Roof Nozzle weld details for API 650 Storage Tank

[MOHAMMED89]

Dear All,

As per API 650, Figure 5.19. Roof nozzle neck to RF pad (6mm weld) & RF pad to roof Plate(5mm weld)is required. So my question is wheather we have to provide the welding for under side of roof plate to nozzle neck also?

Thanks in Advance

 

[IFRs]

If it is not in the code you don't have to do it.
Roof nozzles are not on the pressure boundary and are assumed to have reasonably small loads from piping or equipment.
If you have reason to doubt the strength of the roof plate or roof supporting structure, it is time to examine them for strength and serviceability.

 

[valleytank]

Strictly speaking 650 (New Construction) The answer is not required unless requested.
The same applies to 653 where sometimes you will find an inspector asking for a full-seal at the neck-to-roof joint out of crevice corrosion scares.

 

[PogingLamig1]

MOHAMMED89 in a past two months we have the same problem and valleytank is correct. Unless required otherwise by the client

 

[Duwe6]

On an API-650 tank, the roof is there to keep out the rain, and keep the fumes in. They are *atmospheric* storage tanks.