Lateral or Wye Pipeline Connections

[zdas04]

For my entire career, the conventional wisdom in gathering-system engineering within my company was that "Lateral Connections are bad, they tend to split in the crotch with earth movement".

I can't find anything in the codes that supports that "conventional wisdom", and I have a client that says "we've always used them and never had one split open".

Anyone have any experience or guidance on the safety and long-term utility of these 45-degree branch fittings?

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[stanier]

As rasr as steel goes they are generally not a problem if designed and fabricated to AWWA Manual M11.

I have seen problems with PE welded units as the weld factor and NDT arent as good as the parent material.

 

[nackra]

http://www.uni-bell.org/literature.php

Check Technical Bulletin: Installation Guide for Risers

 

[zdas04]

Nackra,
Sorry, I should have specified that I'll be working in 10-inch Schedule 40. X-42, ERW steel piping. I went to the uni-bell site and the Tech Bulletin anyway and there wasn't anything there on 45 degree tees (Wye or Lateral connections). Did I miss something?

David

 

[de1960]

We design, manufacture, and sell them everyday.
As a design start point we use the old MW Kellogg
piping design standard. (pressure area method)

We have not had any trouble with splitting in the crotch.

We strictly manufacture a forged fitting. The splitting
problem probaly occured in a fabricted fitting.