# Most cost-effective fire wall?



## DwightB (Apr 23, 2012)

2006 IBC, existing 80' x 250' typical steel-framed building, with wood framed offices and mezzanine above.  City had originally thought IIB construction until they learned of the wood construction that had been added inside.  Now the owner wants to add another 80' x 150' and is way over square footage limits for VB construction and the city wants a fire wall.  The owner wants to install 2 layers of sheetrock to the existing skin, then add a stud wall and 2 more layers of sheetrock on the new side of the studs, thus creating a 2 hour wall.  Screws from the inside of the flanges could attach the sheetrock to the studs from the "inside" of the new stud wall and then the sheetrock would no longer be dependent upon support by the existing skin (ave ht 19').  The joints could be overlapped as required and taped, but the tape and finish would be on the inside face of the sheetrock.  Is this "close enough" to UL to be acceptable, or is there a better option?  Gotta be cheap.


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## twistr2002 (Apr 23, 2012)

I would check with the gypsum construction guide, that would provide several different options for a listed firewall assembly.  Here is a link to the pdf

http://www.nationalgypsum.com/resources/construction-guide/NGCGypWallBoard.pdf   Hope this helps


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## TheCommish (Apr 23, 2012)

i would suggest a cmu wall, keep the openings between to a minumim


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## DwightB (Apr 23, 2012)

twister2002: All of the installation instructions talk about fastening the gyp to the studs, even in one case, putting some gyp on one side, then installing on the other side, then returning to the first side to complete the attachment.  Client wants to screw both layers to the sheet metal skin of the building (I calculate about 6,600 pounds), then building a stud wall adjacent to it and screwing at an angle into the flange from the outside and then into the 2 layers of gyp, thus "securing" it to the studs, but without a screw head to hold it to the stud.  Taping the surface of the top layer is impossible because that layer is the one against the metal skin.

How about this option?  Build the stud wall first, leaving a 4" gap between skin and studs.  Then erect the new building with the structure having another 4" gap on the new side.  Get the building weather-tight, then slip the 2 layers of gyp into the 4" gap on the new side to complete the 2 layers on that side.  Then move to the old side, remove the skin from the inside (disassemble girts, cut screws as needed to dislodge the skin), and slip the 2 layers of gyp into the old side of the stud wall to complete the fire wall.

Is all of this trouble less expensive than an simple 6" block wall?


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## cda (Apr 23, 2012)

Does it have to have Structural independence????

Do not have the book

Or at least a tested assembly??

And what to do with penetrations?


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## steveray (Apr 24, 2012)

Personally.....I think there is no "intent" to a lsted assembly...it is or is not.....I have seen equivalecies approved before...just not by me.....


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## Builder Bob (Apr 24, 2012)

2 hour shaft wall with H channel - what is the height invoved for the height of the endwall?


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## DwightB (Apr 24, 2012)

The end wall in question is 16' at the eaves, 22' at the peak, 80' long.  Is that too much to build using shaft wall techniques?


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## DwightB (Apr 24, 2012)

I don't see how a shafwall could have structural independence from either side if the other burns down.


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## Pcinspector1 (Apr 24, 2012)

The cmu wall most likely would need a footing below the slab at 19ft.

But I have a question why is'nt there a design professional making the options available?

pc1


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## DwightB (Apr 24, 2012)

Check my profile.  I am the design professional, looking for the best option.  I thought this forum was open to architects, not just building inspectors.  Sorry if I intruded.


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## cda (Apr 24, 2012)

one problem is we are talking on words, with out some type of plan sometimes hard to make a call.

I would be looking first to a UL or other approved wall design, than try to fit it to the building.

do you have tested assemblies with some of the proposals you are trying to use?????


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## Pcinspector1 (Apr 24, 2012)

Sorry, Dwight no intrusion at all, you are correct this is not only for inspectors. Good luck with this project.


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## fatboy (Apr 24, 2012)

DwightB, of course you are welcome here.


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## cda (Apr 24, 2012)

Dwight I guess where are you getting the design for the rated wall is it UL, some other approved lab, or chapter 721 IBC????

if you reference that,, the ones with more knowledge than me can give you a better answer


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## Paul Sweet (Apr 24, 2012)

Gold Bond says their H-Stud Area Separation Wall can go up to 66' high.  http://www.nationalgypsum.com/products/Product.aspx?ProductID=2390

Steel H-Stud framing members are attached on each side to adjacent framing with breakaway, heat softenable aluminum ASW Clips for lateral stability.  I'm not sure if they can be screwed to the existing metal skin before the wall is built (the most common application is between stud walls of adjoining residences).  Most gypsum board manufacturers offer similar assemblies.


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## DwightB (Apr 24, 2012)

U425 is the owner's choice.  But one side is an existing building.  With weather and security issues, the owner is asking that I specify the two layers of gyp on the existing side be attached originally to the skin of his building, then erect the stud wall, then somehow put in the required screws to the studs.  It seems to me that the primary support for the gyp would be the skin and if a fire was on that side, the skin and gyp would fall, leaving the studs of my fire wall exposed.  Another way would be to leave enough space between the red iron to allow a 4" or more gap between red iron and fire wall studs.  Then, after the building is weatherproof, remove the existing skin and add gyp in the proper sequence working through the original steel structure (girts and columns of the end wall), adding the 2 layers of gyp and taping the outer layer.


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## Codegeek (Apr 24, 2012)

I'll throw this out for consideration...have you thought about Type IIIB?  Only the exterior bearing walls would have to be rated, so if there are no exterior bearing walls, then nothing would have to be rated.  It would increase your allowable square footage so that perhaps this whole issue with the rated wall would go away.


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## DwightB (Apr 24, 2012)

Paul, U347 shows fire from one side, so the Gold Bond detail shows framing on both sides, essentially giving the rating for each side correctly but using only 2 layers of gyp.  In the UL book and the Gold Bond book, both are called "area separation" walls.  The code requires my installation to be a "fire wall".


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## DwightB (Apr 24, 2012)

CodeGeek, great suggestion.  I think the city official was wrong when she said the existing is VB.  I believe it and the new will qualify as IIIB and meets the area limits.


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## syarn (Apr 24, 2012)

the exterior walls still need to be rated unless the building is more than 30 feet away on all sides from an other structures right???

table 602


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## Builder Bob (Apr 24, 2012)

DwightB said:
			
		

> I don't see how a shafwall could have structural independence from either side if the other burns down.


Wrong.... a firewall only has to allow the construction on one side to fail without affect the other side....... A 2 hour shaft wall with aluminum clips tied into both support end walls would qualify as a firewall in the terms of the IBC -----

The strucutral independence went out the window with the old standard code unless the stae or your muunicipality amended the IBC.

FIRE WALL. 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.


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## Codegeek (Apr 24, 2012)

syarn said:
			
		

> the exterior walls still need to be rated unless the building is more than 30 feet away on all sides from an other structures right???table 602


You are correct.  If the wall is greater than ten feet but less than thirty feet to the property line than the exterior walls must be at least one hour.


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## brudgers (Apr 24, 2012)

DwightB said:
			
		

> 2006 IBC, existing 80' x 250' typical steel-framed building, with wood framed offices and mezzanine above.  City had originally thought IIB construction until they learned of the wood construction that had been added inside.  Now the owner wants to add another 80' x 150' and is way over square footage limits for VB construction and the city wants a fire wall.  The owner wants to install 2 layers of sheetrock to the existing skin, then add a stud wall and 2 more layers of sheetrock on the new side of the studs, thus creating a 2 hour wall.  Screws from the inside of the flanges could attach the sheetrock to the studs from the "inside" of the new stud wall and then the sheetrock would no longer be dependent upon support by the existing skin (ave ht 19').  The joints could be overlapped as required and taped, but the tape and finish would be on the inside face of the sheetrock.  Is this "close enough" to UL to be acceptable, or is there a better option?  Gotta be cheap.


  What makes it VB rather than IIIB?


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## imhotep (Apr 24, 2012)

DwightB said:
			
		

> 2006 IBC, existing 80' x 250' typical steel-framed building, with wood framed offices and mezzanine above.  City had originally thought IIB construction until they learned of the wood construction that had been added inside.  Now the owner wants to add another 80' x 150' and is way over square footage limits for VB construction and the city wants a fire wall.  The owner wants to install 2 layers of sheetrock to the existing skin, then add a stud wall and 2 more layers of sheetrock on the new side of the studs, thus creating a 2 hour wall.  Screws from the inside of the flanges could attach the sheetrock to the studs from the "inside" of the new stud wall and then the sheetrock would no longer be dependent upon support by the existing skin (ave ht 19').  The joints could be overlapped as required and taped, but the tape and finish would be on the inside face of the sheetrock.  Is this "close enough" to UL to be acceptable, or is there a better option?  Gotta be cheap.


Typical steel framed building:  Metal clad exterior - metal girts - steel structural frame?  Sounds like a IIIB construction type.

What is the use and occupancy?  If mixed occupancy then Separated or Nonseparated?


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## DwightB (Apr 24, 2012)

CodeGeek:  I have greater than 30' in all directions, so can take the max 75%, which qualifies the building.

Brudgers:  When the local BO learned that wood framed walls and mezzanine floor above had been added, she said, "then it's a VB" and I went along with that.  However, with the suggesting by a member here referring to IIIB, a close examination of the code revealed the 0 hr requirements, except for exterior bearing walls (there are none with the steel framed building), and allows "any material allowed by code" for interior elements, no ratings required.   I agree that the building satisfies the IIIB requirement.  So with a IIIB, I'm allowed enough square footage (with a perimeter increase) that the building qualifies without a fire wall.

Imhotep:  Occupancy is S-2, storage of non-flammables on wood pallets (basically an HVAC wholesaler).  New addition is assumed will be a similar operation.


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## brudgers (Apr 24, 2012)

DwightB said:
			
		

> CodeGeek:  I have greater than 30' in all directions, so can take the max 75%, which qualifies the building.  Brudgers:  When the local BO learned that wood framed walls and mezzanine floor above had been added, she said, "then it's a VB" and I went along with that.  However, with the suggesting by a member here referring to IIIB, a close examination of the code revealed the 0 hr requirements, except for exterior bearing walls (there are none with the steel framed building), and allows "any material allowed by code" for interior elements, no ratings required.   I agree that the building satisfies the IIIB requirement.  So with a IIIB, I'm allowed enough square footage (with a perimeter increase) that the building qualifies without a fire wall.  Imhotep:  Occupancy is S-2, storage of non-flammables on wood pallets (basically an HVAC wholesaler).  New addition is assumed will be a similar operation.


  I take paypal.


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## Builder Bob (Apr 25, 2012)

please define a wall per the building code..... it doesn't exist. the metal panels are not anythiong but a veneer, the purlins that the metal panels attach to are unable to exist without the vertical members that they attach to. the purpose of rating the exterior load bearing walls of a type III buildig is to prevent the exterior walls from collapsing.  (Old town USA - fire cuts)

With the intent being to prevent the exterior walls from collapsing, the interpretation from my old building official would require any vertical load bearing component that purliins attached to be to be fire rated for two hours.......... this prevented the installation of pre-engineered metal buildings with wooden interior partitions ---- So I couldn't have have a S-1 17,500 SF two story facility when in essence it is a type V B construction limited to a single story and 9,000 SF...... because the wooden interior partitions may be protected from fire exposure from one side but not the other when placed along the exterior veneer wall of the building.

FWIW, I do not agree witht the classification of the building as a type III building.


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## syarn (Apr 25, 2012)

does the BO have a record of the bldg permit app for the addition of the wood framed walls & mezzanine floor and what the construction type classification was for that work?


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## DwightB (Apr 25, 2012)

Builder Bob:  The exterior walls are not supporting the roof.  The beams, columns, and purlins are structure that supports the exterior walls and roof.  Table 601 says: "Structure, 0 HR", whether Type IIB, IIIB or Type VB, and specifically defines the "structure' to be columns girders, beams trusses

Interior, the wood partitions and mezz floor (Type IIIB allows any material allowed by code on interior) are not part of the building structure.


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## DwightB (Apr 25, 2012)

syarn: NO, that was an illegal construction.  There was no permit, the city didn't know about it until now.


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## Builder Bob (Apr 25, 2012)

If the exterior all isn't supporting the roof.... define wall per the building code.

The columns are the support (I agree)

However, what is holding up the purlins and the veneer of the exterior section of the building?


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## DwightB (Apr 25, 2012)

Veneer may be a poor choice of words.  Veneer is basically a cosmetic finish surface with no structural ability that is laminated on to a supporting backing.  The metal skin of the building has sufficient strength to span the distance between girts, but is not a bearing wall.  The skin can be completely removed and the building will still stand.  In fact, the skin is the last thing to be applied, unlike a bearing wall, which must be built before the roof or upper levels can be built.

The columns are holding up the purlins and skin, and are specifically excluded from fire rating.

The skin is 30' or greater from adjacent property line, so no requirement there either.


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## mtlogcabin (Apr 25, 2012)

EXTERIOR WALL. A wall, bearing or nonbearing, that is used as an enclosing wall for a building, other than a fire wall , and that has a slope of 60 degrees (1.05 rad) or greater with the horizontal plane.


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## ggmarch (Apr 25, 2012)

wait a second.....just going IIIb doesn't solve the problem that no separation if it's required.....add it up..... a building of 20,000 orig SF plus the 10,000 New SF leaving you with a 30,000 SF building. still an issue and needs a variance IMHO....are there penetrations between old and new?

...... the owner's assembly is not tested therefore, it won't pass muster.....cheapest method....2x6 wall(metal) with double firecode. build section at a time drywall side facing existing bldg, tape joints, tilt in place, brace as required cover inside face with double drywall (X) and repeat. maybe a little more labor intensive is go the UL U336 route.

 it's unfortunate, but the new code doesn't like existing buildings. i just got one through after 2 months of going back and forth with the code official about a steel manufacturing plant addition where the existing building didn't fall nice and neatly into the current code therefore any alteration of the building would have made their whole operation illegal and non compliant. the code official granted our claim of both existing S-2 F-2 in a pre-engineered stl building(fit no building type) and the addition F-2 S-2  in a pre-engineerd stl building both as type IIb and no separation required. i totally redesign for the 2 hr independent wall between existing and new and then one day they called and said, they just made it a non-issue. i'm sure a bunch here will find that offensive, but it's within the code official's right to accept reasonable deviations from the code(if they couldn't, there'd be no reason for a variance hearing board and the code book would be 20' thick instead of 3 inches)


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## mtlogcabin (Apr 25, 2012)

Type IIIB S2 allows 26,000 sq ft. He is allowed an increase because of the 30 ft around the building.

If he had 60 ft it could be unlimited

507.2 Nonsprinklered, one story.

The area of a Group F-2 or S-2 building no more than one story in height shall not be limited when the building is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.


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## Builder Bob (Apr 25, 2012)

The metal skin is a veneer - addressed by table 1405.2  and section 1405.11 of the IBC.

The metal skin is a veneer as it does not provide any structural stability to the building..... the purlins and wind/siemic bracing provide the structural support for racking of a structure.


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## brudgers (Apr 25, 2012)

DwightB said:
			
		

> Veneer may be a poor choice of words.  Veneer is basically a cosmetic finish surface with no structural ability that is laminated on to a supporting backing.  The metal skin of the building has sufficient strength to span the distance between girts, but is not a bearing wall.  The skin can be completely removed and the building will still stand.  In fact, the skin is the last thing to be applied, unlike a bearing wall, which must be built before the roof or upper levels can be built. The columns are holding up the purlins and skin, and are specifically excluded from fire rating. The skin is 30' or greater from adjacent property line, so no requirement there either.


  The correct term is "curtain wall."


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## brudgers (Apr 25, 2012)

ggmarch said:
			
		

> wait a second.....just going IIIb doesn't solve the problem that no separation if it's required.....add it up..... a building of 20,000 orig SF plus the 10,000 New SF leaving you with a 30,000 SF building. still an issue and needs a variance IMHO....are there penetrations between old and new?  ...... the owner's assembly is not tested therefore, it won't pass muster.....cheapest method....2x6 wall(metal) with double firecode. build section at a time drywall side facing existing bldg, tape joints, tilt in place, brace as required cover inside face with double drywall (X) and repeat. maybe a little more labor intensive is go the UL U336 route.     it's unfortunate, but the new code doesn't like existing buildings. i just got one through after 2 months of going back and forth with the code official about a steel manufacturing plant addition where the existing building didn't fall nice and neatly into the current code therefore any alteration of the building would have made their whole operation illegal and non compliant. the code official granted our claim of both existing S-2 F-2 in a pre-engineered stl building(fit no building type) and the addition F-2 S-2  in a pre-engineerd stl building both as type IIb and no separation required. i totally redesign for the 2 hr independent wall between existing and new and then one day they called and said, they just made it a non-issue. i'm sure a bunch here will find that offensive, but it's within the code official's right to accept reasonable deviations from the code(if they couldn't, there'd be no reason for a variance hearing board and the code book would be 20' thick instead of 3 inches)


  Probably use area increase for frontage.


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## DwightB (Apr 25, 2012)

Brudgers: Yes, the perimeter increase gives me the additional square footage needed to be inside the allowable.  We just spent 2 days in our office trying to figure out the tilt-up idea using the exact system you described.  We finally decided that 4 sections, 20' wide and 15' (lowest eave) to 22' (peak) high, but eventually decided that walking around on the gyp while installing and taping might break some of it.  Then, how to lift it without buckling the steel studs looked like an insurmountable problem.  We had a 20' tall interior wall that was being framed up in a building that wasn't completely enclosed, wind got behind it and buckled the studs, folded the framing over.  If a 20' section (or even 10' x 8 sections) bent or bowed the least little bit, I think the studs would buckle and we'd have a pile of useless gyp and steel.  At a minimum, I'd expect some joints to pop if the wall bowed a little.  Two layers of gyp on the 80' wall would amount to 6,600 lbs of gyp. Four sections would still be a lot of weight to pick up and move into position.  Eight sections would still be 1,000 lbs each with steel included; that seemed too heavy to lift 8 sections perfectly without a failure.  That would also assume a stretch of dry days during the process.

We thought there would be another problem linking the sections together since you couldn't tape the hidden backside seam.  Spray firestopping between sections seemed the only option.  We finally came down to a simple 6" block wall, with adequate reinforcing; wouldn't have to be pretty, just effective.

We measured the site all the accuracy of eyeballs and tape and think there may only be 29' to an interior property line.  The owner has instructed his surveyor to provide a new site plan showing a relocated interior lot line that is 30' or greater from the building so we don't have a Table 602 problem.  If the adjacent property ever sells to a separate individual, he'll have a bit less to mow.


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## brudgers (Apr 25, 2012)

Uhh...I didn't describe a system.


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## Builder Bob (Apr 26, 2012)

H channel shaft wall.


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## DwightB (Apr 28, 2012)

Final score:

City: won

Architect: 0

The CBO pointed to 714.5 and said I'd have to fire-rate all of the structure (existing and new) to be IIIB, so I caved, will go with the firewall, choosing 8" block as the cost-effective solution.

While waiting on the city's response, research on the web shows that this issue has been in contention for years, even saw a comment by BuilderBob in '05 on iccsafe.

In the final outcome, Type VB, with the firewall, and qualifying perimeter increases on remaining 3 sides, both buildings are legal.

Client is not thrilled, but content with the solution.


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## imhotep (Apr 28, 2012)

DwightB said:
			
		

> Final score:City: won
> 
> Architect: 0
> 
> ...


Take a minute please and clarify the issue for me if you would.

As I understand the AHJ's interpretation it is that the exterior non-bearing metal cladding attached to girts does not constitute an exterior wall.  That the structural frame the girts and cladding are hung off of is considered to be *within the wall* and so the frame must be protected as if it is a bearing wall - 2HR.  Do I have that right?  You do have > 30' separation on all sides, right?  So I wonder what a non-bearing exterior wall is.


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## DwightB (Apr 28, 2012)

imhotep:  You got it right,  This is the word from CBO:

Dwight, you have read the table correctly, however, as are many other things in the IBC code, some types of construction have requirements in other sections, this is one of those.  Below is the section that refers to structural members in an exterior wall and the requirement that they have the same rating as the exterior bearing wall rating from the table, so to qualify a metal building as type IIIB construction the structure would need to be rated to 2 hours, which requires some sort of fireproofing or wrapping to meet this requirement.  Based on these requirements, the existing buildings would not be classified as IIIB.

I do have 30' or more separation from the nearest interior property line, so no rating requirement because of that.  Some people have told me that the skin actually does perform a structural function for the building, so that might be reason for it to be included in the definition of "bearing".  But the section he quotes here specifically says that the columns must be included also.

I could envision a column and structural slab configuration with inset columns and aluminum storefront walls that would be very hard for any CBO to call "bearing", but I guess I lose on this one.

However, I still agree with you, the exterior structural columns (red iron frames) are hardly "within" the exterior wall and footnote "a", Table 601 specifically excludes structure, with no requirement pertaining to interior/exterior or "within" a wall.

Technically, At the beginning of all this, I did have an interior lot line about 5' away, however, the site has been surveyed and a new description is being written that will adjust the property line to 30' or greater from the wall.

 xxxxxxx, CBO

Building and Neighborhood Improvement Supervisor

City of xxxxxx

(417) xxx-xxxx, Ext xxx

714.5 Exterior structural members. Load-bearing structural members located within the exterior walls or on the outside of a building or structure shall be provided with the highest

fire-resistance rating as determined in accordance with the following:

1. As required by Table 601 for the type of building element based on the type of construction of the building;

2. As required by Table 601 for exterior bearing walls based on the type of construction; and

3. As required by Table 602 for exterior walls based on the fire separation distance.

_Exterior load-bearing structural members, such as columns or girders, must have the same fire-resistance rating as is required for exterior load-bearing walls. As such, the required fire-resistance rating is the higher rating of that found in Table 601 for type of construction for structural elements or bearing walls or as required in Table 602 based upon the separation distance.


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## DwightB (Apr 28, 2012)

Sorry to create confusion, the two paragraphs beginning with "I do have 30' ..." and ending with "...greater from the wall" are mine to clarify for imhotep, not from the CBO.  All of the rest is the CBO's letter to me.


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## DwightB (Apr 28, 2012)

Here's a clearer version:

    imhotep: You got it right, This is the word from CBO:

_Dwight, you have read the table correctly, however, as are many other things in the IBC code, some types of construction have requirements in other sections, this is one of those. Below is the section that refers to structural members in an exterior wall and the requirement that they have the same rating as the exterior bearing wall rating from the table, so to qualify a metal building as type IIIB construction the structure would need to be rated to 2 hours, which requires some sort of fireproofing or wrapping to meet this requirement. Based on these requirements, the existing buildings would not be classified as IIIB._

_      xxxxxxx, CBO_

_    Building and Neighborhood Improvement Supervisor_

_    City of xxxxxx_

_    (417) xxx-xxxx, Ext xxx_

_    714.5 Exterior structural members. Load-bearing structural members located within the exterior walls or on the outside of a building or structure shall be provided with the highest_

_    fire-resistance rating as determined in accordance with the following:_

_    1. As required by Table 601 for the type of building element based on the type of construction of the building;_

_    2. As required by Table 601 for exterior bearing walls based on the type of construction; and_

_    3. As required by Table 602 for exterior walls based on the fire separation distance._

_    _Exterior load-bearing structural members, such as columns or girders, must have the same fire-resistance rating as is required for exterior load-bearing walls. As such, the required fire-resistance rating is the higher rating of that found in Table 601 for type of construction for structural elements or bearing walls or as required in Table 602 based upon the separation distance. _



  I do have 30' or more separation from the nearest interior property line, so no rating requirement because of that. Some people have told me that the skin actually does perform a structural function for the building, so that might be reason for it to be included in the definition of "bearing". But the section he quotes here specifically says that the columns must be included also.

    I could envision a column and structural slab configuration with inset columns and aluminum storefront walls that would be very hard for any CBO to call "bearing", but I guess I lose on this one.

    However, I still agree with you, the exterior structural columns (red iron frames) are hardly "within" the exterior wall and footnote "a", Table 601 specifically excludes structure, with no requirement pertaining to interior/exterior or "within" a wall.

    Technically, At the beginning of all this, I did have an interior lot line about 5' away, however, the site has been surveyed and a new description is being written that will adjust the property line to 30' or greater from the wall.


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## imhotep (Apr 29, 2012)

DwightB said:
			
		

> imhotep:  You got it right,  This is the word from CBOwight, you have read the table correctly, however, as are many other things in the IBC code, some types of construction have requirements in other sections, this is one of those.  Below is the section that refers to structural members in an exterior wall and the requirement that they have the same rating as the exterior bearing wall rating from the table, so to qualify a metal building as type IIIB construction the structure would need to be rated to 2 hours, which requires some sort of fireproofing or wrapping to meet this requirement.  Based on these requirements, the existing buildings would not be classified as IIIB.


Thank you for the response.  Had the same discussion with an AHJ and they determined that the frame was not within the non-combustible non-bearing exterior wall.  Go figure.


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## Builder Bob (Apr 30, 2012)

Gotta change my penname.... my time on the boards has been documented....

"While waiting on the city's response, research on the web shows that this issue has been in contention for years, even saw a comment by BuilderBob in '05 on iccsafe."


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## brudgers (Apr 30, 2012)

Typically metal building columns are not exterior, nor are they within the exterior wall.


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## DwightB (May 3, 2012)

Ok, I still lose.  I got a technical interpretation from ICC and they agree with the city.  The steel framing that is located at the exterior _*is*_ "within" the wall according to ICC and would need 2hr protection if I choose to use a IIIB construction type for the building.  The adviser who called agreed that the verbiage is unclear and pointed out that the wording in the 2000 edition where 713.5 reads "structural members located in exterior walls or along the outer lines of a buillding or structure shall be protected as required by Table 601 for exterior load-bearing walls based on the type of construction."  He said it was "clarified" in the 2003 edition.


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## brudgers (May 3, 2012)

DwightB said:
			
		

> Ok, I still lose.  I got a technical interpretation from ICC and they agree with the city.  The steel framing that is located at the exterior _*is*_ "within" the wall according to ICC and would need 2hr protection if I choose to use a IIIB construction type for the building.  The adviser who called agreed that the verbiage is unclear and pointed out that the wording in the 2000 edition where 713.5 reads "structural members located in exterior walls or along the outer lines of a buillding or structure shall be protected as required by Table 601 for exterior load-bearing walls based on the type of construction."  He said it was "clarified" in the 2003 edition.


  I'm sorry, but that's not consistent with Table 601 footnotes a and g and that is what governs exterior walls per 704.5.  You have a structural frame.

  You have an exterior, non-load bearing wall.

  You have more than 30' from the property lines.

  Where does two hours come from?


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## mtlogcabin (May 3, 2012)

The wall has to be constructed of metal or wood studs or masonry to be a load bearing wall.

ICC and the BO are wrong

Table 601

Nonbearing walls and partitions  Exterior      See Table 602

WALL, LOAD-BEARING. Any wall meeting either of the following classifications:

1. Any metal or wood stud wall that supports more than 100 pounds per linear foot (1459 N/m) of vertical load in addition to its own weight.

2. Any masonry or concrete wall that supports more than 200 pounds per linear foot (2919 N/m) of vertical load in addition to its own weight.


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## DwightB (May 3, 2012)

According to the answer man, the 2 hours is right there in Table 601 under Type IIIB construction, Bearing Walls, Exterior: 2

The fact that footnote a excludes the columns, girders, etc carried no weight.

His primary argument was from 714.5, "Load-bearing structural members located within exterior walls or on the outside of a building or structure shall be determined in accordance the highest fire-resistance rating as determined in accordance with the following:

1.  Table 601 for the element according to construction type. (Exterior wall, IIIB - 2 hr)

2.  Table 601 for exterior bearing walls based upon construction type.  (Exterior wall, IIIB - 2 hr)

2.  Table 602 for exterior walls based upon fire separation distance (30' clear - 0 hr)

He basically agreed that the "within the exterior wall" part of the definition was a poor choice of words and pointed to the 2000 edition where it was more clearly stated as "Structural members located in exterior walls _*or along the outer lines of a building or structure shall be protected as required by Table 601 for exterior bearing walls*_ based on the type of construction."

Using that wording, it's hard to say that the steel main frame members at the purlin line of the exterior wall is not included in the requirement to be rated as according to bearing walls, again a 2 hr requirement.

So, brudgers, yes there is a structural frame and because it is along the exterior wall, must be rated as for an exterior bearing wall.  Whether bearing or non-bearing and 30' or more separation is not a mitigating factor.

So, mtlogcabin, bearing/non-bearing walls, not a factor.  The frame must be rated 2hr because it is structure that is "within" (or more clearly in 2000 IBC, "along the outer lines of the building") the outer wall.

As such, I cannot go with IIIB construction and will go with VB and use a firewall to break it down to legal portions.


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## brudgers (May 4, 2012)

By that definition of "within exterior walls," the two hour rating would apply to all interior columns.

And all exterior walls would be load bearing.

The intent of 714.5 is that when you have a load bearing wall, you cannot interrupt the fire rating for a column, or floor joist.

Furthermore the fact that it has changed, indicates that the language in the 2000 edition *was not* *the intent *of the section.

Even if the reviewer wishes it was.

Tl;dr = it's not a bearing wall.


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## DwightB (May 4, 2012)

So, I'm back to needing an inexpensive firewall to separate buildings.  Owner is balking at 8" block ($13K) and suggesting steel studs laid out horizontally, install rock and tape 2 layers and tilt up in sections, then rock and tape exposed side (that's what I was considering 2 wks ago).  Bldg Mfr is checking to see about just installing the 2 layers on the skin of the existing (how can I possibly tape the "face" of the finished wall on the existing side if it's screwed to an existing building?).  Then add steel studs and 2 more layers of rock.  It seems that a fire on the existing would pull the existing side of rock down and then I would lose the fire wall.

Am I re-inventing a wheel?  How do others firewall between old and new metal buildings?


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## brudgers (May 4, 2012)

DwightB said:
			
		

> Am I re-inventing a wheel?  How do others firewall between old and new metal buildings?


By making it go away through proper interpretation of the current building code rather than applying some half-assed interpretation of the 2000 version.

Otherwise, area separation wall.


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## Big Mac (May 4, 2012)

Well Dwight - I certainly hope you have been adequately straightend out.  The omnipotent one has spoken.


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## syarn (May 4, 2012)

http://www.aicinsulate.com/insulrock.htm

http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=BXUV.U042&ccnshorttitle=Fire+Resistance+Ratings+-+ANSI/UL+263&objid=1074330117&cfgid=1073741824&version=versionless&parent_id=1073984818&sequence=1

will this do it for u?  not sure of the cost....


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## steveray (May 4, 2012)

If that is the direction you are going Dwight....don't forget about the structural independance of that firewall......


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## syarn (May 4, 2012)

http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=BXUV.U930&ccnshorttitle=Fire+Resistance+Ratings+-+ANSI/UL+263&objid=1077945107&cfgid=1073741824&version=versionless&parent_id=1073984818&sequence=1

some of the ICF companies have 2 hour ratings with BEARING...with poured concrete & rebar....stand alone maybe...


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## syarn (May 4, 2012)

704.10 exterior structural members might be it....the structure is load bearing & therefore needs to be 2 hour protected...in IIIB...


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## brudgers (May 4, 2012)

syarn said:
			
		

> 704.10 exterior structural members might be it....the structure is load bearing & therefore needs to be 2 hour protected...in IIIB...


Read the definition of "Wall, Load Bearing."

It's on page 21 of IBC 2009.

It's on page 20 of IBC 2006.

It's on page 269 of IBC 2003.


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## syarn (May 4, 2012)

ok.

hmm...the way I read 704.10 is "load-bearing structural members" (not a wall) have to be provided with a fire-resisance rating as determined by the three following:

1. the construction type IIIB - rating as primary structure 0 hours.

2. construction type IIIB -rating AS A EXTERIOR BEARING WALL (so not that a bearing wall exists BUT that the load bearing structure is) - 2 hours.

3.  exterior walls based on separation > 30 feet - 0 hours.


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## brudgers (May 4, 2012)

The secondary members of a PEMB (e.g. the girts) can reasonably be said to be within the wall.

It's asinine to claim that the bents are.


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## DwightB (May 4, 2012)

Beating a dead horse, will go with 2 hr fire wall.  Owner has chosen wood framing, built horizontally in sections with 2 layers of x-ratedtop gyp on the surface, then the builder insists he can tilt them into position, fire caulk and attach together and to the existing building with alum screws, then 2 layers of x on the new face and finish the new building.


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## brudgers (May 4, 2012)

Two comments:

  1. Isn't this the guy who built without a permit?

  2. With the Owner designing it, at least you won't be sealing it.


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## Polar (May 9, 2012)

Are max. fire areas an issue (also Ch. 7) Block wall can be an effective solution, easily achieving 3 hours with the right opening protectives. Did you say sprinklers? (sorry skimming 4 pages of posts - probably missed a good deal)


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## DwightB (May 9, 2012)

Will be using a GA design for 2x4 stud wall with 2 layers of gyp and insulation.  No sprinklers.  A 2 hr separation is adequate to allow the existing and new buildings with 30' separation on 3 available sides.


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