Option A — as sent 10/23 (v1.1)
Simpler to build. Three straight pipes.
- Each bowl: untrapped 1-1/2" pipe to one floor sink (air break). Sink rim 44-1/2".
- Floor sink → Zurn flow control → grease interceptor → wall. The interceptor serves as the floor sink's trap.
- A 5/8" orifice disk at each bowl drain slows the flow so the floor sink doesn't overflow.
- Known issues: Zurn does not recommend using the interceptor as a trap. The 5/8" disk isn't a listed product (Thermaco declined). Zurn's 11-1/4" outlet would run uphill to the 11-3/8" stub shown, so the stub has to stay low (about 10-7/8").
Option B — revised 10/27 (v1.2)
Addresses Zurn's answers. More fittings.
- A 1-1/2" P-trap under each bowl, joined in one 2" line under the sink. Sink rim 42".
- The Zurn flow control sits in that line, before the floor sink. Its air intake ends open above the backsplash.
- The floor sink has its own 2" P-trap and a 1-1/2" vent to the existing 2" vent. Then the interceptor, then the wall. The cleanout panel is on the hallway side.
- Open: Zurn's written OK on putting the flow control under the sink. Engineer sign-off on fixture units and the floor-sink stand.