DC ductwork design

[MarkE]

What a PITA!

Trying to figure out a good layout for DC ductwork in my shop. I have been using Grizzly's online workshop design program. It is not the greatest, but it is free. The thing is, I am getting no where fast.

I have tried to find some software to help with the task, but have come up short. There are some software packages available, but they are geared toward hvac contractors and are pretty expensive ($300 and up, way up).

I guess I could use Oneida's or Penn State's design service, but they aren't inexpensive either.

Anyone got any advice on how to get some rough idea on how to do this? I am just looking to get a basic set up worked out that I can expand on or re-arrange as needed.

Any advice or suggestions would be appreciated.

 

[Bill Clemmons]

Mark, I designed my system myself, but it's been about 6 or 7 years, so I've forgotten most of what I learned. Here are a few of the things I remember: use the largest size duct work you can for as long as you can. Use reducers at the end of the run, close to the machinery. Keep your runs as straight as possible; turns cause a loss of pressure. Use flex hose ONLY when absolutely necessary to make a connection. Use "sweeps" rather than "elbows" to keep from loosing pressure.

I found a spreadsheet for calculating static pressure loss somewhere on the web. I've got it saved, but have no idea how to include it in this post. It was by Don Beale and Bill Pentz, so you can probably find it on one of their sites. It lets you plug in your data and it calculates static pressure loss for you.

Sorry this wasn't much help. The two books I used in designing mine are: Woodshop Dust Control, by Sandor Nagyszalanczy, and Dust Collection Basics, Recommendations for Home Shop Systems, by Woodstock International, Inc. If you were closer I would be happy to let you borrow them.

Bill

 

[Alan in Little Washington]

I pretty much agree with Bill, but will add a few points-

Every fitting, bend, blast gate, inch of flex, inch of duct adds resistance and decreases performance, so you want keep them to the absolute minimum.

Like Bill said, run the largest sized duct your DC will support from the DC as far as possible- all the way to the machine. Don't reduce at the machine, on the contrary open the port of the machine to the duct size. If your DC has 6" inlet with a 4" X 4" wye- remove the wye (and pitch it!).

Go for performance, not appearance- neat runs along the walls are usually not the best design. A diagonal is always shorter than the sum of the two adjacent sides. It is almost always better (shorter run) to run your main diagonally across the room with branches coming off at 45 deg. so your duct looks like a XMAS tree.

Use multiple, direct branches to multiple machines rather than one long branch that snakes to each machine. Unused branches with closed blast gates at the machine have no impact on the system.

Don't use T's, use wyes. Use long sweep elbows rather than 90's, or even better use 45's.

 

[bobby g]

Mark,

These guys (Air Handling Systems) have always been a helpful resouce for me. http://www.airhand.com/designing.aspx

bobby g

 

[MarkE]

Thanks guys.

The DC I am going to be setting up is the Super Dust Gorrilla, purchased from Scott Smith. It has an 8" inlet.

I can open up some of the ports on some of my tools, but not all of them. For instance the Ridgid Planer has a 4" port that cannot easily be made larger. The port on the tablesaw (Grizzly 1023Z) can be replaced with something larger, but the overhead blade gaurd (thanks Steve) can't.

Should I use mostly 8" pipe and reduce as close to the machine as possible? Or am I better off reducing a little upstream so the transition is not so sudden? Won't a sudden transition cause a loss of velocity in the air stream?

 

[MarkE]

This is a rough idea of what I have so far. The Grizzly design tool doesn't have ductwork parts, so no wyes or sweeps, etc are included in the drawing. You'll have to use your imagination :wsmile:

View image in gallery​

The first branch going to the left is for the drill press and possibly a floor sweep. I may not even need that branch.

The branch on the right side will go to a miter saw station. I already have the PSI miter saw hood, which came with a 4" and/or 5" port, but I could probably open that to 6".

The main branch in the middle will go to the tablesaw/router table/downdraft table that I will be building 'real soon now'. For this I will need multiple connections. One for the TS cabinet, one for the TS blade guard, one for the router/downdraft table, one for the planer and bandsaw (on mobile bases, one hooked up at a time) and possibly one more for a floor sweep on the right side of the TS.

 

[Alan in Little Washington]

I don't think the specs of that Grizzly really support 8" duct, but regardless, 6" right from the cyclone would probably be fine- that way you are only dealing with one size duct, besides you won't find 8" in PVC and any 8" blast gates you may find will be expensive. If you plan to run metal duct, you can make the "trunk" 8" and all branches 6".

Here is a plan view how I would run the duct. It is pretty close to your drawing, but I rotated the cyclone inlet so a 90 and two 45's can be eliminated, making for straighter runs:

 

[MarkE]

Thanks Alan, I think that will work.

I added the tablesaw workstation and the miter saw cabinet back where they will be located and adjusted the angles on the DC and the pipe.

BTW this drawing is to scale as are the lengths and angles of the pipe.

The machines labeled #3(planer) and #4(Bandsaw) are on mobile bases and will be moved into place when needed. I do not need any DC pipe to that area of the shop. The workbench on the bottom right will have a shop vac system similar to what you have in your shop for desktop tools (sanders, small bandsaw, etc) that have ~2.5" dust ports.

The drill press (#5) is on a mobile base, but I would prefer to not have to move it around when I want to use it. I ordered this from Grizzly for the drill press, so I will need to get a 4" line over there if I want that to be it's permanent location.

Here is the current iteration, based on your advice.

View image in gallery​

 

[Bill Clemmons]

Thanks guys.

The DC I am going to be setting up is the Super Dust Gorrilla, purchased from Scott Smith. It has an 8" inlet.

Mark, I have that same DC set up for my shop. If you ever wanted to take a road trip and see how I have mine arranged, you're more than welcome to come see the shop. Alan's design suggestion is very similar to what I have: Straight runs across the ceiling, w/ branches off to the machines. I think I mentioned this when you first started your shop: Some of my connections are under the floor. Are you planning on doing that?

Here are two pics that show some of the duct work running along the ceiling. It's not perfect, but it is the most efficient pattern I could work out. As Alan said, go for efficiency, not appearance. It's not easy to see, but look at the furring strip between the ducts and the ceiling. It is screwed into the ceiling joist, then the duct is attached to it w/ a 50" zip tie. Doing all the duct work by myself, this was a great way to get them all in place and connected, then gradually snug them up by pulling the ties tight.

View image in gallery

View image in gallery​

HTH

Bill

 

[MarkE]

Thanks for those pictures Bill. I have looked through your shop pictures in your gallery and picked up a few ideas.

Are you using 8" duct at the DC? how much of your system is using 8"? Are you using the snap-lock pipe (26 gauge?). Where did you buy your pipe and fixtures?

I don't think I will need quite as much of a system as you have, based on the way I have things laid out in the shop. Not planning to put any pipe under the floor, too much work. As long as the drop to the tablesaw is on the right side, it shouldn't get in the way. I am planning to use your furring strip/ zip tie method for hanging the pipe.

If I can ever get some time freed up I would love to come by and take a look at your shop. Just don't know when that is going to be.

 

[bobby g]

Mark,

If you're going to Bills, you are welcome to stop at my shop on the way and look at my installation. It's an Oneida design. BTW, I've got some Oneida leftovers that I'll sell for 1/2 price. I'll try to get a list together soon.

bobby g

 

[MarkE]

Mark,

If you're going to Bills, you are welcome to stop at my shop on the way and look at my installation. It's an Oneida design. BTW, I've got some Oneida leftovers that I'll sell for 1/2 price. I'll try to get a list together soon.

bobby g

Thanks Bobby. I love leftovers. :banana:

 

[Bill Clemmons]

Thanks for those pictures Bill. I have looked through your shop pictures in your gallery and picked up a few ideas.

Are you using 8" duct at the DC? how much of your system is using 8"? Since the 8" inlet on mine is square, I installed an adapter that took it from 8" sq. to 7" round. I'm running 7" duct as far as I can, which is usually to the first wye. Then I drop down to 6", and finally to the size of the connection at the machines. Are you using the snap-lock pipe (26 gauge?). Where did you buy your pipe and fixtures? I'm using standard HVAC metal duct work from the BORG. I'm not sure what gauge it is, but it wouldn't hurt to have something a little bit heavier. When I first started using it, I only had one 4" blast gate opened, and the suction collapsed a section of the 7" pipe. Since then I always make sure I have at least two gates open. No more problems.

I don't think I will need quite as much of a system as you have, based on the way I have things laid out in the shop. Not planning to put any pipe under the floor, too much work. As long as the drop to the tablesaw is on the right side, it shouldn't get in the way. I am planning to use your furring strip/ zip tie method for hanging the pipe.

If I can ever get some time freed up I would love to come by and take a look at your shop. Just don't know when that is going to be. I'm in the shop almost every afternoon. Just let me know when.

If you decide to come see my shop, a stop at Bobbyg's shop is well worth it. First, because his shop is awesome. Second, because he has the same Oneida DC as I have. If you come by way of Hwy. 64, to Siler City, Bob's shop is right on the way near Pittsboro.

Bill

 

[MarkE]

Stopped by HD on Thursday with my SIL and saw that they had 6" and 8" 'heavy duty' hvac pipe. There was no indication of the gauge, but it sure felt heavier than the standard 30 gauge stuff normally used for an hvac system.

I tried to do a search on line to get more info. HD has it on the web site as Master Flow:

http://www.homedepot.com/Master-Flo...splay?langId=-1&storeId=10051&catalogId=10053

My search led me to GAF. The GAF web site says the Master Flow pipe is 26 gauge aluminum. The stuff I saw, and is listed on HD's site is definitely galvanized steel.

I will probably buy a few sections of this stuff from HD to check it out. The 8" by 5ft sections are only $10.25 each. Best price I have found so far is $19.70 plus shipping. Big price difference there when you add up all the pieces and parts.

 

[bobby g]

Mark,

According to this chart, 26 ga. is about 50% thicker than 30 ga. You could check it with your calipers on your next visit.

bobby g

 

[MarkE]

Mark,

According to this chart, 26 ga. is about 50% thicker than 30 ga. You could check it with your calipers on your next visit.

bobby g

NICE! :thumbs_up Thank you.

Looks like a trip to HD is in my immediate future.

It looks like they carry most of the wyes and elbows too. Except, no 45* elbows that I could find on-line. And the 90* are the shorter adjustables.

 

[Bill Clemmons]

NICE! :thumbs_up Thank you.

Looks like a trip to HD is in my immediate future.

It looks like they carry most of the wyes and elbows too. Except, no 45* elbows that I could find on-line. And the 90* are the shorter adjustables.

Mark, if the "adjustable" elbows are the ones I think they are, the 90*s can also be adjusted to 45*. I would only use those as a last resort. The longer "sweeps" have a much greater arc and cause less resistance / pressure loss. Just FYI.

Bill

 

[DougW]

Mark check with East Coast Metal Distributors in Raleigh (just off Yonkers). They carry Snap-lock and Spiral ducting 24-gauge. The spiral comes in 10-foot lengths and I was there 2 weeks ago and they were cheaper than Penn state. Even if you go with the snap-lock, the quality will be better than what you can get at Home Depot and a cheaper price, by at least half.

Good luck with your system.

Doug