Protection from freezing for condensate traps

[Sifu]

Maybe I have been over-stepping. I have always required some method to protect condensate traps from freezing, and have never been challenged until now. The mechanical engineer has responded to my request by claiming that IPC 1002.7 does not apply. However, upon a close reading I am not so sure. For an RTU with a trap required by the MFR, if it freezes the trap seal will be lost and the unit may not perform, but is this code if the MFR doesn't require it? I always leaned on the fact that the IMC said that condensate drainage had to comply with the IPC, but I am just now noticing that only applies to "joints and connections" per IMC 307.2.2. Have I been wrong all along or have I just forgotten where I came up with this?

 

[north star]

@ ~ @ ~ @

Sifu, ...IMO Section 307.1 might be the Code Section
that you could apply \ reference [ e.g. - "Liquid combustion
by-products of condensing appliances shall be collected and
discharged to an approved plumbing fixture or disposal area" ].

If the P-Trap is frozen then the condensate cannot be
discharged to the approved plumbing fixture or place of
disposal.......Section 307.2.1 also has the same language "shall".

@ ~ @ ~ @

 

[Sifu]

I also found the section I couldn't remember that pulls in the IPC for the equipment drainage, IMC 301.11.

 

[ICE]

So what about condensate that makes it beyond a trap? If the trap is heated to prevent freezing, is the rest of the plumbing also heated? I am curious about the method employed to heat a condensate trap.

 

[Sifu]

Usually see some sort of heat trace/wrap for RTU's. There are products specifically for condensate disposal. As for what happens afterwards, same as any condensate piped to an approved place of disposal I guess but as long as the trap doesn't freeze it wouldn't negatively affect the equipment.

 

[Genduct]

Maybe I have been over-stepping. I have always required some method to protect condensate traps from freezing, and have never been challenged until now. The mechanical engineer has responded to my request by claiming that IPC 1002.7 does not apply. However, upon a close reading I am not so sure. For an RTU with a trap required by the MFR, if it freezes the trap seal will be lost and the unit may not perform, but is this code if the MFR doesn't require it? I always leaned on the fact that the IMC said that condensate drainage had to comply with the IPC, but I am just now noticing that only applies to "joints and connections" per IMC 307.2.2. Have I been wrong all along or have I just forgotten where I came up with this?

Seems like you are referring to the AC coils Condensate and trap and Not the Acidic Condensate produced by a 90% gas fired, condensing warm air heater / furnace

Without the AC running the trap associated with the AC will be dry and there will be No Water to freeze.
The condensate that results from extracting that extra 10% of heat from the Flue Gas Vapor should be running often enough so it won't get the opportunity to freeze.

So I am a little puzzled by your post

 

[Sifu]

Seems like you are referring to the AC coils Condensate and trap and Not the Acidic Condensate produced by a 90% gas fired, condensing warm air heater / furnace

Without the AC running the trap associated with the AC will be dry and there will be No Water to freeze.
The condensate that results from extracting that extra 10% of heat from the Flue Gas Vapor should be running often enough so it won't get the opportunity to freeze.

So I am a little puzzled by your post

I am concerned that any water, whether actively draining, or left over and then subjected to extreme temperatures will freeze and crack, thereby causing a loss of trap seal resulting in a shut down. But, I am open to more education. Like I said, I always assumed ANY drain pipe was subject to the IPC, and I have never had anybody challenge that. Since I am not prone to enforce beyond the code I now want to make sure I am not out of bounds. This is something that has been enforced by most AHJ's I worked with for many years, but that doesn't mean it is correct.

 

[Genduct]

I am concerned that any water, whether actively draining, or left over and then subjected to extreme temperatures will freeze and crack, thereby causing a loss of trap seal resulting in a shut down. But, I am open to more education. Like I said, I always assumed ANY drain pipe was subject to the IPC, and I have never had anybody challenge that. Since I am not prone to enforce beyond the code I now want to make sure I am not out of bounds. This is something that has been enforced by most AHJ's I worked with for many years, but that doesn't mean it is correct.

I am having trouble thinking how the small amount of condensate from the AC Cycle would still be present when it got cold enough to freeze. Warm air from the heat cycle should be "Leaking through the typical 3/4 inch trap while it is providing heat to the space
In the case of the condensate from the condensing gas fired equipment flue gas vapor, it is warm and should escape before it freezes

So in this case, I don't see applying DWV rules to this Mechanical equipment

 

[amarshall]

I think I am with Genduct on this one, I don't think it is a big risk of happening. I live in Illinois and see very cold weather and can't say I seen that as an issue. Walk in freezers typically have that issue but they are going through a defrost cycle which produces a lot of water from melting ice. Or if they have a high efficiency furnace or other equipment draining to the outside that could freeze but if it is just AC i would leave it alone.

 

[Sifu]

Where I am we often see swings in temperature of 40 or 50° or more in a day, with lots of solar load on the building perimeter. So during the day cooling runs, then the sun goes down and overnight temps drop to 15°. In some cases there are internal areas of buildings that are predominately cooling only. Understand that I am not married to the enforcement of these codes, just want to make sure they don't need to be applied given these conditions. I will happily eliminate this idea from my memory banks if I can. The applicant is stating there will be no condensate in the trap during cold weather, so I will just move on. If they are wrong then they will get the phone calls.

 

[klarenbeek]

We have some pretty extreme temperature swings here too, with stretches where we don't get above zero degrees. You'd think busted traps on RTU's would be more of an issue, but while it does occasionally happen it's not a common problem here.

 

[Sifu]

From IMC 301.11:
301.11 Plumbing connections. Potable water supply and
building drainage system connections to equipment and
appliances regulated by this code shall be in accordance with
the International Plumbing Code.

So have I been reading too much into a condensate trap on a roof, and counting it as a "building drainage system" when it is not a building drainage system?

This from the commentary to that section:
This section also triggers the IPC for the drainage associated with
mechanical appliances and equipment, such as those
addressed in Section 307. (307 is the code section on condensate disposal)

FWIW there are lots of stories on the google about frozen condensate lines, how to thaw them and how to prevent them, so I'm not sure it is as rare as some might think, but the question is does code address it.

 

[Genduct]

I think I am with Genduct on this one, I don't think it is a big risk of happening. I live in Illinois and see very cold weather and can't say I seen that as an issue. Walk in freezers typically have that issue but they are going through a defrost cycle which produces a lot of water from melting ice. Or if they have a high efficiency furnace or other equipment draining to the outside that could freeze but if it is just AC i would leave it alone.

Good Point about the walk-in freezers! I didn't think about that application.
That's the value in using the Ad Hoc committee Process

 

[Genduct]

From IMC 301.11:
301.11 Plumbing connections. Potable water supply and
building drainage system connections to equipment and
appliances regulated by this code shall be in accordance with
the International Plumbing Code.

So have I been reading too much into a condensate trap on a roof, and counting it as a "building drainage system" when it is not a building drainage system?

This from the commentary to that section:
This section also triggers the IPC for the drainage associated with
mechanical appliances and equipment, such as those
addressed in Section 307. (307 is the code section on condensate disposal)

FWIW there are lots of stories on the google about frozen condensate lines, how to thaw them and how to prevent them, so I'm not sure it is as rare as some might think, but the question is does code address it.

You said:
So have I been reading too much into a condensate trap on a roof, and counting it as a "building drainage system" when it is not a building drainage system?

I believe you'll find it is an INDIRECT DRAIN that has an air gap so that it doesn't, technically, connect with the sanitary drain so, like the sink that preps the food in a commercial kitchen, we don't get "Bugs" in the AC or Food

In the HVAC world, we had a question about the jurisdictional problem of an NJ HVAC guy installing a condensate drain and NOT being a licensed Plumber. So it was resolved partly because of the Indirect thing. It should have been addressed just on the common sense aspect, but that would have been expecting too much I suppose

 

[Genduct]

We have some pretty extreme temperature swings here too, with stretches where we don't get above zero degrees. You'd think busted traps on RTU's would be more of an issue, but while it does occasionally happen it's not a common problem here.

DON'T YOU GUYS HAVE PERMA-FROST IN SD?
YOU KNOW, THE GROUND NEVER THAWS?
OR IS THAT JUST IN ND?

 

[klarenbeek]

DON'T YOU GUYS HAVE PERMA-FROST IN SD?
YOU KNOW, THE GROUND NEVER THAWS?
OR IS THAT JUST IN ND?

The land of extremes....
100+ in the summer with 80% humidity, -20 in the winter, sometimes plus that lovely thing called wind chill. Then in April and October we can have 80s one day and a dusting of snow the next. We just don't get quite as cold as ND. No hurricanes though!

 

[Genduct]

The land of extremes....
100+ in the summer with 80% humidity, -20 in the winter, sometimes plus that lovely thing called wind chill. Then in April and October we can have 80s one day and a dusting of snow the next. We just don't get quite as cold as ND. No hurricanes though!

When in Basic Training , had a good buddy from Devil's Lake ND, and heard all about living 2 miles from the Arctic Circle
From what I understand, you might have some Climate extremes, but our extremes in Philly are Political. You Guys' ( a Philly term) seem to have a solid, feet on the ground POV that I would like to see us Copy.

One of these days, am going to have to drive across the country and see for myself.

Thanks for taking the bait, I enjoyed your response.

Best, Mike