 Design Pressure. You can easily calculate the hydrotest stresses in vessel at 1.5 times from any PV software like Compress. If your stresses are in permissible limit then you can test the vessel & piping at 235 psig. We had carried out hydrotest at 1.5 D.P instead of 1.3 D.P for vessels as per customer requirement (ASME Inspector allowed us for this case).

For test the system at vessel hydrotest pressure i.e. at 207 Psig, a piping engineer can better guide you.

Rgds,

mechcolor · Post by **mechcolor** » 20 May 2010, 05:36

As per ASME B31.3 para 345.4.3 (b), you can test the piping along with vessel at test pressure of vessel provided that the test pressure of vessel shall not be less than 77% of the test pressure of piping.
And in your case its valid. Go for the test at vessel test pressure.

sharjeel wrote:I have a vessel that has to be hydrotested at 207 Psig, but its associated piping that has already been installed and welded is to be hydrotested at 235 psig. Does ASME code allow me to hydrotest the system at pressure equivalent to vessel hydrotest pressure?

thePetroStreet