# grease trap install



## arkyplumber (Jan 10, 2009)

I have a job that is a small kitchen, ( 3 compartment sink, and a veggie sink) that will have to be installed into a grease trap. MY question being I have never messed with grease traps, as this will be a first, is what will the best size for this job? Another plumber came out and said she needed a 1000 gallon grease trap put in, which seemed a big overkill in my mind, which I might be wrong. So I thought I would get some feed back. Thanks


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## Bill (Jun 17, 2008)

I have installed many of them, all in commercial applications so the plans have the specs already and the GC has already purchased them, so I am not sure. I would say a 1,000 gallon is WAY too much for residential. I will check with my code book ASAP and get back.


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## user4 (Jun 12, 2008)

What does your code stipulate?

A trap capable of 10 GPM would be acceptable in Chicago.


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## nhmaster3015 (Aug 5, 2008)

Size is based on DFU and you should have a chart in your code book.


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## SewerRatz (Apr 25, 2009)

This is right from the Illinois plumbing code on how to size a grease trap.

*Section 890.510 Grease Interceptor Requirements* 

Plumbing systems for institutions or commercial establishments in which grease, fats, culinary oils, or similar waste products from kitchens or food processing areas are wasted, or in which grease, fats, or culinary oils are wasted in connection with utensil, vat, dish, or floor cleaning processes, shall include grease interceptors. All waste lines and drains carrying grease, fats, or culinary oil, in the above type establishments shall be directed to one or more interceptors. (See Appendix E: Illustrations A and B.) 

a) All required grease interceptors shall comply with the following: 

1) Material and Covers. Grease interceptors shall be constructed of durable, corrosion-resistant materials and shall have water-tight covers securely fastened in place. 

2) *Minimum Size*. A grease interceptor installed on the same floor as the fixture shall have one-half the liquid holding capacity of the fixture. A grease interceptor located on a floor below the fixture shall have sixty percent of the liquid holding capacity of the fixture. To determine the liquid holding capacity in gallons of a plumbing fixture, multiply the length by the width by the height in inches, and divide by 231. Where two (2) or more sinks or receptacles are connected to an interceptor the liquid holding capacity shall be based on the combined volume of the fixtures served. 

3) No grease interceptor shall receive the discharge from a food waste disposal or a commercial dishwashing machine. 

4) The flow rate of the interceptor shall be sufficient to handle the maximum demand of the connected system. 

5) All interceptors shall be installed in an accessible location to permit the convenient removal of the lid and internal contents. 

6) All interceptors shall be designed and installed with proper venting so that they do not become air bound. (See Appendix E: Illustration C.) ​b) Prohibited Type. Water cooled grease interceptors are prohibited.​


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## DaveClinch (Aug 3, 2009)

I deal with on occasion the small 50 gallon Grease traps that can be mounted above ground either beside the sink or under the sink. That application is identical to this one. They def need to be set up for easy cleaning but there is nothing to them.


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## stillaround (Mar 11, 2009)

Most build outs here in the 2 counties close by are pushing 1000 gallon. Just did a little ceazars that 2 years ago allowed a 50 lb under the 3 comp sink --not now. And the specs have changed to put hand wash sinks into the grease line. They still work with you here though. A chinese restaurant that had and under sink one was forced to put in a 1000 gal. The city line was showing excessive grease.


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## ESPinc (Jul 18, 2009)

The counties I work in are cracking down on the restaurants. Just did a Ruby Tuesdays, the place been in business for almost 10yrs with a 1000gal capacity tank. Have to bring them up to 4000capacity. The formula they use here is:

Seats x Gallons of waste per seat x Hours of operation/12 x Load factor

Load factor( Interstate Highway 2.00, Other Freeways 2.50, Recreational 1.25, Main Highway 1.00, Other highway .75)

For other than private sewage disposal systems reduce gallon values by 25%




Example:


225 seats x 25 x 11/12(.92) x 1 = 5175 gallon capacity


It was on public sewer so 25% deduct (1294gal) so their tank capacity had to be 3881 gal capacity. We ended up installing 3 1000 gal tanks in the parking lot.


We are working on another place( In business under 4yrs) right now that needs an additional 4500 gallons,already pulled the permit to help the guy from being fined daily, this guy is pissed and fighting, can't say I blame him as the city that approved the 1500gal.(what he has now) about 4 years old, says it does not meet code and they are in the process of shutting him down. It is a mess!!


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## That One Guy (Sep 14, 2008)

Size it according to your code and fixture units like already mentioned. Also your local authorities may have other guidlines you may have to follow. 

Ive done a few large grease interceptors complete with inspection ports, new building sewer, etc. The city plays a major role in the requirments though since they are the authority having jurisdiction blah blah blah.


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## DaveClinch (Aug 3, 2009)

Some counties in Georgia require a in-ground 1000+ Gallon Grease Trap running from any dept that generates grease, while other counties only require a grease trap of any size to be installed. Small above ground, or big in-ground, doesnt matter. Whenever we add them what we do is always dictated by the county code. Ive seen some stores have both, which causes a lot fo grease related problems very quickly if the traps arent maintained to the letter.


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## ROCKSTARPLUMBER (Dec 14, 2008)

Everyone i have ever put in is been 1000 gallon. For entire reasturants.Zurn has a hundred gallon unit, rated at 4gpm, the z1170. List price is $1,1336.00. Current catalog price. Vendor should be able to get it cheaper. But whatever yoy may need, zurn will have it.


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## LEAD INGOT (Jul 15, 2009)

where im at we have to size the grease trap according to dfu's and that can be overidden by bowl size in the sinks. Schrier makes g traps that you can get w/ a 1 or 2 minute drain. the 2 minute drain allows smaller size trap but the end user will have to clean it more often. Check with your inspector he/ she can steer you in the right direction.


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## Airgap (Dec 18, 2008)

Grease traps are the best!


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## Scott K (Oct 12, 2008)

As part of a job specification on a recent restsaurant that was a renovation from a previous restaurant at that location, the mechanical specs listed "clean grease trap to as new condition." So I arranged to have a company that cleans grease traps come clean the grease trap (not our bag). So there is this 40+ woman who shows up in the company van for said company and right away she asks:
"did this used to be the old ...... restaurant" 
I said "yeah." 
She replies: "Ohhhhhh....this grease trap needs to be replaced...." 

So she's in there with a soup ladle and a bunch of buckets and she's scooping it out. Pretty yummy. Then I get the invoice. They have all the pertinent information on top. then they have all these columns that they use to describe the condition of the grease like the colour, texture, consistency, odour, etc. - how much time do you have on your hands? LOL

Anyways, turns out she must really love her job, because this grease trap did need to be replaced.


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