dc ducts on floor or ceiling?

[keith ouellette]

Right now mine are close to the ceiling at 9 ft high. and the motor and fan are about as high.

would dust collection be better if the motor and the ducts were at ground level? At first i thought gravity would not be an issue with fine dust but then figured it may be an issue with the air flow.

what do any of yo think?

[Joel Earl]

I don't really think gravity per se enters into the picture - assuming the blowers under load.

I would always use the least amount of ducting with the most gradual wyes so ---- if that means low can be done without interferring with other things go low. I think we usually assume high/up because we have things against the walls, we have doorways, things like that to overcome.

I have seen many pictures of folks going under the floors and up - slick trick if it can be done.

Whatever works with least LF of duct that is not a nuisance

[chet jamio]

According to the formulas for air flow:

6" pipe, 4000 FPM, 800 CFM, 9 foot climb = 0.35 in H2O
4" pipe, 4000 FPM, 350 CFM, 9 foot climb = 0.50 in H2O

[Rob Russell]

IMO, if you have an adequately sized blower, it's not going to make a difference with the effectiveness of the DC whether you run on the ceiling or floors. I know I wouldn't want to be tripping over piping on the floor and the piping down there would make it harder to move machinery around. With 9' ceilings, I'd run all the piping up high.

[Sonny Edmonds]

All of mine is overhead except the boosted system under the center section of my shop. (Which gets kicked overhead anyway.)
If you look at most manufacturers plants you'll see that their huge systems draw overhead.
The static pressure a system can develop (suction power) is the reliance to it's ability to draw in and lift the debris.
CFM and the static pressure is what moves the stuff to the collector.

[David Giles]

At one point, mine were along the floor and were constantly in the way. When I decided that I needed to roll cabinets around instead of carrying them, the duct went overhead.

[keith ouellette]

thank you for your thoughts. I'm sticking with the ceiling then.