approved plumbing plan says 2"

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smalltowner

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Hello,
For our project we submitted a plumbing plan to the State with input on pipe sizes from our licensed plumber. The drain pipes for this remod of a commercial kitchen in an existing building are 2". The new remod will have a 3 compartment sink, floor drain and hand sink. State approved the plan for the 2" inplace pipe size. Now the plumber has started the work but he called in an inspector and this person says we need to tear up the floor and put in a new 3" line to connect to the 4" line going out to the city sewer. What the heck, help!!?? Anyone, thanks.
 
The reason for the increase to 3" is because of the requirement of sizing for the floor drain as well as the 3 compartment sink and hand sink. A 2" drain line to handle this volume would be insufficient and cause problems. The plumber should know that a connecting floor drain above ground should be 3" (4" below ground at ground level) and the same size of pipe shall continue to the stack or sewer.
If your plumber is surprised by this situation, maybe you need to consult another plumber that is more familiar with plumbing code.
I don't mean to sound harsh, I just feel that this is just a simple part of plumbing that is known to licensed plumbers.
The state may approve the general plan, but it is the plumber's responsibility to apply the local codes to the installation to satistfy the inspectors. If he does not know what codes apply, then he should find out if he is qualified for that area.
UPC,IPC and others all require a 3" floor drain above ground for commercial install and the drain continues, undiminished in size, to the stack or building drain.
 
^ What he said...

Are your plans stamped, signed and approved for work? If so there is not a lot the inspector can do. If your are approved and what you are doing is to code he can not legally make you change it.

We run into this occasionally, sometimes even the inspector is right but if his district stamped and approved them then that is what goes.

Is your inspector with the same agency that approved your plans?

I would try to explain to him first that everything was installed per approved plan and let him know he needs to talk to the approver before you will do anything.

Edit: I typed this before ^ That post, If it will simply not work then now is a much better time to fix it right then when the job is done.

Edit again: Things must be different out here, the district that approves the plans is the same district that sends out the inspector which probably helps with things like this.
 
I am assuming that the connecting floor drain is 3". If not, that is where the problems really started for the inspection.
 
^ What he said...

Are your plans stamped, signed and approved for work? If so there is not a lot the inspector can do. If your are approved and what you are doing is to code he can not legally make you change it.

We run into this occasionally, sometimes even the inspector is right but if his district stamped and approved them then that is what goes.

Is your inspector with the same agency that approved your plans?

I would try to explain to him first that everything was installed per approved plan and let him know he needs to talk to the approver before you will do anything.

Edit: I typed this before ^ That post, If it will simply not work then now is a much better time to fix it right then when the job is done.

Edit again: Things must be different out here, the district that approves the plans is the same district that sends out the inspector which probably helps with things like this.


This small town in the upper midwest has no local codes so we are governed by the state. Yes, the inspector is also employed by the state but he doesnt approve the plans. The plans are approved at a central office at the state capitol. Yes the plans are approved and we have a letter stating we shall now proceed with the work according to the plans then when done roughing in the plumber brings in the inspector to review and run pressure tests as needed.

The floor drain pipe is 2" and it is a take off from the main 4" line. More discussion would be appreciated, thanks.
 
The inspector usually holds all the cards. He is the one with the badge so it will be him that says yea or nay.

In my area an engineered plan certified by a "licensed" engineer that accepts full liability for the outcome would be required to trump the inspector. Plan reviewers miss things and do not have that authority.

It will be much cheaper to change it rather than fight it.
 
Well according to my code 2" pipe is good for 6 fixture units which you should be fine with what you have there. Unless everything is being wet vented. Then that's an issue. You can have a 2" floor drain, just it has to be vented is all. And everything else has to be individually vented but like plbgbiz said the inspector holds the card so what he says goes pretty well.

image-3814743160.jpg
 
Our State code under "load on drainage piping" subpart 2a: Values for intermittent flows: Fixture unit values for interrmittent flows from applicances and equipment which are specially designed for low water use, and used for retrofit in existing plumbing systems only, may be determined as follows: Discharge Capacity (gpm) 8-16 has 2 fixture units, 16-30 gpm has 4 units and 31 to 50 has 6 units. No mention of min. drain size is stated here, however, under new construction there is a complete list of fixture types, unit values and min. drain size on a chart. Our project is not new construction so we would fall under subpart 2a, correct?
 
Sounds about right to me. If the building is existing then yes I would say it sounds like 2a would be about right
 
I would maybe just bring it to either the plumber or inspectors attention. Just be careful with the inspector cause those guys can make you life a living hell lol
 
I think we will first contact the State and talk to the person that approved the plan to see what he says. We will put it in a nice way and make sure they know this is an existing bldg. If the State concurs that 2" is ok on this branch, we will have them notify the plumber and the inspector. We have not butted heads with the inspector yet, and yes, we dont want to see or deal with their 'wrath or supposed powers'.
 
Our State code under "load on drainage piping" subpart 2a: Values for intermittent flows: Fixture unit values for interrmittent flows from applicances and equipment which are specially designed for low water use, and used for retrofit in existing plumbing systems only, may be determined as follows: Discharge Capacity (gpm) 8-16 has 2 fixture units, 16-30 gpm has 4 units and 31 to 50 has 6 units. No mention of min. drain size is stated here, however, under new construction there is a complete list of fixture types, unit values and min. drain size on a chart. Our project is not new construction so we would fall under subpart 2a, correct?

Not correct. Generally intermittent loads are pumped loads from a ejector or sump pump or other Non plumbing fixtures. That table does not apply to regular plumbing fixtures or commercial kitchens. Plus the numbers in that code are not quite correct and have gotten many a plumbing contractor and engineer in trouble in the past.

A three compartment commercial sink really counts as 6 FU's (2 Fu's per compartment) or a 2" line minimum by itself. Some Health departments (commercial kitchens are governed by the health department) require that the three compartment pot sinks be indirect wasted via a floor sink.

Some health departments and some building codes say that floor drains or floor sinks in commercial kitchens be 3" minimum. Most will also require a grease interceptor for the pot sink and any floor drains or floor sinks in the commercial kitchen.

As someone who's designed many hundreds of commercial kitchens, I tend to think that the 2" waste line was perhaps a little small and perhaps the fellow at the state missed it.. You might want to check with the local health department too, to make sure your kitchen is in compliance with local health codes.

Beni Bacon PE, CIPE
 
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Wow 6 f.u.? That's a lot. A flushometer toilet is 6 f.u. Or a bathroom group on its own. In my area we call it two fixture units based on the 2" trap. A 2" pipe isn't gonna go over 1/2 to 1/3 full regardless if you drain all 3 compartments at once. every triple compartment commercial sink I've saw or repiped was 2" with zero issues. However again it depends on jurisdiction, not arguing that I'm right I'm just surprised that it would be 3". Everyone's code book is different depending on jurisdiction I suppose.
 
Wow 6 f.u.? That's a lot. A flushometer toilet is 6 f.u. Or a bathroom group on its own. In my area we call it two fixture units based on the 2" trap. A 2" pipe isn't gonna go over 1/2 to 1/3 full regardless if you drain all 3 compartments at once. every triple compartment commercial sink I've saw or repiped was 2" with zero issues. However again it depends on jurisdiction, not arguing that I'm right I'm just surprised that it would be 3". Everyone's code book is different depending on jurisdiction I suppose.


A 2" drain would be correct for the 3 compartment sink A 2" line will support 6 FU's. A water closet requires the 3" drain due to the short duration of the flush.

The toilet still just flushes either 1.5 or 3 gallons over about 5-6 seconds. Each compartment of the typical three compartment sink holds about 15 gallons of water. Generally that 40-45 gallons is dumped more or less at one time after the pots and pans are washed. So while the flow per second is less then say for a toilet, the longer duration increases the loading of the sewer. So 6 Fu's is quite reasonable.

The 2 inch line hard piped actually slows the flow rate from the three compartment sink down. The horizontal drain will flow at about 3/4 full if not completely full for a short distance. That is till the water level in the sinks gets low and the flow rate reduces. .

If a indirect waste is required then the floor sink would need at least a 3" drain.

The inspector in the OP's opening comment, probably caught that the floor drain, hand sink and pot sink was more then 6 fu's which is the maximum on a 2" line.

Some city's list the pot sink as 3 FU's some at 4 FU's and some at 6 FU's. It varies from city to city even in the same metro areas. The net effect is that the pot sink is a 2 inch line. BTW, Generally a 2" p-trap counts as 3 fu's.
 
With the OPs issues, I might recommend using a 1-1/2" p-trap for the three compartment sink. That would slow the sink discharge rate enough to allow the existing 2" waste to be used with the hand sink and floor drain. Not quite code, but a good engineering solution to an existing 2" waste. It would be worth discussing with the inspector / state anyway...
 
With the OPs issues, I might recommend using a 1-1/2" p-trap for the three compartment sink. That would slow the sink discharge rate enough to allow the existing 2" waste to be used with the hand sink and floor drain. Not quite code, but a good engineering solution to an existing 2" waste. It would be worth discussing with the inspector / state anyway...

Some cities will allow 2'' drain/floor sink on a three compartment sink with the sink drains reduce to 1 1/2.
 
UPC, IPC and local codes aside. One should consider that, depending on the area, that ICC and IMC also apply. This is the case in Pittsburgh where the local code, started in 1969, has been modified to adapt to modern needs and has implemented parts of the IPC to create a close-to-universal element for non-county plumbers.
Regardless of that, smalltowner, I would simply recommend going forward with a 3" line to the main sewer and forego a semantic run-around between the state, the inspector and the plumber...for the sake of completing the job properly and in a timely manner.
 
Beni said:
A 2" drain would be correct for the 3 compartment sink A 2" line will support 6 FU's. A water closet requires the 3" drain due to the short duration of the flush.

The toilet still just flushes either 1.5 or 3 gallons over about 5-6 seconds. Each compartment of the typical three compartment sink holds about 15 gallons of water. Generally that 40-45 gallons is dumped more or less at one time after the pots and pans are washed. So while the flow per second is less then say for a toilet, the longer duration increases the loading of the sewer. So 6 Fu's is quite reasonable.

The 2 inch line hard piped actually slows the flow rate from the three compartment sink down. The horizontal drain will flow at about 3/4 full if not completely full for a short distance. That is till the water level in the sinks gets low and the flow rate reduces. .

If a indirect waste is required then the floor sink would need at least a 3" drain.

The inspector in the OP's opening comment, probably caught that the floor drain, hand sink and pot sink was more then 6 fu's which is the maximum on a 2" line.

Some city's list the pot sink as 3 FU's some at 4 FU's and some at 6 FU's. It varies from city to city even in the same metro areas. The net effect is that the pot sink is a 2 inch line. BTW, Generally a 2" p-trap counts as 3 fu's.

Yeah I suppose I can see if those sinks are full with 15 gallons each that does put it into perspective more so but in our code its considered 2 f.u. And a 2" trap is 2 f.u. In my code book. I guess I was just surprised it would be different in different regions. Fair enough though.
 

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