On Sun, 15 Feb 2015 15:49:04 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

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

I don't know. d8-)

However, here a few formulas, if you want to trust your calculations.
Start with the fact that 4" ASTM-D2729 sewer pipe has a wall thickness
(min.) of 0.075".

http://www.northamericanpipe.com/pro...-sewer---drain

(click on "product spec")

There's a formula near the top of this page...

http://www.lascofittings.com/pressureratingsofplastics

.... for calculating the internal pressure it will take. Then there is
a table lower on the page that relates max. external pressure to the
max. internal pressure -- for schedule 80 pipe.

My question would be what kind of relationship there is between the
internal versus external pressure tolerance for much thinner pipe.
There probably is some aspect of the Euler buckling formula at work,
but I have no clue about what that would be.

If it were me, I'd build it, stand back, and try it. Crumpling is a
lot better than exploding. g

--
Ed Huntress