# Air cleaner placement?



## JCMeyersIV (Mar 8, 2012)

Figure it only a matter of time before I get banned for posting too much :laughing: but until then I have a few more burning questions. This one might get a little long and involved but I feel its curtail to my new shop so here goes... And it'll be a long one!

First off short back story (as usual):
I'll use broad strokes here. Most of you know by now I'm setting up my own shop in half my dad's garage. After a few months of woodworking out there I bought an air cleaner. It's manual pull strings with no timer or auto shut off or anything. Pretty bare bones. It does a good job but I'm not sure if the placement is correct. It takes air in on both sides and exhausts it though one face. Here's the cleaner in its original configuration:










The placement was later shifted 90* with the vent aimed towards the garage door. Here's a drawing of the current placement:










Note the additional walls drawn. They are temporary walls to keep dust and some noise out if the other half of the garage. The main dividing wall is 2x4 studs covered in 1/4 Luan. There is a 10" gap at the top of the dividing wall where I am placing furnace filters to help keep cross ventilation flowing through to the other side where our dogs sleep (my side has all the window and theirs has a screened storm door) The filters are obviously to stop dust. Here's the wall:










I don't feel that the way the cleaner is currently set up it isn't functioning properly. I think that the air isnt being cycled and it pushes more dust away than it collects.
There are two solutions I've thought of:

One: leave filter where it is, attach duct work to the vent and have it blow out the the other half (it's 1 micron so no harmful dust particles) or rig it to vent out the window, but having casements this could be hard. Here's a diagram:











Realizing that proper ventilation scenarios dictate that the cleaner be placed on one wall as to pull the air in and circulate it through the whole room I thought of shifting it 90* again and placing it next to the wall with the vent aimed towards the filters at the top of the wall. The only problem that I have with that is the proper scenarios I mentioned use this placement so the vent blows air out IN LINE to properly circulate it. This would simply suck it in and exhaust it to the other side. Here's a diagram of that idea:










Note the garage door track and beam drawn in to illustrate obstructions in placement of the cleaner anywhere else. 

Both these idea of course are intended to further enhance proper air flow through the garage.


I'm looking into getting a rockler dust right cleaner with the remote and timer but I would like to wait until I'm making more money and also with the ability to open the garage door to force or clean dust out in the summer, I feel it can wait until colder months. I would most likely keep this for carving, hand sanding of extram oomph on the floor as it is designed to be portable as well as permanent. 

Let me know what you think! Back to cleaning for me!


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## JCMeyersIV (Mar 8, 2012)

Afterthought: I do use a shop vac with a cyclone on EVERY tool I have with a dust port.


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## HowardAcheson (Nov 25, 2011)

Here is an excerpt from a article I wrote a few years ago for a woodworking club newsletter. It contains some info on placement of the air cleaner.

Here are some general rules based on Nagyszalanczy's "Workshop Dust Control" and some of my own experiences and thoughts.

The two most important criteria for an air cleaner are the CFM and the filters. You want a CFM factor that will clean the size of your shop and a filter that removes the particle size that you are concerned about.

To determine the size or required air flow, use this formula: Volume of your shop (Length x width x Height) times Number of air changes per hour (typically 6 - 8) divided by 60. This will give you an answer in Cubic Feet per Minute which is how air cleaners are measured. MOST AIR CLEANER MANUFACTURERS RATE THE CFM OF THE FAN ONLY, but there are losses due to the filters. If you are building your own or if the air cleaner you are purchasing rates only the fan, figure you will lose about 25 - 40% for filtering losses.

As important as the air cleaner size is how and where you mount it. Try to mount at about 8-10 feet above the floor (no lower than 6'or 2/3 of the floor to ceiling distance if less than 8' ceiling). Mount along the longest wall so the intake is approximately 1/3 the distance from the shorter wall. Mount no further than 4-6 inches from the wall.

The exhaust is the largest determiner of the circulation pattern. You are trying to encourage circulation parallel to the floor/ceiling so ceiling mounting is not recommended. Use a smoke stick (or a cigar) to observe and maximize circulation. Use a secondary fan to direct air to the intake if necessary. Also, consider that a standard 24" floor fan moves a lot of air and, in some shops, just positioning it in a doorway with a window or other door open can accomplish as much or more than an air cleaner. It's all in the circulation patterns.

The exhaust is the clean air so that is where you want to position yourself. Do not place the air cleaner over the a dust producer. That will guarantee that the operator will be in direct line between the dust producer and the air cleaner. The operator wants to be in the clean air stream. If the dust has to pass your nose to get to the air cleaner, you get no benefits. If you have an odd shaped shop, two smaller units may be better than one large one.

DO NOT RELY ON A AIR CLEANER TO ACT AS A DUST COLLECTOR. The purpose of and air cleaner is to keep airborne dust in suspension and reduce airborne dust as quickly as possible AFTER THE DUST PRODUCER HAS BEEN TURNED OFF. 

Finally, if you are looking for health benefits, you will not find any air cleaner manufacturer that makes health claims because there are few health benefits. CATCHING DUST AT IT'S SOURCE IS THE BEST LONG TERM GOAL. Rick Peters', author of "Controlling Dust in the Workshop", makes the point that spending your money getting the dust at its source is a better investment than trying to capture it after it is already airborne. If the dust is in the air, it's going to be in your nose and lungs too. Robert Witter of Oneida Air Systems has noted that "overhead cleaners can only lower ambient dust levels AFTER THE SOURCE OF EMISSIONS IS SHUT DOWN, and they take several hours to do this. This is why they are not used in industry." The absolute best answer, if health is the primary concern, is to use a NIOSH approved respirator. The dust cleaner will help keep your shop cleaner but have minimal or no health benefits. OSHA takes this position too. They measure the number of particles per a volume and most air cleaners will not satisfy their specs.


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## Shop Dad (May 3, 2011)

The purpose of an air filter is to provide you with clean, filtered air IN YOUR SHOP. If you are going to vent it out of your shop don't bother with the filter, just get a fan. It will be much more efficient as Howard states above. When it's cold or you otherwise don't want outside air coming in you need to filter the shop air without replacing it with outside air.


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## JCMeyersIV (Mar 8, 2012)

Well the other thing about the fan is when the weather gets hot (I'm cold blooded,anything over 70 is too much) I prefer to leave windows and doors shut to trap the cool air in the garage, that concrete slab keeps it comfortable. So I guess if Anything I really just want to know what the best orientation for the cleaner is for now due to its irregular air direction. I have a large fan I use a lot (especially to "dust" the garage with a leaf blower lol)


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