"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 4.170...
"Jim Wilkins" fired this volley in
news:mbt9mu$pih$1
@dont-email.me:

A buried pipe is supported against bulging out at right angles to
where the collapse begins. Yours wasn't.

Exactly how does that address "five story high vertical column
separation"?

This stuff is not used only buried. It's approved (in some few
places) for
vertical vents on DWV systems.

Lloyd

How can you pull a five story (50') vacuum?

The rating may be for the overpressure from a five story high water
hammer.
http://en.wikipedia.org/wiki/Water_hammer
Google isn't too helpful.

-jsw