On Thu, 28 Jul 2005 11:07:55 +0100, "Set Square"
wrote:

In an earlier contribution to this discussion,
andrewpreece wrote:


I cannot perform an air pressure test without much ado, but if you
say that a sewer pipe
should be able to pass an air leak ( when stopped up at the ends )
then I reckon I've
definitely got a problem. I wasn't sure if a metal soil
pipe-to-glazed sewer pipe connection
had to be air tight or merely be able to take a vertical fall of water
without leaking ( in the
same way a roof is waterproof but not watertight ).


Whilst again not claiming to be an expert, I believe that it needs to be
air/water-tight so that leakage doesn't occur into the surrounding soil if
the pipe ever gets blocked further down, and backs up.


When you put a new pipe in, its necessary to preasure test it in the
way being done here, to ensure there are no leaks.

I assume the desire is to stop groundwater contamination, and
unplesant odor.

Rick