Offshore Oil Pipeline Launcher Design >> Quick Opening Closure >> ASME Requirements

[msharptx]

I am designing an Offshore Oil Pipeline Pig Launcher Skid in accordance with ASME B31.4. In regards to the Quick Opening Closure for accessing the Pig, I have seen previous "industry" designs where the closure is specified in accordance with ASME VIII Div. 1 and the Launcher Barrel is in accordance with ASME B31.4.

Can anyone explain to me why ASME VIII Div. 1 is chosen in lieu of ASME B31.4 for the Closure?

Thank you.

 

[LittleInch]

The closure is a complex structure which needs an analysis which 31.4 is not suited for. I believe the use of asme viii is mandated in 31.4 for the closure, if not it is in other codes.

The rest of the launcher though is no more than a manifold and can be designed and analysed with 31.4 better than a pressure vessel code which would result in much greater weight for little or no benefit.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[BigInch]

Actually not much analysis is required, as ASME believes that there is a considerable base of experience in the design of successful launchers and receivers built into the code requirements already. In fact B31.4 does not require that any part of a launcher or receiver be stamped in accordance with ASME Section VIII, so much of which is stated in their interpretation #4-87 issued on 7 June 2010

I hate Windowz 8!!!!

 

[BigInch]

The interpretation however does refer one to section 404.7.1 and 404.7.3 of B31.4-2009 where (as I think I recall) it stipulates that only a mechanical pressure interlock is required, which prohibits opening of the closure while it is under internal pressure.

I hate Windowz 8!!!!