"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 4.170...
I've dug around for quite a while, and although I find all sorts of
"comforting" diagonal data about fall heights, column separation,
etc, I
cannot find a stated vacuum rating for ASTM D2729 pipe (4").

I'm getting ready to re-do a poorly-designed vacuum hold-down system
for
a ShopSabre 4896 that has only ONE 2" pipe to each half of the
table,
even though the pump has a 4" inlet!(duh!)

4" water pipe (sch 20-40-80) is slightly too large to fit in the
space
provided, but 4" ASTM-D2729 sewer pipe will fit. We're only talking
11"
of vacuum (or -5.4psi). But I want some margin of safety, and can't
find
a figure anywhere.

Anyone know?

Thanks,
Lloyd

How about two 3" water pipes? 18 16. Try to avoid sharp corners.

You could cap a piece, pull a good vacuum and drop typical weights for
that site on it, to find its impact resistance which may not be the
same as its collapse rating under uniformly distributed external
pressure, as from ground water.
http://roscoemoss.com/technical-resources/calculators/

-jsw