Cyclone outside venting

[Alan Lightstone]

I don't know how much suction a DC venting outside creates on doors, cracks, etc... But that DC is rated for 2000CFM at 3in WC, which is a lot.

I have a large explosion-proof fan in my finishing room. I don't recall the CFM rating of it, but it's pretty large. The amount of suction it creates looking for makeup air is amazing. Literally, it would slam a door open if you open it a crack. And good luck closing the door to the shop when it is running. It actually sucks air from the elevator shaft, 30 feet away in the garage into the garage to add makeup air from the garage to the workshop. I have to leave the workshop door wide open to use it.

So providing makeup air is a real thing. Especially with the 5HP Oneida. My 5HP Oneida is fully contained in the workshop, so not sure how mine would do exhausting outside, but not going to try.

In my climate in Florida, exhausting outside would make a huge difference in the climate in the shop. I think it would too in your climate in NH in the winter.

YMMV.

[Julie Moriarty]

I don't know how much suction a DC venting outside creates on doors, cracks, etc... But that DC is rated for 2000CFM at 3in WC, which is a lot.

I have a large explosion-proof fan in my finishing room. I don't recall the CFM rating of it, but it's pretty large. The amount of suction it creates looking for makeup air is amazing. Literally, it would slam a door open if you open it a crack. And good luck closing the door to the shop when it is running. It actually sucks air from the elevator shaft, 30 feet away in the garage into the garage to add makeup air from the garage to the workshop. I have to leave the workshop door wide open to use it.

So providing makeup air is a real thing. Especially with the 5HP Oneida. My 5HP Oneida is fully contained in the workshop, so not sure how mine would do exhausting outside, but not going to try.

In my climate in Florida, exhausting outside would make a huge difference in the climate in the shop. I think it would too in your climate in NH in the winter.

YMMV.

When I have the garage door and windows shut and I turn on my 3/4 HP DC (4" vented outside) I can feel the heat from the attic coming through the pull down stairs. In the summer, I will open the door to the garage to let in some of the cool air. I don't dare turn on the DC or the cool air would quickly be gone.

That's one of the reasons I was hoping I could upgrade to a filter system. Then I could work in relative cool during the summer.

[Michael W. Clark]

Best scenario is to be able switch between filters and venting outside. I'm in TN and we have a lot of humidity. I like to work with the doors open in Spring, Fall, and most of summer, but I like hot weather, not cold. If I have the door open (double garage door), the shop gets to ambient temp in short order.

We have done some DC systems for industrial customers that had space conditioned facilities (heating is common, but AC not as common except for certain industries). We brought in outside air make-up near the dust collection point to minimize how much conditioned air is exhausted. Not sure if this is practical for small shop use or not. For example, if you brought in a duct from outside near the planer and jointer, then you would pull in the outside air and exhaust through your DC instead of so much conditioned air.

I seriously doubt a 5HP DC is going to pull 2000 ACFM. It may be rated for that at 3"wg, but I would suspect the system losses are much higher than 3" when pulling 4K FPM through 6" ducting and the typical 4" and 5" ports. This will probably cut that to 1K ACFM.

[Jason Evans]

Great info Keith, very encouraging, thanks. I run my collector for hours on end sometimes. My shop is pretty well insulated and has a concrete floor and doesn't get very cold in the winter or hot in the summer. There's a lot of steel in there and the weather here is pretty moderate.

I think maybe I'll try exhausting out a window before I cut a big hole in the wall and see how it goes.

[Alan Lightstone]

I seriously doubt a 5HP DC is going to pull 2000 ACFM. It may be rated for that at 3"wg, but I would suspect the system losses are much higher than 3" when pulling 4K FPM through 6" ducting and the typical 4" and 5" ports. This will probably cut that to 1K ACFM.

No doubt it's less than 2000 CFM, but even 1000 CFM will remove all of the conditioned air from a workshop extremely quickly. Not an issue in moderate climates, but down here or even more where Julie lives south of me, or the OP in NH, those don't constitute moderate climates. Now if I lived in San Diego or Kapalua, I'd probably give the exact opposite answer. Actually, if I lived in Kapalua I'd be on the 17th green and not reading this. But I digress...

Now I do spray finishes in summer here. Have to. So I do put up with evacuating all the conditioned air from my shop, which my split AC units have to make up. It's not horrible by any means, but it does need to be taken into consideration. And I have to deal with high levels of humidity from the makeup air brought into my finishing room. So very rapidly the 72 degree, 48% RH goes up to 80 degrees and 75% RH. Not intolerable, but it does show just how much things can change quickly by sucking out all of the shop's conditioned air, and replacing it with outside air. I'd imagine that mid winter in coastal NH, that could get ugly. I know, I used to live about 30 miles from there.

[Keith Outten]

The advantage that a workshop has over normal living space is that a shop is full of steel machines, big toolboxes and a large concrete floor. These hold the heat and dampen the effect of exhausting outside. There is obviously some minor heat loss but for me it is well worth the gain of increased performance and not having to continuously empty bags or drums of chips.

RMMV

[Deb Clarkson]

I have often considered exhausting my basement shop DC outdoors. When I calculated CFM of heated air going out even with my measly HF DC it worked out to one air change every 6 minutes. But it occurs to me that instead of completely replacing all the warm air I could bring a vent to supply outside air close to the dc tool ports. Then instead of replacing all of my warm air I'd be directing a narrow stream of cold air through a limited area and back outside. I have electric RFH so no combustion to worry about. This idea didn't occur to me till after I'd spent the money on a good Wynn filter so I'll probably never do it.

[Michael W. Clark]

No doubt it's less than 2000 CFM, but even 1000 CFM will remove all of the conditioned air from a workshop extremely quickly. Not an issue in moderate climates, but down here or even more where Julie lives south of me, or the OP in NH, those don't constitute moderate climates. Now if I lived in San Diego or Kapalua, I'd probably give the exact opposite answer. Actually, if I lived in Kapalua I'd be on the 17th green and not reading this. But I digress...

Now I do spray finishes in summer here. Have to. So I do put up with evacuating all the conditioned air from my shop, which my split AC units have to make up. It's not horrible by any means, but it does need to be taken into consideration. And I have to deal with high levels of humidity from the makeup air brought into my finishing room. So very rapidly the 72 degree, 48% RH goes up to 80 degrees and 75% RH. Not intolerable, but it does show just how much things can change quickly by sucking out all of the shop's conditioned air, and replacing it with outside air. I'd imagine that mid winter in coastal NH, that could get ugly. I know, I used to live about 30 miles from there.

For sure Alan, I didn't mean to imply you wouldn't have a consideration for the make-up, just that I don't think its a 2K ACFM consideration for your 5HP DC. Now your fan for finishes may move that much. If its a wall panel fan or axial fan, they are high volume and low pressure. You may see a noticeable decline in flow from that fan if working against any negative pressure in your shop.

My garage shop is "conditioned". There is one vent from the HVAC unit that supplies heating/cooling. This is a 2car, tandum garage so would hold 4 cars total, theoretically. In summer, in TN, the garage will be in the upper 70s while the house is ~74. When I open the garage door and let in 90F+ high humidity air, I get condensation on some of the cooler surfaces. It stops and dries once things equalize. I spray finish outside whenever possible anyway. I guess there is a humidity/temp limit for the finishes at some point? For small projects or short spraying sessions, you can probably not vent and be OK with just PPE and I've done that for certain finishes. THe longer you spray though, the more the concentration builds and eventually needs to be exhausted/diluted for health and safety.

[William Hodge]

Having a shop set up for venting sawdust outdoors makes all the difference in how well it works.

In the north, the first issue is heat. Combustion heating units need sealed combustion, with outside make up air. The suction will pull smoke down a chimney if the unit isn't sealed. This is especially noticeable with wood stoves when the flames come out the air vent.

Right sized dust collectors allow using smaller collectors for smaller jobs. A shop vac is adequate for a rip saw with over blade dust collection, with a small (1 1/2hp) blower to get the fine airborne dust out of the cabinet. Having a big cabinet allows for fewer clean outs with the blower.

Radiant heat warms stuff, not air. Depending on heating dry air to heat a shop is a big load on the heat source. Heating concrete and cast iron works better. I heat the water for the radiant heat with an electric hot water heater, and I have solar panels to supply electricity. I also use oil filled radiant heaters near where I am working to make the work area and tools warm up. I stack all the clamps on the floor to make them warm when I pick them up.

Producing red sawdust, I can see the extent of the dust plume from my sawdust trailer where it lands on snow. The dust travels 100', lands on the roof of the shop, and covers the back of the shop when there is an east wind. Putting the trailer on the down wind side of the shop has helped, except when it rains, and there is an east wind.

Color matching the truck with the sawdust color has helped. Light brown is optimal for me, given Sapele dust and a gravel road. Painting the shop and sawdust trailer red worked.

Being a one person shop cuts the amount of time the blowers run. The more people there are, the more the blowers run in the same space.

Make up air is provided by opening a window on the up wind side of the shop.

It's hard to clean dusty air to breathable standards with dust collection equipment designed to not cost too much. The output from dust collectors should be adequate to fill Scuba tanks, if we are to consider it clean.