'Large' Shop Dust Collection?

[William Dameron]

Alright guys and gals, I have a few questions about dust collection. Specifically, large-ish shop dust collection. I'm trying to start a community woodshop in Las Vegas - i.e. a large, well equipped shop, open to the public in the form of membership, and classes. You guys might be familiar with Philidelphia Woodworks, Community Woodshop LA, etc. We're hoping our will be similar, and we're well on our way - have a lot of tooling, and a big chunk of the capital saved up - hopefully in the next few months we'll be ready to pull the trigger, lease a building and open the doors... but, thats neither here nor there. What I would like to know about is dust collection for a shop that large. I've worked in a few woodshops over the years, and always had hodge-podge dust collection. I want this to be better. To begin with, here is a tool list:

22" planer, 15" planer, 16" jointer, 8" jointer, 2 sawstop table saws (for now - maybe another down the road), 2 band saws, 2 chop saws, 3 router tables, belt/disc combo sander, spindle sander, drill press, etc. Later on down the road I might add a few tools, and one day would love to have a wide belt sander or dual drum sander. I will also have a lathe section, with 5 or 6 midi lathes, and probably 1 or 2 full size lathes (may get those later on after doors open though).

So, with the above tools, I will officially need a lot of dust collection. I've been researching the heck out of it, and I think I have it narrowed down to two potential types. A big external unit, or if I have to put it indoors, cyclone units. So far, am I correct?

Next, can anyone recommend the amount of cfms I need to move? According to Bill Pentz's chart, it's about 8000. According to other info I've found on the web it could be down around 6000. I definitely want the air to be clean, so overkill is a better, within reason.

If I do go with internal cyclones (I may have to, depending on what modifications to the building my future landlord will allow), should I go with multiple small ones? Or a couple of large ones? If I do go with larger ones, noise is a concern - and if I have to build an enclosure around the collectors, I get into a whole nother world of fire codes I have to deal with (in Las Vegas inspections can be very strict), and will most likely have to have a sprinkler/s installed in that room, and possibly have to build fully certified dust proof and non-flammable rooms, similar to a spray booth. This could get expensive in a hurry, and really slow down how long it takes me to build up enough capital to get doors open.

So, can anyone lend advice? Cyclones or external? Total CFMs? Good cyclone units which arent' stupidly loud? Cost effective solutions?

Thanks in advance,

Will

[Myk Rian]

Call Oneida and have them design and supply what you need. No matter how you look at it, it is going to be pricey.

[Mark Bolton]

I'd think in your situation individual units may be better. At least that way if your having a turning workshop you only have to run the DC for that station rather than having a massive industrial DC running to serve a few small tools.

Its different in an industrial application where you will have many production tools running at the same time.

I'd assume proffitablilty will be a major issue with a venture like this so keeping operating expenses very low would seem key.

I'd love to hear about the insurance issues as I and others on another forum have kicked around the idea of classes/workshops but lawyers have always told me its a liability nightnare.

[William Dameron]

Mark - thanks for the advice. Several smaller units are certainly easier to install and hookup, versus long duct runs by my contractor.

As for insurance, liability, and lawyers, I have it all in the budget thus far, and thus far, the numbers are still working out. My biggest question mark and expense left is dust collection. If I can get a handle on this, I'll be in a good way I think

Will

[Kevin Jenness]

There are a lot of things to consider in your situation- ducting design, blower size, filtration area and type, filter cleaning,, chip storage and disposal, and of course permitting. Start with doing a basic floor plan with machine layout, refer to industry standards and manufacturer's specs for duct requirements to each machine, decide how many machines will likely be in use at once and that will lead you to the correct size blower. The filtration area should be at least 10sq ft per 100 cfm; more is better. Cartridge type filters are popular and compact, but may have trouble with large volumes of fine sanding dust. My own (25 year old Oneida) system has worked well with simple felt tube filters clamped to 5 gallon mud buckets, smacked with a stick periodically for cleaning. You need to think about the volume of chips you will generate and how to dispose of them, whether in barrels, bags, dumpsters or whatever. One shop near here has the chips drop out of a cyclone through a rotary air lock into a dump trailer to minimize handling.

The choice of whether to use a cyclone(s) is independent of the indoor or outdoor location. A cyclone will separate out most of the particles before the airstream hits the filters. If it is before the blower(under negative pressure) it will prevent large, possibly spark inducing chunks from going through the impeller. You should be able to get noise specs from the system manufacturer. If the system noise turns out excessive, you can dampen it with an acoustic foam enclosure(subject to fire regs).

My guess is you are going to need at least a 5000 cfm system, but you need to do the calculations to find out. Air Handling Systems has a good guide available on line for this. It would be wise to get a copy of the NFPA book on dust systems, because that is what the fire marshal will be referring to. I believe 5000 cfm is the line above which very expensive spark detector/suppression systems are required. Separating your setup into smaller independent systems might let you avoid that, but in the end it will be up to the fire marshal or whatever inspection agency you have to deal with. Your insurance carrier may weigh in as well- I imagine you will need a good relationship with them in a community/school shop situation.

Collecting as much dust as possible at the source with a central system and vacs on portable tools is key, but you will probably want to supplement with ambient air cleaners for what the primary systems miss.

Good luck with your venture.

[David Kumm]

You might also want to check into a system with pneumatic gates, at least on zones. Running a large system when sometimes usage might be light can get more expensive than the upfront cost of some gates and a smaller system. You need a design specialist to get it right. Dave

[Michael W. Clark]

For something like this, you will likely have to adhere to NFPA 664 (Combustible Dust standard for wood processing and woodworking facilities.) Basically, if you are commercial (non-homeowner) you can be subject to it. Keeping the volumes below 5000 CFM and using open type collectors (single stage bagger units) is the most flexible and inexpensive way to go. It is also the most econimical way to comply with NFPA.

If you put something outside, you will have to find out if you need to get an air permit. If you go cyclone and put it outside, there are cyclone manufacturers that build high efficiency cyclones to guarantee the removal efficiency to hit outdoor emission limits and negate the need for a bag filter. Put a quality airlock on the bottom and discharge into a rollaway hopper. This is still small for an industrial system and it is intermittent, so permitting may not be an issue.

You will probably need some type of filter or baghouse unit for the widebelt sander in the future. This could be a separate dedicated system and only run when the sander does.

Mike