Thread: Neighbors new loud horizontal furnace vent

Hello everyone, this is my first post here at inspection news.

My neighbor just installed a new high efficiency furnace at it has a pvc exhaust pipe sticking ou the side of his house. this pipe is pointing right at my back door its about 10' away. its very loud when the furnace kicks on.

kind of like a high pitch whining noise. if i have any windows open its super loud and takes over. also, in the winter steam is blowing directly on my car. the pipe is only 2' away from my driveway.

is there any way to quiet this down? muffler device? noise cancellation? up turn the pipe and run it out the top floor? anything at this point would help..

Thanks, Jeff Check

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Where is the property line from his house? About mid-way to your house (which would be about 5 feet)?

We don't have those types of high efficiency furnaces as such in our area so I have no clue of the noise you mention.

If I was you, I would place a speaker in one of your windows and play some of that rap crap when it comes on to drown it out.

rick

Originally Posted by fritzkelly

I would keep the windows closed in the winter but that's just me. I know they make mufflers for the Lennox pulse and probably some others. I would ask them the manufacturer and contact them. You would need something that the manufacturer says is OK. Elbowing it upward might help. Get a loud siren pointed at their house and run it whenever their furnace comes on. Trade ditching the siren for them installing a muffler.

Fritzkelly, its June 3rd and it got really cool for this time of year so it kicked on just yesterday. I live in Michigan. Good to know about the mufflers. Guys who installed it looked like they knew what they were doing although it was not code - the intake and exhaust are directly next to each other and exhaust less than 3' from my property line.

i have so much un-code stuff in my basement like a full heat treat furnace i can not even go down that path with him (but my stuff would be to code if mini PID ovens were allowed).

Originally Posted by Rick Hurst

We don't have those types of high efficiency furnaces as such in our area so I have no clue of the noise you mention.

If I was you, I would place a speaker in one of your windows and play some of that rap crap when it comes on to drown it out.

rick

If it comes down to that i'll just hang a mic out there pipe that to my computer, generate a cancellation frequency band and then have same program control the volume and tone of the amp. its actually all off the shelf noise cancellation. But that would be pr*ck like and i think he didn't plan on this happening. Younger dood pretty cool neighbor.

Jeff,

What I'm thinking about are those old large satellite dishes, the 5 foot diameter ones - you can probably find an old one cheap, mount it right at your property line facing the neighbor so the center is aimed at that pipe. That should do a pretty good job of reflecting all that noise, odor, etc., back their way.

Originally Posted by Jerry Peck

Jeff,

What I'm thinking about are those old large satellite dishes, the 5 foot diameter ones - you can probably find an old one cheap, mount it right at your property line facing the neighbor so the center is aimed at that pipe. That should do a pretty good job of reflecting all that noise, odor, etc., back their way.

In an ideal situation.. yes.

Coming up with an elaborate cancellation method would be a fun challenge. Don't contractors let people know these furnaces have loud vent fans? sounds like a hair drier on half speed.

Originally Posted by jeff check

In an ideal situation.. yes.

Coming up with an elaborate cancellation method would be a fun challenge. Don't contractors let people know these furnaces have loud vent fans? sounds like a hair drier on half speed.

It is most likely a Pulse furnace, not fan noise.

Good morning, Jeff:

You aren’t the first to complain about these units. I have seen these terminate less than four feet from an adjoining neighbor’s deck! (Why someone would ever want to live that close to anyone is a mystery to me….)

In any event, unless you work closely with your neighbor, you are not likely to reach a satisfactory solution. And you will likely foot the bill. We point out that although the exhaust locations may meet code, they are not consistent with good Industrial Hygiene practices and procedures, and may contribute to harmful exposures to combustin emissions. The exhaust gases are reentering his home and your home.

According to the ASHRAE (1) ventilation standard, the minimum separation distance for an air intake (including your doors and windows) from combustion appliances (2) is 15 feet and the minimum separation from noxious exhausts is 30 feet. The interpretation of the distinction between whether the exhaust meets the definition of “noxious� remains an open question until the exhaust gases are characterized. However, our general application is that exhaust gases do meet the ASHRAE definition of noxious since exhaust gases are an “…exhaust air with highly objectionable fumes or gases and/or exhaust air with potentially dangerous particles, bioaerosols, or gases at concentrations high enough to be considered harmful.� We can usually demonstrate potential harm even with “high efficiency� furnaces. As such, the minimum separation should be 30 feet, or all reasonable attempts to puncture the building envelop. At the moment, the exhaust gases are being dumped into the his building envelop and yours. (“Building envelope� as used here is different than the way Home Inspectors will use the term).

I recommend the terminal for the exhaust be extended to the above the roof line.

Good luck.

Cheers!
CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Industrial Hygiene

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG


1) American Society of Heating Refrigeration and Air-conditioning Engineers And the American National Standards Institute, Ventilation for Acceptable Indoor Air Quality - ANSI/ASHRAE Standard 62.1-2007 (Includes ANSI/ASHRAE Addenda)

2) ASHRAE Table 5-1

Originally Posted by Caoimhín P. Connell

Good morning, Jeff:

You aren’t the first to complain about these units. I have seen these terminate less than four feet from an adjoining neighbor’s deck! (Why someone would ever want to live that close to anyone is a mystery to me….)

In any event, unless you work closely with your neighbor, you are not likely to reach a satisfactory solution. And you will likely foot the bill. We point out that although the exhaust locations may meet code, they are not consistent with good Industrial Hygiene practices and procedures, and may contribute to harmful exposures to combustin emissions. The exhaust gases are reentering his home and your home.

According to the ASHRAE (1) ventilation standard, the minimum separation distance for an air intake (including your doors and windows) from combustion appliances (2) is 15 feet and the minimum separation from noxious exhausts is 30 feet. The interpretation of the distinction between whether the exhaust meets the definition of “noxious” remains an open question until the exhaust gases are characterized. However, our general application is that exhaust gases do meet the ASHRAE definition of noxious since exhaust gases are an “…exhaust air with highly objectionable fumes or gases and/or exhaust air with potentially dangerous particles, bioaerosols, or gases at concentrations high enough to be considered harmful.” We can usually demonstrate potential harm even with “high efficiency” furnaces. As such, the minimum separation should be 30 feet, or all reasonable attempts to puncture the building envelop. At the moment, the exhaust gases are being dumped into the his building envelop and yours. (“Building envelope” as used here is different than the way Home Inspectors will use the term).

I recommend the terminal for the exhaust be extended to the above the roof line.

Good luck.

Cheers!
Caoimhín P. Connell
Forensic Industrial Hygienist
Forensic Industrial Hygiene

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG


1) American Society of Heating Refrigeration and Air-conditioning Engineers And the American National Standards Institute, Ventilation for Acceptable Indoor Air Quality - ANSI/ASHRAE Standard 62.1-2007 (Includes ANSI/ASHRAE Addenda)

2) ASHRAE Table 5-1

Thanks a bunch Caoimhín, this is one of those neighbor moments for sure. At frist i only worried about noise pollution but now i'm also worried about acidic exhaust air full of NOx and other pollutants. So noise cancellation alone wont do! thanks for your tips - i will follow that up for sure.

Living in Dearborn, my home is about 12-13' away from my neighbor, just enough for a driveway and walkway. With the Auto economy crushing my town i am very happy he is a good neighbor in general so i will be careful how i handle this one. thanks again, Jeff

I would just talk to the neighbor and explain and show them how loud it is. If that does not work, I would then contact the city. I would bet that it is above the permitted decibel level that is allowed in your area, if it is like you are saying.

I would also bet that an elbow could be placed on the pipe. With it pointing to the ground it should really reduce the sound.

Originally Posted by Scott Patterson

I would just talk to the neighbor and explain and show them how loud it is. If that does not work, I would then contact the city. I would bet that it is above the permitted decibel level that is allowed in your area, if it is like you are saying.

I would also bet that an elbow could be placed on the pipe. With it pointing to the ground it should really reduce the sound.

Scott, i will talk with him next time he's out in the yard. Issue with the down elbow is the steam and exhaust will still blanket my driveway even if the db is reduced.

Originally Posted by jeff check

Scott, i will talk with him next time he's out in the yard. Issue with the down elbow is the steam and exhaust will still blanket my driveway even if the db is reduced.

All of the high E systems I have seen really do not produce all that much exhaust. The flue gas is so cool by the time it leaves the heat exchangers that is it more condensation than anything. This is the reason that PVC pipe can be used. I really doubt that it would be that much steam coming out of the pipe and if it is it should rise fairly quickly in the cold air.

Good morning, Jeff and Scott:

We have not fully characterized the exhausts, and so we rely on the language of the ASHRAE standard whose level of care is “potentially dangerous” and also includes particles.

I have measured the exhausts for CO and also for nanopaticles and have found the exhaust of brand new furnaces to be less than 500 particles per cubic centimeter of exhaust (0.5Kp/cm3) – which is not currently thought to be of concern. Our concern lies with our experience with other “high efficiency” units that have produced excessive levels of CO and particles. In April of this year, for example, we measured 227 Kp/cm3 (which is extremely elevated), coming from a “high efficiency” gas-fired fireplace that similarly exhausted at the side of the structure (and whose exhaust gases were immediately reintrained into the residence).

We have also seen “high efficiency” standalone gas fired space heaters, designed for operation at sea level put out excessive amounts of CO when installed and operated at my altitude (where houses can be at 12,000 feet). We have not seen any data on NOx or SOx associated with the exhausts.

The units do not always operate “as designed” and the operations can, in our experience, vary with potentially serious consequences. For example the fireplace mentioned above was almost certainly the cause for exacerbated respiratory problems experienced by two of the three occupants in the home (one of whom was an otherwise very healthy pilot).

We agree that the “high efficiency” furnaces seem to have a good track record, however, given the potential for serious adverse health consequences, and the fact that the units are apparently NEVER evaluated in situ, and the fact that we are not bound to comply with building codes (or ASHRAE or ANSI for that matter), it remains our policy to recommend the highest standard of care and recommend that the exhausts are terminated above the roof line.

Finally, on the exhaust issue, pursuant to the ASHRAE standard, (Section 5.3 Exhaust Duct Locations), any exhaust duct conveying potentially harmful contaminants (such as furnace exhausts), are required to be under negative pressure throughout their length where they pass through a structure. In the case of the HE furnaces, the furnace exhaust duct is actually under positive pressure through the length of the exhaust.

All of this just gives me pause for thought and seems to be a potential for a deadly mix of contributors that could conspire to result in a tragic end. I am fortunate that I am permitted to go beyond codes and standards in my work.

Lastly, we have done a considerable amount of work in sound and noise measurement and monitoring, so, if you would like to pursue that issue please let me know.

Cheers!
Caoimhín P. Connell
Forensic Industrial Hygienist
Forensic Industrial Hygiene

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

The 2008 Addenda for 62.1 recognizes the vent separations in the building codes. The 15 foot separation from a vent is nice but not real world as this would outlaw about 60% of all installations while the 30 foot separation would outlaw about 99%. If the home is constructed properly with a neutral balance WRT outdoors, you won't have significant infiltration of products of combustion into the home.

The scientific community needs to do a better job of correlating measured indoor levels of pollution with actual exhaust gases and the physics of each structure and the mechanisms of infiltration such as depressurization and patheways for entrainment and the effects of local weather. Until then, we ARE bound to abide by the codes because they are LAW.

I would be interested to know what is the etiology of the indoor particulates you sampled and what levels of pm2.5 you are measuring off a gas furnace.

Section 5.3 deals with ducts--not vents so it does not apply to high eff. furnace venting directly. The point there is, if you have harmful 'stuff' to exhaust, it is safer and desireable to suck it out of the structure under negative pressure. That way, any leaks work in your favor instead of spilling into the structure. Now, I understand your point about high eff. furnace venting and it is very valid. The codes and listings are virtually silent on the type of material approved for this application and there is no testing for the patency of the venting or performance testing for spillage of combustion products or adequate exhaust flow. I am working on making changes in the IRC to effect these changes.

When high eff. furnaces are vented through long, cold runs, you can get significant condensation problems. Among these include condensate forming ice plugs blocking the vent in horizontal runs, iced terminations, and simply too much total restriction.
Bob

Hello Bob –

Thanks for the comments.

“If the home is constructed properly with a neutral balance WRT outdoors, you won't have significant infiltration of products of combustion into the home.�

As you know, when any building is constructed, pressure differentials between the interior and exterior of the building are inadvertently created. The phenomenon becomes more pronounced when there is a significant difference between indoor and outdoor temperatures, or when a breeze is blowing against the building. This pressure differential, (dP), is mostly due to the "Stack Effect." A building can mimic an exhaust stack, and is under negative pressure with regard to the surrounding environment (See figure here). Typically, the dP produced by the stack effect is greater toward the bottom portion of the building and is equalized near the top of the building at a point called the "plane of neutral pressure." Above the plane of neutral pressure, the pressure in the structure is reversed, and air is moving out of the building shell. The effect is exaggerated by “negative pressure inducers� such as bathroom fans, clothes dryers, kitchen hood, furnaces, hot water heaters and other appliances which are exhausting air from the structure. The stack effect can be balanced by maintaining the building under a slight positive pressure, but virtually no home is so built – and the presence of a stack effect does not imply that the structure is improperly built.

Therefore, homes that are “constructed properly� will still primarily be under negative pressure WRT outside. Presence of the stack effect does not indicate faulty design or construction; virtually every structure would exhibit a stack effect under passive ventilation conditions.

As these pressure differentials are established, (especially via the stack effect), the building can be under negative pressure with the surrounding soils and air, and if contaminants are in those media, they may enter the building along pressure gradients.

To satisfy the negative pressure induced in a building by the stack effect, the net air movement toward the bottom of the building is generally from the outside of the building to the inside of the building. The "naturally occurring" make-up air is in the form of infiltration which is being pulled into the building at all locations below the plane of neutral pressure. Due to this effect, very complex pressure differentials are established in each building in a manner which is unique to that building, and difficult to predict. The negative pressure in a structure is important in the context of the “building envelope� which surrounds the structure and how waste gases from a building are exhausted from the building into the building envelope.

So, when we see exhausts from these HE furnaces (see here), or gas-fired fire places (see here), as an Industrial Hygienist, I naturally become concerned.

"The scientific community needs to do a better job of correlating measured indoor levels of pollution with actual exhaust gases and the physics of each structure and the mechanisms of infiltration such as depressurization and pathways for entrainment and the effects of local weather. Until then, we ARE bound to abide by the codes because they are LAW.

Of course, and your point is well taken. Unfortunately, the gumshoes out in the field, like you and me, actually doing the work, don’t have the funds to investigate these issues as fully as we would like. For example, I’m working on an indoor pesticide exposure issue today as a result of the application of pesticides around the exterior of the house - my ENTIRE budget is $1,800 including analysis. What kind of an investigation can I do for that kind of money?

I would be interested to know what is the etiology of the indoor particulates you sampled and what levels of pm2.5 you are measuring off a gas furnace.

During our assessment of both of the residences I mentioned in my post, we measured ultrafine particles (UFPs) using a nephelometer manufactured by TSI (Model P-Trak™). Although UFPs are generally considered to be particles less than 0.2 µm aerodynamic diameter, the instrument we used is capable of measuring particles in the range of 0.02 µm to slightly larger than 1.0 µm aerodynamic diameter. Therefore, the predominant faction of PM 2.5s are massive flying bricks compared to what we are typically looking at. The UFPs are (probably) almost exclusively coalesced reduced carbon (but I don’t really know). Some years ago, I did submit some samples for SEM/EDX and TEM and we mostly found reduced carbon – however, maybe the HE furnaces are different? I just don’t know.

Section 5.3 deals with ducts--not vents so it does not apply to high eff. furnace venting directly.

Sorry – I don't believe you are correct. 5.3 states: “Exhaust ducts that convey potentially harmful contaminants shall be negatively pressurized relative to spaces through which they pass, so that exhaust air cannot leak into occupied spaces; supply return or outdoor air ducts or plenums.� And as I point out in my original post, the ducts I see associated with the HE furnaces are under positive pressure – and I have never seen one that isn’t. Perhaps your experiences in your part of the country are different.

I am working on making changes in the IRC to effect these changes.

Thanks for your efforts. I’m on the ASTM side of things, and it is a burden and huge expenditure of resources, that frankly, I would rather spend elsewhere (on me for example!).

CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Industrial Hygiene

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

OK, I got lost right after Good morning!

"properly constructed" in my book includes proper HVACR. Without mechanical ventilation, you have a HACR ('hacker' ;-) Passive MUA does not work as demonstrated in an ASHRAE study back in 2000. If you use mechanical ventilation drawing in air from a relatively fresh location, you can maintain relatively neutral balance (if you know what you're doing and don't pressurize the structure driving water vapor into interstitial spaces). The other trick is to identify sources of outdoor pollution and do two things to mitigate this potential problem: provide a reasonably weatherized building shell around the pollution and two, provide a better path of least resistance away from the pollution located in fresh air. Yeah, I know, hold your breath...

You're preaching to the choir on the house physics as I am with you.

Stack effect is negligible if not non-existent often in summer as the natural draft can reverse while in cooling mode. In winter, it's not uncommon to measure -5 Pascals WRT of stack effect alone. Add to that negative pressure gradients from leaky ducts and uncompensated mechanical exhausts and yes, the depressurization can be amazing. I've measured a 27 Pascal gradient btw front door to back door with a 20 mph wind blowing. I've measured -68 Pa just from a leaky return duct. Real killers.

The language they use for "ducts" as I understand it refers to exhausts such as clothes dryers, bathroom fans, etc.--not combustion vents, which are clearly addressed elsewhere in 5.1 . You are correct high eff. furnaces vent under Cat IV positive vent pressure. That's the problem. The codes are all worried about using test balls on the DWV pipes but totally miss a combustion vent, which unlike the DWV, is under pos. pressure. Unreal. No combustion analysis required either. That's partly due to ASHRAE's battle with the NAHB and ICC over performance stds. and depressurization testing. The Canadians are close to finalizing their version. I'll post a link when it's done. A friend of mine sits on the cmte.

Have you ever seen some PLM slides on these particulates? I know the SEM gives you an elemental analysis but I was also interested in what might be considered soot clusters from short chain aliphatic hydrocarbons in the sub micron range. I know you can get them in the 0.2 to as heavy as 10.0 micron range with a lot of combustion equipment but haven't seen the ultrfine particulates as a component of Black Particulate Matter soiling cases.

Yeah, I know what you mean about resources. I have no budget and my industry's current focus is strictly on the current tax credits, emissions, Green Building, LEEDS, and energy eff. Still, there may be some other avenues. I was speaking with Hal Gil at EPA two months ago and he is interested. Could be some huge grant money out there. HUGE.

Anyway, I always enjoy your posts here Caoimhin.
Warmest regards,
Bob

Originally Posted by Bob Harper

That's the problem. The codes are all worried about using test balls on the DWV pipes but totally miss a combustion vent, which unlike the DWV, is under pos. pressure. Unreal. No combustion analysis required either.

Man did you nail this one Bob.

There are still too many assumptions taken as truths, till that changes the assumptions will continue.

Originally Posted by Scott Patterson

All of the high E systems I have seen really do not produce all that much exhaust. The flue gas is so cool by the time it leaves the heat exchangers that is it more condensation than anything. This is the reason that PVC pipe can be used. I really doubt that it would be that much steam coming out of the pipe and if it is it should rise fairly quickly in the cold air.

"It Depends" (phrase they teach you at all BPI Classes).

Regarding efficiency, does your car always get rated mileage? Towing a trailer? Just because it's HI EFFICIENCY doesn't mean it's operating that way. Over sized? Under sized duct work? Combustion properly set (Unlikely, until serviced by quality tech - installers are so pressed for time they fire and fly). Even then there is all kinds of nastyness in the combustion gases.

And NYSERDA/BPI Requires combustion gas test on all combustion appliances, new and existing.

A t/wye at the end of the pipe allows condensate to drip out but deflects noise. They are allowed on roof installs, so a sidewall should not be a problem either.