Hydrotest for rubber lined tanks 2

[Inspector89]

Hello guys,

There is a rubber lined tank used to store Hydrochloric Acid. The material of construction is SA283 Grade C. Recently a leak occurred from the shell, lining was partially removed and shell insert plate replacement was performed. This is a major repair. According to API 653, major repairs needs to be hydrotested unless exempted by storage tank engineer & owner/operator with fitness for service evaluation.

Can a rubber lining tank be hydrotested after the shell plate replacement? Will hydrotest impact the condition of the existing rubber lining?

 

[0707]

After repair plate of the vessel, you can do the hidrotest. After that, you repair your rabber lining and do a spark test to the lining to evaluate the final condiction of the rubber lining.

luis

 

[Dhurjati Sen]

These tanks are hydro-tested after erection an completion of fabrication, but a long time before commissioning.

Once hydro-test is done, applicaton of rubber lining starts and ends after which the lining is cured and hardness and holiday tests are carried out.

We have done LPI and being the owner ourselves, have exempted the hydro-test.

More critical is the application of the rubber lining in the newly fabricated portion of the shell, assessment of any deterioration of the existinig lining due to heat from cutting and welding, checking the hardness of the existing lining and detection of further holidays.

No point in hydro-testing the tank after application of the lining, it is the lining that is vital for such tanks, unless there is severe external corrosion.

That also happens, as these tanks have external rafters.


DHURJATI SEN
Kolkata, India