Size & material for drain pipe from pan under water heater

[Matthew Hardy]

I am working on a longer post with several items related to a install of a new AO Smith water heater, but hoping for a quick answer to a short question.

Our previous water heater had a 1" copper pipe from the T&P valve and a 1" copper pipe from the drain pan that tied together to a 1" copper pipe that drained to the outside. I live in Southern California and am almost positive that tying the two together is a no go especially since the pipe diameter is the same size as the two incoming pipes. We cannot discharge the T&P valve into the pan.

I have a 30" pan under the water heater that has a 1" PVC coupling for the drain pipe. I have always used copper for the drain pipe from the pan, but am wondering if 1) PVC is acceptable and 2) what the minimum pipe size allowed is.

I seem to remember 3/4" pipe being acceptable; however, I am wondering if the fact that the pan has a 1" outlet will require to maintain that size similar to not being able to downsize the T&P discharge pipe. Am planning on using an adapter to join a copper pipe for the discharge, but also wondering if PVC is 1) allowed and 2) viable since the water would be cooled once it sits in the pan.

Options are:

1) 1" PVC drain pipe
2) use a 3/4" reducing coupling to a 3/4" PVC drain pipe
3) using an adapter to connect a 1" copper pipe
4) using an adapter to connect a 3/4" copper pipe

Any help / recommendations are appreciated.

 

[MACPLUMB]

Yes 1" PVC is allowed do "NOT" Reduce the size this is supposed to carry run off from your heater leaking which can be a lot of water !

 

[Sponsor]

 

[Ladiesman217]

I am working on a longer post with several items related to a install of a new AO Smith water heater, but hoping for a quick answer to a short question.

Our previous water heater had a 1" copper pipe from the T&P valve and a 1" copper pipe from the drain pan that tied together to a 1" copper pipe that drained to the outside. I live in Southern California and am almost positive that tying the two together is a no go especially since the pipe diameter is the same size as the two incoming pipes. We cannot discharge the T&P valve into the pan.

I have a 30" pan under the water heater that has a 1" PVC coupling for the drain pipe. I have always used copper for the drain pipe from the pan, but am wondering if 1) PVC is acceptable and 2) what the minimum pipe size allowed is.

I seem to remember 3/4" pipe being acceptable; however, I am wondering if the fact that the pan has a 1" outlet will require to maintain that size similar to not being able to downsize the T&P discharge pipe. Am planning on using an adapter to join a copper pipe for the discharge, but also wondering if PVC is 1) allowed and 2) viable since the water would be cooled once it sits in the pan.

Options are:

1) 1" PVC drain pipe
2) use a 3/4" reducing coupling to a 3/4" PVC drain pipe
3) using an adapter to connect a 1" copper pipe
4) using an adapter to connect a 3/4" copper pipe

Any help / recommendations are appreciated.

Are you over thinking this?

How did your house pass inspection if it did not pass code at the time the house was built?

I don't have a water heater pan nor any floor drain of any kind.

 

[Dj2]

In my city "only metal pipe" - copper or other - is acceptable for T&P valve discharge pipe.

You live in CA, check with your building department.

 

[Matthew Hardy]

Are you over thinking this?

How did your house pass inspection if it did not pass code at the time the house was built?

I don't have a water heater pan nor any floor drain of any kind.

Our inspector did a terrible job on this house. He missed many things overall including a number of things with the water heater. Our water heater is on a platform in our garage (along with two furnace units). We are required to drain both the T&P valve and the drain pan outside so the previous water heater had the T&P valve drain pipe and the pan drain pipe connected before they exit the garage. Both bids I got on the water heater installation flagged this so I am separating the lines and punching a hole in the wall for the second pipe.

To be clear - I have already piped the drain pipe for the T&P valve and it is a 3/4" copper pipe as the unit has a 3/4" T&P valve. The only reason I ask about PVC is because all of the drain pans have PVC adapters in the holes where the water exits. I am wondering if those are PVC that the rest of the pipe might be able to be PVC also, but have never seen that hence the question.

 

[Ladiesman217]

Does this drawing conform to code in California? The T&P Valve drain discharges per IRC UPC.





Read the last post on this thread. Specifically the quote "but I was recently asked why so many discharge pipes are seen inside."


"Quote:
Originally Posted by jpope
UPC 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 piping and fittings, CPVC, or listed relief valve drain tube with fittings which 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. No part of such drain pipe shall be trapped or subject to freezing. The terminal end of the drain pipe shall not be threaded.
Not to dig up an old thread, but I see this is indeed the code for California,

but I was recently asked why so many discharge pipes are seen inside.

So looking up Los Angeles plan checks, last updated 2014,
http://ladbs.org/docs/default-source...rr106-2014.pdf

Quote:
Pressure relief valves for water
heaters installed inside a building shall discharge
to a floor drain, floor sink or similar fixture
So apparently the city either didn't adopt the code, or never changed their verbiage.


https://www.nachi.org/forum/f22/cod...ndex3.html?s=5691d62acb8957e2f8582cebaf6bd2e9

"Quote:
Originally Posted by jpope
UPC 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 piping and fittings, CPVC, or listed relief valve drain tube with fittings which 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. No part of such drain pipe shall be trapped or subject to freezing. The terminal end of the drain pipe shall not be threaded.

Not to dig up an old thread, but I see this is indeed the code for California,

but I was recently asked why so many discharge pipes are seen inside.

So looking up Los Angeles plan checks, last updated 2014,
http://ladbs.org/docs/default-source...rr106-2014.pdf

Quote:
Pressure relief valves for water
heaters installed inside a building shall discharge
to a floor drain, floor sink or similar fixture

So apparently the city either didn't adopt the code, or never changed their verbiage. "

 

[Ladiesman217]

Quote from home inspection article.

"When a water heater is installed in a garage, attached storage room or similar location, simply extending the discharge pipe toward the floor is a common practice. So long as any discharged water will not cause structural damage, this is generally the preferred method of directing it to a safe location. The pipe should not terminate more than 6 inches above the floor because of splash concerns or closer than two pipe diameters to the floor, a potential cross-connection issue. A pipe too close to the floor could end up submerged and could siphon dirty water into the tank."

http://www.ashireporter.org/HomeInspection/Articles/The-Temperature-Pressure-Relief-Valve/1568

 

[Cool Blue Harley]

California is currently using the 2016 UPC with California amendments.

 

[Dj2]

"I allow PVC because the California Plumbing Code has change in the last cycle. Current code states that the
discharge pipe must be rated to handle the water temperature. 2013 code cycle specifically said galvanized steel, CPVC, copper, PP, or listed drain tube so that part of the code has changed."

Good to know the code change. Is it in LA as well?

 

[Ladiesman217]

Disregard the above home inspection article as crap.

California is currently using the 2016 UPC with California amendments.

I allow a 3/4 inch pipe off the Smitty pan drain adapter because the inside of the adapter is designed for a 3/4" PVC glue joint. One inch pipe is better.

I allow PVC because the California Plumbing Code has change in the last cycle. Current code states that the
discharge pipe must be rated to handle the water temperature. 2013 code cycle specifically said galvanized steel, CPVC, copper, PP, or listed drain tube so that part of the code has changed.

I allow combining the discharge of the pan drain and TPR on the vertical, the thought being that if the pressure relief valve trips, I don't want scalding water blasting back into the pan.

I allow the piping to go to the floor if there is a floor drain capable of handling it and the floor is sloped. Termination is 6" minimum, 24" maximum. I am not worried about cross connection.

If an inspector wants to be a dick and go out there and crack heads, nothing would pass. There are plenty of them. The best inspectors used to be plumbers. Preferably good plumbers.

The code is a minimum standard which is easy to meet. Keep it safe and focus on the important parts.

I noticed that you continuously use the term "I allow". Just wondering what gives you the authority to use that term?

What is wrong with simply terminating the T&P valve about 6" above the finished garage floor when the water heater is located in the garage with no drain? After all, a vehicle is not always dry when it is put in the garage.

In my area, water heaters are typically located in basements. No floor drains. Exterior terminations are in a freeze area. A water heater pan is not piped anywhere. A water heater leak in a basement will not cause "structural" damage, so I assume that is why it is allowed.

 

[hj]

Damage to the structure OR surrounding area, which could be items stored on the floor. PVC is all that is required for the pan drain line because it is NOT under any pressure.

 

[Ladiesman217]

Damage to the structure OR surrounding area, which could be items stored on the floor. PVC is all that is required for the pan drain line because it is NOT under any pressure.

I doubt that interpretation is accurate. Parking a vehicle in a garage after driving in rain, sleet or snow will get those same items wet. Moisture from flooring cement will also damage those items.


The following interpretation applies in MA.


http://www.mass.gov/ocabr/licensee/...es/product-policies/water-heater-storage.html


Regarding Safe Waste Pans for Water Heaters & Storage Tanks

In 248 CMR section 10.12 (1) (h) Safe Waste Required, it states:

Safe Waste Required.

1. A safe waste pan shall be installed under water heaters or hot water storage tanks that are six (6) gallons in capacity or larger and are installed in a position elevated above any occupied space.

2. The safe waste pan shall be installed under water heaters and hot water storage tanks where there is occupancy below and shall be piped indirectly to a properly trapped and vented fixture.

When installing a replacement water heater or hot water storage tank that is in a position elevated above any occupied space, it may not be practical to install a safe waste pan.

Policy:

When installing a replacement water heater or hot water storage tank and it is not practical to install a safe waste pan and related safe waste drain piping, an acceptable alternate method to satisfy the requirements of 248 CMR 10.12 (1) (h) may be to install a product approved automatic water heater shut off device and a safe waste pan without the related drain piping.

If this method is used, the water heater temperature and pressure relief valve shall discharge into the water heater safe waste pan.