Furnace vent in return air

[mathew stouffer]

Does the IRC specifically address this issue. The furnace vent passes through the return in to different areas.

[Jerry Peck]

I see open holes which need to be closed up and fireblocked.

Hopefully that entire wall and framing is not that way.

[mathew stouffer]

It is. But I am more concerned about the furnace exhaust vent in the return air. I can't find anything in the IRC, not to say that will prevent me from putting it in the report.

[Jerry Peck]

Mat,

What's that hole over to the right?

Address it this way, as it definitely does not meet this:
- M1601.1 Duct design. Duct systems serving heating, cooling and ventilation equipment shall be fabricated in accordance with the provisions of this section and ACCA Manual D or other approved methods.
- - M1601.1.1 Above-ground duct systems. Above-ground duct systems shall conform to the following:
- - - 1. Equipment connected to duct systems shall be designed to limit discharge air temperature to a maximum of 250°F (121°C).

- - - 2. Factory-made air ducts shall be constructed of Class 0 or Class 1 materials as designated in Table M1601.1.1(1).
- - - 3. Fibrous duct construction shall conform to the SMACNA Fibrous Glass Duct Construction Standards or NAIMA Fibrous Glass Duct Construction Standards.
- - - 4. Minimum thickness of metal duct material shall be as listed in Table M1601.1.1(2). Galvanized steel shall conform to ASTM A 653.
- - - 5. Use of gypsum products to construct return air ducts or plenums is permitted, provided that the air temperature does not exceed 125°F (52°C) and exposed surfaces are not subject to condensation.
- - - 6. Duct systems shall be constructed of materials having a flame spread index not greater than 200.
- - - 7. Stud wall cavities and the spaces between solid floor joists to be used as air plenums shall comply with the following conditions:
- - - - 7.1. These cavities or spaces shall not be used as a plenum for supply air.
- - - - 7.2. These cavities or spaces shall not be part of a required fire-resistance-rated assembly.
- - - - 7.3. Stud wall cavities shall not convey air from more than one floor level.
- - - - 7.4. Stud wall cavities and joist-space plenums shall be isolated from adjacent concealed spaces by tight-fitting fire blocking in accordance with Section R602.8.

- M1801.8 Duct penetrations. Chimneys, vents and vent connectors shall not extend into or through supply and return air ducts or plenums.

[mathew stouffer]

Jerry,
Thank M 1801.8 says it all. The is a vent penetrating the return.

[mathew stouffer]

The hole to the right, crap I didn't even see that. Well the whole thing is fubar anyway;)

[Phillip Bates]

Hello: In the province of Ontario,canada the Natural Gas & Propane Installation Code has sections dealing with your issue:
8.10.12 A flue gas vent or vent connector shall not be installed in either a duct or a shaft used for return air,hot air,ventilating air, or combustion air.
8.10.13 A false ceiling space, or a confined space used for return air, shall not contain a vent or vent connector that does not have sealed joints or seams.
As most furnace manufacturers also include this stipulation in the installation instructions of their appliances, & as such that is a certified document, & as all furnace amnufacturers are American, I would think US states would have this rule as well.Perhaps you might go online to a manufacturers site & ask them their regulations regarding the issue.Gas Codes support manufacturers specs generally, especially as regards safety issues.
One of the problems with PVC exhaust vents is that we've seen glued joints deteriorate over a short period of time(signs are what appears to be rust deposit around an exhaust vent joint),& therefore leak combustion products.