IMPACT TESTING FOR BASE PLATES WITH SA-283 Gr. C

[TheMehanic08]

Hi,

We are designing a CS vertical vessel supported on a skirt. The MOC is as under
Shell/Head = SA 516 Gr. 60
Flanges = SA-105
Nozzle Necks = SA-106 Gr. B
Skirt = SA-516 Gr. 60
Base plate = SA-283 Gr. C

The MDMT = -7 Deg C. (Also the ambient temperature = -7 Deg C)

The Pressure parts (shell, head , nozzles & flanges) do not need impact testing based on the thickness as checked for w.r.t UCS-66.
However the base plate is around 30 mm thick.
The question is should we impact test the base plate material considering the ambient temperature - 7 deg C ? As the ASME code says Components, such as shells, heads, nozzles, manways,reinforcing pads, flanges, tubesheets, flat cover plates,backing strips which remain in place, and attachments which are essential to the structural integrity of the vessel when welded to pressure retaining components, shall be treated as separate components.
Here we see the base plate is welded to the skirt and not directly to a pressure part. So does this still call for the baseplate to be impact tested.

Seeking advice.

 

[weldstan]

It is not required under VIII, Div.1. You would need to perform a stress analysis of the base plate to skirt weld under design wind loading and seismic coditions to determine the need to confirm toughness.

 

[Duwe6]

Not required, and IMHO unnecessary. Minus 2°C // +28°F is not an unreasonably cold temperature for structural use of A/SA283-C.

 

[sharmass]

Base plate is outside the geometrical limits of Code and hence requirements of UCS-66 are not applicable