Rolling offset

[jimpiper60777]

Hi!

The client has issued a project memo to avoid trim elbows. As stated on paragraph 328.4(b)(c) of B31.3 that the max. trim on a ASME B16.9 elbow is 3 degrees.

I am revising the configuration of the pipe and I found out that the only way to connect the line to avoid trimming is to roll two 45 degree elbows.

Can anyone explain and give a theorem/computation or technique in rolling and offseting the 45 degrees elbow without trimming it. It seems to be very difficult to converge them with no percent error.

Best Regards,

Jimpiper

 

[LUDPEKA1]

I use “The pipe fitter’s and pipe welder’s handbook” by Thomas W. Frankland as a reference and also found the following at Google books.

http://books.google.com/books?id=c4QOZm9El4IC&pg=RA1-PA397&dq=45+degree+rolling+offset