fire wall at noncombustible deck - trying to remove parapet

[aztec]

I have a H5/Type II B fully sprinkler building, and need to change my 3hr fire barrier to a 3hr fire wall. Turns out a lot of the material has already been ordered and mechanical/structural will have to make many adjustments if I cannot remove the 30 in parapet requirement.

Section 706.6 Vertical Continuity (IBC 2009), exception 3 seems to be the saving grace: "Walls shall be permitted to terminate at the underside of noncombustible roof sheathing, deck or slabs where both buildings are provided with not less than a class B roof covering. Operings in the roof shall not be located within 4 feet."

I have a TPO roof covering, which as of right now I do not know what was specified (just got on the project). I do know the metal deck is ordered and is galvanized, and is not fire rated.

IF the TPO is is class B AND the metal deck is noncombustible, then I should be ok to terminate the 3hr wall at the bottom of the deck? Does that sound correct?

IF the galvanized metal deck is combustible, then do I have any options? I was told I could spray something on the underside of the deck, but of course structure mentioned galvanized deck do not take materials very well.

Any thoughts or suggestions would be great. Thanks.

 

[mark handler]

IF the galvanized metal deck is combustible, then do I have any options?

A galvanized metal deck is NOT combustible, so I don't understand that portion.

You can not just wave a wond and change the Wall to a Barrier

A firewall is a wall separating transformers, structures, or buildings or a wall subdividing a building to prevent the spread of fire and having a fire resistance rating and structural stability.

A fire barrier , also referred to as a fire partition, is a fire rated wall assembly which is not a fire wall. Typically, the main differences is that a fire barrier wall is not structurally stable, and does not extend through the roof, or to the underside of the floor above.

 

[mark handler]

By the way welcome to the board

 

[aztec]

Mark,

Thanks for the clarification. I do understand I'll need to find the proper UL load bearing wall type, and re-draw it. In order for me to terminate my new fire wall, the code says it must terminate at a noncombustible roof deck. I guess I thought I could add something to it, but I have a nasty feeling that I'm screwed on this one. Like you said, I cannot make the roof deck noncombustible, it it's not. And from your comment it's not. Fire rating and noncombustible was messing me up. Had the fire wall been 2hr, then I could have used the 1-hr rating, 4' on either side rule. But I can't. Maybe that's why people were suggesting I spray something on the deck.

I wanted to see what options I had i.e. re-order new combustible roof deck or have structure/mechanical re-do their design in order to allow for this new firewall with the 30" parapet. It appears the best solution may be to buy the right material, and this assumes the TPO is ALSO class B.

Thanks.

 

[aztec]

Oops. I read your post too fast. NOT combustible! That is great news! I'll need to check the specs...sorry, my head is on fire right now

 

[cda]

How are you going to achieve structural stability?????

Can you answer why the three hour is needed???

Welcome

How did you find us???

What are you doing laboring on pre labor day???

 

[aztec]

I don't have the UL book with me, but there is a UL 3hr load bearing wall, I think it has 4 layer of gyp and uses metal studs. There are a few other pieces in the wall section, but if UL says it's load bearing then I assume it will be structural stability. The three hours comes from the code, table 705.4 group H-5 needs 3 hours.

As far as finding this place, well when I realized my confusion I started doing a search and found a post on here. Just a good ol google search. Pre labor day, trying not to read any code. My head is hurting.

Thanks again!

 

[cda]

706.2 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.

Cannot guaranty that the ul design will take into what is required above

Doing one of those buildings??? They are interesting to deal with

What edition and section is the requirement coming from????

 

[mark handler]

You don't seem to understand

First, You need to determine if you need a fire Wall or Barrier, before you look for a UL assembly

If you don’t know then, you need to find someone that does

FIRE BARRIERS

A fire-resistance rated wall assembly of materials designed to restrict the spread of fire in which continuity is maintained. This wall is Vertical Only.

If the fire barrier is to run in a horizontal position, it is now referred to as a HORIZONTAL ASSEMBLY.

A Fire Barrier is used:

• To separate a (SINGLE USE-OCCUPANCY) within the building into smaller FIRE AREAS to eliminate the requirement for sprinklers.

• To separate different types of occupancies. (MIXED USE-OCCUPANCY SEPARATION)

• To separate INCIDENTAL USE AREAS.

• For Shaft/Exit Enclosures (stairs, elevators, mechanical)

• For Horizontal Exits

• For Exit Passageways

• For Atriums

• For Control Areas

• Ducts and air transfer openings

FIRE WALLS

A fire resistance rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall. This wall is a Vertical Only

Assembly. There is an exception to this in the code for Open and Enclosed Parking Garages.

A Fire Wall is used:

• To separate the building into TWO SEPARATE BUILDINGS to meet compliance with the maximum allowable area requirements in Chapter 5. (AREA SEPARATION)

• To separate the building into TWO SEPARATE BUILDINGS having two different construction types.

• To separate the building into TWO SEPARATE BUILDINGS due to fire flow requirements. (IFC)

• To separate an un-sprinklered area of a building from the sprinklered area, therefore, allowing for a fully sprinklered building.

• Ducts and air transfer openings in fire walls to be protected with fire dampers.

 

[mark handler]

If you don’t know, you need to find someone that does

 

[peach]

The old SBCCI required "fire walls" to be 4 hour.. period. Since the IBC changes that, you may have different design options available.

 

[aztec]

cda,

I'm using IBC 2009 fifth edition. From Section 706.6, it says I need a 30" parapet. I know I need a firewall vs a fire barrier because 1) the code official wrote that we needed a fire wall vs a fire barrier 2) because I am separating three buildings on one lot. Due to max. allowable area requirements, we have to separate with a fire wall. Knowing that I need a fire wall is pretty easy, it's the parapet condition that is an issue. Mark, you are completely correct - I guess I didn't really spelll out that I know I need a firewall. I appreciate the points though. What happened was someone drew up a 3-hr fire barrier, and that clearly wasn't correct, hence the note from the code official.

Peach, thanks for filling the 4-hr question I had: our new building is adjoining two other buildings and I noticed there is a 4-hr fire wall in the as built drawings (between the two we are building up to). I could not figure out why that was there, but now I know. The buildings are all H-5/Type II B full sprinklered construction. The building separation line is somewhat of an issue, but like I mentioned before, the parapet is the real challenge. That's why I looked at Section 706.6 Exemption 3. My thought was that IF I had the right construction materials in the roof, I could get rid of the parapet. Mark said the galvanized metal deck is not combustible, so I'll confirm that tomorrow at work. The last part is the class B roof covering - I know it's TPO but I have no idea what was specified. I'll need to dig around tomorrow.

Again, as Mark has stated I am using a firewall to separate the building into THREE SEPARATE BUILDINGS to meet compliance with the maximum allowable area requirements. That's why I know I need a fire wall vs a fire barrier. Thanks for all the comments. I'm ready for monday!

 

[aztec]

Can you answer why the three hour is needed???

cda, I meant to write TABLE 706.4 (IBC 2009 5th ed): group H-5 = 3hr.

sorry, typing too fast.

 

[cda]

You have an existing H-5?

How many sq ftis the entire bldg???