[I'mYourTourGuide]

What type of backflow prevention do you guys use for these?

We use pressure type vacuum breakers here.

 

[pydoplumbing]

most of the ones we use are already protected by a airgap on the device.

 

[Protech]

Me too. We use the 3-way type. The middle leg faces down and drips when the side legs flow thru. There are 2 slats on the side of the drip chamber that function as an air gap for the middle drain leg.

 

[Bill]

most of the ones we use are already protected by a airgap on the device.

Same here