Thread: TPR extension

It's required now to have a air gap and piped to the exterior in our area now. The way I see it they run the 3/4 over to the foundation wall and then have the PVC plumbed to the exterior at the wall. The 3/4 dumps into a funnel type fitting on the top of the PVC (don't know the name of it). I talked to a plumber buddy and he is calling the head AHJ about the PVC because it is not rated but allowed.

Originally Posted by Mike Schulz

It's required now to have a air gap and piped to the exterior in our area now. The way I see it they run the 3/4 over to the foundation wall and then have the PVC plumbed to the exterior at the wall. The 3/4 dumps into a funnel type fitting on the top of the PVC (don't know the name of it). I talked to a plumber buddy and he is calling the head AHJ about the PVC because it is not rated but allowed.

Mike, I ran into one of those about 18 mos. ago. No way I can find the picture though. Old plumber had been to a seminar or plumbing update course and was told about the requirement for an "air-gap". He installed a 3/4 to 1" adapter in the T&P extension about 12" from the top of the tank, similar to the one pictured at the beginning of this thread. The water heater was in the crawlspace, and the drain line was plumbed to the exterior, as he was told it should be.

I checked with a friend, who is also a local AHJ, who said it was totally wrong. The intent was to have an air-gap at the bottom of the T&P extension, just like when it is above an overflow pan. I did not inquire about the use of PVC and don't remember if that is what was used. If the T&P extension is of an approved material and extends to within 6" of the floor or ground, then I don't see why PVC could not be used to drain it the rest of the way to the exterior as it would now be a drain or waste line and not under pressure.

I wrote it up and never heard a word about it.. I did see that it was corrected during a repair verification I did several weeks latter.

Originally Posted by Vern Heiler

I don't see why PVC could not be used to drain it the rest of the way to the exterior as it would now be a drain or waste line and not under pressure.

First and foremost, PVC is not approved for that temperature range.

Secondly (first and foremost to some) is that it is not one of the approved piping materials for use as a T&P discharge line (which are the same as for distribution piping, and PVC is not approved for that either).

Originally Posted by Jerry Peck

First and foremost, PVC is not approved for that temperature range.

Secondly (first and foremost to some) is that it is not one of the approved piping materials for use as a T&P discharge line (which are the same as for distribution piping, and PVC is not approved for that either).

I was not suggesting using PVC for the T&P extension (the pipe going down from the T&P valve) but only saying I don't see a problem with using PVC from the overflow pan or funnel device to the exterior of the foundation.

Originally Posted by Vern Heiler

but only saying I don't see a problem with using PVC from the overflow pan or funnel device to the exterior of the foundation.

That's the part I was talking about too.

Not allowed and not approved, for the reasons I gave.

Think about it, is that 210 degree water going to magically reduce far enough in temperature to as to not affect the PVC in that short T&P discharge pipe?

Besides it not being an air gap.

And besides the end of the PVC not being supported and it would blow downward, then soften and droop away.

And besides not being rated for ...

The drain line from the overflow pans that I see installed in attics are almost always PVC. I must admit that I never really thought about it as a problem.

Originally Posted by Vern Heiler

The drain line from the overflow pans that I see installed in attics are almost always PVC. I must admit that I never really thought about it as a problem.

Not supposed to be PVC.

From the 2006 IRC. (underlining is mine)
(This chapter is water heaters.)
- P2801.5.1 Pan size and drain.The pan shall be not less than 11/2 inches (38 mm) deep and shall be of sufficient size and shape to receive all dripping or condensate from the tank or water heater. The pan shall be drained by an indirect waste pipe having a minimum diameter of 3/4 inch (19 mm). Piping for safety pan drains shall be of those materials listed in Table P2904.5.

- TABLE P2904.5

- - WATER DISTRIBUTION PIPE

NC 2006 Plumbing Code says its OK! I don't have the ability to copy & Paste the code (as I'm too cheap to buy it on disk) but looking at the code on-line it says the drain line from the pan will be from Table 605.4 which is the supply and Table 702.1 which is the DWV. PVC is in there!

Originally Posted by Vern Heiler

NC 2006 Plumbing Code says its OK! I don't have the ability to copy & Paste the code (as I'm too cheap to buy it on disk) but looking at the code on-line it says the drain line from the pan will be from Table 605.4 which is the supply and Table 702.1 which is the DWV. PVC is in there!

Vern,

Your post really confused me (which is not hard to do), here is why:

You said: "NC 2006 Plumbing Code says its OK! ... looking at the code on-line it says the drain line from the pan will be from Table 605.4 ... [/quote]

That's what the IPC says also.

Then you added " ... which is the supply ... "

Correct. The water heater drain pan is to be of material listed in Table 605.4, which is piping suitable for distribution (supply) piping (which means suitable for pressure and for both hot and cold).

Then you added " ... and Table 702.1 which is the DWV.", which is DWV, but the reference comes from where? You stated "PVC is in there!", yes, PVC is a drain material, just not a drain material for a water heater drain pan.

The following is from the 2006 IPC, does the NC IPC read like this:

- 504.7.1 Pan size and drain.

The pan shall be not less than 1.5 inches (38 mm) deep and shall be of sufficient size and shape to receive all dripping or condensate from the tank or water heater. The pan shall be drained by an indirect waste pipe having a minimum diameter of 0.75 inch (19 mm). Piping for safety pan drains shall be of those materials listed in Table 605.4.

There's that same reference to Table 605.4, distribution piping.

Do you have a link to the on-line code you are referencing? I suspect you will see that PVC is not in the table referenced for that drain line.

504.6.2 Materials. Relief valve discharge piping shall be of......

then (Piping from safety pan drains shall be of those materials listed in Tables 605.4 and 702.1.)

Table 702.1 has PVC listed.

I am not that good of a typist so I only xposed what is relevant.

2006 North Carolina Plumbing Code

Try this link.

Originally Posted by Vern Heiler

2006 North Carolina Plumbing Code

Try this link.

Thanks, no IRC?

The NC PC:
- 504.7.1 Pan size and drain. The pan shall be not less than 1.5 inches (38 mm) deep and shall be of sufficient size and shape to receive all dripping or condensate from the tank or water heater. The pan shall be drained by an indirect waste pipe having a minimum diameter of 1 inch (25 mm).

That wording is from the 2003 IPC, which does not have the requirement for what material to use.

The reason why that requirement was added to the IPC and IRC was exactly because you are finding what you are finding - PVC used for that drain line which is used for HOT WATER, and the piping itself is not rated for use with HOT WATER.

Thus, to make sure that those AHJ understand that *the properly rated material was supposed to be used*, whether it was spelled out or not, *it is now spelled out in the code*.

However, here is one key (in the NC PC) to help you address that problem with a code without the 2006 wording:
- 701.7 Connections. Direct connection of steam exhaust, blowoff or drip pipe shall not be made with the building drainage system. Wastewater when discharged into the building drainage system shall be at a temperature not higher than 140 degree F (60 degrees C). When higher temperatures exist, approved cooling methods shall be provided.

Did the link work?

If it does, look at page 33, Code 504.6.2. Materials.

Go to the end of the paragraph where it says. "Piping from safety drains shall ve of those materials listed in Tables 605.4 and 702.1"

Originally Posted by Vern Heiler

Did the link work?

If it does, look at page 33, Code 504.6.2. Materials.

Go to the end of the paragraph where it says. "Piping from safety drains shall ve of those materials listed in Tables 605.4 and 702.1"

The link worked, but I missed that section.

However, that section shows that the safety pan drain is not allowed to be PVC.

You even so state in your post, here is why:

Go to the end of the paragraph where it says. "Piping from safety drains shall ve of those materials listed in Tables 605.4 and 702.1"

That states that the drain pan material shall be listed in table wxy AND table abc, and PVC *is not* listed in both tables.

Combine that with the references I provided out of the NC PC and you will see, should see, that PVC is not allowed for that drain pan drain line.

The newer wording in the 2006 IPC and IRC resolve that conflict.

Just spoke with the Assistant Chief Plumbing Inspector in Mecklenburg Co. Two mis-prints have been corrected in the 2009 code section 504.6.2. Table 605.5 was a ref. to fittings and has now been corrected to table 605.3 water service pipe. The last sentence has been changed from Tables 605.4 and 702.1 to Tables 605.4 or 702.1.

PVC is allowed in NC.

The reasoning given that PVC is acceptable, was to compare it to the PVC drains at kitchen sinks. How much hotter can water be than straining off boiling pasta?

Originally Posted by Vern Heiler

Just spoke with the Assistant Chief Plumbing Inspector in Mecklenburg Co. Two mis-prints have been corrected in the 2009 code section 504.6.2. Table 605.5 was a ref. to fittings and has now been corrected to table 605.3 water service pipe. The last sentence has been changed from Tables 605.4 and 702.1 to Tables 605.4 or 702.1.

PVC is allowed in NC.

Then go for it.

The reasoning given that PVC is acceptable, was to compare it to the PVC drains at kitchen sinks. How much hotter can water be than straining off boiling pasta?

A lot.

When the T&P goes under emergency conditions it would well be at 210 degrees F. At full force, for a while as it cools down with the cold water drawn into the water heater.

The amount of water from the boiling pasta is limited (very limited) and by the time it gets through the sink and into the drain it is cooled considerably. Mix that cooled water with water already in the trap and it is even cooler. Mix that water with water from the faucet (I've always seen the water running when pasta is drained) and you are mixing maybe 130 degree water with it.

The simple answer is that the water from draining boiling pasta is VERY LIMITED in amount and duration as compared to the amount of VERY HOT water from a water heater.

Sounds to me like someone came up with a stretch of an argument to try to justify allowing PVC for those drains while others across the country do not allow PVC for those drains, and the NC PC code does not even allow for that in its limitation on temperature being discharged into the drain system. I think you need to ask that guy about the drain temperature limitation ... maybe he will get that removed too?

Originally Posted by Jerry Peck

Then go for it.

Sounds to me like someone came up with a stretch of an argument to try to justify allowing PVC for those drains while others across the country do not allow PVC for those drains, and the NC PC code does not even allow for that in its limitation on temperature being discharged into the drain system. I think you need to ask that guy about the drain temperature limitation ... maybe he will get that removed too?

The Assistant Chief Inspector did not write the code, I am not going to try to change the code, and all of my NC colleages need to know that it is allowed in NC.

It would be interesting to know if HI's in other parts of the country see PVC from the safety drain pan?

Originally Posted by Wayne Carlisle

Compliant? How does PVC comply for hot water and protection from UV rays on the exterior of the structure?

wayne,
i wiilll taalllkkk slloowweer fooorrr yyyooouuu. usssee theee pppvvvcc fooorrr aaa ssslllleevvvee for a compliant material such as copper,cpvc,galvanize,etc..

That was harder to read than the 1st post!

Originally Posted by brian schmitt

wayne,
i wiilll taalllkkk slloowweer fooorrr yyyooouuu. usssee theee pppvvvcc fooorrr aaa ssslllleevvvee for a compliant material such as copper,cpvc,galvanize,etc..

Jerry, could you give us the meaning of "compliant"?

The drain pan for the water heater is meant to drain water froma lewak that may occur and the water would be trickling. If the tank were to outright rupture then it would over flow the pan anyway. To try to blow off the TPR valve into the drain pan is foolish. Practically none will stay kin and then drain down the drain line. Most will blow down, hit the pan with a bib force and slash, we, be blown out of the pan.

I think it is a dumb idea to discharge the TPR to a drain pan. For a slight trickling leak from a leaking water heater I don't see the pipe being over heated as the water will cool trickling out and into the pan making its way to the drain line.

I see drain pans being drained by PVC all the time. Many have started to change to copper. Most attics they are not taking the chance and usually use copper. The garage would be a different story.

I do right them up. But being just a drain from the trickling leak in a water heater I cannot see it being an issue. Blowing the TPR valve into the drain pan is just simply dumb.

Again if the water heater ruptures that pan is not doing a darn thing anyway.

This is new and past by the ahj

Originally Posted by Ted Menelly

The drain pan for the water heater is meant to drain water froma lewak that may occur and the water would be trickling. If the tank were to outright rupture then it would over flow the pan anyway. To try to blow off the TPR valve into the drain pan is foolish. Practically none will stay kin and then drain down the drain line. Most will blow down, hit the pan with a bib force and slash, we, be blown out of the pan.

I think it is a dumb idea to discharge the TPR to a drain pan. For a slight trickling leak from a leaking water heater I don't see the pipe being over heated as the water will cool trickling out and into the pan making its way to the drain line.

I see drain pans being drained by PVC all the time. Many have started to change to copper. Most attics they are not taking the chance and usually use copper. The garage would be a different story.

I do right them up. But being just a drain from the trickling leak in a water heater I cannot see it being an issue. Blowing the TPR valve into the drain pan is just simply dumb.

Again if the water heater ruptures that pan is not doing a darn thing anyway.

i'm in total agreement here ted. calif plumbing code does not allow the tpr drain to go to the pan for the reasons you mentioned. pvc for the pan drain only is the norm here as the code does not specify the type of material for the drain.

Originally Posted by Vern Heiler

Jerry, could you give us the meaning of "compliant"?

"Compliant"

To comply with

To be in compliance with

To conform to the minimum requirements of

To meet the minimum requirements of

Originally Posted by Jerry Peck

"Compliant"

To comply with

To be in compliance with

To conform to the minimum requirements of

To meet the minimum requirements of

Like as in "2006 North Carolina Plumbing Code" ?

Originally Posted by Vern Heiler

Like as in "2006 North Carolina Plumbing Code" ?

With that wording change from "and" to "or", yep.

Just don't confuse "compliant" with "common sense" or "doing things right".

When I test those, I don't see what I call a great deal of force to the flow.
I have never seen one 'blow" due to excessive pressure. Anybody have any info / video of that. Even if it is alot, it would only be temporary. I don't see much difference in terminating the tp drain pipe at the pan and that 'approved and past' configuration posted by Mike Shulz.- similar amount of potential damage.

Originally Posted by Richard Stanley

When I test those, I don't see what I call a great deal of force to the flow.
I have never seen one 'blow" due to excessive pressure. Anybody have any info / video of that. Even if it is alot, it would only be temporary. I don't see much difference in terminating the tp drain pipe at the pan and that 'approved and past' configuration posted by Mike Shulz.- similar amount of potential damage.

Well. When you release it it is just water pressure. When the tank blows from a bad valve not opening it blows thru the roof and lands a block away. That is a serious difference. You are dealing with a water heater that has built up to 3 times the water pressure and if the valve is slightly faulty but not bad enough to blow the tank it could be a serious amount of water pressure behind it with almost super heated water.

Just type in. images of water heaters blowing up in a search

Just at releasing at the designed pressure and or temp it will blow out of the end of the pipe hard enough to blow right out of the pan. God forbid you were standing next to it with the water blowing into the pan and up into your face. I can see you in the emergency room now. That would be like your wife throwing boiling water in your face with 150 pounds pressure behind it.

A short clip of the Watts video is here ( Explosion - Danger Lurks! ), you can order a free DVD here ( Learn About - Danger Scalding Lurks! Free DVD, hot water scald, safety mixing valve )

I've uploaded the video, you can view it here: AskCodeMan.com

Originally Posted by Mike Schulz

This is new and past by the ahj

I am discouraged to see that the new code has relaxed the safety against hot water splash to this extent. But the code now only has a minimum distance from the ground or waste receptor. No maximum distance to the receptor. So by code the funnel could be at the ground and no pipe installed on the T&P valve. REALLY BAD CODE WRITTING in my opinoin.

Originally Posted by Richard Stanley

When I test those, I don't see what I call a great deal of force to the flow.
I have never seen one 'blow" due to excessive pressure. Anybody have any info / video of that. Even if it is alot, it would only be temporary. I don't see much difference in terminating the tp drain pipe at the pan and that 'approved and past' configuration posted by Mike Shulz.- similar amount of potential damage.

Rick H. had a picture of one blowing at the outlet end... It was a brick house I think. Since Rick is a nice guy, he may dig it out for you.

Nice video and a good addition to the askcodeman site.
I am familiar with the explosive factor.
The part I was particularly interested in was the demo of the amount of water / steam / force that was emitted from the TPRV drain pipe when it was activated by pressure - temperature.
They were calling them HOT water heaters. Shame!
Thanks for that and all you do Jerry.

Here is the thread / pic I was referring to:

http://www.inspectionnews.net/home_i...st-got-me.html

Originally Posted by Vern Heiler

I am discouraged to see that the new code has relaxed the safety against hot water splash to this extent. But the code now only has a minimum distance from the ground or waste receptor. No maximum distance to the receptor. So by code the funnel could be at the ground and no pipe installed on the T&P valve. REALLY BAD CODE WRITTING in my opinoin.

Huh?

Read 504.6.1 Discharge in that link you provided.

First sentence. Underlining is NOT mine, it is in that code. It indicates a change.

504.6.1 Discharge. (that's the section title)
(first sentence) The relief valve shall discharge full size to a safe place of disposal such as within 6 inches (152 mm) of the floor, outside the building or indirect waste receptor.

In the IPC, the entire section is written differently, but that 6" maximum is still in there: (underlining is mine)

- 504.6 Requirements for discharge piping.The discharge piping serving a pressure relief valve, temperature relief valve or combination thereof shall:
- - 10. Not terminate more than 6 inches (152 mm) above the floor or waste receptor.

Originally Posted by Jerry Peck

Huh?

Read 504.6.1 Discharge in that link you provided.

First sentence. Underlining is NOT mine, it is in that code. It indicates a change.

504.6.1 Discharge. (that's the section title)
(first sentence) The relief valve shall discharge full size to a safe place of disposal such as within 6 inches (152 mm) of the floor, outside the building or indirect waste receptor.

In the IPC, the entire section is written differently, but that 6" maximum is still in there: (underlining is mine)

- 504.6 Requirements for discharge piping.The discharge piping serving a pressure relief valve, temperature relief valve or combination thereof shall:
- - 10. Not terminate more than 6 inches (152 mm) above the floor or waste receptor.

Jerry, I thought the same thing, but after sending the picture in Mike's post to the same AHJ I called about the pan drain line material, he responded with

"This one would be approved by code- the code establishes the minimum air gap- but no maximums...thanks"

I expressed my concern to him as well! But I doubt it will change the writing or the interpretation by AHJ's here in NC.

Originally Posted by Vern Heiler

Jerry, I thought the same thing, but after sending the picture in Mike's post to the same AHJ I called about the pan drain line material, he responded with

"This one would be approved by code- the code establishes the minimum air gap- but no maximums...thanks"

I expressed my concern to him as well! But I doubt it will change the writing or the interpretation by AHJ's here in NC.

Vern,

That's where you have to know what to ask next, because, like many things, it depends on how you ask or on what the responder is thinking about or just thought about.

If you mentioned "air gap", he is correct. There are "minimum" "air gap" requirements.

However, regarding the water heater T&P relief valve discharge line, there is ALSO (yes, the minimum air gap does apply) a maximum height distance.

I'm guessing that is you send that back to him and ask him if that photo meets: 1) the minimum air gap requirement; and 2) the maximum height above the floor/receptor requirement in this "504.6.1 Discharge. The relief valve shall discharge full size to a safe place of disposal such as within 6 inches (152 mm) of the floor, outside the building or indirect waste receptor.", AND include that reference from the NC PC, ... I'm guessing you will get an entirely different answer.

I'm guessing you will get a 'While that does meet the minimum air gap requirements, no, that does not meet the maximum height limitation above the floor/receptor.'

That same person you talked to may even say 'Oh, right, I FORGOT ABOUT THAT SECTION, but you are correct, it DOES NOT meet that section.'

You do not have enough persistence in asking question, you ask incorrect answer way to easily. You think the AHJ never makes mistakes? You know better than that.

I did not ask him anything about the air gap requirement. What I did was send him the picture from Mike's post and asked if the pictured T&P system was code compliant. As Mike said it was passed by the AHJ in his area, I must assume that they are all interpreting the code the same way.

Originally Posted by Vern Heiler

I did not ask him anything about the air gap requirement. What I did was send him the picture from Mike's post and asked if the pictured T&P system was code compliant.

Which gets back to what I said:

Originally Posted by Jerry Peck

That's where you have to know what to ask next, because, like many things, it depends on how you ask or on what the responder is thinking about or just thought about.

I'm guessing that is you send that back to him and ask him if that photo meets: 1) the minimum air gap requirement; and 2) the maximum height above the floor/receptor requirement in this "504.6.1 Discharge. The relief valve shall discharge full size to a safe place of disposal such as within 6 inches (152 mm) of the floor, outside the building or indirect waste receptor.", AND include that reference from the NC PC, ... I'm guessing you will get an entirely different answer.

I'm guessing you will get a 'While that does meet the minimum air gap requirements, no, that does not meet the maximum height limitation above the floor/receptor.'

That same person you talked to may even say 'Oh, right, I FORGOT ABOUT THAT SECTION, but you are correct, it DOES NOT meet that section.'

If you get back to that person, provide them with that code section, provide them with the photo, it then gives them the opportunity - which is what needs to be done when asking questions, is to give the person the opportunity to address what it really is that you are asking - give them the opportunity to address that from the code reference you are asking about.

Simply asking is that compliant allows for a quick glance and, yeah, that looks okay, without really having to stop and think about if it is compliant or not.

In this case, that in not compliant as the height above the receptor exceeds 6 inches.

When discussing codes and requirements, you must first get the persons attention, as I said in my other post "or on what the responder is thinking about or just thought about.", he may well have just been addressing air gaps with some, thus, his first thought was 'yeah, that meets the air gap requirements'.

Your question, your call. If you are satisfied with a less than fully correct answer, accept it.

I have sent a copy of post #100 to the AHJ along with the concerns. I'll let you know what the response is.

Well here is the response:

"I was incorrect, it should be within 6" of the receptor; we have had so many w/heater change-outs,(w/out permits-and that was illegal after July 2003, all w/heaters must be permited and inspected) I would wonder had this really been inspected by a Code Inspector- the 6" is just a safe guard for splashing, but it does not have to be to the floor dimension, it could as you see from the top of the waste receptor, and it can be at any height."

This is what I first thought but was discouraged by Mike's post stating it had been passed by AHJ. Then the first response from local AHJ. My faith is somewhat restored!

I hope Mike sees this post and that I have not mis-lead anyone.

Vern,

I must say, that is some quick response time from your AHJ.

That is great.

Here is todays, at least it's in the receptor

Originally Posted by Mike Schulz

Here is todays, at least it's in the receptor

Except that it is not allowed to be "in" the receptor. There needs to be at least a 1-1/2" air gap between the bottom of the discharge pipe and the top of the receptor.

Thanks Jerry,
I'm still working on the report, where do I find that it needs to be 1-1/2" at...........

Originally Posted by Mike Schulz

Thanks Jerry,
I'm still working on the report, where do I find that it needs to be 1-1/2" at...........

From the 2006 IRC.

- First, the requirement for an air gap: (underlining is mine)

- - P2803.6.1 Requirements for discharge pipe.The discharge piping serving a pressure-relief valve, temperature relief valve or combination valve shall:

- - - 1. Not be directly connected to the drainage system.
- - - 2. Discharge through an air gap located in the same room as the water heater.
- - - 3. Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
- - - 4. Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
- - - 5. Discharge to the floor, to an indirect waste receptor or to the outdoors. Where discharging to the outdoors in areas subject to freezing, discharge piping shall be first piped to an indirect waste receptor through an air gap located in a conditioned area.
- - - 6. Discharge in a manner that does not cause personal injury or structural damage.
- - - 7. Discharge to a termination point that is readily observable by the building occupants.
- - - 8. Not be trapped.
- - - 9. Be installed to flow by gravity.
- - - 10. Not terminate more than 6 inches (152 mm) above the floor or waste receptor.
- - - 11. Not have a threaded connection at the end of the piping.
- - - 12. Not have valves or tee fittings.
- - - 13. Be constructed of those materials listed in Section
P2904.5 or materials tested, rated and approved for

such use in accordance with ASME A112.4.1.

Now for the size of the air gap.

- Table P2902.3.1
- - Minimum Air Gaps
- - - Sink, laundry trays, gooseneck back faucets and other fixtures with effective openings not greater than 3/4 inch in diameter
- - - - Away from a walla - 1.5 inches
- - - - Close to a walla - 2.5 inches
- - - - - notea for distance to wall: a. 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.

Table P2902.3.1
- - Minimum Air Gaps
- - - Sink, laundry trays, gooseneck back faucets and other fixtures

Jerry correct me if I am wrong but that pertains to fixtures not discharge or drain pipes correct...........What part of that setup on the water heater discharge would be called a fixture.

Mike, go to this link:

2006 North Carolina Plumbing Code

Sec, 802.2.1 gives the requirement of the air gap.

Originally Posted by Mike Schulz

Jerry correct me if I am wrong but that pertains to fixtures not discharge or drain pipes correct...........What part of that setup on the water heater discharge would be called a fixture.

Here: (see underlining), however, it is also stated with bold (the rule of thumb - and what I've seen in every code so far - is the air gap much be twice the diameter of the outlet discharge size)
- P2902.3 Backflow protection.

A means of protection against backflow shall be provided in accordance with Sections P2902.3.1 through P2902.3.6. Backflow prevention applications shall conform to Table P2902.3, except as specifically stated in Sections P2902.4 through P2902.5.5.
- - P2902.3.1 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 P2902.3.1. 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.

Oh, and here too ... ... by definition.

- PLUMBING FIXTURE.A receptor or device that requires both a water-supply connection and a discharge to the drainage system, such as water closets, lavatories, bathtubs and sinks. Plumbing appliances as a special class of fixture are further defined.

Thanks Guy's..........

Mike,

Difference between an Air Gap(drainage system) and an Air Break(drainage system) is one of your "issue" questions.

Originally Posted by Mike Schulz

Jerry correct me if I am wrong but that pertains to fixtures not discharge or drain pipes correct...........What part of that setup on the water heater discharge would be called a fixture.

Originally Posted by Vern Heiler

Mike, go to this link:

2006 North Carolina Plumbing Code

Sec, 802.2.1 gives the requirement of the air gap.

Please review Chapter 2 Section 202 General Definitions (before doing so review Section 201).

Note the following:
AIR BREAK (Drainage System) (note use of term "flood level rim" and compare the difference between AIR BREAK and AIR GAP.
AIR GAP (Drainage System)
AIR GAP (Water Distribution System)
DISCHARGE PIPE
DRAIN
DRAINAGE FITTINGS
EMERGENCY FLOOR DRAIN (note exclusions)
EXISTING INSTALLATIONS
FAUCET
FIXTURE (see Plumbing Fixture)
FIXTURE BRANCH
FIXTURE FITTING - (Note - review all Supply fitting through and including Waste fitting).
FLOOD LEVEL RIM (note receptacle)
HOT WATER
INDIRECT WASTE PIPE
INDIRECT WASTE RECEPTOR (Note - that it is defined herein as a plumbing fixture and is underlined in its entirety)
PLUMBING
PLUMBING APPLIANCE (note arrow in margin and note use of the term plumbing fixture)
PLUMBING APPURTENANCE
PLUMBING FIXTURE
RIM
WATER HEATER
WATER OUTLET
WATER SUPPLY SYSTEM
WASTE
WASTE PIPE

Make special note as to the difference between what an AIR GAP (drainage) is versus an AIR BREAK.

Then as you review ALL of chapter 5 paying special attention to underlined areas keep those definitions in mind unless further clarified and defined in that chapter as well as chapter 8.

Keep in mind the differences between what is allowed for the discharge pipe (of the T&P), its (the discharge pipe of the T&P) POINT OF DISCHARGE (top of air gap) and what is allowed on the other (bottom) side of that required air gap - i.e. floor, indirect waste pipe, drainage system, outdoors, etc..

Expansion room for steam or near steam for heat release to atmosphere and unobstructed free flow if max pressure at max flow for discharge pipe outlet is one of the primary reasons for the air gap (rapid reduction of energy, release of heat Btu to air, release of pressure to equalize to air to slow expansion) in addition to the isolation from contamination.

The importance of the materials and unobstructed discharge and drainage considerations are not so much for the nuisance dribble discharge as much as they are for the emergent worst case situation. The T&P is supposed to be the last line of defense to a steam flash blast not the first. Ask yourself what is the worst case situation discharge (assuming the T&P is functioning properly, isn't scaled over, etc.) is what temperature and what pressure if all safety limits have failed or been exceeded in the design and characteristics of a closed or open system that requires that T&P to open and discharge effectively to prevent a steam flash/explosion. Remember steam flash occurs at different temperatures depending on the pressure.

803 Special Wastes
803.1 Wastewater temperature. Steam pipes shall not connect to any part of a drainage or plumbing system and water above 140 degrees F (60 degrees C) shall not be discharged into any part of a drainage system. Such pipes shall discharge into an indirect waste receptor connected to the drainage system.

I'm at a loss at how that PVC through the foundation wall to the ground complies with the Rodent proofing requirements or the spirt of the intent of Appendix H which is incorporated as a part of the code.

I believe if you first review Chapter 2 then re-review chapter 5 paying special attention to when specific terms (especially when a two or three word phrase which is defined) are used, and special attention to underlining and markings in the margins, and make yourself a diagram you will find the answers you seek applicable to your jurisdiction. The requirements for the materials for the discharge pipe from the T&P to its outlet/air gap then those on the receiving end of the airgap. I have made no review of NC adoptions, amenments, or the history of NC codes, only briefly scanned the aforementioned code link specifically the mentioned chapters and appendix.

Mike, that last series of photos and the sections 502.6 through 507.4 (entirely underlined) seem at first glance to be inter-related (and poorly written/broken up), review especially 502.7.4. Might be a photographic illusion but I do not see evidence of a proper pitch or slope to the horizontal to provide a natural drain even if there was a proper air gap. The difference of elevation seems to imply that crawl-space installation might have many other issues in addition to missing required defined air gap/safe outlet of the discharge pipe itself for the T&P (versus air gap). Among other things looks like an open invitation to snakes and rodents to enter the crawl space, and should there be minor flooding or a few inches of exterior water collection - an avenue to flood the crawl space - how many inches above grade is that horizontal?


I hope that helps.

Originally Posted by H.G. Watson, Sr.

803 Special Wastes
803.1 Wastewater temperature. Steam pipes shall not connect to any part of a drainage or plumbing system and water above 140 degrees F (60 degrees C) shall not be discharged into any part of a drainage system. Such pipes shall discharge into an indirect waste receptor connected to the drainage system.

As I posted above in Chapter 7, Sanitary Drainage:

Originally Posted by Jerry Peck

However, here is one key (in the NC PC) to help you address that problem with a code without the 2006 wording:
- 701.7 Connections. Direct connection of steam exhaust, blowoff or drip pipe shall not be made with the building drainage system. Wastewater when discharged into the building drainage system shall be at a temperature not higher than 140 degree F (60 degrees C). When higher temperatures exist, approved cooling methods shall be provided.

H.G,

Thanks for the great break down and time you spent on your post. The exterior part of that PVC drain is only 3" above grade. It should be 6" The pipe was pitched to the exterior.

The material is wrong and I am still waiting for the reply about this from a friend who knows the Head AHJ.

Your right also about the vermin that can enter into the crawl. That is also one of the questions that will be asked.

Thanks again to all that replied for your help.

Mike,

You are welcome and good luck with your endeavors.