RE: Banching from pipes

From: <ed>
Date: Tue May 04 2004 - 16:30:00 EDT

I agree with you, Chris........making saddle connections is not for the faint of heart much more for the inexperienced.

But assuming that workmanshipwise everything is equal (some contractors have the expertise and the experience to do quality saddle connection), then the rest is labor and material. Try a 36" main and a 24" branch Carbon Steel assembly.

If you do a saddle connection, you have your 36" & 24" pipe (most probably in stock or readily available) and a 24" weld and 1 1/2 times fit up time than a butt weld.

If you go the fitting way, you have the cost of the 36" x 24" reduced tee and not readily available. You have (2) 36" weld and (1) 24" weld with buttweld fit-ups. The scenario just got worse if the reducing tee is not available, then you have to go to a full size tee and a 36" X 24" reducer.

Multiply these scenario umpteenth times........better yet, make the material Stainless Steel or better.....

-----Original Message-----
From: Christopher Wright [mailto:chrisw@skypoint.com] Sent: Tuesday, May 04, 2004 11:45 AM
To: Pipingdesign
Subject: Re: [PipingDesign] Banching from pipes

>By a comparison between direct pipe to pipe connection and making use
of
>fittings or self reinforced fittings for taking branch ,it goes without

>saying that the quality and easiness of the job would be much better in

>the latter case but regarding cost the former would be cheaper.
I haven't done any real estimating for years, but it's hard to imagine that the hand fit-up work would be enough cheaper to justify the likelihood of poorer quality welding. I think if it were truly cheap enough, it's because someone's taking liberties with weld quality. A welded tee requires 3 girth welds, but they're straightforward butt welds
with minimal fit-up.

If I understand you correctly, a 'direct pipe to pipe connection' means a
hole manually burned in the run, and the branch hand burned and ground to
the contour of the run. If the joint isn't fit up properly it will be a starting point for a fatigue or corrosion failure, and if it isn't cleaned up with no protruding edges, it'll be a mess for fluid flow. My own opinion is that if such an operation truly is cheaper, it's because weld quality is compromised, and that isn't really cheaper at all

Christopher Wright P.E.    |"They couldn't hit an elephant at
chrisw@skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)

http://www.skypoint.com/~chrisw

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