Grease interceptor and commercial sink (oops)

[KAdams4458]

I'm trying to correct the installation of a grease interceptor and a three compartment commercial sink, and I thought someone here might have some suggestions.

The sink and interceptor as they are now:

But wait! Look at what didn't get installed! The flow control:

As you see in the last picture, there isn't much room for adding the flow control. In this picture, you can see that the interceptor can't be moved any further back than it already is:

Now, I'm no plumber, but with lots of research and questions, I've managed to successfully play one from time to time. So, how the heck do I fit the flow control in place without having things look like Rube Goldberg did it? As always, your suggestions and guidance will be appreciated!

 

[Terry]

So, how the heck do I fit the flow control in place without having things look like Rube Goldberg did it?

Just cut the drains from the sinks off higher and run them from farther back.
Did you check with the inspector? I doubt that he will let you run the interceptor into a floor drain like that.

The smell from a grease interceptor can make you feel like you are going to throw up.
If I ever pull the lid on one, I put on a respirator to knock out the smell, you know, the one with twin filters?

Most of the time, they make me run this into a 3" line.

 

[Sponsor]

 

[KAdams4458]

Just cut the drains from the sinks off higher and run them from farther back.
Did you check with the inspector? I doubt that he will let you run the interceptor into a floor drain like that.

The smell from a grease interceptor can make you feel like you are going to throw up.
If I ever pull the lid on one, I put on a respirator to knock out the smell, you know, the one with twin filters?

Most of the time, they make me run this into a 3" line.

You know, the stench point is a good one, but the inspector wanted it to drain in to the floor sink for some reason. She felt the air gap needed to be after the interceptor.

Maybe I should ask her about the stench issue? It hadn't dawned on me until you mentioned it, but I do remember smelling these things as a kid, and they were, indeed, prone to making you want to spontaneously vomit.

 

[SewerRatz]

Here in Chicago with the sinks hard piped with an above the ground interceptor they want the drain hard piped as well, but with a floor drain tied into the sewer within a few feet of the interceptor drain line so if their is a blockage it would back up out of the floor drain.

In the suburbs of Chicago they want the sinks to drain via an air gap between the sink and the interceptor.

 

[KAdams4458]

SewerRatz, the diagram you posted looks makes sense to my non-plumber brain. Sadly, were it permissible here, (and it may well be,) it would be prohibitively expensive to make the modifications to the building, which has a slab floor.

Does it help any that the grease interceptor is mostly a formality? The building was built as an espresso stand, but is in the process of being turned in to a hot dog stand. Hot dogs aren't exactly ripe with globs of grease, so maybe a good weekly cleaning of the interceptor will keep the stink at bay.

 

[Terry]

In Seattle, restaurants that serve hot dogs require grease traps.
Cutting the slab is not a big deal.

Why do people always think that it costs too much to do things right?
When I travel to places like Belize and Guatemala, I come back and I'm so glad we have permit's and inspections here.

There is a reason our health is better, and we are making more money here. Financially, it's our difference.
We have less days off of work because of sickness.
Therefore we can work better and with more energy.

In Seattle, they don't require the floor drain, but it does make sense.
But then, go eight different places, and they will require slight changes based on the city and inspector.

 

[Kingsotall]

Why would getting into the slab be a formality? Floor drain's already there. Just need to get into the wall. You guys need a plumber out there.

 

[KAdams4458]

In Seattle, restaurants that serve hot dogs require grease traps.
Cutting the slab is not a big deal.

Why do people always think that it costs too much to do things right?
When I travel to places like Belize and Guatemala, I come back and I'm so glad we have permit's and inspections here.

There is a reason our health is better, and we are making more money here. Financially, it's our difference.
We have less days off of work because of sickness.
Therefore we can work better and with more energy.

I've pretty much asked myself the same question about a dozen times over the past two weeks. The owners are husband and wife, and the wife understands me completely, but the husband, well, he's a nervous combination of uneducated about building codes, unwilling, and in a rush to get opened. I can understand his wanting to get open and start bringing money in, but when I have to rework things for him that got screwed up by some of the people he's hired to do things... Let's just not go there, because I've never had a high blood pressure problem, and I don't want to start having one now.

It isn't plumbing related, but boy howdy, you should see the POS sheet vinyl flooring he had installed by two Mexican guys just one day after I offered to install VCT tiles. There were about two dozen tears in it before the "installers" left, and with material and labour, he spent twice as much as what it would have cost him for me to lay down something good. My labour is entirely free, by the way, and I believe in doing things right. If my wife wasn't good friends with his wife, I'd have probably told someone where to stick it by now.

Dang it... There goes my blood pressure.

I'm seriously going to flag the grease interceptor draining in to the floor sink, now. I can't, in good conscience, allow something so potentially stinky to fly, even if it costs the owners more money to fix it right. When the plumbing inspector shows up on Tuesday, I'll ask her about it, because common sense says that this can't be acceptable. Maybe she missed it somehow?

 

[KAdams4458]

Why would getting into the slab be a formality¿ Floor drain's already there. Just need to get into the wall. You guys need a plumber out there.

There have been two plumbers out already, and everything is still a mess.

I think what you meant to say is, we need to get a good plumber out here.

 

[SewerRatz]

There have been two plumbers out already, and everything is still a mess.

I think what you meant to say is, we need to get a good plumber out here.

What city and state are you in?

 

[KAdams4458]

What city and state are you in?

Could be helpful, eh?

Both I, and the business are in Everett, county of Snohomish, Washington.

 

[FloridaOrange]

Ratz and I had a conversation relating to this recently.

Anyway, to the OP:
Put a 90 on the closest sink drain, connect to the middle and when collecting the third drain make the turn back to the interceptor. That will still be tight but will allow you to install the flow control and vent.

It's a tight fit to install it but it can work with the right trap. A shallow/wide trap may be required or maybe recessing the trap into the concrete will allow the connection to the trap at a lower height.

In your picture the third compartment is not connected to the grease trap; why not? That would not fly down here.

but the inspector wanted it to drain in to the floor sink for some reason. She felt the air gap needed to be after the interceptor.

The reason for having an indirect connect is so that if there is backflow up into the sink (I know, unlikely) and the person working there does not notice (again, unlikely) and then the backflow receeds everything that is in the sink is now contaminated. This is covered in most codes and again covered in some health regulations.

 

[SewerRatz]

Thing is having the interceptor drain into a floor drain via an air gap does not prevent this hard piped sinks from backing up when the interceptor has a blockage within it. The only true way to meet the health code is to have the sinks indirectly drain into the interceptor.

I guess it is all how the powers to be interrupt the code.

 

[FloridaOrange]

Thing is having the interceptor drain into a floor drain via an air gap does not prevent this hard piped sinks from backing up when the interceptor has a blockage within it. The only true way to meet the health code is to have the sinks indirectly drain into the interceptor.

I guess it is all how the powers to be interrupt the code.

True. I used to require the sink to drain into a funnel receptor connected to the trap, the engineer I work for likes it the other way around. He who signs my checks shall get what He asks for.


Down here AHJ's are requiring traps or interceptors for any food type establishment; doesn't matter if it's grease producing or not. The store may be sold in a few years and changed or the owner changes the original menu.

 

[hj]

interceptor

Usually the criteria for an interceptor is whether there are pots and pans which require washing, AND/OR dishes, as opposed to throw away or carry out.

 

[agent99]

Thing is having the interceptor drain into a floor drain via an air gap does not prevent this hard piped sinks from backing up when the interceptor has a blockage within it. The only true way to meet the health code is to have the sinks indirectly drain into the interceptor.

I guess it is all how the powers to be interrupt the code.

I am in Chicago. If we cannot drain into a floor drain leading to a grease trap because it is in the basement, could we have the 3 c sink drain w/ an air gap into a bell funnel with a p trap that leads to the grease trap then to a building drain pipe with vent that goes below the slab? I have never seen this in Chicago and have only seen the grease traps directly connected without an air gap. I also have rarely seen a flow control device installed and never a vent for the flow control. Must a small 1" flow control be tied to the main plumbing system vent or can't it just rise by the fixture above water level? Can this small vent tube be pvc in Chicago?

Seems like in your diagram, the "fixture" vent would be redundant and not needed with the grease trap vented and possibly a flow control vented. According to large manufacturers like Rockford and Zurn, the flow control slows down the water drainage to about 2 minutes and cuts the size of the grease trap needed in half. But, if you had that larger double sized grease trap, it seems that a flow control and its vent would not be needed. The calculations calculate w x d x l x 3 /233 = gpm rating and then 75% of that is the size needed according to Rockford. But, then they say it should only be 50% of that if using a flow control.

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Can a floor drain be pvc connected to copper? We have sinks on the first floor leading to an air gap and pvc floor drain (w/stainless strainer) leading to another grease trap in the basement far away from the 3c sink. I was going to spray it with fire block foam.

Also, we have a 2 wok with 2 faucets. It has 2" pvc drain pipe that connects to copper that goes through the floor and then w/ an air gap into an old bell funnel with a p-trap that leads to that grease trap that handles the sinks above (veggie prep, mop, hand, and small bar 3c sinks). Must the fixture drain lines be copper in Chicago? Must it be a floor drain or can you have that bell trap below the floor?

I know a bunch of questions, so thanks a bunch in advance!!!! This gets very confusing.

 

[hj]

connect the two sinks together with a "high line" end outlet continuous waste draining down from the right hand sink. THen you will have plenty of room for the flow control. compaare the opening in the flow control to the size of your drain line to determine if it is necessary. Usually it is, unless it is a very large capacity grease interceptor.

 

[Goat]

hi terry, great web site. I was wondering on installing a grease interceptor for a 3 compartment sink, would it be ok to have the 3 drains tied together draining with an air gap into a 3''x 2'' reducer with a 2'' p-trap going a short distance to a flow control tee and use the vent on the flow control as the one venting that line and from there go to the grease interceptor and the outlet direct into the main sewer line. the main sewer line has a vent going out the roof probably about 6 feet down stream from the outlet of the interceptor

 

[hj]

The nitty gritty of that installation is that you have an "S" trap which would probably siphon the contents out of the trap under the right flow conditions.

 

[Goat]

The nitty gritty of that installation is that you have an "S" trap which would probably siphon the contents out of the trap under the right flow conditions.

hi hj, was that in response to me. if so what would be the solution? another vent before the flow control tee vent? im real limited on space. I want to keep the smell down that's the reason for the trap on the indirect drain. its an above ground interceptor and there's no floor sink. what you think hj thanks for your time