Grease Traps

[Deleted User]

you put in the normal 1 1/2'' or 2'' p-trap (depending on the size of waste fittings) then you have to vent this trap, just like normal, then comes the flow control's AIR INTAKE PIPE, which is customerily called the flow control vent,tho its not a vent. this does however get tied into the venting system. then the grease trap, which has to be vented on its discharge pipe also. experiance has shown when using the grease trap as a fixture trap, the smell becomes really bad after awhile. thats why we dont do it that way anymore. think sour milk....P.U. much worse than grease.-------www.pdionline.org

Chuck_7

When installing a grease separator for (only) a 3-bay sink do you install a trap w/ vent before the separator or do you use the separator as the trap???

The new NY state code addresses this specifically but I am looking for common practice.

For separators that are not used as traps is there a vent on the separator and also the discharge?

Bill_14

Grease Interceptor

The interceptor is your trap and the vent should be upstream from the interceptor inlet...if I remember correctly.

Bill Russell

Chuck_7

If the separator is the trap, the vent should be connected down stream of the sep. You do not want a vent connected with no trap between the sink and the vent connection.

Chuck_7

If the separator is the trap, the vent should be connected down stream of the sep. You do not want a vent connected with no trap between the sink and the vent connection.

Chuck_7

If the separator is the trap, the vent should be connected down stream of the sep. You do not want a vent connected with no trap between the sink and the vent connection.

Bill_14

Sorry, I guess I wasn't clear. The sink WILL have a trap in all cases. I was referring to the fact that an approved grease interceptor ALSO has an internal trap. The vent will go where I said orginally...upstream of the inlet.

You gotta vent the sink and the interceptor.

Bill Russell

Kevin Coppinger

don't confuse...

the two. there are grease traps and grease interceptors. you need a trap w/ the interceptor but not the trap. The difference is in the baffle (if the baffle leaks/ breaks you will have a leak onthe outside. In the interceptor case put the trap after the interceptor & vent the interceptor w/mfg. guidelines(usually a 3/4" "candycane". PDI (plumbing and drainage institute)has guidelines.

Bill_14

You guys are killing me...

I give up...

Bill R.

Jed_2

Bill

Do you use a Plumbing & Heating Wholesaler who handles Drainage(Zurn,Watts,J.R Smith)? Seems to me the answer is closer than you think.

Jed

Bill_14

Yes,

We use Wade and Zurn drainage products exclusively. Yes, we purchase from several plumbing and heating wholesalers/suppliers. Also, I pay lots of attention to the PDI folks. I just needed a pencil and paper to "sketch out" my poor choice of written words...just frustrated I guess.

First of all, I simply do not know what the difference is between a grease "trap" and a grease "interceptor". They are one in the same in my opinion.

Personally, I feel the sink waste should be re-vented back to the main vent stack so it is taken care of vent-wise. In addition, I know you gotta vent the grease trap...some call in an air intake. If the sink and the grease trap are close together, the that air intake (vent) will serve both fixture units...I just don't like to do it that way.

All I know is that we get a lot of jobs inspected and approved by consulting engineers, by plumbing inspectors and by health department inspectors. Whatever we do, seems to work and our guys understand what they are installing.

Hope these threads don't bore our heating friends. I'm finished.

Bill Russell

Jim Walls_2

grease trap

In Ohio , a grease trap may serve as the fixture trap in accordance w/ manufacturers installation instructions for a single fixture or combonation sink of not more than 3 compartments . Where the vertical distance from the fixture outlet to the inlet of the interceptor does not exceed 30" & the developed length of the waste pipe from the uppermost outlet to the inlet of the interceptor does not exceed 60" . Check the manufacturer's installation instructions , there will most likely be a flow control device to slow the drainage and enable seperation , this device will be on the inlet side of the grease trap and it requires a vent to the atmosphere at least 6" above the flood level rim of the fixture. Venting of the trap depends on how far you are from a vented main or branch with the runout to the trap and if you have any vertical rise to reach the outlet. In most cases you would have to vent the trap . i.e. if the trap is above the floor and your drain is below you must vent . Hope this is not to confusing & of some assistance

Jim Walls

oops

Sorry , I stand corrected, all grease traps must be vented ,distance from horizontal vented main or branch does not apply

Frank_5

The correct way to pipe a grease trap

This as per NYC Code:
The grease trap is the fixture trap and must be located within 6' vertically and 4' horizontally from the fixture. (If it cannot be located within those dimentions, then you need to install an unvented P trap below the fixture and then pipe to the G.T. Assuming the G.T.is within the dimentions, each tailpiece must enter the G.T. through an air break (three comp. sink, with three air breaks either into a funnel at the trap, or into a mannifold.)then you must install the flow restrictor w/ the bull of that T ending w/a goose neck above the flood level rim of the fixture. (This is not a vent, but rather an air intake for the flow restrictor. If you tie this into the sanitary vent, sewer gases will be able to flow into the room through the air breaks.) Then into the G.T. which is treated as any trap requiring a vent connection within two feet of the trap.
If the G.T. is located outside the dimentions, then the flow restrictor may be connected to the sanitary vent system, as a vent connection, 6" min. above the flood level rim of the sink.( You can do this because the P trap will stop the flow of sewer gases.)
NYCDEP has issued a directive that sets the sizes of the G.T. according to the cu. in. capacity of the entire fixture(s) They may be reached at 718 595 4718 By the way, a floor drain is also needed in the kitchen, and that must go into the G.T. and is considered as 1540 Cu.In.
NYCDEP will violate the premesis if the flow restrictor is not in place, or if the G.T. is too smoall. The individual air gap is a requirement of the Dept. of Health. Their feeling is if all the tail pieces are tied in together before an air break, and a stoppage occurs, contaminated flow can back up into a "clean" compartment and contaminate what ever is in it. (Food or clean cooking equipment)
All of the above is what is required to install a G.T. correctly. Trust me I know, I used to work for these people, and this is the only acceptable method.

Dave Yates (PAH)

code variances

My article recently submitted on grease traps will be in Contractor next month. Unfortunately, as the posts indicate, there has been much confusion regarding grease trap sizing, piping, venting and which fixtures are required to be connected to the grease trap. Although PDI has developed standards that should be acceptable to everyone involved, the plumbing codes put their own rules into the mix and then allow every individual permitting department to adjust them as they see fit. As a result, every township/city/borough in my area will size the exact same fixture grease trap differently. Some require the relief vent, others do not. Some allow the flow restrictor, some will not allow their use. Some want the dishwasher connected, others will not allow a DW to be connected.

Architects love to spec grease traps that are dramatically undersized, which causes interesting reactions from owners once they get the newly revised pricing! Can't say as I blame the architects though. With the mass confusion created by having no one follow a set guideline, it's no wonder they simply pull a model out of their CAD programs. Last one was a 40Lb model where a 150Lb model was required.

Have you read the PDI recomendations for cleaning cycles??? I damn near fell off my chair due to laughing so hard. Not at their recomendation, but at the thought of a restaurant owner actually following the guideline.



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Frank_5

Flow restrictors are per the mfg. If you dump a DW that has 160 degree rinse water, the grease will melt and be discharged into the sanitary waste system. You can still hook up the DW if you pipe in a cold water solunoid valve wired to the dump valve of the DW. When the dump valve opens, the cold water is introduced into the drain, tempering the discharge. In meat packing factories where they steam clean the floors, they use a dilution tank w/a thermostat wired to a solunoid valve. Don't want grease coagulating in the city's sewers.

Bill_14

Or house sewers

You want to size your grease trap correctly and you don't want to allow grease to clog up the downstream house sewer either.

One must know how the sewer line will be used, how the grease trap will be maintained and how much grease the customer will be dumping into the system.

Dave is correct about his comments.

Bill Russell

Dave Yates (PAH)

Hoe they are maintained - not!

Only the City of York requires a once a year inspection & even at that, the owners squalk about the inconvienence and cost! No inspection required anywhere else, so you already know there is no cleaning going on on a routine basis.

Local mall - pizza shop - owner observes us cleaning grease trap - we leave - he removes baffles (employee snitched) - one year later main line in mall (6" line over 400' long) is clogged with grease. No other stores developed that use this line yet, so mall bills him for our cleaning of line using both mechanical auger and jetter - pizza shop owner denies any responsibility - claims he's been cleaning the trap - yeah, right.

Most restaurants need a gazillion pound grease trap! Glass seperator in advance of grease traps in bars should be required - makes for nasty infections.

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Bill_14

My favorite

was a donut shop in a large strip shopping center. This shop was on the high end of a 6" sanitary sewer running down under all the other shops. Each shop (about 15) had a 4" line tying into this main.

The tenant would call us for sewer stoppage problems for a while, then the downstream tenants started calling. Finally, the landlord asked us to solve the problem permanently since he thought the donut tenant is getting mad enough to break his lease. It took a short time to uncover the donut man was pouring his grease down the water closet. Of course, he denied it.

He was given an option to move out or pay to have his underground plumbing revised to handle grease...he moved out.

Landlords need to do a better job of dealing with these types of tenants before they sign the lease agreements. It is ridiculous how little common sense some people possess.

Bill Russell

[Deleted User]

well, the new york described method sure wont fly here in ohio

or california, or illinois.

[Deleted User]

frank, actually PDI standards recommend

putting the dishwasher thru the grease traps. the hot water actually does the opposite of what we would expect and helps seperate the fats/oil/grease in the center chamber. i didn't make it up, its in their literature.

Bill_14

Nor Oklahoma (nm)

mp1969

Grease Trap

In Wisconsin we vent the outlet side of the grease trap and since the sink also needs a trap to protect it we also vent the arm that serves up to two compartments /trap. Separate traps require separate vents because they usually are on separate elevations (or planes) vents allow flow and protect against plus or minus pressure that could be created by restrictions etc.

MP1969

Grease King

Try this site for ALL your grease trap needs....

http://www.pdionline.org/default.htm

Look at the online publications.

Mark Eatherton1

The ultimate grease trap...

would have a refrigeration coil built into the jacket of the grease trap. This would chill the trap, causing a much higher retention factor, all while recovering the waste heat out of the drain where it could be used to preheat the hot water being used in the processes, and conserving our most precious resource, water.

If you can imagine it, it can happen...

ME

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