Thread: Plumbing vent too close to bath exhaust vent

Plumbing vent too close to bath exhaust vent; is this okay; I think not. BTW; it is 12 inches from side wall and window is fixed (non-openable). Just need a 2nd opinion. Thanks

From the 2010 FBC-Residential
- P3103.5 Location of vent terminal.
- - An open vent terminal from a drainage system shall not be located less than 4 feet (1219 mm) directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building, nor shall any such vent terminal be within 10 feet (3048 mm) horizontally of such an opening unless it is at least 2 feet (610 mm) above the top of such opening.

Now for a question: Have you ever been in a bathroom and noticed air *coming in* from bathroom exhaust fan vents? (Your answer is likely something to the effect of "Sure, all the time.")

If so, this part applies:
- "or other air intake opening of the building or of an adjacent building, nor shall any such vent terminal be within 10 feet (3048 mm) horizontally of such an opening unless it is at least 2 feet (610 mm) above the top of such opening"

Originally Posted by Jerry Peck

From the 2010 FBC-Residential
- P3103.5 Location of vent terminal.
- - An open vent terminal from a drainage system shall not be located less than 4 feet (1219 mm) directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building, nor shall any such vent terminal be within 10 feet (3048 mm) horizontally of such an opening unless it is at least 2 feet (610 mm) above the top of such opening.

Now for a question: Have you ever been in a bathroom and noticed air *coming in* from bathroom exhaust fan vents? (Your answer is likely something to the effect of "Sure, all the time.")

If so, this part applies:
- "or other air intake opening of the building or of an adjacent building, nor shall any such vent terminal be within 10 feet (3048 mm) horizontally of such an opening unless it is at least 2 feet (610 mm) above the top of such opening"

Jerry, thanks for the quick reply. I kind of knew the answer but just wanted confirmation.

Originally Posted by Kevin Wood

Although Jerry is right about the reverse air flow possibility with no back draft preventer you cannot apply that rule to the vent and exhaust.

OK I give. Does this mean Jerry doesn't know what he's talking about, or is it I don't understand what your talking about.

Originally Posted by Kevin Wood

Although Jerry is right about the reverse air flow possibility with no back draft preventer you cannot apply that rule to the vent and exhaust.

I 'm not convenced The code appears to Not address the picture as both are exhauasting and should be allowed as the exhaust fan shou;d have a draft closure ?

- - - Updated - - -

Originally Posted by Jerry Peck

From the 2010 FBC-Residential
- P3103.5 Location of vent terminal.
- - An open vent terminal from a drainage system shall not be located less than 4 feet (1219 mm) directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building, nor shall any such vent terminal be within 10 feet (3048 mm) horizontally of such an opening unless it is at least 2 feet (610 mm) above the top of such opening.

Now for a question: Have you ever been in a bathroom and noticed air *coming in* from bathroom exhaust fan vents? (Your answer is likely something to the effect of "Sure, all the time.")

If so, this part applies:
- "or other air intake opening of the building or of an adjacent building, nor shall any such vent terminal be within 10 feet (3048 mm) horizontally of such an opening unless it is at least 2 feet (610 mm) above the top of such opening"

Normally would expect to see a plumbing roof jack
yes?

Originally Posted by Kevin Wood

Although Jerry is right about the reverse air flow possibility with no back draft preventer you cannot apply that rule to the vent and exhaust.

You absolutely can apply that rule as the code states "or other air intake opening", which also includes soffit vents ... and ANY "other air intake opening". If that is a ridge vent at the top of the photo (can't tell from the photo) then the ridge vent is also included as it can serve as an air intake.

If there is an opening and the opening allows for air intake, then that opening is included.

Now, *if* the exhaust fan was a continuously running exhaust fan (which is an option in the code but no one installs them in a dwelling covered by the Residential Code - at least not that I have ever seen) ... a continuously running exhaust fan would no permit the opening to serve as an "intake".

On condos and apartment buildings, it is not uncommon at all to have continuously running roof mounted exhaust fans connected to exhaust duct risers and which are in turn connected to an exhaust grille in each bathroom.

Code doesn't say "any opening" It says "air intake opening". The bathroom exhaust is not an "air intake opening". Neither is a ridge vent. Soffit vents are intake, ridge and roof are exhaust.

Could the bathroom exhaust and / or a ridge vent be working improperly and pulling air into the house, sure...but code does not address "what if" scenarios. That's like saying "what if" the fixed window isn't sealed properly therefore it could allow sewer gas to get in, therefore you can't have a fixed window that close.

Originally Posted by Ken Rowe

Code doesn't say "any opening" It says "air intake opening". The bathroom exhaust is not an "air intake opening". Neither is a ridge vent. Soffit vents are intake, ridge and roof are exhaust.

Could the bathroom exhaust and / or a ridge vent be working improperly and pulling air into the house, sure...but code does not address "what if" scenarios. That's like saying "what if" the fixed window isn't sealed properly therefore it could allow sewer gas to get in, therefore you can't have a fixed window that close.

Ken,

Define an "air intake opening".

Keep in mind that the code does not state that the opening is 'intended to serve as an' "air intake opening".

Sorry Jerry but I'm not going to play this game with you. You're wrong. Nothing more to say.

Originally Posted by Ken Rowe

Sorry Jerry but I'm not going to play this game with you. You're wrong. Nothing more to say.

Nothing more to say ... other than a correction - that you are incorrect.

For someone who calls himself "codeman" its hard to believe you don't know the difference between an intake vent and exhaust vent. Or, how code differentiates the two.

Yup the photo indicates why this set up is a deal blower. Not.
This set up would never have found its way into any report that I would write.

Originally Posted by Ken Rowe

For someone who calls himself "codeman" its hard to believe you don't know the difference between an intake vent and exhaust vent. Or, how code differentiates the two.

For someone who calls himself a home inspector it's hard to believe you don't know and understand the concept of keeping sewer gas out of a home and that an "air intake opening" is any opening which permits air into a building. However, based on past posts you've made, it really isn't hard to believe you don' t grasp the concept of keeping sewer gas out.

Originally Posted by Jerry Peck

For someone who calls himself a home inspector it's hard to believe you don't know and understand the concept of keeping sewer gas out of a home and that an "air intake opening" is any opening which permits air into a building. However, based on past posts you've made, it really isn't hard to believe you don' t grasp the concept of keeping sewer gas out.

A question here: Hey guys, if we are talking about an exhaust fan, shouldn't it have a spring activated damper on it to prevent outside air from coming in when not in operation? If not, then when the power is off, outside air could enter the home....what am I missing here?

Originally Posted by Loren Sanders Sr.

A question here: Hey guys, if we are talking about an exhaust fan, shouldn't it have a spring activated damper on it to prevent outside air from coming in when not in operation? If not, then when the power is off, outside air could enter the home....what am I missing here?

Being spring activated would be nice, instead, though, the little dampers and gravity acting and don't even seal or stop air when closed.

With a slight wind blowing, those little gravity dampers are flapping back and forth (stand under a typical bathroom exhaust fan on a breezy day and you can hear the damper flapping back and forth - and on slightly windy days you can even feel the air coming in.

I first noticed this issue when, on a construction project several new home owners asked me to find out why sand and dirt kept accumulating on their bathroom floors.

After standing in one of the bathrooms and listening to the damper flapping back and forth and not thinking much of it doing so ... without warning a small dust storm blew from the bathroom vent right into my face ... it was just about that same exact instant that the light in my head came on and connected the damper flapping back and forth with air coming in past the damper ...

If the exhaust fan isn't running those roof vents make very good intake openings.

Originally Posted by Kevin Wood

Can you imagine how confused we would be trying to figure out if a "ridge vent" could become an "exhaust vent" and whether we should make sure when we go inspect it is really windy so we can here that flapper going on the "exhaust vent" so we can write in our report.

What do you call the door you go in through to get into the house?

Oh, wait, yeah, that is an "egress door", therefore it must not ever be called an "entry door" ... because its REQUIRED (and intended) purpose is to allow you to "egress" through it ... got it now ... NOT!

Jerry, just because an exhaust vent is malfunctioning doesn't make it an air intake vent. It's a malfunctioning exhaust vent.

Bathroom vents are considered "exhaust vents" in every building code out there. Exhaust vents are not mentioned in the code you've cited. Would it be best to keep the bathroom exhaust away from the waste vent pipe in case of a malfunction? Sure, but it's not required by code.

Ken,

Those bathroom exhaust fans are not "malfunctioning" as they are not designed to "seal tightly".

Egress doors are in every building code too.

ANY opening which permits air intake is mentioned ... "or other" ... the codes do not mention each and every item, codes will state some items and then state "or" or "and" - such as "similar room or area" ... you DO recognize that, don't you?

Jerry,

Code differentiates between air intake vents (mechanical and gravity) and exhaust vents.
Code has separate location requirements for the different types of vents (air intake vs exhaust).
Bathroom exhaust vent are specifically listed by code to be exhaust vents.

Code does not list definitions of common sense terms like intake and exhaust. They expect people to be smart enough to know the difference.

(sigh)

(done with this thread as I am talking to what appears to be a dense object ... such as a brick wall )

Originally Posted by mark petty

Plumbing vent too close to bath exhaust vent; is this okay; I think not. BTW; it is 12 inches from side wall and window is fixed (non-openable). Just need a 2nd opinion. Thanks

Interpretation of specifications is as important as the inspection process itself. The FIRST requirement is that we UNDERSTAND why a code exists. THis code is health code based. In this case to assure that septic (read disease carrying) and possibly combustible gasses do not enter a home and cause illness or worse. (If you dont believe that sewer gasses have combustible components then we have a lot more to talk about before we begin, remember that there are now stoves built to burn those gasses that are regularly use in third world countries).

Now that we have determined the GOAL of the code (to stop septic gasses from EVER entering the building) we can look at what the code states regarding requirements. IF any air is intaking from any kind of vent under any circumstance then the horizontal/vertical separation requirement for a sewer vent riser must be met to assure no infiltration of contaminated (yuk) air exists. Let us also remember that we are not looking at just one instant in time, we are looking at 30 to 50 years of repeated instances of time and the long term build up of contaminants involved (disease carrying contaminants building up on surfaces etc.)

Therefore if there is evidence that the exhaust vent design will allow air intake at all then horizontal/vertical separation MUST be met. The key word being evidence. This can be by known design, by evidence of dust and dirt entery through a specific vent, by testing etc. Even tribal knowledge could possibly apply under many circumstances (personal experience with similar design and circumstance).

All of this being considered, I am in total agreement that unless there is a positive vent closure that secures all entry of ALL air into the vent exists, in fact separation is required by code and for good reason. I have never seen an exhaust flapper that stops all air, period. They always leave some back flow.

No one has even suggested that under the roof shingles there is an overlap of the two flashings involved and in fact the shingles by thier attachment are possibly creating leak points as the shingle do not look as if they could possibly have maintained thier minimum vertical lap requirements. Another issue entirely.

Personally, I would note this installation is suspect at best for roofing reasons and NOTE the possiblity of contaminated air intrusion into the envelope of the home. THis is a health and safety consideration, period.

I wold suggest that the exhaust be moved to a soffit vent. I wouid write this up as a possible area to watch for leaks and suggest that IF leaks are discovered at any later time, that the bathroom vent be re-routed as a soffit vent (if the horizontal distance and turns in the routing allow) and the shingles replaced properly there.

This would be a much cleaner and safer install and also resolve possible leaks as well as health issues and frankly, the design of soffit vents is much better as they do not degrade or rust and have less backflow of air in winds etc.. Any time a break through in a roof can be eliminated one has a better roof, period.

I am basically in agreement with Jerry on this one. Health and safety prevails over someone attempting to determine what is a vent and what is an intake only because of the design intent.
BTW, this would be true of any ridge vent as well. if the vent is down wind at any time then it can intake the contaminated air into the attic envelope, period. Horizontal/vertical separation would then definitely be required in my opinion (if you dont believe me then look at the design for radon pumps, they always install with horizontal and vertical separation even to the ridge as if they were a chimney stack).

Health and safety in code intent defines the requirement, not semantics. I think Jerry made a good call overall. Even though it was not a simpel process.

Dirk,

You're wrong on many different levels. See post #25 below:

Originally Posted by Ken Rowe

Jerry,

Code differentiates between air intake vents (mechanical and gravity) and exhaust vents.
Code has separate location requirements for the different types of vents (air intake vs exhaust).
Bathroom exhaust vent are specifically listed by code to be exhaust vents.

Code does not list definitions of common sense terms like intake and exhaust. They expect people to be smart enough to know the difference.

You also gave a recommendation to move the bathroom exhaust vent to the soffit. This is wrong because the soffit vents will suck the discharged air back into the attic.

You're also wrong about radon vents. They don't require the vent to discharge above the ridge vent, but only above the roof surface with a 10 foot separation to openings. And these "requirements" are only suggestions by the EPA and not enforceable.

Radon mitigation system requirements are done at the state level. In Minnesota there is no code requirements regarding how a radon mitigation system is installed. I honestly don't know about other states, but I've yet to see an enforceable installation code for mitigation systems. Only "suggested" installation guidelines.

Originally Posted by Ken Rowe

Dirk,

You're wrong on many different levels. See post #25 below:
This is wrong because the soffit vents will suck the discharged air back into the attic.
You're also wrong about radon vents.

Geez people here are so legalistic regarding what is said! I know you understood my meanings and the principals involved.

You are correct about the 10 ft OR above the ridge. This usually means above the ridge on the installations of radon pumps I have seen, they generally are close to centerline of the house and therefore centerline of the ridge. I was only using radon as an example as everyone can realize that it is a health based system (pumping unhealthy gasses from the area) and what its function and design are, as well as the fact that allowing the gas to return would be bad.
Generally, engineers design each radon pump system to each location using standard pumps and (usually) pvc pipes. All the ones I have seen here were discharging near the ridge and usually 3 ft or more above the ridge line! I suppose that in some situations the radon pump would discharge through the foundation instead.

Yes, of coarse a soffit vent will allow reentry of the exhaust to the attic if too close to vents in the soffits. Soffit vents are sold in every building supply for good reason. They allow exhaust without roof penetration! Ventilated and non ventilated soffit materials are available. One would need proper separation between the soffit exhaust vent and ventilated soffit. I agree and in fact the code requrement has already been referenced if I am not mistaken.

When I moved my bathroom vents to a fully vented soffit, I covered the perforated area of the soffit materials to meet the code using the old plywood soffit material that was removed and replaced by the vented aluminum. Not a problem at all. If i had solid soffit material on site I would have installed it there instead. I may still do that some day.

It was also wonderful you did not disagree with the evaluation I made regarding interpretation and application of the specification (agreeing with Jerry), nor regarding my observation about the possible leak area due to the break throughs/flashings being too close together.

Thank you!

Originally Posted by Dan Harris

OK I give. Does this mean Jerry doesn't know what he's talking about, or is it I don't understand what your talking about.

I am not an "inspector" ( might be one day) but I have been around the block a few hundred times and have read a few hundred if not thousands ( bet people might wonder why) of Jerry's response/comments on here and I would bet my money, any day or time on his answers/ opinions/ interpretations of things against others. Jerry, when I end up back in Florida I hope to meet you one day as I agree there is no substitute for experience......keep doing what you are doing.....

and I read all the responses before coming back to this to post ........

Originally Posted by Dirk Jeanis

Geez people here are so legalistic regarding what is said! I know you understood my meanings and the principals involved.

Your interpretations of "meanings and principals" are worthless if not backed by code. As home inspectors, we can't just go about reporting deficiencies without something to back up our findings. Code is one of the things we use to back up our findings.

Originally Posted by Dirk Jeanis

It was also wonderful you did not disagree with the evaluation I made regarding interpretation and application of the specification (agreeing with Jerry), nor regarding my observation about the possible leak area due to the break throughs/flashings being too close together.

Thank you!

Apparently you missed my previous post where I stated bathroom exhaust vents are defined, by code as "exhaust vents" therefore not subject to the same code requirements as intake vents or passive openings in the structure.

Your flashing comments have no relativity to the original posts, therefore no need for me to comments on them.

Originally Posted by Mike Pagozalski

I am not an "inspector" ( might be one day) but I have been around the block a few hundred times and have read a few hundred if not thousands ( bet people might wonder why) of Jerry's response/comments on here and I would bet my money, any day or time on his answers/ opinions/ interpretations of things against others. Jerry, when I end up back in Florida I hope to meet you one day as I agree there is no substitute for experience......keep doing what you are doing.....

and I read all the responses before coming back to this to post ........

And this is why I argue these incorrect posts so aggressively. Jerry is correct a good percentage of the time, but when he's wrong and knows it, he never admits it. He just stops posting on the thread. Then some unsuspecting person, like Mike here, reads Jerry's response and takes it as gospel.

Jerry previously posted this code regarding the location of the waste vent termination:

From the 2010 FBC-Residential
- P3103.5 Location of vent terminal.
- - An open vent terminal from a drainage system shall not be located less than 4 feet (1219 mm) directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building, nor shall any such vent terminal be within 10 feet (3048 mm) horizontally of such an opening unless it is at least 2 feet (610 mm) above the top of such opening.

But failed to provide this code regarding the location of intakes and exhaust, which also clearly defines the differences between the two and lists bathroom vents as exhausts.

R303.4 Opening location.

Outdoor intake and exhaust openings shall be located in accordance with Sections R303.4.1 and R303.4.2.
R303.4.1 Intake openings.
Mechanical and gravity outdoor air intake openings shall be located a minimum of 10 feet (3048 mm) from any hazardous or noxious contaminant, such as vents, chimneys, plumbing vents, streets, alleys, parking lots and loading docks, except as otherwise specified in this code. Where a source of contaminant is located within 10 feet (3048 mm) of an intake opening, such opening shall be located a minimum of 2 feet (610 mm) below the contaminant source. For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious.

R303.4.2 Exhaust openings.
Exhaust air shall not be directed onto walkways

[QUOTE=Ken Rowe;249762]An open vent terminal from a drainage system shall not be located less than 4 feet (1219 mm) directly beneath

Where a source of contaminant is located within 10 feet (3048 mm) of an intake opening, such opening shall be located a minimum of 2 feet (610 mm) below the contaminant source.

For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious.QUOTE]

Ken,
Please note that the code considers septic gasses so dangerous to health that they are not allowed within 4 ft below an operable window or door. THis explains the seriousness of spetic gas entry.

Now note that within 10 ft of any intake the source must be at minimum 2 ft above the intake. THis indicates that septic gasses are generally lighter than air and will move upward given a chance. (remember that in this case the seperation is uphill and only a few inches!)

Now let's examine the last statement. It defines EXHAUST from toilet rooms as non-noxious and non-hazardous. It makes no statement regarding the system being defined as only an exhaust and never will.

Simple dictionary definition (Webster Collegiate (most common dictionary used in contracts and definitions))
Exhaust: the withdrawing of air, gas, etc. from a container or enclosure, as by means of a fan or pump (OR course that air or gas itself).
Intake: An opening by which a fluid is admitted into a container or conduit (air/gas being a fluid in most instances)
since the dictionary defines an intake for us we can now apply the definition to any port that allows such to happen at any time. Whether the system is operating as per design or the design failed it makes no difference, we have created an intake. Such an intake is allowing gasses defined by code to be DANGEROUS to enter the envelope. THis must be resolved when known.

All that Jerry has told us is that his experience has proved that these simple exhaust systems become intakes on some regular basis. My experience does as well and that this is MOST likely when there is an above roof termination, especially where wind can open the simple valve in the conduit. Jerry has given us a diamond from his experience, that in fact these simple systems can cause undesireable conditions and such can be noted and or addressed when and as required.

My experience is that a run to a soffited vent from a bathroom exhaust is much better for many reasons, not the least of which is that the air will not usually reverse flow as easily (usually the termination is at the same level or so on both ends and the run is higher than the terminations when one uses soffit vents). Neither of mine has reversed flow since being moved but had reversed flow before that. This was one reason I moved them.

I would not want to wait to find out that an occupant was sick or unhealthy to determine septic gasses the cause when there was such an obvious point of entry for such gasses.

I would note it as a suspect condition and move on, make suggestions that when re-rooofed or any work takes place at that point on the roof, to "upgrade" the design and assure proper separation or suggest that the vent be extended upward as required by code where an intake exists.

Originally Posted by Ken Rowe

And this is why I argue these incorrect posts so aggressively. Jerry is correct a good percentage of the time, but when he's wrong and knows it, he never admits it. He just stops posting on the thread.

Ken,

You knew your so-far-off-base post would get me to reply, because even you know you are wrong with the above.

I have taken my 40 lashes with a wet noodle, stated that I was wrong, etc, before - and have stated that I have been wrong before and will be wrong again.

That said, I stop posting after I realize that I am talking to a brick wall which does not have the sense to understand what is being discussed or why things are that way or the reason things are that way.

I still reply for a while, hoping that the brick wall has a hole in its outer shell through which some common sense will seep through ... when it becomes apparent that is not the case - I stop trying to educate the uneducateable ...

Dirk,

I've provided code references to back up my position. Yes, I've already stated several posts back that the exhaust may allow intake, if not functioning properly, and would be best if not so close to the waste vent. However, code allows it. Notice in my previous post that code list intake and exhaust vent locations independently. Also notice how the line "For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious." This tells you that the vents from bathrooms are considered "exhaust" vents and not subject to the same location requirements as "intake vents".

But I can see we're just going around in circles here. Please back up your position that bathroom exhausts are not always defined by code as exhaust vents and they are not allowed near the waste vent pipe. Please give code references.

Ken you and I both know since we live in cold weather regions that soffit exhaust vents are not favoured due to icing from condensation from the exhaust and that can lead to roof decking problems.
Better a roof vent for cold weather locations.

Soffit exhaust might work in temperate climate but not in northern climates fwiw.

Originally Posted by Ken Rowe

Dirk,

code allows it

Ken,
The MOMENT a vent reverses direction it reverses function (exhaust to intake). If a vent had no valve in it, the flow would be ALWAYS by pressure..high to low and would allow free intake and exhaust at the whim of air conditioning and wind systems etc, even hot and cold air could cause circulation through the system as intake or exhaust . Many vents in the 50's allowed this kind of flow regularly (unvalued) or even failed and remained open valved.

It makes no difference that the INTENT of a device would be exhaust, an unvalved vent is TWO way and becomes intake. A vent without positive valve direction is TWO way unless kept under positive, negative or neutral pressure (depending upon design), period. This is true EVEN IF NOT INTENDED by design. The valves I have seen allow high to low pressure direction of flow, not just one way flow and therefore are almost the same as unvalveded for this situation.

That being said, I have already sent you the dictionary definition most likely used or called out in the IBC as the basis of definitions. (Websters College Dictionary is used in most contracts and legal definitions and engineering documents etc that I have read). ANY point that allows entry of air into a building envelope, regardless of circumstance becomes an INTAKE by definition.

The ONLY substantial statement made by the code is that toilet room exhaust is not considered contaminated air. Other than that the code applies to any place air enters the envelope through a conduit point.

Nothing is said that if installed as an exhaust it shall not be considered an intake if it takes in air. The condition of intaking air makes it an intake when that happens by definition.

Consider:
The o ring of the Challenger space craft was in fact a kind of pressure valve that failed and allowed pressure to move to the LOW pressure side with catastrophic results. The failure of the design caused severe damage as well as loss of life.
Does the fact that it was to specification and called a specific kind of "O ring" or device change the fact that it let the pressure move to the low pressure side when it should not have or that the results caused harm?
Design and specification were met, the failure of intended purpose caused deaths.

Consider:
furnace and stove systems with external air sources (as required in most situations now). What would happen if the flow reversed when the system was fired up? Catastrophic failure and a fire? The intake would have become an exhaust by definition and the failed system then became dangerous.
But is was not an exhaust it was an intake you say (it said so in the drawings and codes and it therefore it could only have been an intake and therefore not dangerous).

Symantics
We are not dealing in symantics here, we are dealing in health related issues and codes to protect from them. Call it what you want, but the moment you allow entry of air into a closed envelope by a conduit it is an air intake. Always has been and always will be, regardless of what it was called when installed.

The code does not allow the shown configuration WHEN the system intakes air, it does if it ONLY exhausts air. Air reversing direction actually re-defines the system to its new state, regardless of design intent, and then the code takes over.

Knowledge
This was supposed to be a small diamond of knowledge that one could remember for the right circumstance and help reduce real world issues found in inspections (like dust and dirt entering a bathroom as well as this configuration shown in the picture and possible ways to test or address it for health reasons)

Reality:
I would never have allowed the exhaust to be placed next to that vent when I was running roofing crews (many years ago). I would have pulled it and moved it before roofing began. And yes, I moved many exhausts before starting roofing, some similar to this one and others for various other reasons. IN fact I moved some just because they were too close to other break throughs and made the job harder and or the roof look cluttered and or possible water tight issues from being to close together. The funny part, I had never read a single code back then. Just common sense.

All this over a suspect condition in picture! really?

Every one of your examples are instances of failures and malfunctions. Code does not address malfunctions, but only items considered to be working as designed. You can play the "what if" game all day; an exhaust vent doesn't magically turn into an intake vent when it malfunctions...it's considered a malfunctioning exhaust vent.

As I've asked previously, please provide code references to back up your views. I've already given them for mine.

Originally Posted by Ken Rowe

Every one of your examples are instances of failures and malfunctions. Code does not address malfunctions, but only items considered to be working as designed. You can play the "what if" game all day; an exhaust vent doesn't magically turn into an intake vent when it malfunctions...it's considered a malfunctioning exhaust vent.

As I've asked previously, please provide code references to back up your views. I've already given them for mine.

IF one will not agree to a defintion of a word there is little to agree upon beyond that. No code exists without defined words. I gave you the definitions from the most common source used in contract law and codes etc.

In my house and the ones that were described by Jerry and in several others I have seen the exhaust became and intake. The issue is SEPTIC gasses entering the house and harming people. Malfunction or not people can get VERY Sick, even long term undefined malaise can be from this kind of problem.

If three people in this house got cholera or some other disease because of intake of septic gasses from that vent, that would just be bad luck according to you. It could not have been avoided and it was only due to a failed system, not because the contractor put the vent to close to the exhaust to begin with. That is your opinion and you are welcome to it.

There is NO point in talking to someone who will not understand that the PURPOSE of ANY flipping code is health and safety based. Meeting the INTENT of the code in protecting people is the point. It doesnt matter if there is a code at all, common sense would tell me never to allow this configuratiuon and in fact as I said when roofing I would never allow it and I had no idea what a code was at that time.

We are done here.

Cholera from plumbing vent air? Its only transmitted through water and food contaminated with cholera bacterium.

Originally Posted by Raymond Wand

Cholera from plumbing vent air? Its only transmitted through water and food contaminated with cholera bacterium.

Typhoid fever, gastrointeritis, cholera, dysentery, infectious hepatitus, aseptic menengitis, ecephalitis. The list goes on and on. water borne and air borne as well as vector borne.

As stated earlier this is about health issues and unsafe gasses and proximities (remember the code requires 4 feet below a door or window or minimum 2 feet above, this tells us how unsafe it is to have proximitiy to ANY infiltration into the envelope).

Ok, so you believe that this can not be transmitted by this open vent. How about by the vectors that enter and exit the vent? How about long term contamination transfer? These are unscreened (possibly 1/4 inch screen on the "exhaust") vents and could easily have mosquitos and many other critters pass through them. How hard do you think it would be to have a mosquito blown into the "intake" and transmit a disease from the septic system over a 30 to 80 year life span of the system? with proper wind conditions a very high probability, say X per year rather than X per system life time.

Also as stated, even when I knew nothing of codes and was supervising roof installs this would never have been allowed on my roofs for many reasons, mostly as it is just bad roofing installation, period.

I am done with this post, turning off my notifications for this post.

thank you.

Dirk, you make no sense. You say that since the vent can malfunction and allow air in, it should not be located near the waste vent pipe. Code or not.

That's like saying the waste vent pipe shouldn't be so close to the fixed window as the window can break, allowing sewer gas into the house. Or, the waste vent pipe shouldn't be located so close to the roof because a tree branch could fall on the roof, creating a hole, and allowing the sewer gas into the house.

As I said earlier, you can play the "what if" game all you want. The fact is, the vent is considered an exhaust vent, by code, and is allowable, by code, to be that close to the waste vent.

- - - Updated - - -

Originally Posted by Kevin Wood

OK now this has just entered into the twilight zone.
OBC 2006
(4) Except for a fresh air inlet, where a vent pipe is terminated in open air, the terminal shall
be located,
(a) not less than 1 000 mm above or not less than 3.5 m in any other direction from
every air inlet, openable window or door,
So again!!! What is an air inlet?

According to Dirk, the air inlet is the window when it breaks.

Yes there are many if's.

Where is CaoimhÃ*n Connell when he is needed?

Originally Posted by Jerry Peck

With a slight wind blowing, those little gravity dampers are flapping back and forth

That is due to negative pressure pulling the damper open. Oh, and you are wrong as the fan vent is not an "intake" as the word intake is used within the context of the code.

Originally Posted by David Bertrams

That is due to negative pressure pulling the damper open. Oh, and you are wrong as the fan vent is not an "intake" as the word intake is used within the context of the code.

Wrap the "exhaust" fan grille in plastic wrap (Saran Wrap TM or similar), make sure it is sealed to the ceiling too, then watch the plastic wrap "breathe" back and forth.

THEN tell me that that "exhaust" fan is not also an "intake" opening into the house.

Whenever I have wrapped an "exhaust" fan grille with plastic sheeting, I can watch the plastic sheeting "breathe" back and forth as the air moves in and out through the exhaust fan - on a windy day, I haven't tried it on a calm day, but now I am curious as to what it does on a calm day ... ... any takers?

Oh, and make sure the "exhaust" fan is connected through to the outdoors and not just open to the attic.

Some sections of the code specifically state "mechanical intake" to indicate that it is the intake of a mechanically driven fan, that is not the case with the code section in question as it simply states "intake opening" and any opening into the building, including soffit vents, etc., are "intake openings".

Originally Posted by Jerry Peck

Some sections of the code specifically state "mechanical intake" to indicate that it is the intake of a mechanically driven fan, that is not the case with the code section in question as it simply states "intake opening" and any opening into the building, including soffit vents, etc., are "intake openings".

Please show us the code which refers to the bathroom exhaust vent as both an intake opening and exhaust opening. This is the third time I've asked for you to back up your statements with a code reference, and you haven't done it yet.

Why don't you simply admit that you were mistaken and code does not address the proximity of bathroom exhaust vent to waste vent pipes? Maybe it should...but it doesn't.

Originally Posted by Ken Rowe

Please show us the code which refers to the bathroom exhaust vent as both an intake opening and exhaust opening. This is the third time I've asked for you to back up your statements with a code reference, and you haven't done it yet.

Please show us the code which says that an opening which allows air in is not an intake opening.

You are constantly being asked to back up your statements and fail to do so - here is one more chance for you to back up your statement that it is not an intake opening.

[QUOTE=Jerry Peck;249922]

Wrap the "exhaust" fan grille in plastic wrap (Saran Wrap TM or similar), make sure it is sealed to the ceiling too, then watch the plastic wrap "breathe" back and forth.

Your experiment and suppositions are meaningless.

any opening into the building, including soffit vents, etc., are "intake openings".

Soffit vents are openings into the soffit. Into the building as it is used by code refers to the dwelling space, not the attic.
An opening into a building could be any hole, flue, chimney and yes the bathroom fan vent. That does not make any of them "intake openings". An intake opening is there for the express purpose of allowing air into the building. The only intake opening that could be impacted by a waste vent would be a fresh air intake on certian HVAC equipment that is roof mounted.

Oh, and make sure the "exhaust" fan is connected through to the outdoors and not just open to the attic.

This is one almost made it.

Originally Posted by Jerry Peck

Please show us the code which says that an opening which allows air in is not an intake opening.

You are constantly being asked to back up your statements and fail to do so - here is one more chance for you to back up your statement that it is not an intake opening.

We're not talking about "an opening which allows air in". We're talking about a dedicated exhaust vent.

I've posted the requirements several times, but apparently you've missed it. Here it is again:

R303.4 Opening location.

Outdoor intake and exhaust openings shall be located in accordance with Sections R303.4.1 and R303.4.2.
R303.4.1 Intake openings.
Mechanical and gravity outdoor air intake openings shall be located a minimum of 10 feet (3048 mm) from any hazardous or noxious contaminant, such as vents, chimneys, plumbing vents, streets, alleys, parking lots and loading docks, except as otherwise specified in this code. Where a source of contaminant is located within 10 feet (3048 mm) of an intake opening, such opening shall be located a minimum of 2 feet (610 mm) below the contaminant source. For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious.

R303.4.2 Exhaust openings.
Exhaust air shall not be directed onto walkways

Notice there are no restrictions for exhaust openings at DWV pipes.

I'll ask for the fourth time. Please provide the code that backs up your statements.

I am going to add the fact that wind blowing over a roof will create negative pressure on the leeward side, thus lifting the flap in an exhaust which in turn because of negative pressure will cause air to be pulled out, never in.

If the vent is on the wind side sure the flapper may lift and allow air in but even then its a real stretch to say categorically that the vent gasses from the plumbing vent will be pulled into the exhaust vent.