Thread: tpr valve drain pipe

How do I tell if this tape is an approved material for the TPR drain pipe?

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Look for the ASTM markings. Sometimes they are on the edge of the tape!

John,

It has to be Scotch brand tape, which must be identified as such with a hand written note from the installer's bartender.

Thanks. You guys are awesome. This board is such a valuable font of wisdom, it's just unbelievable.

GO PHILLIES !!!!!!!

"This message has been deleted by Vern Heiler. Reason: Didn't see the smiley"

I hates smileys and all of them emoticons.

If i'd looked closer at who posted i'da known better

I know this is off the subject.... But how do I post a new question?

Originally Posted by Richard Mobley

I know this is off the subject.... But how do I post a new question?

Go to the top of this page and click on "InspectonNews-Home Inspection" then select the arrea that deals with your post. The at the bottom select "New Thread"

Originally Posted by Richard Mobley

I know this is off the subject.... But how do I post a new question?

You just did....

Can a flexible copper pipe be used as a TPR drain?

No flex for tprv

Thanks Wayne, That is what I thought. Never seen it before and it didn't look right.

Originally Posted by Wayne Carlisle

No flex for tprv

2006 IRC
T&P Valve dishcarge

P2803.6.1 Requirements for discharge pipe. The discharge
piping serving a pressure-relief valve, temperaturerelief
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. ( is that 1/2 or 3/4 pipe)
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.

Doesn't say it can't be flexible.

Most all the copper flex lines "decrease" the diameter size output from the TPR Valve and that is not allowed. With that in mind ... doesn't matter if it is "flex" or not ... but most all flex that I've seen do not maintain the required diameter.

Roger, there is no secret handshake required. As far as I know, as long as you have registered a username, you should be able to post a new thread.

Nolan, that's what I was thinking as well. That flex looks smaller than the TPR valve.

What I am still confused about is the required "air gap" for TPR discharge. I just don't see the purpose. Why can it not discharge directly outside? Maybe I'm just not interpreting it correctly.

Originally Posted by Nolan Kienitz

Most all the copper flex lines "decrease" the diameter size output from the TPR Valve and that is not allowed. With that in mind ... doesn't matter if it is "flex" or not ... but most all flex that I've seen do not maintain the required diameter.

I'm not positive but I think there is a statement in the code that all sizes are nominal. So if the flex is listed as the same size as the outlet of the T&P valve it would be ok. Must be secured at the bottom.

I think the air-gap requirement is to insure that there is no blockage such as ice, mud dobbers, kinks, etc.

No on the flex connector on many levels, one being it has a threading connection at the outlet side, and could therefore be plugged by someone, thus creating a bomb should the TPRV need to open. You are not allowed to reduce the Internal Diameter of the pipe size from the TPRV discharge. You are limited as to the type and amount of offset of such a discharge. You are limited to using approved materials and diameter/size. You are likewise required to follow the instructions, precautions, safety warnings and recommendations of the TPRV manufacturer as well as the WH vessle.


Why bother to post a section and blow by #11? (threading) did you miss that?

then highlight #13 and not post what it refers to?

Notice you didn't post P2904.5 Vern, why stop where you did?

How could you possibly conclude what was pictured was correct Vern Heiler? What you quoted says it is not permitted if you read it.

Originally Posted by Brent Crouse

Roger, there is no secret handshake required. As far as I know, as long as you have registered a username, you should be able to post a new thread.

Nolan, that's what I was thinking as well. That flex looks smaller than the TPR valve.

What I am still confused about is the required "air gap" for TPR discharge. I just don't see the purpose. Why can it not discharge directly outside? Maybe I'm just not interpreting it correctly.

Few reasons, one being if a vacuum/syphon situation or a drain backup won't contaminate the TPRV discharge line and thereby the WH vessel itself (TPRV may open or may not be closed completely - i.e. drip situation post discharge or test) thus allowing transfer of contaminated to potable water system, the other reason is to allow for an un-constrained release of energy high temperature water and high pressure energy can be released/equalized before discharge to drain, preventing a steam blast/flash, especially if the TPRV was slow to open (such as when insulated with scale) and not rupture the drain pipe.

The emphasis that the air gap/break or first discharge point be in the same area as the WH and visable is so that the resident occupant will SEE the discharge activity (be it a flow, gush, or drip) and take the appropriate measures to address the emergent situation.

Originally Posted by H.G. Watson, Sr.

No on the flex connector on many levels, one being it has a threading connection at the outlet side, and could therefore be plugged by someone, thus creating a bomb should the TPRV need to open. You are not allowed to reduce the Internal Diameter of the pipe size from the TPRV discharge. You are limited as to the type and amount of offset of such a discharge. You are limited to using approved materials and diameter/size. You are likewise required to follow the instructions, precautions, safety warnings and recommendations of the TPRV manufacturer as well as the WH vessle.


Why bother to post a section and blow by #11? (threading) did you miss that? 11. Not have a threaded connection at the end of the piping.

Pictured piping is not threaded at the end of the pipe!

then highlight #13 and not post what it refers to? P2803.6.1 Requirements for discharge pipe. The discharge
piping serving a pressure-relief valve, temperaturerelief
valve or combination valve shall:
At the very beginning of the post!


Notice you didn't post P2904.5 Vern, why stop where you did?

I can only view the Code, don't have copy/paste rights.

How could you possibly conclude what was pictured was correct Vern Heiler? What you quoted says it is not permitted if you read it.

If you look closely at the pictured flex you can see that the inside diameter of the flex is the same as the diameter of the 1/2" pipe it is connected to.

BTW I can't think of a good reason to use flex. Just can't say it is wrong!

The emphasis that the air gap/break or first discharge point be in the same area as the WH and visable is so that the resident occupant will SEE the discharge activity (be it a flow, gush, or drip) and take the appropriate measures to address the emergent situation.

Many of the water heaters I inspect are in attics and crawlspaces. Neither of which could you get a homeowner to enter without a cattle prod.

You just don't "get it" Vern Heiler so I'm not going to waste too much time 'splaining this to you.

1. There is a reduction, that's not allowed. Most TPR Valves for WHs of this size are 3/4" valves, if 3/4" then 3/4" discharge is required (see that 3/4 off the top of the tank in the pic I reposted and pointed to) you're not allowed to reduce it to 1/2" anything, especially not soft flexible copper threaded connector designed for 80 psi distribution, a TPR Valve discharges at 150 PSI or 210 degrees F.

2. You don't seem to get what "trapped" means. It doesn't mean an ornate p-trap, it means any obstruction or bend that prevents the entire discharge line to be emptied completely and quickly by gravity alone, thereby allowing no mineral buildup or retained discharge should there be a full open or a minor drip occuring.

3. You show me a flex line that is labeled as tested and approved for above 150 psi and above 210 degrees F (99 degrees C) rated.

It isn't approved, not on the list for several reasons already outlined, Just as PVC isn't approved although often used by the idiotic DIYer who doesn't know the difference between CPVC and PVC.

IF CPVC is used it cannot be directly attached to the valve a metal to CPVC adapter must be first.

Flex is not allowed because it cannot be secured and is not permanent in its shape or path, it can be kinked, twisted, bent creating an obstruction or creating a TRAPing situation. It is also not sleek, creates drag and friction and prevents fast unobstructed evacuation of near steam blast discharge (210 degrees F at sea-level and potentially at 150 PSI). It is also not allowed because it can be easily plugged or capped. Neither the soft copper tubing or its connectors are approved for the purpose of high temperature and extreme pressure distribution.

Ken writes a better article than I, and uses smaller words, perhaps you'll get it if you read it...slowly:
The Temperature Pressure Relief Valve | ASHI Reporter

FYI you won't. The IAMPO reports and the standards their aproved for (The corregated copper water heater connectors) are rated for Max Pressure of 125 psi (8.62 bar) and Max Temperature of 180 degrees F (82.22 degrees C), some are lower.

That's important, lets repeat that:
corregated copper water heater connectors - Max Pressure: 125 PSI - Max Temperature: 180 degrees F.

Why is that important? Because a water heater Temperature Pressure Relief Valve discharges at?.....drum roll.....: 150 PSI and/or 210 degrees F (99 degrees C).

Why do we have all these rules about even having a discharge pipe for the TPR Valve in the first place? To prevent scalding and burn injuries to the resident occupants and persons who service them. So the party can get to the water heater and shut it down during the emergent situation and prevent an explosion!, fire, injury or loss of life etc.; secondarily, to prevent or minimize property damage.

7/8" or 1" OD with 3/4" FIP nuts, not what is in the picture.

If that ain't enuf for you, or the dang label that is attached to the connector, since you can't read the very codes you quote, nothing will be.

Oh, and appliance connectors for gas, other flexible connectors, and garden hoses also aren't approved TPR Valve discharge materials.

You can sometimes get a clue by what the product is called (WH Connector, faucet connector) as to what its intended purpose is and what it isn't. Those labels and tags that are not supposed to be removed also provide valuable information, like warnings and cautions, and ratings (max temp/pressure).

http://www.watts.com/pdf/ES-WB&T-LFWaterFlex.pdf

http://pld.iapmo.org/file_info.asp?file_no=0002498

You're right it wasn't "nice". You also didn't spell it correctly.

H.G. Your right! That sure does look like a 3/4" compression fitting. My bad. I knew it wasn't 1/2. But doesn't a compression fitting maintain the same id? I thought the discharge end of the piping would be where the water would discharge. I was not aware that every joint in piping was considered a discharge .

That CPVC and PEX is great stuff huh! Rated at 150psi and 210 degrees and all. I guess copper just can't stand up to the new stuff.

I can now see how that long radius bend in the flex is much more restrictive than say four 90 degree elbows.

That darn thing is absolutely no good for high pressure distribution either with that 3/4" hole in the end. If you are going to distribute high pressure you have to maintain it so it is useful at the end point.

And the way that 3/4" pipe stops at the bottom of the picture it will blow all over someone's chest.

Originally Posted by Vern Heiler

H.G. Your right! That sure does look like a 3/4" compression fitting. My bad. I knew it wasn't 1/2. But doesn't a compression fitting maintain the same id? I thought the discharge end of the piping would be where the water would discharge. I was not aware that every joint in piping was considered a discharge .

That CPVC and PEX is great stuff huh! Rated at 150psi and 210 degrees and all. I guess copper just can't stand up to the new stuff.

I can now see how that long radius bend in the flex is much more restrictive than say four 90 degree elbows.

That darn thing is absolutely no good for high pressure distribution either with that 3/4" hole in the end. If you are going to distribute high pressure you have to maintain it so it is useful at the end point.

And the way that 3/4" pipe stops at the bottom of the picture it will blow all over someone's chest.

Vern Heiler,

Regarding the highlighted in the quote above, NO CPVC IS NOT rated at 150 PSI @ 210 degrees F!!!!! And your #s are likewise incorrect for PEX (Limited to 200 degrees for heating distribution and 180 degrees F for potable distribution - "emergency ratings" aside), however PEX doesn't apply for the TPV discharge in CALIFORNIA (as outlined for DG below).

It really doesn't matter, it (corregated copper tube) isn't allowed. 2007 California Plumbing Code is based on the UPC with State-wide ammendments (Dave Gilstrap's stated location is Rescue, California!). By the way CPVC is not rated for 210 degrees at 150 PSI, apparently you are unaware of the Derating factors (for working pressures when the temperature is higher than 80 degrees F).

"CPVC pipe for plumbing systems is manufactured by extrusion in sizes ¼" through 2" copper tube size (CTS) dimensions. The CTS plumbing products are made to copper tube outside diameter dimensions, in accordance with ASTM D-2846 specifications, and have an SDR 11 wall thickness. The pressure ratings of the CTS SDR 11 systems are 400 psi (pounds per square inch) at 73 F and 100 psi at 180 F." (derating factor 0.25 @ 180F).


"THE MAXIMUM SERVICE TEMPERATURE FOR CPVC IS 200°F."
What's the pressure derating factor at 200 degrees F? 0.20! (80 PSI)

Solvent cemented joints should be utilized when working at or near maximum temperatures...does not recommend the use of CPVC for threaded connections at temperatures above 150°F; use flanged joints, unions, or roll grooved couplings where disassembly is necessary at elevated temperatures.

Threading of Sch 40 CPVC pipe is not a recommended practice due to insufficient wall thickness. Thread only Sch 80 or heavier walls.

Threading requires a 50% reduction in pressure rating stated for plain end pipe @73°F."

Higher temperature limits the pressure limits which are substantially reduced/limited when other than solvent welds are used.

Originally Posted by Dave Gilstrap

Can a flexible copper pipe be used as a TPR drain?

Originally Posted by Wayne Carlisle

No flex for tprv

Dave Gilstrap:

Originally Posted by 2007 California Plumbing Code

- 608.5 Relief valves located inside a building shall be provided with a drain, not smaller than the relief valve outlet, of galvanized steel, hard-drawn copper pipe and fittings, CPVC, or listed relief valve drain tube with fittings that will not reduce the internal bore of the pipe or tubing (straight lengths as opposed to coils) and shall extend from the valve to the outside of the building, with the end of the pipe not more than two (2) feet (610 mm) nor less than six (6) inches (152 mm) above the ground or the flood level of the area receiving the discharge and pointing downward. Such drains may terminate at other approved locations. Relief valve drains shall not terminate in a building's crawl space. No part of such drain pipe shall be trapped or subject to freezing. The terminal end of the drain pipe shall not be threaded.

Originally Posted by 2007 California Plumbing Code

- 609.0 Installation, Testing, Unions, and Location.
-- 609.1 Installation. All water piping shall be adequately supported in accordance with Secction 314.0. Burred ends shall be reamed to the full bore of the pipe or tube. Changes in direction shall be made by the appropirate use of fittings, except that changes in direction in copper tubing may be made with bends, provided that such bends are made with bending equipment that does not deform or create a loss in the cross-sectional area of the tubing. Changes in direction are allowed with flexible pipe and tubing without fittings in accordance witht he manufacturer's installation instructions. Provisions shall be made for expansion in hot-water piping. All piping, equipment, appurtenances, and devices shall be installed in a workmanlike manner in conformity with the provisions and intent of the code. All water service yard piping shall be at least twelve (12) inches (305 mm) below the average local frost depth. The minimum cover shall be twelve (12) inches (305 mm) below finish grade.

So, again, No on the corregated copper in the TPRV discharge, especially in California, despite what Vern Heiler has said, and sarcastically pontificated.

As I understand the recent ammendments incorporating PEX for distribution piping, it does NOT change the requirements for this application (relief valve discharge drain) or section (despite PEX's high emergency temperature rating) for numerous reasons including its prohibition of being exposed to UV and exposed outdoors and the CPC's requirement that:

Originally Posted by 2007 California Plumbing Code

- 604.13.2 Water Heater Connections. PEX-AL, PEX or PE-AL-PE tubing shall not be installed within the first eighteen (18) inches of piping connected to a water heater.

P.S. I also don't see any strapping on that upper 1/3rd of the vessle.