Dust collection..yes, again.

[Mike Cunningham]

Soon I will be installing a DC system in my new shop. I've read pretty much all of the stuff available (I think). Anyway, I'm debating between running the ducting above the ceiling or beneath the wood floor. I'm leaning to doing it beneath the floor, mainly to get it completely out of the way and I'll have full access to it if need be. I'd like to hear from anyone that has experience with ducting beneath the floor and whether they've experienced any problems, in particular problems with the blower lifting the dust at the collector. Also, anyone that has switched between floor and ceiling or vice-versa and what they've found in doing so, one "better" than the other. Thanks guys.

[Howard Barlow]

Hi Mike, I had all my ducts up against the ceiling except for my table saw. That line ran under the floor. Both upper and lower met at a tee along the wall, about 3' off the floor, going into the dc. The only problem I had was if I did a lot of planing, jointing, etc. with the gate closed to the saw, the line below the tee would fill up with chips.

Sometimes I would have to pull the cleanout plug under the shop and knock all the chips to the ground. If I left the saw gate open some, it wasn't a problem. It fed from both ends to the tee.

[Jim Izat]

What are some of the details of the system you have in mind? How many machines of what type? What was your thought process as you decided which direction to go in to deal with your dust?

As you can tell, I too am trying to make some of these same decisions.

Jim Izat

[Mike Cunningham]

Thank you for the replies. Nothing out of the ordinary or unusual in the thought process. All of the usual machines in a small woodshop, TS, RAS, joiner, planer, BS, lathe, sanding center, etc. plus I want a floor sweep. One desire that I had, since I'm building a new shop, was to install a wood floor. Easiest on the feet, plus I wanted to be able to install some outlets in the floor for some of the aforementioned tools, to avoid drop down cords and extension cords and just wire generally on the floor. Having done so, I began thinking about putting the DC pipes under the floor rather than over the ceiling joists. Mainly, for a reason similar to the wiring, to avoid pipes running between machines and the ceiling and along the floor. Running beneath the floor, My concern is accumulation of chips, whether the DC will lift the chips or just dust, leaving the chips behind. Anyway, I'm going to use 5" or 6" S/D plastic and I'll have strategically located cleanouts.

[Doug Edwards]

From an air movement standpoint, it doesn't matter if it is above or below the floor. There is generally equal lift for either method. Avoid tapping in on the bottom of the duct as mentioned and make sure there is access if a cleanout is required. If the air velocity is above about 3500 fpm, you shouldn't have a problem either in horizontals or verticals. It should also make for a more attractive system.