Pipeline Transition Piece
Pipeline Transition Piece
(OP)
I'm doing a pipeline project. Only my second one. Been a piping designer in shipbuilding and various plants for over 30 years. I have a situation where I have 10" STD wall (.365") pipe going to an 8" SCH80 wall (.500") pipe. I am told I need a transition piece. I just figured this would be a reducer, but I am not sure. Usually when going from a large pipe to a smaller pipe the wall gets thinner. In this case the wall thickness is greater. What exactly is a transition piece in the pipeline world, and how to I transition in my situation? This is a 1200 psi system. The wall thicknesses I state above are required at this location in the system by the client. So I have no options. I have to make the transition.
Thanks,
CAD
Thanks,
CAD





RE: Pipeline Transition Piece
A transition piece in pipeline terminology is normally the same size, but "transitions" from a higher grade material to a lower grade material, made out of the higher grade material. E.g. a 10" X60 pipe of 10mm wall thickness (wt) transitioning to a 10" Grade B pipe of 18mm wt would be a short pup piece (say 500mm long), made of X60 18mm wt, with one end machined down at an internal angle of at least 1:4 or better to a wt of 10mm.
In the pipeline world, material strength of pipe is the thing to look for as this is directly inversely proportional to the wall thickness allowed.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Pipeline Transition Piece
I've inherited problems on several system that the Engineer got "clever" and ran 5 miles of one size then transitioned to the next bigger size because of the velocity increase due to the friction drop. I've frequently said really ugly things about the clever Engineers.
If you must do it, then like LittleInch said it is often possible to transition the pipe wall thickness in the reducer.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"
RE: Pipeline Transition Piece
CAD