Impact Testing as per SHELL DEP for Unfired Pressure Vessels

[TheMehanic08]

Hello Fellow Engineers,

We are currently fabricating some pressure vessels for a project, which follows SHELL DEP & the vessel design code is ASME section VIII- Div 1.
Our MDMT is about -6 DEG C. Max thickness for pressure parts is 15 mm.(varying from 6 mm to 15 mm)
A cl. in the SHELL DEP for unfired pressure vessels states the following
"Impact Testing and Impact values shall comply as per the code of construction. Exemptions to impact testing or a change in impact test temperature if permitted by the code shall not be permitted."

Does the above mean that irrespective of the thickness we need to impact test the material for pressure parts?

 

[Duwe6]

Did your material require a footnoted exemption in VIII? Does it meet the basic requirements? That is my 'read' of this spec paragraph. Your temperature is pretty benign; -6°C = +20°F. In VIII, negative 20°F is pretty much the standard.

 

[weldstan]

With proper selection of materials, you need not impact test under the requirements; however, due to the open-endedness of the last sentence, I would have advised you to have provided your own interpretation to the requirements with your bid; e.g., vessel will comply with UCS-66 and UCS-67.

 

[TheMehanic08]

Thanks for your reply guys.

we have selected the following materials
plates : SA 516 Gr 60
Pipes : SA 106 Gr. B
Flanges : SA 105
Fittings : WPB SA 234 Gr. WPB

Well we did check for the material as per figure UCS-66 per which the materials do not require any impact testing.
not claiming any exemptions from UG-20(f) and no reduction in temperatures per UCS-66.1

 

[SnTMan]

TheMehanic08, your most sure course of action is to clarify with the client. Not the quickest course however

Regards,

Mike