On Sat, 29 Mar 2008 21:59:03 -0700 (PDT), RichH
wrote:

Bruce is somewhat correct ... the tank has to be padded with an inert
gas such as Nitrogen, etc. Welders on transmission lines 'hot-tap'
repairs all the time ... just need someone who KNOWS how to weld
such.


The point about making a hot tap is that you are welding on a closed
pipe that is filled completely with oil - no air. some what different
then an empty tank.

I have no idea why the A.F. procedure was to steam the tank. Certainly
we had all kinds of inert gas available but that was the procedure.
Maybe because it worked?




Bruce-in-Bangkok
(correct email address for reply)