MERV 16 (or HEPA) Air Scrubber/ Filtration

[ian maybury]

Not 100% sure what's around in the US now, and what the makers are claiming re. full HEPA filters - until recently at least it seemed like properly certified items were not readily available.

Pressure drop won't be a problem provided you install enough filter area. Sizing/square footage will be determined by the rate of recirculation of air you decide you want - but that's a bit of a double edged sword by all accounts in that if you get into high enough airflows you may also (at least temporarily) raise a lot of dust in the workshop. Effective diffusion may be important. i.e. exhausting through a bag or something over a large area so that it wouldn't create draughts.

The other issue though is that if too much fine dust is making it into the air (whatever about the effect on your lungs) because your at source dust collection system is not working very well the filters may blind up too quickly. i.e. effective at source collection is going to matter anyway.

I don't think you're going to get anybody providing genuinely definitive information for a system along the lines you are thinking of - in that even if the work has been done, and even if an effective system can be achieved via this route it doesn't seem widely published or used. There may just be a reason for this....

The other way of looking at it is that experience says that a high CFM Pentz style dust collection system seems to work pretty well as an air cleaner anyway - whether it does so by drawing in fresh air to replace that which has been exhausted, or recirculates it through a set of high quality filters. (they are easily set up so that both options are available by opening a blast gate) In a smaller workshop like i have anyway....

If you're already on the DIY road to build some sort of super air cleaner, and already committed to reworking the dust collection system by buying a cyclone to drop out chips before exhuasting the rest, and are going to need/already have properly sized ducting to get effective at source collection then maybe there's no reason why you shouldn't alternatively and for similar input build a Pentz style system - it'd only require buying a 16in Clear Vue impeller and motor to suit... (the rest can be built DIY as i did)

Which if true would bring it down to the question of which solution is likely to deliver the best results in terms of air quality and serviceability...

ian

[Jeff Duncan]

OK I know this is not exactly what you want so I'll apologize ahead of time, but some things to consider...

First, it's impossible to collect all the dust at the source, even if you have brand spanking new top of the line Euro equipment there's still going to be dust that escapes, so your right about looking to improve your air filtration. I don't know the practicality of filtering out to sub 1 micron so I'll leave that to the engineers. In fact you may want to track down an HVAC forum to ask your specific question on matching motor/fan size to Merv rating and filter area?

Second, if you feel your having some health issues related to dust now is the time to make changes before it gets worse. Optimizing your dust collection and air filtration are good steps. Another thing to think about is the types of wood you work with. If your one of those guys who loves working with exotics, you may have to reconsider. Exotics generally speaking are especially toxic for us to breathe and you'll probably want to avoid them. Other woods like cedars can also be irritating to the lungs. Many domestic hardwoods like maple, poplar, and oak are less irritating to work with.

good luck,
JeffD

[Kelly Colin Mark]

I bought a used Abatement Technologies Predator 600 air scrubber from my local Craigslist/Kijiji. It's used for containment in construction, is built like a tank, easily moved around, very quiet compared to my Steel City overhead filter I have at my cottage, has a HEPA filter and most importantly does an incredible job of reducing fine dust particles as measured by my Dylos.

I was a little worried that it would be too small for my very small shop, but it does a good job.

[David Kumm]

I would buy a good face mask for sanding as that is when the fine dust will overpower the scrubber, and buy MERV 14 inner filters for the overhead. You are filtering the shop air every 4 minutes so the submicron stuff will be passing through quickly enough that even if the filter is only 33% efficient it will clean up the air in a few passes. All the other air you breathe won't be filtered as well as the shop. Dave