Vented eave less than 5' from property line

[Robert]

CA: According to Table 302.1 (unsprinklered), projections from 2'-5' from property line need to be 1 hour rated on the underside UNLESS (footnote c) no gable vents are installed. If I install soffit strip vents (not gable vents) am I still allowed no rating? Thank you.

 

[Francis Vineyard]

Robert, the 2015 (and 2018) IRC change that to clarify "zero hours on the underside of the rake overhang where gable vent openings are not installed."

 

[mark handler]

CA: According to Table 302.1 (unsprinklered), projections from 2'-5' from property line need to be 1 hour rated on the underside UNLESS (footnote c) no gable vents are installed. If I install soffit strip vents (not gable vents) am I still allowed no rating? Thank you.

No, you cannot. Soffit strip vents are openings and not allowed.

You may be able to convince the AHJ to use a product like this:
Vulcan VSC2120 Fire Stopping Soffit Vent
https://www.guntermanufacturing.com/protect/fire-resistant-vulcan-vents/

 

[conarb]

CA: According to Table 302.1 (unsprinklered), projections from 2'-5' from property line need to be 1 hour rated on the underside UNLESS (footnote c) no gable vents are installed. If I install soffit strip vents (not gable vents) am I still allowed no rating? Thank you.

Nobody is answering his question, absent something else it appears that if he doesn't have gable vents he's free to use any kind of vents he wants. As to fire dampened soffit vents, I installed them on a home recently and they cost me $17,000, I completely circled the home from around the eaves and up and down the gables including 7 dutch gables.

 

[Robert]

Thanks for the replies. Now Mark brings up a point...is a strip vent an opening? If so, what about foundation vents? In our WUI code (Wildland Urban Interface) in high fire areas, these are allowed but with a restriction on mesh size. This job, however, is not in a high fire area, so back to square one, which as conarb mentioned, I'm free to use any vent as long as there are no gable vents. I suppose a zero hour rating at the underside of the eave could, in effect, be a completely open eave/soffit, thereby allowing any kind of venting/strip venting, screened holes in blocking, etc. Is this a giant leap of faith?

 

[Francis Vineyard]

The gable vent provisions relates to the gable wall and rake fire separation distance, has nothing to do with the soffit side of exposure.

 

[mark handler]

Thanks for the replies. Now Mark brings up a point...is a strip vent an opening? If so, what about foundation vents? In our WUI code (Wildland Urban Interface) in high fire areas, these are allowed but with a restriction on mesh size. This job, however, is not in a high fire area, so back to square one, which as conarb mentioned, I'm free to use any vent as long as there are no gable vents. I suppose a zero hour rating at the underside of the eave could, in effect, be a completely open eave/soffit, thereby allowing any kind of venting/strip venting, screened holes in blocking, etc. Is this a giant leap of faith?

If the AHJ allows them Use VFS (Vulcan Foundation, Soffit) Vents
https://www.guntermanufacturing.com/protect/foundation-vents-2/

 

[mark handler]

The gable vent provisions relates to the gable wall and rake fire separation distance, has nothing to do with the soffit side of exposure.

Get off the dormer thing he read the wrong footnote; he cannot have any openings less than three feet, per CRC Table 302.1, as I stated above.

 

[conarb]

The gable vent provisions relates to the gable wall and rake fire separation distance, has nothing to do with the soffit side of exposure.

I box my soffits, everything I have built in years is in some fire zone so I run soffit vents up and down my gables.

If so, what about foundation vents?

Yes, in all fire zones I use fire dampened foundation vents too, my AHJs are very strict on this because of all the wildfires in Caifornia, I've seen pictures of stucco homes with tile roofs burned down, they say it's because of embers blowing through vents. I'd say this is much more important than sprinklers and other fire protection requirements.

 

[Robert]

The eave is 3'-6" from the property line and the wall in question is not the gable/rake wall so the gable vent footnote has nothing to do with the eave wall (thank you for pointing that out). The other footnote (A) states if fireblocking is installed from plate to underside of sheathing, the 1 hour fire rating is not required. That said, am I allowed to drill those blocks and use the fire rated round vents in the blocking? As an aside....openings in walls in this location are allowed to be 25% unprotected....so would these vents fall into that category? Or would they fall under "penetrations" which have no restrictions greater than 3' from property line?

 

[mark handler]

The eave is 3'-6" from the property line and the wall in question is not the gable/rake wall so the gable vent footnote has nothing to do with the eave wall (thank you for pointing that out). The other footnote (A) states if fireblocking is installed from plate to underside of sheathing, the 1 hour fire rating is not required. That said, am I allowed to drill those blocks and use the fire rated round vents in the blocking? As an aside....openings in walls in this location are allowed to be 25% unprotected....so would these vents fall into that category? Or would they fall under "penetrations" which have no restrictions greater than 3' from property line?

Talk to the AHJ, Fire Department Or Building Department, they will tell you what they will except.
I would not except unprotected soffit penitrations. Heat builds up in enclosed soffits causing spontaneous combustion.

 

[Robert]

Thank you. It's only 30' of eave so I'll err on the side of caution and use the fire rated vents.

 

[cda]

Spontaneous



http://www.aflab.com/spontaneous-combustion-explained/


Auto


https://www.safeopedia.com/definition/630/autoignition-temperature