ASME B31.3 Skid design / fabricating
ASME B31.3 Skid design / fabricating
(OP)
We normally design gas processing skids under PED. However for this American project we have to work under ASME B31.3 and I want to verify a few things.
-This system falls under normal fluid service.
-We will source U-stamped pressure vessels and integrate those into the skids as our skid fabricator does not have a CoA.
-Max pressure: 290 psig, AISI 304, 300# flanges, max pipe size is 6".
1.) Is a NoBO required for design validation (assembly integration validation), PID validation?
2.) Is a flexibility calculation required? To my understanding this is not needed if T is below 150 °F.
3.) To my understanding the Client has to send an inspector to inspect the piping, correct?
4.) 100% VT and 5% RT of welds required.
5.) Are there any other requirements we need to be aware of when commissioning the skid on site?
Thanks!
-This system falls under normal fluid service.
-We will source U-stamped pressure vessels and integrate those into the skids as our skid fabricator does not have a CoA.
-Max pressure: 290 psig, AISI 304, 300# flanges, max pipe size is 6".
1.) Is a NoBO required for design validation (assembly integration validation), PID validation?
2.) Is a flexibility calculation required? To my understanding this is not needed if T is below 150 °F.
3.) To my understanding the Client has to send an inspector to inspect the piping, correct?
4.) 100% VT and 5% RT of welds required.
5.) Are there any other requirements we need to be aware of when commissioning the skid on site?
Thanks!





RE: ASME B31.3 Skid design / fabricating
1 - no
2 - it must be "considered". This could mean a one sentence explanation or an exhaustive analysis and report, but if no one is checking and the risk is nil....
3 - it is not mandatory and rarely happens until turnover to the client.
4 - as a minimum, yes.
5a - check with your client. Different industries have different levels of regulatory oversight. A "process safety analysis" (PSA) of the P&IDs is commonplace in my industry.
5b - if you are offering or providing any engineering services to a client outside of your company, the work must be done under the "responsible charge" of a licensed professional engineer registered in the state(s) involved. In most states your company must also be registered.
In most places it is the "Wild West" but there a few places (California comes to mind) where the bureaucrat class has taken root.