Air cleaner Location

[Eric Porter]

All,
Finally setting up my basement shop as mentioned in my recent thread about lighting. Now, I'm in a quandary about the best location for my air cleaner. I have a Powermatic PM1200 that I recently purchased off CL (stealth gloat - looks brand new and you don't even want to know what I paid for it). My shop is divided by a main support beam for the house, and next to it are the main air supply duct, waste line, etc. This is all boxed in but hangs about 14" below the ceiling. On the attached shop layout this is marked by the thin rectangle spanning the full width of the shop left to right. The additional, much smaller rectangle is the boxed in return duct that also hangs 14" below the ceiling. Where do you think would be the best location for the air cleaner? Should I use and auxiliary fan on the opposite side of the shop to ensure the air keeps moving? Has anyone connected a fan to their air cleaner to switch on and off with it?

workshop.jpg

Thanks for any input.

Eric

[Larry Browning]

I'm no expert, but I would think that 1 air cleaner for 34x26 space would not be adequate. Plus the way your shop is partitioned would also present a challenge for a single unit. I would think you would need at least one more, maybe even 2.

[Michael W. Clark]

I tend to agree with Larry. However, if you just have one, I would put it in the main area where your workbench and TS are located. The jointer and planer are not going to make as much fine dust as sanding will. I'm assuming most of your sanding would be done in the workbench area. Maybe think of that area like its own shop and locate the cleaner accordingly.

Mike

[Chris Damm]

High on the longest wall with the intake 1/3 from the intersecting wall. That's what I have always been told.

[Eric Porter]

Larry/Michael,
Ha! I only wish my shop was 34'x26'. Your replies made me realize that I poorly named my attached picture. I should have called it basement layout, and indicated that the large room on the left, the bathroom, and closet containing the water heater are not part of "my shop". That is family/living area, walled off from the shop by staggered stud walls to reduce noise transmission. So my shop is L-shaped to the right of the stairwell and turning left until reaching the closet wall.

Chris,
Thanks for the info.

Eric

[David Hostetler]

I see the way you are setup from your pic. With that support beam, the fact your space is set up in an L shape etc... You really ought to consider adding another air cleaner to your shop. Simply put, it is going to be VERY hard for one air cleaner to move the air around enough to do a good job...

[Paul Wunder]

+1

"High on the longest wall with the intake 1/3 from the intersecting wall. That's what I have always been told."

Your Powermatic is a powerful unit. I have a smaller unit (750 cfm). in a 25X25 basement shop with a center beam down the middle and it does what I need. Keep in mind that an air cleaner cannot be thought of as a "primary collector". That must be accomplished at each tool.

[Howard Acheson]

This might be helpful.

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.

[Brian Tymchak]

I have a similar situation in my shop, although my shop is not an L-shape. It is rectangular, but bisected by 2 soffits housing a support beam and hvac. So essentially my shop is divided into 3rds on the ceiling plane. I hung my air cleaner on the wall >below< the lowest hanging soffit, with the intake nearest to the bench and the exhaust stirring the air. I put it below the soffit, figuring that was the best place to get a circulation moving in my shop.

[Kent A Bathurst]

Chris, Paul, and Howie are all correct.

In my case, however, I suspended it directly over the TS for a few reasons:

1. The "ideal" location simply is not available in my basement.
2. Over the TS - very little chance of it getting inadvertently whacked.
3. Right beside the TS is the main workbench - where the sanding takes place. The intake is toward the workbench,

Bottom line: It all depends.

[Michael W. Clark]

Larry/Michael,
Ha! I only wish my shop was 34'x26'. Your replies made me realize that I poorly named my attached picture. I should have called it basement layout, and indicated that the large room on the left, the bathroom, and closet containing the water heater are not part of "my shop". That is family/living area, walled off from the shop by staggered stud walls to reduce noise transmission. So my shop is L-shaped to the right of the stairwell and turning left until reaching the closet wall.

Chris,
Thanks for the info.

Eric

Eric, I understood the layout. Your drawing is very easy to read, nice job.

Since you only have one cleaner, you have the ceiling obstructions, and the L shape is why I thought the one would be best in the bench area. The cleaner is to scrub the air of the fine particles the DC misses. There are not as many fine particles generated at jointer and planer.

[jeff schnell]

I have a 3 car garage and put in 3 air cleaners in about 8 feet. Also when I was installing them they sounded real noisey and it turned out the motor caps were in plastic box without being mounting. I drilled a few holes in the boxes to put wire ties around them and also some silcone. Now they sound a lot quieter.