Correct fitting for back-to-back kitchen sinks

[Nickel]

I have a duplex and I'm moving the kitchens to the common wall. I'm wondering what is the correct fitting to connect the drains and vent. I see the Double Fixture is probably the correct fitting 2" for drain and vent, and 1-1/2" for the sink drains, but there are 2 different types, one is much wider with a longer sweep (Ferguson is about 5-1/2"), and one is compact with almost no sweep (Charlotte is about 3"). Is there a preferred option in this situation?

Also, tapping into the 4" iron stack there seems to be only one option which is the 4x4x2 san-tee, a very short sweep. Is this correct?

Thanks!

 

[wwhitney]

I see the Double Fixture is probably the correct fitting 2" for drain and vent, and 1-1/2" for the sink drains, but there are 2 different types, one is much wider with a longer sweep (Ferguson is about 5-1/2"), and one is compact with almost no sweep (Charlotte is about 3"). Is there a preferred option in this situation?

I don't think that's correct, it sounds more like you're comparing a double fixture fitting from one manufacturer with either a double sanitary tee or a double combo from another.

Anyway, the double fixture fitting is the correct choice, e.g. this one:

2 x 2 x 1-1/2 x 1-1/2 in. PVC DWV Double Fixture Fitting | Ferguson

Shop for 2 x 2 x 1-1/2 x 1-1/2 in. PVC DWV Double Fixture Fitting At Ferguson. Ferguson is the #1 US plumbing supply company and a top distributor of HVAC parts, waterworks supplies, and MRO products.

www.ferguson.com

I think the following is true or very close: on a double sanitary tee, the top of the side hubs will be definitely below the top of the top hub; on a double fixture fittings, they will be very close to the same height; and on a double combo they will be definitely above the top of the top hub.

Cheers, Wayne

 

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[Tuttles Revenge]

Double fixture cross is the best fitting for back to back fixtures with a common vent. If the overall length is too much because each will stick too far into the cabinet, install it cross ways and use a 90° bend to stub out for each sink. Drains do not need to be centered in the cabinet.. and often work better for installing double basin sinks when they aren't.

 

[Nickel]

I don't think that's correct, it sounds more like you're comparing a double fixture fitting from one manufacturer with either a double sanitary tee or a double combo from another.

Anyway, the double fixture fitting is the correct choice, e.g. this one:

2 x 2 x 1-1/2 x 1-1/2 in. PVC DWV Double Fixture Fitting | Ferguson

Shop for 2 x 2 x 1-1/2 x 1-1/2 in. PVC DWV Double Fixture Fitting At Ferguson. Ferguson is the #1 US plumbing supply company and a top distributor of HVAC parts, waterworks supplies, and MRO products.

www.ferguson.com

I think the following is true or very close: on a double sanitary tee, the top of the side hubs will be definitely below the top of the top hub; on a double fixture fittings, they will be very close to the same height; and on a double combo they will be definitely above the top of the top hub.

Cheers, Wayne

Thank you Wayne for the confirmation.