Water Softener air gaps generally are installed near the laundry facilities in the garage, basement or in the laundry room for convenient access to the house drainage piping and secondly, there almost never exists a dedicated (unused) standpipe just waiting to be used by the installer for surmounting their drain line air gap. Thus the critical feature of the air gap is its ability to share a standpipe with the washing machine drain hose.
Properly designed and installed, air gaps, like check valves, allow water to flow only in the desired direction. The key characteristics for an air gap is protection from back flow and back siphonage.
All units are dual listed by IPC and UPC©. Dual listing conveys generally this important message: countrywide as well as international acceptance.