Booth air intake

Lizer

Mad Scientist
I'm building my new booth in my new shop. It's more like a well-lit, exhausted contained area for painting. One side of it will be a curtain so I can open it up to the rest of the shop and get the space back. The front of it is a 14' tall stud wall I'm building.

I'm considering putting the air intake filters near the floor at the front of the booth and up to 36" from the floor. There were a few reasons for this. First is I have a rolling tool bench that is going to become my paint mixing bench. It's 24" deep, and I'm going to put a new top on it that's about 30-36" deep and the extra length will go off the back. My bench will be rolled up against that wall but there will still be a 6" gap behind the bench and wall due to the counter top stick out the back, and that will leave room to pull air in through there and through the filters.

The other reason is because the concrete floor is cool in the summer so I can hopefully pull a little cooler air in, and the floor is heated in the winter. Then if I need to spray in the winter and need to supplement heat, I can roll the bench out of the way and put a salamander on the floor 8' in front of the intake filters or so, and suck the warm air right into the booth.

My current booth I put the air intake in the ceiling and that's a big mistake because it pulls all the hot air straight down from the truss space in the summer and it gets to be over 100 degrees in there.

Is there a reason I wouldn't want my air intake coming in low? My exhaust will be on the floor on the opposite end. Then I'd just be worried about the air moving straight across the floor and either stirring up dust or not being effective at clearing overspray. Since once side of the booth is a curtain, it will be pulling a lot of air in from the space between top of the curtain and the track, so 100% of the air is not getting pulled in through the intake.


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Are you setting it up to use tacky booth intake filters? They are usually 20x20”.
That was a subsequent question, what are people using for filters? My old booth I was just using 16 x 20 furnace filters. Was also curious on how people are physically attaching or mounting the filters.
 
That was a subsequent question, what are people using for filters? My old booth I was just using 16 x 20 furnace filters. Was also curious on how people are physically attaching or mounting the filters.
The tacky booth filters have an internal frame that friction fits into a frame of the appropriate size.
 
How long do they usually last?
They would last about 1-2 months in the last Shop I was at. It was not a clean Shop either. Very dirty. They last a long time. You use them till you notice that the booth is pulling hard. Quality ones will never get so dirty that they transfer dirt/dust to the booth, they just "stop up" and you lose airflow. When they start losing airflow is when you change them. And if the booth isn't running they aren't getting dirty no matter how dusty and dirty your Shop is. Situation like yours I would bet they last a year or so. Those tacky oversized filters (with a steel frame) are the only way to go for intakes.

And Don answered your previous question but I'll add to what he said. Your concern about mounting the filters high is unwarranted. Yes it will pull hot air from up top in the summer time but if you have your Shop door open in about 5 minutes of the booth running the hot air is gone. I've worked in a Shop with 20 foot high ceilings (in the center of the building, near the intakes) and here in southern VA it gets really hot. It's not really a concern. Once you start moving air, the air temps will cool off considerably as you are pulling air in from outside. And in the winter it can only help. I know you have radiant heating but warm air still rises. Mounting them low will result in more dust getting pulled in the cracks and filters that get dirty easier. Poor airflow as well. High to low works best when considering airflow.

Best place to put your filters in a conventional cross draft or semi down draft is above the door. Build a filter box of sorts that goes on the roof of the booth and pulls the air down then across the car. Exhaust wall for exit. Copy existing designs. A good semi downdraft or crossdraft configuration will work really well for you.
 
hmm............im backwards then. my fan is at the bottom of the rafters. i dont have a paint booth though. i could see the reasoning in a fairly clean booth type environment. noted.
Most booths the fan is mounted high so you are not wrong. Some mount the fan near the top of the stack on the roof. Most conventional type booths use a tubeaxial mounted behind the exhaust manifold. Typical one will be 6 or 7 feet off the ground. Some are mounted higher like I said above. In ductwork mounting it higher helps with flow. Similar to a chimney.
 
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Most booths the fan is mounted high so you are not wrong. Some mount the fan near the top of the stack on the roof. Most conventional type booths use a tubeaxial mounted behind the exhaust manifold. Typical one will be 6 or 7 feet off the ground. Some are mounted higher like I said above. In ductwork mounting it higher helps with flow. Similar to a chimney.
the reality in my shop is that the fan is so big it creates a negative pressure in the whole building. this is why i cant burn the wood stove with it on, it will reverse the chimney draft. i initially set it up for welding fumes, and it works very well for that. of course it expels paint fumes too..........i highly suspect it is the reason i get so many nibs also. too much air movement. in any case, its what i have to work with. if i was to build a real booth, or as close as i could come, i can now see a benefit to a low exhaust.
 
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