Butt Welded HDPE Pipe - Friction Loss Due To Weld Beads

Gents
an HDPE supplier/installer has been asked by his client to debead the weld inside an HDPE pipeline. The reason given is thought to be increased pipeline friction due to the weld beads. The line is 1400mm OD (18m lengths), 56mm wall and the beads are said to be 10mm high (which seems a little low to me). I did a few rough sums treating the weld as an orifice plate. The outcome was that the weld friction loss is less than 3% of the pipe friction loss, which didnt surprise me.
I am looking for an authoritative (quotable) study/reference on this subject.
Any leads?
Thanks

Steve Received on Fri May 14 18:34:00 2004