Fwd: [STM] Hot Tapping of Chilled Water Piping

From: <Christopher>
Date: Thu May 04 2006 - 10:39:00 EDT

I saw this on the steam list. If anyone has any ideas for Ehrfurth maybe you could e-mail him direct

Begin forwarded message:

> From: "Ehrfurth, Jay - DOA" <Jay.Ehrfurth@Wisconsin.gov>
> Date: May 4, 2006 8:35:29 AM CDT
> To: "steam-list@lists.cc.utexas.edu" <steam-list@lists.cc.utexas.edu>
> Subject: [STM] Hot Tapping of Chilled Water Piping
> Reply-To: <a href="/group/PipingDesign/post?postID=mCoPFAynBUG5H59pJgmxeEnHPsbxiWQYk7P4gUoi8K5R5tVF7YWXS1lpa2icCKWA7jRdhjg5Cwj32HZfNxtOSXWf6etkGePv0Q">steam-list@lists.cc.utexas.edu</a>
>
> My question pertains to hot tapping an in-service chilled water line.
>  
> Since this is not a Power Piping Code welding scenario our
> specifications require welding certs from the National Certified Pipe
> Welding Bureau.  The welding procedure specification submittal
> indicates on the WPS and associated PQRs a minimum preheat of 50degF. 
> Our chilled water system runs around 40-42degF.  Has anybody run into
> this issue when needing to hot tap into their system?  
>  
> Some of my other concerns are:
>  - As to welding on a flooded pipe with a temperature less than the
> preheat temperature what should be my concerns with the
> structural integrity of the weld?
> - What concerns should I have about flashing the water in contact with
> the weld?
>  
> Thanks,
>  
> Jay Ehrfurth

Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=kRd6yZR846asacHzlelj3tlZnpytS3FdTLgAPG-WbJgFPro4k95BZNMpcAO6ZWyQAQDILRzELBOL">chrisw@skypoint.com</a> | this distance" (last words of Gen.

.......................................| John Sedgwick, Spotsylvania

1864)
<a href="http://www.skypoint.com/~chrisw/">http://www.skypoint.com/~chrisw/</a> Received on Thu May 04 10:39:00 2006