Air Gap on drain

[Clutchcargo]

re: 3 bay sink (again). I thought I had this all worked out but I discovered I don't have a wide enough air gap.

I have 3-bay sink with a 1.5" drain. The requirements for the sink is that it needs an air-gapped drain.
If I run a 1.5" p-trap following the air-gap, can I expect that the drain would keep up with the drainage flow?

My original plan was to upsize the plumbing following the air-gap to 2". My method of air-gap is to use a 4x2 reducing coupling (as seen in pic). The developed length is 10'.
The problem is that I cannot get the required air-gap (3" - 2x drain pipe size).

The routing is: from the sink, drop into the air-gap with p-trap (directly next to sink), then follow the wall above the foundation, around the corner (two 45° elbows), under the electrical conduit body, into the riser (next to laundry sink).

TIA

 

[Bannerman]

Your application appears to be a commercial kitchen sink. As such, the photo below shows a 3 basin commercial kitchen sink drain utilizing an air gap above the floor drain.

 

[Sponsor]

 

[John Gayewski]

Yes we use 1.5" for those.

 

[Clutchcargo]

Yes we use 1.5" for those.

Thanks John,
Is there a minimum standpipe length following the air-gap? I'll only have a few inches before the p-trap to not encroach to 3" air-gap

 

[John Gayewski]

Thanks John,
Is there a minimum standpipe length following the air-gap? I'll only have a few inches before the p-trap to not encroach to 3" air-gap

No. A lot of times we drain them into a floor sink.

 

[Breplum]

most jurisdictions plumbing inspector and required health inspectors only allow floor sinks.
Plus, you will need a vent thru roof if you do your p-trap with increaser as a receptor.
No grease trap required by your district? Really? That is usually a requirement when any FOG is expected and believe me, any district that doesn't require it, grease build up is a disaster waiting to happen and clog into a mess in the middle of business. Don't forget required clean-out.