Woodshop Dust Collection

This situation like many recent ones highlight how important decision making has become in DMS leadership. That also extends to committee leadership and key volunteers.

There is no need to rush unless there was an expectation set with the Fire Marshall. We cannot knee jerk a solution and then not follow up either.

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Itā€™s a fair bit more complicated that that. The overall static pressure of the system, the cumulative frictive loss of a given airflow, the actual pressure drop created by the fan, and the volume and weight of the material being transported, all need to be known in advance, to calculate the size of the fan needed on the other end (the collector size). That size is calculated by determining the system parameters, and then using the desired air velocity within the duct. Air velocity is the ultimate requirement. If it moves too slow, the chips fall out of the stream, and accumulate in the duct, or are simply not pulled out of the machine in the first place. If you open any of the machines, and look inside them, youā€™ll see the direct result of too-low velocity. If youā€™ve used the jointer, and had to stop and clean out the duct and hose because it was clogged, you can thank low air velocity as well.

Thereā€™s a pretty good explanation of the basic parameters to a system Here.

In order to correctly size a collector, an Engineer needs to first calculate the overall pressure conditions of the system as designed, and then determine what the worst case condition would be (i.e. highest expected number of users at stations at the far end of the system normally). This will dictate the size of the collector (with a clean exhaust filter).

Since there is no existing design, no one has done this, and therefore it logically follows that no one knows how big it needs to be. The salesman just did a wild-ass guess that it would be big enough. Then he chummed up a nonsense estimate on an external collector, which included a lot of made up numbers which favored selection of his product.

Speaking as an Engineer who has three years working in our woodshop, and having a working familiarity of our useage, current system performance, and future needs, Iā€™m going to make an educated guess that the system needs to be about twice as large as the unit proposed by Andrew. But thats just a guess.

Conditioning all this, is that the Building Inspection Plans examiner that reviews our permit application, is going to require engineering drawings, and very likely require them to be stamped by an engineer. The Fire Marshall (who will also review the application) will likely want the same thing.

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I could not agree more. The scary thing, is that for the first time, we will be in a situation where there isnā€™t lots of extra money available to hide mistakes and poor judgement.

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Yes, obviously, hence my use of words and phrases like ā€œback-of the envelopeā€, ā€œsimplistic calculationā€, and ā€œclose toā€. Engaging in analysis paralysis here wonā€™t help. Conveying need that a better discussion and more expert consensus is in order, and that we are not in any immediate hurry, is whatā€™s important (I think), and which last several posts have sufficiently accomplished (I hope).

What is the size of the unit that Andrew proposed?

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Here is an outdated list of tools and their manufacturerā€™s recommended flowrate. But hey, some dude is about to get a sweet commission on a collector that totally is gonna work dude.

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4000 CFM.

Teeeeeeeeeeee-wenty.

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The good news is I just figured out how to use most of our new expansion sq footage:

https://www.industrialvacuum.com/dust-collectors/stationary-dust-collectors/filt-aire-20000-cfm-dust-collector


The downside is we also need to build our own coal fired power plant.

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With the expansion coming up it kind of makes sense to me to at least wait and see where we end up settling. If woodshop gets repositioned next to the back wall, maybe by the ramp even, (cough @John_Marlow) this could become so much more of an easier issue to resolve. Then all the cost of tubing to an outdoor unit is minimizedā€¦

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Let me first say that I am not a technical expert in dust collection requirements nor systems. I do not have a preferred solution in mind. However:

(a) We cannot wait for expansion to solve our dust collection problem (not saying that we are waiting for that, just emphasizing that we canā€™t). Best case, by the time we get construction/installation completed and (whatever relevant portions of) Woodshop moved, it will likely be October or later. That will be nearly one year after the Fire Marshallā€™s review.
(b) Whatever we do needs to be something that we can either transfer or enlarge in conjunction with expansion, without losing any significant part of our investment.
Ā© We shouldnā€™t install it in a location or in a manner that will be destroyed if/when we cut a hole in the Woodshop wall to connect with Suite 102. It is possible that we will sacrifice the eastern end of Woodshop to make a passageway into Suite 102 so that people donā€™t have to walk through a shop to get into the other suite.
(d) The DC system needs to be sized for the assumption that we will add additional equipment. At the very least we will add a duplicate planer, jointer, and probably another table saw - not in the near future but we need to size the system accordingly - or it needs to be something that can be modularly enlarged without losing our investment.
(e) @IanLee - we have permission from the landlord to install an exterior dust collection system if thatā€™s what we want to do. I am not saying that is the right solution, and I understand it is not what was proposed to the board, but we have permission to do that if necessary.

The only analysis I saw that included CFM assessment concerned me, but I am not a flow engineer.

Perhaps we should spend a few dollars and pay an engineering professional to size the system for us ā€¦

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Needs more power. Letā€™s rewire it.

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Just another thought. Any reason we canā€™t use the existing DC in addition to the new DC? Use existing to be dedicated to 1 or 2 machines each and new dust collector for everything else? I am in the same camp as @John_Marlow that Iā€™m not an expert but agree we canā€™t wait another 6 months.

I whole heartedly agree. Itā€™s a system that needs to be engineered. Not just for the use now but in the future. In my opinion we are doing it backwards. The engineer needs to size what we need & make the equipment selection based off that need. I feel that this purchase needed to be fully vetted. I do not want us just throwing money out of the window.

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I believe that Andrew is tentatively considering using one of the older DCā€™s dedicated to the lathes (after the expansion).

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Is there any thought to putting the lathes in a separate ā€œturningā€ room using their own collector? (For safety too) It also seems that a lathe needs a collector running for a long time, where the other tools are used for a shorter duration and not always at the same time.

We could keep the wood shop where it is, add a new collector now, and move the lathes out when thereā€™s new space.

Maybe it is just me, but Iā€™d also be more in favor of multiple smaller systems for redundancy (failure of one wouldnā€™t take down the entire shop) and to reduce duct distance.

Finally, are we also looking at air filters to collect airborne dust that the machine collection doesnā€™t get?

(Sorry if all of this has been covered before. I havenā€™t read every previous post)

There is some thought of that. Thatā€™s what Woodshop has requested.

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What a brilliant idea! This sounds like a plan that makes sense, ask an expert!

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Iā€™m available tomorrow in the a.m.

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But then you would still have the issue with the HVAC returns in the woodshopā€¦