It's complete baloney. Sure, wood burns, but there's a lot less flammable stuff in my shop than my house. Less sources of ignition as well. The liability of the system failing and soaking the shop would be devastating. Granted, that does not happen often, but it does.

My current plan for dust collection is a 20hp baghouse outside that I've already got, and a few of the small Oneida high vacuum cyclones on the benches to handle the chop boxes and sanders on the benches. Adding walls, even temporary ones, is going to make running that stuff an absolute nightmare.

I'm planning on dumping the air from the baghouse outside in the summer. Dust collection also serves to cool equipment, so it's sucking heat out of the machine, running it across the ceiling through pipes that are warm, and the dust collector itself makes a bit of heat just from compressing the air. Dumping that hot air back into the shop when it's 80º outside and warmer inside just makes things more miserable. Unless you have AC, then you're just a jerk and I'm jealous.

Speaking of AC, I don't be able to afford it right off the bat, but I've got room to do geothermal. AC is much cheaper to run if you can cool the condenser with ground water rather than air. Something like four times as efficient.