On Mon, 19 Feb 2007 20:38:32 GMT, "trs80" wrote:

Would a small shop DC system run ok with the mains at 4" smooth bore PVC
ducting vs 6"? I would have about 30' of main and 4 drops using a 2hp
1600cfm unit and air blocks for the station no used. The DC has a 5" intake
and 12" impeller.

I cannot find locally PVC 6" sewer and drain pipe. I can find galvanized 6"
duct at about $1.40/ft and 4" smooth bore S&D PVC pipe at $0.58/ft. I hate
to spend more of the duct then the DC which would happen if I go the metal
pipe route.

I visited all local Home supply brands (HD, Lowes, CW) and all dont carry
over 4" pVC. And I called an irrigation supply and they dont carry the
light duty 6" PVC pipe (i think its schedule 2379 or something like that).
Im guessing that its not a big seller inmy area for some reason to do with
building codes for such things.

So any way, I was wondering how much performance I lose by going the 4" vs
6" route.

Any thoughts appreciated!


Well, 6" is better than 4", and 4" is better than 2". The larger pipe
simply can move more air. There are other factors like length of
pipe, turns, turbulence, etc. Four-inch DC pipe and connectors are
easily obtained, plus many machines are fitted with 4" ports. You can
compensate (a little) with a DC that moves more cfm.