Sam
Yep.
Before you do this, you should check with the local authorities, as draining
into the street gutter may not be permitted.
0.0408 * 16 sq.in. * 100 ft.
--------------------------- = ~520 gal/minute
2 ft./sec.
re: DeWalt Plumbing Professional Reference
"Sammy bin Snoozin" <SammyBi...@REyahooMOVE.com> wrote in message
news:cLrOi.3059$Cd7.1485@trnddc03...
"Dennis" <webm...@npcc.net> wrote in message news:CHyOi.9919$vS1.6324@trndny08...
Yes, it's OK here.
500 gpm seems like a rather high flow rate for gravity flow in a 4"
plastic pipe with a drop of 1/4" per foot.
If my calcs are correct....500 gpm thru a 4" pipe yields about 12 ft/
sec not 2 ft/sec
at 2 ft/sec, completely full, the 4" pipe, the pipe will flow ~80
gpm....
I haven't done the gravity flow calcs for a 4" pipe at 1/4" per ft but
I'm guessing its more like 50 gpm max (just a WAG).
Like I said, I haven't done the calcs, but my 3" drainline with ~1/4"
per foot drop easily handles the ~15 gpm output of a garden hose but I
doubt if it would handle 15x that flow.
After a lot of searching I found
http://vylonpipe.com/brochures/plasticpipe.pdf
page 15 gives the Manning formula for gravity flow......stumbling
through the calcs at midnight, I got
~70 gpm for a 4" PVC line with a 1/4" drop per foot
somebody please double check these numbers?
cheers
Bob
(New calculator, still have figured the blasted thing out. Somehow it took
16 and squared it, when 16 was already a square. Everything seems backward -
best excuse I can think of....)
The Dewalt formula is simply listed as gallons per minute through a pipe. It
doesn't give the type of pipe (roughness or corrosion) so I would tend to
believe that the .0408 takes the worst case into consideration which would
correlate to the low figure being generated.