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Dust Collection

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Forum topic by eregister posted 1300 days ago 1707 views 0 times favorited 23 replies Add to Favorites Watch
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eregister

14 posts in 1319 days


1300 days ago

Topic tags/keywords: dust collection

I’ve been reading a lot about dust collection on Bill Pentz site and he advocates a cyclone vented to the outside if possible. I like the idea of the dust that’s left after the cyclone getting vented outside as there would be no dust passing through filters to the inside of the workspace. In my shop I will be able to vent to the outside, my question is does anyone know of any regulations about venting dust to the outdoors? Is this a normal/acceptable practice?

Thanks,
Ed


23 replies so far

View ChunkyC's profile

ChunkyC

856 posts in 1881 days


#1 posted 1300 days ago

Remember this, all the air that you exhaust outside, all of that air has to be “made up”, brought in from outside. It takes quite the air handling system to make up that much air. If your shop isn’t heated or cooled, then just leave the door open. If not …

-- Chunk's Workshop pictures: http://spadfest.rcspads.com/thumbnails.php?album=135

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dbhost

5378 posts in 1859 days


#2 posted 1300 days ago

Bill Pentz has some fantastic ideas, that I have bumped head with on several occasions, mostly because he comes at dust collection from an engineering perspective, and not the perspective of what is manageable by the majority of woodworkers. Exhausting your shop dust outside is great if you are working in an unheated, and uncooled space. Which in 99% of the planet is a miserable existence. You will need to get make up air to take the place of what is getting blown outside, and just how clean is that make up air? How much of that fine dust that is being blown outside is getting pulled right back into the shop?

I would think that for most woodworking shops, the ideal is to capture as much dust as physically possible at the source, cyclone separate it to keep as much as possible from hitting the filter, and using a pleated filter to present as much surface area as possible to the air stream, at a fine enough filtration level to keep the dangerous stuff from getting pumped back in to the air. For the most part, 1 micron is the accepted standard, but lower is better…

Once that is done, and the work is done in the shop, it is best to clean the air as much as possible with an ambient air filtration system so that whatever got missed by the dust collector, doesn’t just linger in the shop air, but instead gets sucked up into yet more filters.

Once that is done, while I can’t prove it yet (no particulate meter of my own) but I would almost be willing to bet, depending on where you live, the air in your shop, should be healthier to breathe than say the air in most major U.S. cities, that is unless your shop IS in a major U.S. city…

-- My workshop blog can be found at http://daves-workshop.blogspot.com

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Resurrected

671 posts in 1319 days


#3 posted 1300 days ago

I’d say go with it, just remember about the presure your creating inside. Regulations, ah I would not be to concerned if your just a small hobby or home shop. Some LJ’s will say different but there bigger shop owners likely.

-- Who can I block now???????????????????????

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Pop

419 posts in 2573 days


#4 posted 1300 days ago

It gets cold in Charleston. If your shop big or small is heated venting all that air to the outside will pump your heat out with the dust. I don’t know your shop layout, but the ideal way is to put the cyclone in a small enclosed room , use a good filter on the cyclone & use a furnace filter on the air coming back in your shop from the enclosure. Then as dbhost said back it up with a ambient air filtration system.

Pop

-- One who works with his hands is a laborer, his hands & head A craftsman, his hands, head & heart a artist

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eregister

14 posts in 1319 days


#5 posted 1300 days ago

Seems pretty silly but I never considered all the dust I blew outside needed to be replaced, and thus there goes all my heat and a/c. Guess that’s why I asked for the help!

All have made very valid comments. I did see a design with the cyclone in a seperate room and I’m thinking that would work the best, I should have enough space to build a cyclone room.

Thanks for the help!

View rieferman's profile

rieferman

39 posts in 1318 days


#6 posted 1299 days ago

I’m venting outside. My shop is an insulated/heated barn, but the construction is loose enough that makeup air is no issue (for example, just the small gaps around a garage door let in a fair amount of air).

Makeup air, if not loose construction like mine, amounts to a window cracked open, or a louvered vent that opens under pressure if you want something easier.

As for taking conditioned air out of the shop… The objects in the room hold a ton of heat. The air is easy to re-heat. Think about opening the garage door in a heated garage. Wooooooo, blast of cold air. Close the door. Two minutes later, the shop is warm again. How? The objects in the room are holding heat. If you’re like many, and like me, your DC won’t generally be running for an hour straight that often, so your room will be fine in terms of temperature.

In my opinion, the expense, hassle, and space taken up by filters isn’t worth the couple pennies in heating cost. I choose to expel outside.

NOTE: If you decide to vent outside, consider saving a boat load of money and use a thien separator instead of a cyclone to catch the chips. Who cares if a cyclone is better at chip collection if the excess is vented into open air anyways? (this assumes you’re not blasting the exhaust into your neighbor’s kitchen etc.)

As for regulations, my township emailed me and said I’m fine. They do have regulations for larger operations, but for home owner shops, he gave me a pass. He was surprised I even called to inquire.

-- New to woodworking, old to barn fixin'

View GaryK's profile

GaryK

10262 posts in 2615 days


#7 posted 1299 days ago

If you should decide to keep everything inside here is what I did:

Click for details

When it’s over 100 degrees outside I like to keep in all the cool I can.

As to what rieferman says about heat might be valid if you keep your shop heated 24/7, but if you are only in there a few times during the week with the heat on, then nothing will be warm and will take a lot of time to warm up.

Washable filters are cheap and last for many years. Why lose you heated or cool air if you don’t have to.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View ChunkyC's profile

ChunkyC

856 posts in 1881 days


#8 posted 1299 days ago

It’s a little more than a ” couple pennies.” I talked with our Refrigeration Engineer this morning and we came up a simple equation. We made A LOT of assumptions to simplify things but for my setup, a HF 2 hp 3450 CFM rated DC, would cost about $1.65 / hour. Assuming that you are raising / lowering the temperature 20 degrees and and energy cost of $0.10 kWH. At a Delta T of 40 degrees, a day like today, then it would cost about $3.30/hr to keep the shop warm.

To get more accurate numbers, there are a lot of other factors that need to considered, heat load, efficiency, relative humidity, and on and on. The point is, it’s a little more costly than one might expect to condition the make up air.

If you believe the ratings of the HF DC then it would exchange the air in my shop about 85 times an hour! That’s a lot of air moving going on.

Also, if you shop is in the house, someone is going to be complaining about cold drafts at some point.

-- Chunk's Workshop pictures: http://spadfest.rcspads.com/thumbnails.php?album=135

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rieferman

39 posts in 1318 days


#9 posted 1299 days ago

Assuming that a one man hobby shop does not run a DC continuously for hours on end while in the shop, I contend that the heat loss isn’t as big of a deal as people will scare you to think. Personally, a lot of my time in the shop is spent figuring stuff out and setting things up. The actual cut takes only a few seconds, therefore the DC is on for just a few seconds.

If you are a production shop that runs your DC non-stop, AND you live in a cold weather climate, AND you have a big budget to buy an expensive cyclone and expensive filters… perhaps venting inside makes the most sense for you. However, if you’re like me (a budget-minded, one man, hobby shop, running the DC in spurts, living in a mixed climate, working a couple hours per night and on weekends) building a $30 thien separator, and venting outside (free!... errr, plus killowatts per hour heating I guess..) might work out very well for you like it has worked out for many others.

-- New to woodworking, old to barn fixin'

View crank49's profile

crank49

3371 posts in 1598 days


#10 posted 1299 days ago

You probably need to bleed a portion of your collector air outside and replace it with makeup air to get rid of vapors and fumes anyway if your shop is inside your home. You can make an air to air heat exchanger to temper the makeup air. Think for example if you had a large radiator, like from a car, mounted on an outside wall. You send exhaust air into the top fluid port and pipe the bottom drain port outside. Now your radiator is being heated or cooled by the exhaust air. If you had an opening behind the radiator letting makeup air pass through a furnace filter and then the fins of the radiator, it would recover a lot of the energy being exhausted outside; almost for free, and it would be filtered air.

The true power of the EPA is not understood by most folks. They have the right, the law, and the enforcement capability to fine any business, any entity, or any person they find to be in non-compliance. You exhaust anything out of a shop, technically you are supposed to have a permit. The paperwork is hell. It’s best to just try to stay under the radar.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View dbray45's profile

dbray45

2488 posts in 1404 days


#11 posted 1299 days ago

Do NOT vent your DC outside if you heat with anything other than electic heat. You will pull the fumes into the space or dwelling from the stack as soon as the heat comes on. Put the DC in a different room that is vented back to the shop but maintain the envelope. This will help with noise as well.

-- David in Damascus, MD

View ChunkyC's profile

ChunkyC

856 posts in 1881 days


#12 posted 1299 days ago

I agree to politely disagree. I know that when I use my planer, jointer, router table, et al, the dc runs for 5 minutes or more, not seconds and I’m barely a hobby woodworker.

David is right. The CO is a great point that I hadn’t considered (I live in an all electric world!) A DC could easily cause a down draft in a gas fired furnace pulling the CO into the shop.

-- Chunk's Workshop pictures: http://spadfest.rcspads.com/thumbnails.php?album=135

View Resurrected's profile

Resurrected

671 posts in 1319 days


#13 posted 1299 days ago

LOL

Thread is on regulation.

Eregister- Small hooby shops should be fine. Just call your local inspector if you want to be 100% for sure.

As far as loss of heat and all the other stuff, everyone has their own opinion. Do whats right for you and ignore the rest.

Just be safe doing it.

-- Who can I block now???????????????????????

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eregister

14 posts in 1319 days


#14 posted 1299 days ago

Great information, thanks to all for taking time to offer your suggestions.

I’ll be posting progress pics as I get underway.

View dbray45's profile

dbray45

2488 posts in 1404 days


#15 posted 1298 days ago

The way I look at it, if you govern your life on regulation, you wouldn’t do much or you would end up killing yourself because there isn’t a regulation that covers it. The whole idea here is to be safe. Yes, people will do what they will and that is a good thing.

It is not just a CO issue here, ask any firefighter how many house fires they put out caused by a downdraft in the fireplace, I know a lot of people that use wood burning stoves for heating their shops. When you introduce moving a lot of air accros a fire as that of a DC, you create in essence, a forge – with smoke. To test this, stick your DC under your grill vents, start a nice wood fire in ithe grill and turn your DC on. Call the fire dept first – saves on total damage. Keep in mind that many flues are smaller than your average DC.

For a gas or oil furnace and water heater – it is strickly a CO problem. This is easy to test with a CO detector and by putting your DC outside and putting a 6” hose the the same room as the furnace. Set the CO detector on the floor, CO is heavy. This takes less time than sucking air from the other room but the overall result is the same.

Keep safe.

-- David in Damascus, MD

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