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return vent 10' from wood stove


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Return vent in ceiling of finished basement, I'd guess 9' ceiling without pulling out a tape measure. A wood stove just underneath the return vent. The home buyer wanted an heating expert in addition to a home inspector. So, why didn't the licensed, certified, professional HVAC contractor that was there there mention this as a concern to the buyer? Am I missing something?

(sorry about the quality of the picture)

I also got on a ladder and pulled the return vent cover off to make sure that the wood stove exhaust vent wasn't passing through the return air chase (it is not, there is blocking between the I-joists that separates the return air chase).

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My concern is that any smoke exhaust from the wood stove would enter into the HVAC duct system (i.e. when you open the door of the wood stove).

To answer the other question:

It is not the only return vent in the home (2 more on main level). I was not aware that if there was more than one vent, it was ok to place one within 10 feet of a drafting combustion device. Is is ok if there are more returns?

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The 'exceptions' always throw me.

Exceptions:

2.3. Return-air inlets shall not be located

within 10 feet (3048 mm) of any appliance

firebox or draft hood in the same

room or space.

3. Rooms or spaces containing solid-fuel burning

appliances, provided that return-air inlets are

located not less than 10 feet (3048 mm) from

the firebox of such appliances.

Ok, it is a big family room that opens to a hallway, and stairway to the main floor. So there is plenty of air capacity, even with combustion air for the wood stove. But the way that I interpret it, because it is big room it is ok to have a return vent, but still must be at least 10-foot separation between the return and wood stove. Am I reading it wrong?

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While Bill is correct, I would caution you on this practice. If you have an EPA certified woodstove, it should be able to handle up to -15Pa of depressurization. However, an old clunker leaky POS non-EPA stove can leak at equilibrium. At the very least, this would probably cause smoke odors throughout the house.

IF you're hell bent on doing this, at the very least install low level unlisted CO monitors outside the sleeping rooms and on every floor level.

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  • 8 months later...

The minimum 10' rule only applies if the room serves as the only source of return air.

Hi guys, I signed up to this forum so I could respond directly to Bill's comment. My question is, how can you confirm that the rule about return vents proximity to solid fuel heating devices only applies if the return air vent is the only source of return air?

I mean the code doesn't seem to say anything about that, so how can I confirm for myself that extra bit of information that Bill is saying is correct?

Thanks for any and all responses.

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Look for other return air vents. Follow the returns from the furnace back through the house. If there aren't any other vents, I'd say you'd confirmed it.

Thanks for the reply Kurt, but I think maybe I wasn't clear on the question.

Let me try to clarify what I am asking. The code clearly says;

2.3. Return-air inlets shall not be located

within 10 feet (3048 mm) of any appliance

firebox or draft hood in the same

room or space.

3. Rooms or spaces containing solid-fuel burning

appliances, provided that return-air inlets are

located not less than 10 feet (3048 mm) from

the firebox of such appliances.

Bill says; The minimum 10' rule only applies if the room serves as the only source of return air.

My question is, how can I confirm what Bill is saying that the 10' rule only applies if the room serves as the only return air source?

Where does that information come from? It doesn't appear to be part of the wording in the code, so where does it come from?

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What you underlined are the exceptions to the prohibition of having a return air opening in a room with a fuel-burning appliance when the room contains the sole source of return air.

In other words, you can not place a return air vent within 10' of a solid fuel burning appliance if the room has the only source of return air.

IRC, chapter 16 somewhere. I have no idea what code applies to your village in BC.

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What you underlined are the exceptions to the prohibition of having a return air opening in a room with a fuel-burning appliance when the room contains the sole source of return air.

In other words, you can not place a return air vent within 10' of a solid fuel burning appliance if the room has the only source of return air.

IRC, chapter 16 somewhere. I have no idea what code applies to your village in BC.

Thanks for jumping in here Bill, I'm just trying to understand the building codes.

They definitely don't apply to the particular area where I live as I live in a zoning area that has no building codes restrictions.

But back on the subject, if those are the exception to the rule, does that mean that the return air vent in the OP situation would still not be meet the code? Assuming this is not the only return air vent in the house, but it is less that the 10' minimum between the stove and the vent.

2013516235011_return%20vent%20over%20stove.jpg

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Code or not, if there is a potential for back drafting I would report on it.

I'm confused now, I thought that minimum 10' requirement was part of the exception to the rule allowing a return air vent in the same room as a wood burning.

The way I'm understanding it, and correct me if I'm wrong, is that you can't have a return air vent in the same room as a wood burning appliance unless the vent is a minimum of 10' from that wood burning appliance.

If that is not right, does this mean you could have a return air vent directly behind the wood burning appliance, providing that room is not the sole source of return air?

Does anybody have a copy or a link to the rest of the code relating to this issue?

Perhaps I could have my question answered more directly by asking:

Does the OP vent meet code or not?

(1) Yes

(2) No

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Code or not, if there is a potential for back drafting I would report on it.

I'm confused now, I thought that minimum 10' requirement was part of the exception to the rule allowing a return air vent in the same room as a wood burning.

The way I'm understanding it, and correct me if I'm wrong, is that you can't have a return air vent in the same room as a wood burning appliance unless the vent is a minimum of 10' from that wood burning appliance.

If that is not right, does this mean you could have a return air vent directly behind the wood burning appliance, providing that room is not the sole source of return air?

Does anybody have a copy or a link to the rest of the code relating to this issue?

Perhaps I could have my question answered more directly by asking:

Does the OP vent meet code or not?

(1) Yes

(2) No

I don't have access to your Canadian codes so I can't help.

The OP would not be a problem with the US IRC.

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Thanks Jim, as mentioned earlier I'm not asking about Canadian codes, or my particular situation. I'm trying to understand how the IRC applies in the US. It seems it gets interpreted differently by different people, I'm looking for a clear explanation, that's why I thought I might be able to get it on this inspector's journal forum. People seem to quote the same bit of the code and interpret it completely oppositely.

Is this the entire part of the code that deals with this, or is there more to it? Because it doesn't seem to mention anything about the 10' exception applying only if they are the room serves as the only source of return air.

SECTION M1602 RETURN AIR

M1602.1 Return air.

Return air shall be taken from inside the dwelling. Dilution of return air with outdoor air shall be permitted.

M1602.2 Prohibited sources.

Outdoor and return air for a forced-air heating or cooling system shall not be taken from the following locations:

1. Closer than 10 feet (3048 mm) to an appliance vent outlet, a vent opening from a plumbing drainage system or the discharge outlet of an exhaust fan, unless the outlet is 3 feet (914 mm) above the outside air inlet.

2. Where flammable vapors are present; or where located less than 10 feet (3048 mm) above the surface of any abutting public way or driveway; or where located at grade level by a sidewalk, street, alley or driveway.

3. A room or space, the volume of which is less than 25 percent of the entire volume served by the system. Where connected by a permanent opening having an area sized in accordance with ACCA Manual D, adjoining rooms or spaces shall be considered as a single room or space for the purpose of determining the volume of the rooms or spaces.

Exception: The minimum volume requirement shall not apply where the amount of return air taken from a room or space is less than or equal to the amount of supply air delivered to the room or space.

4. A closet, bathroom, toilet room, kitchen, garage, boiler room, furnace room, unconditioned attic or other dwelling unit.

Exception: Dedicated forced-air systems serving only a garage shall not be prohibited from obtaining return air from the garage.

5. A room or space containing a fuel-burning appliance where such room or space serves as the sole source of return air.

Exceptions:

1. The fuel-burning appliance is a direct-vent appliance or an appliance not requiring a vent in accordance with Section M1801.1 or Chapter 24.

2. The room or space complies with the following requirements:

2.1. The return air shall be taken from a room or space having a volume exceeding 1 cubic foot for each 10 Btu/h (9.6 L/W) of combined input rating of all fuel-burning appliances therein.

2.2. The volume of supply air discharged back into the same space shall be approximately equal to the volume of return air taken from the space.

2.3. Return-air inlets shall not be located within 10 feet (3048 mm) of a draft hood in the same room or space or the combustion chamber of any atmospheric-burner appliance in the same room or space.

3. Rooms or spaces containing solid-fuel burning appliances, if return-air inlets are located not less than 10 feet (3048 mm) from the firebox of those appliances.

6. An unconditioned crawl space by means of direct connection to the return side of a forced air system. Transfer openings in the crawl space enclosure shall not be prohibited.

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