95% of my piping is under slab.
The key to prevent plugging up, is the strength of your collector, and also if you ever surface pine lumber, ease up on the cut depth.
Pine emits long slivers of wood, not small chips like hardwood.
I recommend to put in an extra floor inlet while you are at it. Never know when you want to add another machine. It can be flush to the floor, and make a round, slightly tapered wood plug to plug it off.
I have two extra inlets with plugs. I pull the plugs out when brooming the shop floor and let that go outside also.
I've never seen any water/condensation settle in my pvc piping