Please help me with window opening questions

[Angelachow]

Hi everyone,
We're renovating and adding additions to an old 2-unit office building to transform it into a 4-unit R-2 multifamily building (basement to 3rd floor).
We use NFPA13R because of R-2, change of occupancy, and addition. The distance between the existing building and the property line is about 3'~4'. We got our building permit approved and started the work about 2-3 months ago.
But now the city has found out the distance is less than 5' according to IBC 705.8 Openings, we are not allowed to have any window openings, not even existing windows. We didn't notice that problem cause most of the windows are existing ones and I thought our NFPA13R could give us a 15% opening.
It turns out we need to have NFPA 13 instead or make it "Protected". But I'm not sure if we are capable of doing NFPA13. The fire suppression company is evaluating that.
My contractor is working on maybe fire-rated windows, but we have 10+ windows, those are too expensive. And we're asking the city if we can do window sprinklers instead.
Can anyone give me some suggestions or if there are code exceptions we can work around this problem? Or maybe there are some easier ways to turn the building to "Protected"?

Thanks a lot!! Really appreciate it!

 

[Angelachow]

Big thanks to CDA.
CDA helped me find something that may help me exempt from the opening limitation.

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1012.6.3 Opening protectives.​

Openings in exterior walls shall be protected as required by the International Building Code. Where openings in the exterior walls are required to be protected because of their distance from the lot line, the sum of the area of such openings shall not exceed 50 percent of the total area of the wall in each story.

Exceptions:

1. Where the International Building Code permits openings in excess of 50 percent.
2. Protected openings shall not be required in buildings of Group R occupancy that do not exceed three stories in height and that are located not less than 3 feet (914 mm) from the lot line.

we're basement to 3rd floor. Does that count as 3 stories in height or 4?

3.Where exterior opening protectives are required, an automatic sprinkler system throughout may be substituted for opening protection.
does NFPA13R count?

4.Exterior opening protectives are not required when the change of occupancy group is to an equal or lower hazard classification in accordance with Table 1012.6.
--> We changed from B to R. It's the same classification.


But I'm not sure how it works.
First of all, we need to follow IEBC -> change of occupancy -> triggers IBC chapter 9 -> triggers 705.8 openings?? Is that correct?

And now we use IEBC 1012.6.3 Opening Protectives
Exception 2 or 3 or 4 to request that we don't need to have opening protectives to have a 15% allowable open area?
Is that it? Are they only applying to existing windows or both existing and new ones?

Any idea or comment will be appreciated!
Thanks.

 

[Yankee Chronicler]

The IBC typically views building height as feet or stories above the grade plane. Thus, a building with a ground floor, two upper floors, a basement and a sub-basement would be a 3-story building, but it would contain five stories.

 

[mtlogcabin]

But I'm not sure how it works.
First of all, we need to follow IEBC -> change of occupancy -> triggers IBC chapter 9 -> triggers 705.8 openings?? Is that correct?

IBC 705.8 is only triggered if you cannot meet one of the following exceptions in the IEBC. Your post states you meet 3 of them. Yes NFPA 13R is the minimum required for an R occupancy. The exceptions apply to all openings, new or existing.

1011.6.3 Opening protectives.
Openings in exterior walls shall be protected as required by the International Building Code. Where openings in the exterior walls are required to be protected because of their distance from the lot line, the sum of the area of such openings shall not exceed 50 percent of the total area of the wall in each story.

Exceptions:

1. Where the International Building Code permits openings in excess of 50 percent.

2. Protected openings shall not be required in buildings of Group R occupancy that do not exceed three stories in height and that are located not less than 3 feet (914 mm) from the lot line.

3. Exterior opening protectives are not required where an automatic sprinkler system has been installed throughout.

4. Exterior opening protectives are not required where the change of occupancy group is to an equal or lower hazard classification in accordance with Table 1011.6.

 

[steveray]

But I'm not sure how it works.
First of all, we need to follow IEBC -> change of occupancy -> triggers IBC chapter 9 -> triggers 705.8 openings?? Is that correct?

Yeah...sorta....but the IEBC 1011.6.3 gives you the way out of "new" IBC 705.8