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airgap 08-25-2009 12:20 PM

airgap plumbing code problem
 
Owner of a new kitchen sink with no airgap hole(porcelain and cast iron) with wallmounted faucets so there is a 5 inch gap above flood line and 3 inch gap from wall to sink wall, plenty of room for an airgap to fit behind without being over the sink. Considering airgap dishwasher/disposal is required for so non-potable(disposal water) doesn't go back into dishwasher(potable), my plumber based the airgap in that space gap.
Now the inspector is saying it is required in my town to have airgap on sink or counter meaning drilling which I don't want in brand new expensive sink. Does anybody have any precedent for placing airgap hidden behind sink as long as it is above flood line. I'm in California and my town follow CA codes which state airgap has to be 1 inch above flood line-which mine is- but doesn't state it has to drain into the sink.

Help on suggestions for dealing with inspector on this would be great.

thanks.

JDC 08-25-2009 10:13 PM

Ask the inspector to show you exactly where in the code book it states that the air gap must be mounted on your sink or countertop. If the code doesnt state this the inspector may say the airgap must "be accessible" since it can and will fail over time. If the inspector cannot provide you with the code section that requires this then you should be able to get by.

What I'm not clear on is where the airgap is draining. Airgaps typically drain into the garbage disposal or into a dishwasher tailpiece, either of which is under the sink. If the airgap is just tied into a drain without a trap then no you cant do that.

Termite 08-25-2009 10:39 PM

I'm with JDC on this one. Not too sure where he's getting this air gap thing relative to your faucet. Assuming this is a residence, right?

airgap 08-26-2009 03:02 PM

Sorry if it sounded confusing (Why I'm not a contractor and was thoroughly confused by this with inspector)

It is a 2 hole kitchen sink with disposal in one hole. Dishwasher drainage line goes into airgap device behind the sink wall. The other line of airgap goes into line that connects to disposal and drains into main outflow from there. So all of this happens out of counterview which seems to be inspector's problem though he said "Our city requires it to be on the sink" but couldn't show it to me. My city follows the CA plumbing code and states this on the inspection website so I think I have a case. Does this make sense?

Termite 08-26-2009 04:07 PM

Is the other line possibly the dishwasher drain? Air gaps are required on them, but nearly all dishwashers have integrated air gaps in them these days.

MACPLUMB 08-26-2009 07:50 PM

Air gap for dishwasher
 
THE CONFUSION IS OVER THE PLUMBING CODE WHICH IS A SET OF RULES AS WELL AS THAT WHICH IS DONE BY COMMON PRACTICE, :thumbsup:

SEE U.P.C. AIRGAPS

IN THIS CASE THE AIRGAP FOR THE "DISHWASHER" DRAIN IS INSTALLED ON
THE SINK TOP BECAUSE MANY TIMES IF THE GARBAGE DISPOSER IS FULL
OR THE THE THE DRAIN HOSE IS CLOGGED WHICH SOMETIMES HAPPENS
THEN WHEN THE DISHWASHER DISCHARGES ALL THAT WATER "FLOODS"
OUT ACROSS THE THE COUNTER AND THE FLOOR ! ! :thumbsup:

I HAVE SEEN THIS HAPPEN MANY TIMES EVEN WHEN HOME OWNERS TURN
THAT UGLY GRILL BACK TOWARD THE WALL NOT REALIZING IT NEEDS TO
RUN INTO THE SINK ! ! :thumbsup:

Plumber101 08-26-2009 08:08 PM

Many people realize the [COLOR=blue !important][COLOR=blue !important]dishwasher[/COLOR][/COLOR] connects to a little thing on top of the sink, some even know that it is called an air gap. However, many people wonder "what is an air gap for?" The air gap is there to prevent the water from being siphoned out of the dishwasher. When water flows through the drain hose, it creates a suction on the water still in the dishwasher. The air gap, makes a hole for air to get in. That way, the water only leaves the dishwasher when it supposed to, when it is pumped out. Another benefit of an air gap is that if the drain hose becomes clogged, the dishwasher can still pump out the water. Instead of flowing through the hose, as it should, it can flow out the air gap and into the sink.


http://www.acmehowto.com/howto/appli...poserplumb.gif

Termite 08-26-2009 11:49 PM

I've inspected THOUSANDS of homes and have never once seen this done! That's a new one on me for sure, but it seems pretty valid. As I mentioned, I think it is pretty hard to find a dishwasher these days that doesn't have an integral air gap inside the unit itself so the installation of such a system seems rather redundant.

Plumber101 08-27-2009 05:45 PM

A link to CA plumbing code


http://www.iapmo.org/Pages/californiaplumbingcode.aspx

Termite 08-27-2009 09:55 PM

I have no doubt that its in there! :thumbsup:

Plumber101 08-27-2009 10:02 PM

Quote:

Originally Posted by thekctermite (Post 320340)
I have no doubt that its in there! :thumbsup:

I guess what I am trying to say is that like you the UPC and IPC must not be as strick as the CA code.

I have never seen on of the airgaps that mount on the countertop as well. But, I'm sure it's coming.

Lots of differences from CA to the rest of the 49

airgap 08-28-2009 02:38 PM

You all have hit my exact problem as far as getting an exact answer. I live in Burbank and the inspection website said the city follows CA plumbing code (as linked above) under I believe section 807.4 for indirect waste is listed need for an approved airgap between diswasher drainage line and line to disposal but never states it has to be mounted on the sinktop. I really don't want to attempt drilling through the porcelain/cast iron sink and crack finish etc.(already looked all that up on here about how to do it). I understand the "what if line to disposal clogs and backs up the airgap?" reasoning for airgap to expel backed up water into the sink rather than under counter. But for my own asthetic and non-invasive drilling reasons(and realizing I may flood underneath my sink if gap is under it but above flood level and does back up), I can't find anything that says sinktop mounted. Inspector said that is what city code requires even though that contradicts what is listed by their own inspection site. Just don't need a fight with inspection office but don't want to do unnecessary and potentially damaging drilling in my sink unless absolutely required - so looking for a leg to stand on. Even other plumbers in neighboring cities follow CA code and though most sinks have an airgap mounted, it is not required and they have done exactly what I am trying to do.

silkyblue4 09-15-2009 07:45 PM

dishwasher air gap and soap dispenser
 
Hi, I am also having issue with dishwasher and sink.

I have a 4 hole sink, but I bought faucet that has a sprayer and soap dispenser.

so my contractor put the air gap in the sink cabinet. this is not working!

if I fill the sink with water then drain, water comes out under the cabinet.

any suggestions on how I can have proper air gap for the dishwasher and keep my pretty soap dispenser?

thanks!

pbinCA 03-12-2014 05:22 PM

Reasons for air gap
 
The air gap comes into play as a means to prevent sewage-contaminated bacteria from backflowing into the dishwasher.

If you connect the output hose from the dishwasher DIRECTLY to the garbage disposal, the pump in the dishwasher being 12" below the height of the GD and p-trap drainage connection, gravity siphoning will occur right after the dishwasher pump shuts off, and whatever yucky stuff resides in the GD will end up contaminating the dishwasher pump and basin. With the air gap elevated above both systems, the gravity-siphoning is broken. Now, you've assured that the flow from the dishwasher is 1-way.

The "internal air gap" in the newer dishwashers is supposed to provide the same level of protection. However, let's say your drain pipe is completely clogged. As the sewage water height starts building up in your toilets, hopefully you notice, and take action. But what if your only toilet is upstairs and the lowest floodable fixture is the kitchen sink. As the sewage level builds up in the sink, hopefully you notice and take action. However, without an air gap plumbed into the dishwasher effluent hose and mounted above the "flood level" of the sink, the sewage works its way all the way into the dishwasher's "air gap" which has no place to spill over into. It's not a real air gap at the proper height, but rather a check valve making sure there isn't reverse flow.

The difference between this internal air gap and the one up on the sink ledge is nuanced, but in the case of a drain blockage that floods the sink, contamination has worked its way further into the DW than is possible with an external air gap at the countertop height.

Most all homes nowadays have a downstairs toilet that will overflow before anything reaches high enough to back up into the kitchen sink. And you have to be a meth addict to not care about the toilet overflowing. So the air gap's 2nd function, to keep a backed up drain from polluting the DW's output hose, is rarely going to be invoked.

In this regard the CA plumbing code is a bit outdated and inflexible regarding the air gap placement on the sink ledge. When enough inspectors "get it" and accept the internal "air gap" in the DW as functionally adequate, perhaps the UPC will get modified. I hate the site of the air gap, and very few people understand its function. It was much more important in the early days of dishwashers than today.

Ghostmaker 03-12-2014 06:02 PM

Only time an air gap is required under the IPC is in a commercial dishwasher. It actually requires a standpipe with an air gap.
To each his own. But are we not taking learning a lesson out of the equation? The first time a home owner forgets to clear his disposal and floods his kitchen unless they are brain dead it would probably be the last time.


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