Fire wall

[Mech]

Fire Wall:

Section 705

I have a 200 ft long wall on a main building with a 50 ft high roof. I would like to create a fire wall to separate an attached portion of the building that is 60 ft long with a lower roof height. The 60 ft long section is centered on the 200 ft long wall. Do I need to create a fire wall along the entire 200 ft long wall or can I stop the fire wall 4 ft. on either side of the 60 ft section?

Can I egress through the firewall as one of my two required exits? Both sides of the firewall have the same use group.

Below is a plan view of the building (Not to scale.) :lol: You can disregard the ....... - I needed them to make the picture look right.

_________________________

|.................................|

|...........Main Bldg...........|

|.................................|

|_______________________|

.......... | Attached |

.......... | .. Bldg .. |

.......... --------------

Please list code sections if you can.

Thanks in advance.

 

[Plans Approver]

Re: Fire wall

There is a lot of information missing from your post. But, read the rest of Section 705, your answers are there. 705.2 through 705.11.

 

[Coug Dad]

Re: Fire wall

A fire wall often is used as a two way horizontal exit.

 

[texasbo]

Re: Fire wall

You do not need to have a rating beyond the fire wall for 4' along the 200' section of wall (last sentence 705.5.1, intersection equal to or greater than 180 degrees). You will have to rate the 90 degree walls of the attached building per 705.5.1.

Make sure you look at vertical continuity per 705.6 for the rating of the wall above the lower roof. There is not enough info in your post to say for certain what you will have to do there.

As Coug Dad said, you may have openings in the fire wall per 705.8 and 715.4. Maximum 120 square feet (unless sprinklered), and maximum aggregate of width of 25% of the length of the wall on any floor.

 

[Mech]

Re: Fire wall

Thanks for the responses.

Texasbo: My vertical continuity falls under 705.6.1 Stepped Buildings. This part I totally understand.

During my original review of section 705.5, I thought the "exterior walls" that the fire wall must be continuous from and extend beyond were the intersecting walls from the main building. (Meaning the fire wall must start at or beyond one side of the 200 ft wall and end at or beyond the other end of the 200 ft wall.

I reread the section and realize that the fire wall starts at or near the intersection of the attached building wall and the common wall between buildings and ends at the other intersection of the attached building wall and common wall between buildings.

So if I have this correct, the fire wall portion will be 60 feet long, (the length of wall the two buildings share) and then the two intersecting walls from the attached building need to be rated. Correct?

Coug Dad: I was not sure if I could exit from one building through another.

I appreciate the help from everyone. And I can't wait for my regular code interpreter co-worker to return from vacation!!! :mrgreen:

 

[Coug Dad]

Re: Fire wall

From the 2009 IBC:

EXIT, HORIZONTAL. A path of egress travel from one building to an area in another building on approximately the same level, or a path of egress travel through or around a wall or partition to an area on approximately the same level in the same building, which affords safety from fire and smoke from the area of incidence and areas communicating therewith.

It is clearly allowed and often done.

 

[TJacobs]

Re: Fire wall

Don't forget that to be a fire wall it must be structurally independent from both buildings.

705.2 Structural stability.

Fire walls shall have sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall for the duration of time indicated by the required fire-resistance rating.