Floor Sink

We just started a restaurant TI and have an issue with the depth of the existing sewer lines.

The top of the existing 4" sewer lines are 4 1/2 inches below the bottom of the 4" slab. We need to put in 2 floor sinks. One for a 3 compartment bar sink and one for the beverage station.

We hired a locater to trace the lines throughout the building and just before it goes into the walk in cooler the line is 17 1/4" below the bottom of the slab.

Based on the distance the sewer lines are not deep enough there either.

I figure we have 3 options.

1. Raise the floor sink out of the slab and encase it in concrete. (Can a floor sink at a 3 compartment bar sink and beverage station be elevated with a concrete shell out of the slab?)

2. Install a sewage ejector pump in the suite.

3. Install a new sewer line from outside the building for these fixtures.

Is there any other options? Can a floor sink be elevated out of the slab and if so is there a height limit?

Architect will be out there tomorrow but I want some professional input before the meeting.

If it were me, I would choose
2. Install a sewage ejector pump in the suite.

I would install the sinks the way they were intended to be installed

explain to the local inspector what you have found and see if he will allow a funnel type drain. basicly the floor sink is used to create an air break or air gap. you can do the same by running the drain out of the wall then you a trap with a 2x3 bell reducer on top and have the 3 bay sink dump into that. if the drain backs up it will back up out of the funnel and not back into the sink. I have seen that done a number of times. It depends on your local inspector. it would save you ALOT of money and still protect the items in the sink from backups.

floor sinks

Floor sinks are not necessarily floor drains and I have elevated them many times. Then a row of floor tile was installed around the concrete perimeter of the drain. There are also shallow floor sinks which might fit your application.

I would definitely want to avoid a pump on a floor drain! They tend to catch a lot of crap!