CobusvanJ
Mechanical
- Dec 6, 2008
- 45
I received a concession request from our tank manufacturer to install two roof nozzles (8") on a tank with a conical bottom after the waterfill test.
Reason for this is that the tank will have precision engineered rotating internals, and we want to minimise exposure to liquids etc. to limit corrosion by installing these parts after waterfill test. The two nozzles will be used for driveshafts, therefore alignment can only be done when internals are installed.
I have read through API 650 incl. 7.3.5 and 7.3.6 along with 7.2.1.11 and API 620, but for me it is not clear whether the code allows nozzles to be welded to the roof after waterfill test, only appurtenances.
The two nozzles are PWHT assemblies (insert plates), so the proposal is that roof will be cut after test and the nozzle assembly will be welded in with 100% RT of the weld.
Does the proposal violate API requirements?
Tank is designed according to API 650 with API 620 for the conical section and constructed from SA-516.
Reason for this is that the tank will have precision engineered rotating internals, and we want to minimise exposure to liquids etc. to limit corrosion by installing these parts after waterfill test. The two nozzles will be used for driveshafts, therefore alignment can only be done when internals are installed.
I have read through API 650 incl. 7.3.5 and 7.3.6 along with 7.2.1.11 and API 620, but for me it is not clear whether the code allows nozzles to be welded to the roof after waterfill test, only appurtenances.
The two nozzles are PWHT assemblies (insert plates), so the proposal is that roof will be cut after test and the nozzle assembly will be welded in with 100% RT of the weld.
Does the proposal violate API requirements?
Tank is designed according to API 650 with API 620 for the conical section and constructed from SA-516.
