Thread: Vents

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Not much potential and I would not comment.

I would write it up.

The VTR (vent through roof) is required to be at least 10 feet from any building opening *or* intake opening.

That attic exhaust fan *is* "a building opening".

More likely than drawing sewer gas 'into' the attic would be the powered fan pressurizing the vent pipe, blowing the sewer gases past the trap seals.

It might not meet code, but its not going to produce any more of a wind that would happen on a normal day. Chance are that the vent stack was in place before the power vent was installed.

If you want to right it up that's up to you, but I'm with Eric. It would not make my report. Now you also have about a 90% chance that the motor is burned out on that power vent, they only last a few years.

Originally Posted by Scott Patterson

Now you also have about a 90% chance that the motor is burned out on that power vent, they only last a few years.

Which makes the plumbing vent within 10 feet of a building opening.

Why would you *not* write that up?

Would you write a plumbing vent up is it was within 10 feet of an operable window?

Around here attic air vents out through roof vents - not much in the way of reverse flow. As for windows, air could just as easily enter as exit - I would not make such an exception for windows.

I think that the proximity of a soil stack to a roof vent is a situation where one could slide on the 10 foot rule. After all, we are professional inspectors and should be able to make such judgments. I really don't think that "code" requirements are always correct and need to be taken literally.

Originally Posted by Eric Barker

I think that the proximity of a soil stack to a roof vent is a situation where one could slide on the 10 foot rule. After all, we are professional inspectors and should be able to make such judgments. I really don't think that "code" requirements are always correct and need to be taken literally.

Guess we have different standards, then.

Mine are defensible should I ever get into court. I have the code backing me up, not just me saying 'Well, gee, this ought to be okay.'.

Eric said it fairly well, and I will add this. I do not do code complaint inspections, this is why I would not note it. Now if I'm doing a code compliant inspection, I would have noted it. This is not to say that I don't use the codes to back-up my findings if needed, because I will and have.

My code book does not have my name on it anywhere nor did I write it, so I call out code violations as I see them. We all should if you knowingly know something is wrong.

JMHO

The stack is higher then the mushroom cap. If it where inline or below I would probably state it might be a problem.

Quote from Scott:
"If you want to right/write it up that's up to you, but I'm with Eric. It would not make my report. Now you also have about a 90% chance that the motor is burned out on that power vent, they only last a few years."

I have to agree with Mike Schulz's assessment that since that vent stack is higher than the mushroom cap, It doesen't really pose a problem.

Rich

Originally Posted by Richard Rushing

I have to agree with Mike Schulz's assessment that since that vent stack is higher than the mushroom cap, It doesen't really pose a problem.

Actually, it poses just as great a problem being that high above as being that far below.

The sewer gases vent out, not just 'up', but 'out' ... in all directions, including falling back down.

Now, if the vent stack were 2 feet higher, I would agree, it would not be a problem, but then again, it would also not be a code issue if it were 2' higher either.

Wonder if there is a reason for that?

- 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.

That exhaust fan *IS* an intake opening. Especially, as has been aptly pointed out, once the motor burns out - because then it can no longer be an exhaust at any time, it's just an opening allowing for the free movement of air through it, both in and out.

I find it interesting that some of us grab onto some code sections but dismiss others ... guess it's because they know more than all the minds which went into writing the code?

Look at it this way...

What type of air is being expelled out of that mechanical vent? Before you answer that question, let's assume that the vent does NOT work (burned out).

Now, what is being expelled out of that vent--Gravity fed warm/ hot attic air (whether working or not). What is being sucked in thru the plumbing vent-- nothing. The vent is only a positive/negative pressure relief.

Now, I'll ask... what is being drawn into the home? Everything from both the non-working (worst case assumption) mechanical vent and the plumbing vent are gravity fed-- nothing is being sucked in.

Is everything in the code perfectly written... nope-- but most are. This just happens to be one of those that you ask yourself, does it cause a safety concern? Does it have the potential to cost the homeowner a monetary issue? Does it create a health issue? Does it create a functionality issue for either the plumbing or attic ventilation?

I just think this is one of the "small fish" that won't make me loose any sleep at night over.

Rich

"What type of air is being expelled out of that mechanical vent? Before you answer that question, let's assume that the vent does NOT work (burned out)."

Okey dokey, the powered vent is not working.

"Now, what is being expelled out of that vent--Gravity fed warm/ hot attic air (whether working or not)."

On warm and hot days, yes. But the reverse occurs on cooler nights and days. Outside air is being drawn into the attic space.

"What is being sucked in thru the plumbing vent-- nothing. The vent is only a positive/negative pressure relief."

Tis only partially true. Air is sucked into the plumbing vent every time water goes down a drain pipe.

Ah, but what is being *expelled from* the plumbing vent? Sewer gas. Which not only rises but settles and disperses, some of it going *down into* the building opening which is constantly open (the non-working powered vent). From this ... see your next comment below ...

"Now, I'll ask... what is being drawn into the home? Everything from both the non-working (worst case assumption) mechanical vent and the plumbing vent are gravity fed-- nothing is being sucked in."

Yeah it is. See my comment above.

"Is everything in the code perfectly written... nope-- but most are."

Cannot agree more there. Code is a consensus document, it is what 'has been agreed to' and voted on. That is why code is not strict nor the best way, it is simply 'the worst way everyone could agree to'.

"This just happens to be one of those that you ask yourself, does it cause a safety concern?"

Yes it is. See my comments above.

"Does it have the potential to cost the homeowner a monetary issue? Does it create a health issue? Does it create a functionality issue for either the plumbing or attic ventilation?"

Yes, to all three.

"I just think this is one of the "small fish" that won't make me loose any sleep at night over."

I hope you don't lose much, if any, sleep over most things on inspections, it is not worth it, but, it is well worth writing that up.

If you don't, and don't want to, *I* certainly am not losing any sleep over it, *it is not my* clients who will be living there.

Jerry,

That is a turtle-vent cover... look at the bottom of the "turtle" shell-type cover and look at the top of the vent pipe. Now, how are the massive amounts (pun intended) of sewage gasses going to be sucked into the attic??

Oh, I'm sure it could be with the fan motor reversed and a WILMA force wind blowing into the attic vent. But then, if WILMA were to come back then there would also be tiny tornadic activity in the attic where funnel clouds of insulation would surely be swirling also.

Now, without the fan motor being reversed and there not being much of a possibility of WILMA coming back, or atleast in Warren's neck of the woods, I just don't see that drawing gasses into the attic.

Richard

Just for argument's sake here,

What would happen if the vent or fan were located on the other side of the ridge (the steep side of the pic)?

Would that change anything because of the elevation?

Just wondering?

Richard,
If the fan is not on, winter, not working, etc. Cold draws to hot, (at least thats what they said in insulation class) so naturally cold air will enter through the fan "when it's not on" and into the attic area along with any expelled sewer gas. How much? how often? to many variables.
So Jerry is correct but I thinks if the owners where smelling gasses they would of had it checked out long ago. Or they are moving because of it. The buyers could always install a pilot light on the fan and make it a flame thrower

Originally Posted by Mike Schulz

Richard,
If the fan is not on, winter, not working, etc. Cold draws to hot, (at least thats what they said in insulation class) so naturally cold air will enter through the fan "when it's not on" and into the attic area along with any expelled sewer gas...

Well kinda. But that wan't my point. My contention was that the bottom of the 'turtule' cover is where the opening is-- not the top of the turtle cover. The distance between the bottom of that mechanical vent cover and the top of the vent pips would provide (in my opinion) a significant barrier of ambient air to prevent the drawing of any gasses into the home. There is a considerable 'air' barrier present between the bottom of the turtle vent and the top of the p-vent.

By the way, Warren... was the (mechanical attic) vent working or not? My bet is that if a hurd of grizzley bears broke into the home and ate the a wedding-party's barbecue beans out of the refrigerator, then decided to have a farting contest, the vent would expell the gastrious flatulence and said exuberances would NOT make it back into the attic.

The turtle vent is DESIGNED to assist in deflecting winds and other of natures events. Even if the the 'winds' and events are from an ursus-arse.

JMHO

RR

Very interesting. I have always heard, and experienced,that hot air rises. That in an attic air enters through soffit vents and exits through roof vents. Now I'm hearing that air is actually pulled in from the top. When did all these dynamics of attic ventilation change? I am constantly amazed at what I am still learning.

Let me get the basics of what Richard is saying straight.

Hot air rises, so the hot air rises to the top of the fan cover and cannot escape, because, as hot air rises, *it will not* spill down and under the lower edges of the cover.

Cold air settles, so the cold air will settle past the bottom of the cover, and by the same forces which prevent the hot air from escaping, the cold air will not settle into the opening under the bottom of the vent cover.

Sounds like either magic is at work here, or there is a new theory for physics and the movement of air.

Also sounds like someone is going to extremes to try to justify *not* writing it up.

You can try to justify it however you want to try, for as often as you want to, in as many ways as you want to, but none of them will change the fact that *some* sewer gas *will* enter the attic, and that *is prohibited by the code* when separating the two would solve the problem to the greatest extent readily solvable. (sigh)

"Hot air rises, so the hot air rises to the top of the fan cover and cannot escape, because, as hot air rises, *it will not* spill down and under the lower edges of the cover."-- Whaaaaaa??? This is just a goofy statement.

"Cold air settles, so the cold air will settle past the bottom of the cover, and by the same forces which prevent the hot air from escaping, the cold air will not settle into the opening under the bottom of the vent cover."-- Hell, that's even goofier...



"Let me get the basics of what Richard is saying straight."-- Yep, that's the thing to do, get it straight.

Rich

"Hot air rises, so the hot air rises to the top of the fan cover and cannot escape, because, as hot air rises, *it will not* spill down and under the lower edges of the cover."-- Whaaaaaa??? This is just a goofy statement.

Yeah, it is, but it's the only reasoning I can think of that you are applying.


"Cold air settles, so the cold air will settle past the bottom of the cover, and by the same forces which prevent the hot air from escaping, the cold air will not settle into the opening under the bottom of the vent cover."-- Hell, that's even goofier...

Well, I'm learning from a good teacher - you!

I got to get a grip on that new physics for air movement you are applying.

Time out boys or I'll send you to your rooms.

Lets just glue a cap on the plumbing vent and then the case is solved.

Originally Posted by Tim Moreira

Time out boys or I'll send you to your rooms.

Lets just glue a cap on the plumbing vent and then the case is solved.

DANG!

Why didn't we think of that?

No charge today. That was a free one

I'm all for capping the vent. After all, if convection currents are no longer what they were, the sewer gas will no longer be expelled form the vent. So then, why not cap it?

I Know!
Put a AAV on it and problem solved

Very interesting. I have always heard, and experienced,that hot air rises. That in an attic air enters through soffit vents and exits through roof vents. Now I'm hearing that air is actually pulled in from the top. When did all these dynamics of attic ventilation change? I am constantly amazed at what I am still learning.Today 10:14 AM

If it is winter then no hot air is rising if the insulation is up to par. My attic is preety fridget. So when the fan is not on air can be drawn in. I guess that is why they put dampers on exhaust fans such as dryers, range hood and baths.

Now I wonder where the "house chimney stack effect" plays in this? Hmmm
Have to ponder that one!