DC pipe routing

[Don Buck]

I'm installing a Grizzly 220v 3 hp dual bag dust collector in my 20 x 36' shop. I purchased the DC and hundreds of feet of 6" PVC (narrow sewer) & connectors from a contractor who closed doors. The DC has a stated static pressure of 16.7" and is rated 2300 CFM. My question is about routing the vent pipes in the shop. I've got two design in mind.

Option #1 - I started routing 6" pipe hugging the ceiling & wall on either side of the shop (see below) which will involve two 90 degree turns for each line. I would use 2 @ 45's seperated by a short joint of pipe to reduce the severarity of the bend. I compute the total loss of static pressure to be approx. 5" to the most distant tool (future 8" jointer). Nice neat install but I am aware of the rule of the straighter the better. Static pressure at the most distant port: 11.8"

Option #2 - run the 6" main down the center of the shop and run the 6" branches off the center line. This will eliminate one 90 degree turn. A little tricky due to the location of my overhead lights but it will fit. Not as neat to the eye but straighter and by the same calculation I will gain 1" of static pressure. Static pressure at the most distant port: 12.8"

Perhaps a no brainer due to the static pressure differential. However, given the "suction" I have to start with and that this is a one man shop and only one piece of equipment will be in operation at any given time, is the 1" gain or loss really significant? I expect that I will have to have at least 1 other gate open when I use a tool due to the power of the DC.

The longest run in the system is about 20' from the DC. The price of the install will be about equal either way as I have plenty of parts to use. The largest dust/chip producer I have is a 20" planer. I've also already dry fitted the start of the parimeter run but they can be removed and rerouted.

Based on the size of my shop and single use at any give time is there significant reason to go with option #2?
IMG_1069.jpg

[Jim O'Dell]

I personally like the straighter set up. My best advice is to keep the piping as simple as possible. I leave my cyclone with straight pipe for about 11 feet, then a wye goes down for the two table saws. The remaining pipe goes straight for another 2 or 3 feet, then wyes off to make two 90 degree turns to go to each side of the shop: one to the BS and RT, the other to the multifunction wall that accepts a variety of tools that roll into one port, including the SCMS and the lunchbox planer. It gives me the least amount of pipe, and the fewest joints and turns. While I don't think I have a problem with the amount of air I move, I don't want to leave some capability in the piping either. Jim.

[Jim Becker]

The worst design for duct work is a "perimeter" design...very inefficient. A main run down some vector through the shop with drops to where collection is needed works much better as it minimizes the distance that the air and debris has to travel from an open gate to the collection device. Any professional design you get from a "real" DC outfit will take this approach.

[Dan Hintz]

For my shop (roughly 14'x18'), the DC is in the middle of the far wall. Main stack pipe goes straight up the wall to the ceiling, then splits towards each side of the room. Corners are turned using double 45s, and run down both sides of the room with appropriate drops.

[Alan Schaffter]

I go with Jim and Jim- Christmas tree layout. I don't have any 90's in my system- I use 45 wyes and 45's everywhere.

[Don Buck]

Thanks Jim, Jim, Dan & Alan for the suggestions, I think I'll compromise and keep the 90 degree going to the left (in photo) as I'll have a sanding station in that corner and I can't reach it with just one "Y". I'll run a central line down the middle of the shop and run "Y's" to all drops left and right.

[Kirk Poore]

The worst design for duct work is a "perimeter" design...very inefficient. A main run down some vector through the shop with drops to where collection is needed works much better as it minimizes the distance that the air and debris has to travel from an open gate to the collection device. Any professional design you get from a "real" DC outfit will take this approach.

I'm sure you're right about the drop in efficiency. However, when I put in my setup this fall, it will be an all-perimeter setup. Vertical piping in the middle of the room is just asking to get banged up, interferes with material handling, and it's ugly to boot. My shop has a floor trench to get 6" pipe to the planer/tablesaw/shaper cluster in the middle, and then all other machines are arranged along the walls. A few hundred dollars in extra horsepower & piping and a few cents a week in extra electricity are well worth the cleaner arrangement.

Kirk

[David Kumm]

While the christmas tree layout is best, there can be efficiency tradeoffs there as well. The key to a perimeter design is keeping to the same size pipe as the cyclone inlet at least until you go around the first corner and then use only 2.5 radius ells. The christmas tree design often adds an additional 90 degree ell because you branch off the main and then drop down rather than do it all at once as you can do on a perimeter design. Granted you can branch horizontally on a perimeter and drop down as well but if you are trying to save SP, go with larger first stage pipe and drop down with larger branches before you reduce for the vertical pipe. Dave

[Aaron Montgomery]

I'm sure you're right about the drop in efficiency. However, when I put in my setup this fall, it will be an all-perimeter setup. Vertical piping in the middle of the room is just asking to get banged up, interferes with material handling, and it's ugly to boot. My shop has a floor trench to get 6" pipe to the planer/tablesaw/shaper cluster in the middle, and then all other machines are arranged along the walls. A few hundred dollars in extra horsepower & piping and a few cents a week in extra electricity are well worth the cleaner arrangement.
Kirk

I did this as well - 6" S&D around the perimeter. My shop is not THAT big that it should make a noticeable difference and it made the overhead much easier to live with. I did use long radius 90's at all of the corners. I'm quite happy with the performance of my Oneida V3000 in this arrangement. I'll try to post a picture when I get home.

[Dan Hintz]

The worst design for duct work is a "perimeter" design...very inefficient. A main run down some vector through the shop with drops to where collection is needed works much better as it minimizes the distance that the air and debris has to travel from an open gate to the collection device. Any professional design you get from a "real" DC outfit will take this approach.

Considering I have tools lining both sides of the room, and the DC has to be at one end or the other, the difference in travel distance for a perimeter system for the worst run is likely no more than about 10% compared to a run through the middle of the room... I can live with that.

[Alan Schaffter]

A couple of notes-

If you place the DC in the corner the run along one wall will be a straight shot.

If you have a cyclone you should have at least 10 diameters (5' or more) of pipe running straight into the cyclone.

Think outside the box. You can make diagonal wall runs the DC inlet is high. Run the pipe diagonally down the wall, almost to the floor at the next wall. That way the drops can be connect to the main with only a 45 wye instead of a 45 wye and another 45 like you would need with a horizontal wall run. (every knows not to use 90's)

There are many ways to achieve efficient runs, but I think you will find what looks nice and what works best are often at opposite ends of the spectrum. Also, what works best usually takes the least amount of fittings of all types, certainly the least amount of pipe.

[Mike Cruz]

Don, not sure if you've completed your system yet, but a word of warning...that DC does NOT live up to those stats! It will pull no where near 2300 cfm. Depending on the age of it, it has either a 12 or 12 3/4" impeller. If you might be pulling up to 1400-1500 cfm...and that is at the intake. A couple more notes about it: You said it is the two bag model (I assume you mean what they call the four bag model). I have this same DC. (Well, I still have it, but it will be on CL soon...I've upgraded to a cyclone.) If you are going to stay with it, change out the upper bags with the heavier bags (feltlike). They aren't that expensive, and work much better on the fine stuff. And if it isn't too late, you probably ought to make some sort of quick disconnect at the intake of the DC. If you leave the "grill" on the intake, it will clog quite easily. Even if you remove it (cut it off...which makes your impeller and the blower housing vulnerable to large chunks that get sucked up) shavings will build up on the impeller itself. So, one or the other will need fairly often periodic clearing. I'm speaking out of experience. Not trying to burst your bubble over your purchase. Just sharing and giving you a heads up. Good luck.

[Don Buck]

Thanks for your comments & suggestions, esp. on an potentially over spec'ed 4 bag Grizzley. I have the 6" PVC pipes mounted in the shop and hope to start building the blast gates this weekend. I tried out the system last night by running a 15" wide piece of poplar through my 20" planer (6" flex to 6" PVC, straight 20' shot back to the DC) and it did fine. I couldn't find a flake of dust after running the board through 6 times.

As the DC and pipe came out of a closing business, I only have $300 invested in the entire DC system and will have over 100' of 4" & 6" metal and PVC pipe left over after my installation so my bubble hasn't cost much! I'll run it for a while and either add a filter/bag assembly or possibly (mosts probable) upgrade the DC with a cyclone like your plan. The DC grill had been removed by the previous owner so I will try to keep large objects from the system.

The DC is isolated in a seperate room and I am currently venting the room through an open window. I built in a filtered return in the wall with filter near the ceiling collecting the warmer DC air and forcing it back through the wall with the return near the floor. I need to improve the weatherseal under the connecting doors and my access sliding barn door but I think it will work fine for my one man shop. If the DC "bites the dust" I still saved $$$ on just the 6" PVC, wye's & 45's.

Thanks to all for their thoughts and recommendations and I did modify the design with less bends in the layout. I'll post some photos when the shop is operational.

[Jim Neeley]

You mention 16.7" of static pressure and 2300 CFM. Please understand that this does not mean that you will be able to accomodate 16.7" of pressure drop at 2300 CFM. The 16.7 is the maximum suction at no flow and the rated CFM is (supposted to be) the flow with zero (or limited, if stated) pressure drop. To figure out what you can expect, you'll need to get the fan curve for that collector which will show the flow reductions as the pressure drop increases, and try a few points until you figure about where you are on the curve.

I've attached the fan curve from an Oneida true-industrial premium performance and price ($3,300) 5-hp DC as a reference.

Oneida High Pressure DC.jpg

The link to the web site is below.

http://www.oneida-air.com/inventoryD.asp?item_no=XXK050133&CatId={73B95A00-5FFF-443F-99A7-55FFD915A08C}

Jim