Dust Collection at Altitude


Howdy, I am setting up a home shop and in the process of designing the dust collection system. My location is at 7000 ft elevation so the question is, what efficency drop will the duct collector suffer due to the altitude? Anyone ever dealt with this issue? I called Jet tech support and they didnt have an answer. The books I have read dont even mention effects of altitude on DC performance..... anyone have any input?
TIA, of course
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Even without knowing the power of your DC, any minor loss of air pressure-density will be offset by the ability of the impeller to spin a _bit_ more rapidly. I'll bet that you'll hardly notice a difference, if at all. Tom
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Not quite.... the static pressure will be less, but the air density is also less.... at 8,000 ft the air density is down 26% from that at sea level.
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Figure your CFM requirements as 'sea level' and then add 25% as an altitude adjustment. That will get you close enough.
Woody
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you need.
Dave
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Initially, I was considering using a 4" main line with 4" legs to the machines. According to the book, that works (presumably at sea level). I wonder if going to a 6" main with 4" legs would make up for the altitude factor? I already have the DC, a Jet 1100 so really need to make that work if possible. Wish money was no object.....
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About 4in vs 6in. If you want the best i would go with 6in. Just remember you want to move mass of air and your not trying to lift water. The larger the pipe the smaller dust particles you will catch. I just got the jet 1100rck put up my 6in pipe for main line then ran shorter smaller pipe to equipment. I can say my router table is 99% dust free when using.
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Higher the altitudes the bigger the impeller needs to be.
check out this http://billpentz.com/woodworking/cyclone/Index.cfm
no simple answer with any vacuum system.
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wrote:

There won't be much difference. But I recommend getting more HP than you think might need for other reasons that have a much larger impact. Like curves, turbulence, length of piping, leaks, adding a drop box, exaggerated HP claims, etc. I have a 1.5 HP and really can really use a 2HP, but I use what I got.
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