# Fire Wall or Two separate Adjacent Buildings?



## Mech (May 18, 2020)

2015 IBC
Type 2B Construction
F-1/S-1/B/A


The existing building area is maxed out per Table 506.2 and the owner wants to expand.  If my thinking is correct, there are only two options.

1. Add a 3 hour fire wall (Table 706.4), which allows openings between the existing and proposed buildings, or

2. Retain the existing 3 hour rated exterior wall (not a fire wall) and build a 2 hour fire rated exterior wall (Table 602) for the addition and consider these as two separate buildings with a zero fire separation distance.  The downside is that neither building can have openings along the common wall.

Is option 2 legitimate?  Are there any other ways to add building area?

Thanks.


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## cda (May 18, 2020)

Will let the experts talk,,

But don’t butt them???

Tunnel, walk way, canopy between them,, Short one


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## cda (May 18, 2020)

Does 602 apply?


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## cda (May 18, 2020)

Maybe::


Check against your book


Cannot find this in a more current edition


“”Section 717.5.1 of the 2012 IBC states that firewalls can create separate buildings within a structure. These multiple buildings may be on a sin‐gle lot, or in the case of zero lot line construction, the firewall may be located on the lot line. In the case where the fire wall separates different buildings on different lots, the code does not permit openings per Sections 706.1.1 and 706.11 as was mentioned earlier. In such instances, no penetrations are permitted.“””

""””””””””” Where the firewall is not located on a lot line, the wall is permitted to have penetrations provided the opening is protected per the requirements of the Code.“”””””


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## Mech (May 18, 2020)

Section 602 comes into play.  I used Table 602 to arrive at the required 2 hour rated exterior walls.  Table 705.8 restricts the opening area in exterior walls.


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## cda (May 18, 2020)

Mech said:


> Section 602 comes into play.  I used Table 602 to arrive at the required 2 hour rated exterior walls.  Table 705.8 restricts the opening area in exterior walls.




I think you are correct

RGLA best place to go for  reply


https://boatx.org/fire-separation-distance/


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## cda (May 18, 2020)

Read thru this while waiting on answers 


http://specsandcodes.com/articles/code_corner/The Code Corner No. 37 - Fire Walls.pdf


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## Builder Bob (May 18, 2020)

Need Photographs or a more detailed plan - This isn't a party wall where a property line runs thru the lot is it?


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## RLGA (May 18, 2020)

Construct a 2-hour wall adjacent to the existing 3-hour exterior wall. This will be considered a double fire wall, which NFPA 221 recognizes. Getting approval for that situation via a code modification should not be that difficult. The problem is now the openings.

If the opening between the two buildings is to remain open, then double overhead coiling fire doors can seal the opening during a fire. If the opening is intended to be controlled by a door, then a double swinging door will not work. How I've addressed this is to create a structural door opening in which its frame has its own structural footings and is not physically connected to either wall. The door must remain in place should either wall collapse.


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## cda (May 18, 2020)

What he said


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## steveray (May 19, 2020)

Or.....use this section out of 2018:

706.1.1 Party walls. Any wall located on a lot line
between adjacent buildings, which is used or adapted for
joint service between the two buildings, shall be constructed
as a fire wall in accordance with Section 706.
Party walls shall be constructed without openings and
shall create separate buildings.
Exceptions:
1. Openings in a party wall separating an anchor
building and a mall shall be in accordance with
Section 402.4.2.2.1.
2. Fire walls are not required on lot lines dividing a
building for ownership purposes where the aggregate
height and area of the portions of the building
located on both sides of the lot line do not
exceed the maximum height and area requirements
of this code. For the code official’s review
and approval, he or she shall be provided with
copies of dedicated access easements and contractual
agreements that permit the owners of
portions of the building located on either side of
the lot line access to the other side for purposes of
maintaining fire and life safety systems necessary
for the operation of the building.


Draw a lot line and some agreements and do nothing....maybe....Might not work with your one building being maxed out unless you can go unlimited....Really have to see the details for this one...

How many stories and where is the A located?


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## RLGA (May 19, 2020)

steveray said:


> Or.....use this section out of 2018:
> 
> 706.1.1 Party walls. Any wall located on a lot line
> between adjacent buildings, which is used or adapted for
> ...


The OP said the building area was maxed out.


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## Mech (May 19, 2020)

Thanks for the responses thus far.

There is no lot line, everything is on one property.

The existing 'A' use is the company cafeteria; it is either on the 2nd or 3rd floor.  It probably fits the requirements of accessory use as it is less than 10% of the building area.  The addition / new building will contain another company cafeteria, although it its size relative to the addition / new building will not allow it to be an accessory use.

I have a drawing, just trying to get it uploaded now.


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## Mech (May 19, 2020)

Here is a link to a sketch.  I have not figured out how to get the image to appear automatically from Dropbox.  
https://dl.dropboxusercontent.com/preview/Building Code Forum/C 3 STORY.jpg?​
The second shared wall in the sketch is not rated, so I know that needs attention - fire wall or fire rating & fire separation distance.


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## classicT (May 19, 2020)

Mech said:


> Here is a link to a sketch.  I have not figured out how to get the image to appear automatically from Dropbox.
> https://dl.dropboxusercontent.com/preview/Building Code Forum/C 3 STORY.jpg?​
> The second shared wall in the sketch is not rated, so I know that needs attention - fire wall or fire rating & fire separation distance.


Link requires that you sign in and have permission.


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## Mech (May 19, 2020)

Try this one.

https://www.dropbox.com/s/pt8w15oo8grd83a/C 3 STORY.jpg?dl=0


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## Builder Bob (May 20, 2020)

Lots of room, Can a pedestrian walkway connect and limit the fire wall construction to a narrow segment? This is from the plan provided, not sure of site obstacles or S& R Overhead door locations.


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## Mech (May 21, 2020)

Thanks for suggestion and sketch Builder Bob!  Very easy to follow.

The current plan is to investigate the 3 hour wall construction and see if it can modified into a bonified 3 hour fire wall.  (Our structural engineers know the requirements for a fire wall, so they can make the assessment.)  The owner would like to keep the new building touching the existing buildings for passageways, reduced construction costs, and preserve land for future additions.

Once we are allowed in the plant to investigate, we will have a better idea of which direction we will go.  It may end up with a separate 2 hour wall like RLGA suggested in an effort to best utilize building space.


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