Trap Primer

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1

Originally Posted By: eharden
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http://www.nachi.org/tips/1619.gif


I have never seen this. Are there certain areas of the country where they are more prevalent?

--
Eric Harden
First Choice Inspection Services

"That which does not kill me, makes me stronger."

2

Originally Posted By: jpeck
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Wherever there is a floor drain, there should be a trap primer somewhere.


The ones I see are never, I repeat, NEVER, plumbed off the supply line (cross contamination issues), but are tapped off the tail piece (like an upside down dishwasher connection to the tail piece). Every time the faucet is used, some of the draining water runs into the drain, keeping it primed.

--
Jerry Peck
South Florida

3

Originally Posted By: eharden
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Jerry,


Thank you for your feedback. From now on I will certainly look much closer for any priming mechanisms that should be in place, and report accordingly.

–
Eric Harden


First Choice Inspection Services


"That which does not kill me, makes me stronger."
4

Originally Posted By: Mike Parks
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Make sure there is a gap between the water source and the floor drain.


Mike P.

5

Originally Posted By: jpeck
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Mike Parks wrote:
Make sure there is a gap between the water source and the floor drain.

Mike P.


A gap is not needed when the primer is supplied from the drain.

An air gap is absolute 'must' if supplied from the potable water supply, and the air gap must be *at least* 1", minimum.

--
Jerry Peck
South Florida
6

Originally Posted By: Mike Parks
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Jerry is correct.


I was using the above picture. I should have been more clear.

Thanxs Jerry.

Mike P.

7

Originally Posted By: gbeaumont
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Hi to all,


Here is a slide from "tip's of the day" that should show what we are discussing:

![](upload://hDtBlC70DUMDGpREL5sZh5DhUMU.gif)

I hope this helps

Regards

Gerry

--
Gerry Beaumont
NACHI Education Committee
e-mail : education@nachi.org
NACHI phone 484-429-5466

Inspection Depot Education
gbeaumont@inspectiondepot.com

"Education is a journey, not a destination"

8

Originally Posted By: jpeck
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Gerry,


That drawing shows EXACTLY HOW NOT TO DO IT.

![](upload://OJNGzDCygYYKelPpWVWq2O4Q07.jpeg)

--
Jerry Peck
South Florida

9

Originally Posted By: gbeaumont
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Jerry,


Much as I truely hate pedantic discusions over building standards issues, I do have to ask you why you feel the need to improve over Carson Dunlop. I am not aware in any code that the surface area of and air gap must be a certain size, am I wrong ???

Regards

Gerry

--
Gerry Beaumont
NACHI Education Committee
e-mail : education@nachi.org
NACHI phone 484-429-5466

Inspection Depot Education
gbeaumont@inspectiondepot.com

"Education is a journey, not a destination"

10

Originally Posted By: jpeck
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The drawing, from Carson-Dunlop or from anyone, is wrong.


An air gap means that the end of the one tube (in this case) is above and clear of the other tube. Thus the gap of air (that's why it is called an "air gap".

The air gap has a supply (in your drawing, from the lavatory faucet supply), a gap through free air (the air gap), then the receptor (the outer tube in your drawing).

In the drawing you supplied, the inner tube could become filled to the top, making the supply tube immersed down into the contaminated fluid in the 'drain' tube, cross contaminating the supply.

From the 2003 IRC, Plumbing section (highlighting with underlining and bold is mine)

P2902.2.1 Air gaps. Air gaps shall comply with ASME A112.1.2 and air gap fittings shall comply with ASME A112.1.3. The minimum air gap shall be measured vertically from the lowest end of a water supply outlet to the flood level rim of the fixture or receptor into which such potable water outlets discharge. The minimum required air gap shall be twice the diameter of the effective opening of the outlet, but in no case less than the values specified in Table P2902.2.1. An air gap is required at the discharge point of a relief valve or piping. Air gap devices shall be incorporated in dishwashing and clothes washing appliances.

TABLE P2902.2.1 - MINIMUM AIR GAPS
- Effective openings greater than 1 inch / Away from a wall* (inches) / Two times the diameter of the effective opening
- Effective openings greater than 1 inch / Close to a wall (inches) / Three times the diameter of the effective opening
- Lavatories and other fixtures with effective opening not greater than 1/2 inch in diameter / Away from a wall* (inches) / 1
- Lavatories and other fixtures with effective opening not greater than 1/2 inch in diameter / Close to a wall (inches) / 1.5
- Over-rim bath fillers and other fixtures with effective openings not greater than 1 inch in diameter / Away from a wall* (inches) / 2
- Over-rim bath fillers and other fixtures with effective openings not greater than 1 inch in diameter / Close to a wall (inches) / 3
- Sink, laundry trays, gooseneck back faucets and other fixtures with effective openings not greater than 3/4 inch in diameter / Away from a wall* (inches) / 1.5
- Sink, laundry trays, gooseneck back faucets and other fixtures with effective openings not greater than 3/4 inch in diameter / Close to a wall (inches) / 2.5
For SI: 1 inch = 25.4 mm.
* Applicable where walls or obstructions are spaced from the nearest inside edge of the spout opening a distance greater than three times the diameter of the effective opening for a single wall, or a distance greater than four times the diameter of the effective opening for two intersecting walls.

Gerry, It's not just me, it's the code.

--
Jerry Peck
South Florida

11

Originally Posted By: jfarsetta
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Yup…


An air gap is an open gap, which prevents contamination.

--
Joe Farsetta

Illigitimi Non Carborundum
"Dont let the bastards grind you down..."

12

Originally Posted By: eharden
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It is nice to see that I finally posted something that has generated some discussion. icon_lol.gif

–
Eric Harden


First Choice Inspection Services


"That which does not kill me, makes me stronger."
13

Originally Posted By: Mike Parks
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Eric


Be like me and ask stupid questions. I always get a response. ![icon_lol.gif](upload://zEgbBCXRskkCTwEux7Bi20ZySza.gif)

Mike P.

14

Originally Posted By: eharden
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Mike


I prefer to remain quiet and have people think that I am cranially challenged, instead of opening my mouth and removing all doubt. icon_smile.gif

–
Eric Harden


First Choice Inspection Services


"That which does not kill me, makes me stronger."
15

Originally Posted By: John Murray
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In Mr Peck’s diagram, isn’t it safe to say that the “drain tube” is eliminated? I see no need for one if there needs to be an “air gap”!


Wouldn't that leave a mold/pest/odor problem? Looking at Gerry's diagram the drain is 2 or 3 feet in front of the sink. Wouldn't that create alot of safety issues for humans and pets?

I've seen Gerry's example in households while I've seen Mr. Pecks example in commercial settings.

16

Originally Posted By: jpeck
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John,


Not quite sure what you mean by "drain tube".

The only difference I made to Gerry's drawing (the one he posted) was removing the supply tube from the primer tube (your "drain tube"?) and replacing it with an air gap and a receptacle for the supply to drop into, with the primer tube (my term, for lack of a better name) connected to it, which still goes to the trap as in Gerry's drawing. I may not have made the air gap receptacle device clear, trying to keep it simple and all (I was trying to show the "air gap" versus the "tube in a tube").

--
Jerry Peck
South Florida

17

Originally Posted By: John Murray
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Thanks for your response.


I am still a little unclear on some things.


May be I’m looking at the diagrams wrong.


Anyhow I’ll try this: My “drain tube” was the polyethelene pipe (extension of the trap primer) as labeled in Gerry’s diagram. It is simply an extension from the trap primer that allows an extension to the drain.


My question concerned your diagram compared to Gerry’s. Your diagram had a gap between the trap primer (tube) and the trap primer extension (tube) that goes into the drain. If your diagram is correct, what would be the purpose of the trap primer extension tube if it is hanging loosely away from the main supply (trap primer tube)?


Wouldn’t the water have to travel a certain open distance on the floor to make the floor drain, assuming that the floor slop is proper?


In Gerry’s diagram, the floor drain is about 2 or 3 feet in front of the sink.


Wouldn’t that create some problems?


Thanks

18

Originally Posted By: wpedley
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–
BPedley


Inspecting for the unexpected

19

Originally Posted By: jpeck
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My diagram was showing that there needs to be an air gap between the trap primer supply (coming down from the faucet ) and the trap primer (or the trap primer extension).


This can be accomplished by placing the air gap at almost any location above the overflow level of the floor drain. I choose to show the air gap where I did simply because it was easy to re-do the drawing right there.

The purpose of the air gap is to prevent backing up into, or cross contamination of, the supply from the waste water in the drain.

Did I do that any clearer?

The location of the floor drain, with its required cover (to keep fingers, toes, etc.,) out of the drain, should not be a problem. Granted, not being directly in front of the sink would be better, but, hey, that is just a drawing for illustration purposes.

--
Jerry Peck
South Florida

20

Originally Posted By: arosenbaum
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Wow… all these new plumbing things… I’m used to the old school book of plumbing icon_smile.gif Of course, I don’t deal with new homes that much.