Fire Walls/ Fire Barriers intersection at exterior wall, please help

[liarchitect]

Please help , i have been reading the code for 3 days now, and each time i read it i conclude something different

When a fire wall intersects an exterior non-combustible wall, how far if any does the fire wall need to extend on the exterior wall in a perpendicular direction on each side. If this continuation is required can a door be placed in that areas as long as it is rate correctly

Building information

existing 35,000 warehouse

unsprinklered

that the client wants to seperate into 4 seperate fire divisions in

type 2b construciton

occupancy f-2 television filming no audience

thank you in advance

The question i keep coming across is

 

[Examiner]

How do you come up with the F-2 for the warehouse and the television filming? A fire wall has to stand on its own upon the collapse of the building. Kind of hard to do in an existing building. You are most likely looking at a fire barrier. I see a problem with the occupancy use group before we can discuss fire areas.

 

[Codegeek]

Try Section 706.5.1 in the 2009 IBC.

 

[liarchitect]

this building is located in brooklyn ny 2008 NYC BUILDING CODE and is stated under a f-2 see attached image television filming (no spectators)

 

[liarchitect]

sorry i do not know how to attach an image

 

[liarchitect]

I would agree, fire barrier

 

[Examiner]

So what is an F-2 under the NYC code. What types of manufacturing uses are allowed? The IBC list what is allowed in an F-2.

I only go up to 2006 IBC. None of the AHJ around here are using any newer codes.

What year of the IBC did NYC use and then change the Title and other changes?

I am still thinking you will have an occupancy separation or maybe none separated occupancy.

Office software will not allow me to see attached pictures on this forum.

Went to a site that I have saved which list the NYC code. Yep, f-2 allows Television filming (without spectators).

 

[Examiner]

10,500-sf Table allowed floor area for Type II-B (F-2)

Floor area increases allowed:

7,875; 75% perimeter increase (100% of the perimeter with 30-ft clear from property lines or assumed property lines) [if you do not have the clearance then the percent value will be lower]

31,500; 300% spr one story increase

21,000; 200% spr multi story increase

10,500 + 7,875 + 31,500 = 49,875

If the perimeter is calculated the same as the IBC and the sprinkler increases are also the same; then why do you need separate fire areas? The building is allowed to be larger than you listed.

Since F-2 is not listed in the Chapter 9 of your code, you are not required to sprinkle the building. So you would not get the sprinkler increase if there is not a sprinkler system in the existing building.

Therefore without a sprinkler system the allowable area after increases are; 10,500 + 7, 875 = 18,375-sf per floor. The result lists the existing building is too large without a sprinkler system. Do you have a fully automatic fire suppression system in the building?

If you have a mixed occupancy condition Section 508.3 would apply. From the brief look I did they appear to be the same as the IBC’s. Do you have a mixed occupancy condition? If so then one of the three choices you have in 508.3 would apply.

 

[liarchitect]

we plan on dividing the building into 4 seperate fire areas

 

[Examiner]

After looking over your first post, I see that the building does not have a sprinkler system. Therefore, the building is currently too large for the occupancy use group and construction type. Fire Areas are of no help with a building already too large. You cannot exceed the allowable building area without FIREWALLS not Fire Barriers. If you use FIREWALLS each area will be affect due to perimeter loss. You will have to calculate the allowable area between each FIREWALL. Each FIREWALL affects the perimeter length.

10,500 + 7,875 = 18,375-sf ALLOWABLE BUILDING AREA per FLOOR; Assuming you have the perimeter clearance around the building is your allowable area after increases. Your existing buidling is 35,000-sf which is larger than the allowable. The ACTUAL Buiding AREA cannot EXCEED The ALLOWABLE. How did the building get to be so large in the first place?

 

[texasbo]

liarchitect: In a nonsprinklered building, fire fire walls may terminate at noncombustible exterior walls, but the exterior walls must be rated for a distance of 4 feet on each side of the fire wall. Rating shall be 1 hour, openings 3/4 hour. See 705.5, 705.5.1, 2006 IBC.

However, as examiner said, fire walls shall remain in place if building collapses on one side per 705.2, and i don't think you're going to be able to do that in this building.