Air Filtration Silly?

[Steve Mathews]

This is not criticism of anyone that uses air filtration for their shop or for the concept itself but I felt sort of silly after installing one of the two units purchased for my 40' x 60' barn/shop. After getting one up and running I looked back at my handiwork and thought how could that little box (3'x2'x2') do much good in a space this large even with 2 of them running. Then I thought why not just open up the overhead door and one or both of the 'Mister Ed' doors along one wall instead and let nature do the work. I think that's what I'll do weather permitting and only use the air filtration units when everything is closed up. And yes, it makes eminently more sense to catch the dust at its source. So I'll be putting more effort into improving that equipment in the future. Sometimes you just have to do something silly to make better sense of the situation.

[Wade Lippman]

If you have doors like that and don't mind having them open, then good for you; you have your solution. I don't, and find the air filters work well.
I try not to even have my garage door open, for all the crap the wind blows in. And then there's heat and cooling loss.

[glenn bradley]

Different needs for different shops. I live in sunny SoCal but, I also live in suburbia. I live in a foothill area that has a near-constant breeze that blows into the garage door as opposed to out or past it. This brings in a lot of debris so it pretty mush just stays closed.

I use a 1600 CFM gable fan in a shop made housing that has intake filters. Even with my 2HP cyclone capturing at the source the filters catch quite a lot. Whenever I wonder if it is doing any good I just have to pull the filter and look at what I would otherwise be breathing.

[Steve Mathews]

Different needs for different shops. I live in sunny SoCal but, I also live in suburbia. I live in a foothill area that has a near-constant breeze that blows into the garage door as opposed to out or past it. This brings in a lot of debris so it pretty mush just stays closed.

I use a 1600 CFM gable fan in a shop made housing that has intake filters. Even with my 2HP cyclone capturing at the source the filters catch quite a lot. Whenever I wonder if it is doing any good I just have to pull the filter and look at what I would otherwise be breathing.

If you're pulling that much air (and debris) that far to your gable vents why filter it? The fan will operate more efficiently and besides, the dust has already reached a point where it isn't doing any damage. Not criticising your setup, just curious.

[Van Huskey]

There is no denying that venting your dust collector outside and venting the shop with open doors and a large fan isn't the "best" solution. The problem is many have gotten used to conditioned air and also want to avoid large quick swings in RH.

One of my issues with the ambient air filters marketed to woodworkers is they have poor filtration compared to a good dust collector. The best cost/benefit solution I have seen is the Pentz ambient filter. It is simple to build (but I would suggest a pre-filter around it) uses a large Wynn filter and an inexpensive fan which is easy to source from Amazon etc (you can use higher CFM versions than Pentz). Add a time delay switch and remote control if you like and have all the features of a store bought system that will be much more cost effective in the long run and produce much better air quality.

Edit with your square footage even with just 10' ceilings you need 2,400 to 4,000 CFM to get the proper number of turns per hour...

[Jay Aubuchon]

It may be a gable fan, but I'm pretty sure that it's not in his gable.

[Tim Bueler]

Different strokes for different folks I guess.

I'm farm raised in an era before cabbed tractors. Our fields ran the same direction as the prevailing breeze. One direction you got wind burn. The other direction the dust would hang right with you. Sometimes to the point where you'd have to stop the tractor just find out where you were going. At the end of the day blowing mud out of your nose was just what you did.

Then I spent 30+ yrs building houses. Dirt, dust, pressure treated lumber, MDF dust, prefinished millwork...you get the point.

We lived in a region where the coal trains rumbled through. The coal dust would turn freshly pressure-washed concrete coal black within 6 months. Our dog was on steroids and wouldn't have lived another 6 months.

To say I have sinus problems would be a gross understatement.

Now I have nice little cabinet shop in a region without city or coal trains. First time in my life I've had dust collection in a controlled environment. I'm currently looking into purchasing some Festool products for their superior dust collection. I keep the doors closed and my dust collection systems running whenever I'm in the shop. My sinuses have improved markedly and my dog, some 2 years later, is still alive and well (and off steroids).

Couple that with temps of over 100 in the summer and sub-zero in the winter and I'm more than happy to keep my doors closed and the dust collection system running full steam. I can breathe!!!! Woo Hoo!

[John K Jordan]

...After getting one up and running I looked back at my handiwork and thought how could that little box (3'x2'x2') do much good in a space this large even with 2 of them running...

To check the fine dust in the air regardless of the system you use, consider getting a particulate air quality monitor. I have a Dylos that uses a laser to discriminate and count particles. The monitor shows an air filter does make a significant difference in removing the fine dust floating in the air, assuming the cleaner is installed correctly so it will move air in a big circle in the room. The instructions for mine suggest installing high near a long wall or mounted directly on the wall. A smoke stick/generator can be used to see if the air is actually moving effectively.

My Dylos monitor shows that removing fine dust in the air may take some time. If I create dust where the DC can't remove it, the particle counts go through the roof. If I exit the shop for a while with the cleaner running, the dust in the air drops to safe levels.

Using an opening to the outside might work if you used fans to move the dusty air out and the clean air in. A Dylos monitor could show you if it is actually doing anything useful. I personally like to control the temperature and humidity with the central HVAC system.

The Dylos:
https://www.amazon.com/gp/product/B004AWEG0Y

JKJ

[glenn bradley]

If you're pulling that much air (and debris) that far to your gable vents why filter it? The fan will operate more efficiently and besides, the dust has already reached a point where it isn't doing any damage. Not criticising your setup, just curious.

The gabel fan is the blower for the ambient cleaner. It's not in the gabel. Sorry for the confusion :-)

[Art Mann]

My Dylos monitor shows that removing fine dust in the air may take some time. If I create dust where the DC can't remove it, the particle counts go through the roof. If I exit the shop for a while with the cleaner running, the dust in the air drops to safe levels.

JKJ

If a dangerous level of dust is circulating around the shop so that a filter machine can capture it then your lungs are also capturing it. If the dust escapes the machine and is in the air, it seem to me that it is too late.

[John K Jordan]

If a dangerous level of dust is circulating around the shop so that a filter machine can capture it then your lungs are also capturing it. If the dust escapes the machine and is in the air, it seem to me that it is too late.

So true, but only if you are not wearing your respirator. If I have to make dust I can't collect, usually with sanders with poor or no dust collection, I wear a respirator, make the dust, then continue to wear the respirator or leave until the air clears.

respirator.jpg

The nice thing about the air quality monitor is not having to guess when the fine dust is cleared.

Since it is spring here now (66 today) I like to do such sanding outside. When I built my shop I included an 8x12 concreted porch on the shop with a roof - my favorite place to make dust.

JKJ

[William Fretwell]

On those wonderful temperate days having the door open to work is splendid. I still run my air cleaner.