Under floor piping

[John Scott]

I am building a shop over a crawl space and hope to rout the DC PVC under the floor. To do this, I'm guessing I will need to use two 90 degree elbows to reach the cyclone inlet. Will these turns be too much of a detriment to air flow?

[McRabbet]

I am installing 6" PVC under the floor of my shop that has a 4' to 9' crawl space. I'm installing my CV1800 on a concrete pad and will rout duct mains horizontally below the floor joists. Where I want risers, I use a 6" Wye with a short segment of straight pipe to a 45º elbow and then straight pipe through the floor (at the end of a run, I use a 45 instead of the Wye). I have the option of adding a blast gate at the floor or continue the straight pipe up to any desired height or adding another fitting like a Wye or a 45º or 90º elbow. I was able to find good 90º sweep (6" inside radius) elbows at my pipe supplier.

[Ed]

John,
If you stick with long radius turns (use two 45 deg els and a short piece of pipe in between) you will be fine. I ended up with two close radius turns on my installation to get up in the attic and it still works fine, but I lost a lot with the close radius turns. One thing to think about.... if you install your ducting in the crawl space, you will end up coming up to your machines. That will put the blast gates under the machines in hard to reach places. Do some planning before you commit to that. The other problem is that it will be much harder to change ducting around later as you change your layout. I said "as" you change your layout because it seems inevitable that everyone buys new machines, starts working on a project that needs more floor space and machines need to be moved to accommodate these things. Hope this helps.

Ed