# 1 hour rated 1-sided partition



## IndianaJonesy (Jun 29, 2018)

So I have a unique condition where we're building an addition where the mechanical room with one side partially against the existing wall assembly. The owner just requested an upgrade in boiler size at the 11th hour which puts us over the 400k btu/hr threshold and we now need 1 hour separation. I'm trying to figure out a way to make this separation against that existing wall with a one-sided partition or furring detail. The existing wall assembly is brick veneer over metal stud. 







Any suggestions would be appreciated. (IBC 2009)


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## cda (Jun 29, 2018)

Welcome

We do not do "unique condition"" only codes

Anyway give it a little time and you will get some great answers.


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## cda (Jun 29, 2018)

Oh I can answer that, as in one possibility of a thousand.

Just build a one hour wall against the exiting.

Not sure if I will describe it correctly, but find a UL or other approved one hour listed design.

Just start with half the rated wall against the existing wall, add the studs or built it on the ground and stand it, than add the other layer of sheet rock.

Wella a one hour rated wall.


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## cda (Jun 29, 2018)

OR what is the rating of the exiting wall you are going to build against???

There is the build your own rated wall in the IBC, will have to look for the section.


What building code and edition, helps when asking questions, and state??????


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## cda (Jun 29, 2018)

Can someone post the build your own fire wall out of IBC

It might be 721 and 722 IBC 2015


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## IndianaJonesy (Jun 29, 2018)

I'm IBC 2009 as stated, project is located in New Hampshire.

Good idea on the calculated assemblies...I hadn't thought of that in my mini panic attack. I'll see if this meets the one hour required as-is.


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## RLGA (Jun 29, 2018)

I assume you need the 1-hour because of the incidental accessory occupancy requirements per Table 508.2.5 and that the building is not sprinklered.

What is the thickness of the brick veneer? If the veneer is solid, then an equivalent thickness of 2.7 inches is enough to provide a 1-hour rating per Table 721.4.1(1).


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## IndianaJonesy (Jun 29, 2018)

RLGA said:


> I assume you need the 1-hour because of the incidental accessory occupancy requirements per Table 508.2.5 and that the building is not sprinklered.



Correct.



RLGA said:


> What is the thickness of the brick veneer? If the veneer is solid, then an equivalent thickness of 2.7 inches is enough to provide a 1-hour rating per Table 721.4.1(1).



Right, I just found the same thing from cda's post. It's 3-5/8" brick, so it's fine and as simple as specifying appropriate joint systems. 

Thanks for the help...I probably would've gotten there eventually, but with a deadline coming soon, I just didn't think that through all the way!


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## mtlogcabin (Jun 29, 2018)

Use a shaft liner and steel H-studs similar to a townhouse fire separation


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## mtlogcabin (Jun 29, 2018)




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## cda (Jun 29, 2018)

IJ

You know you can become a forum
Supporting “ Sawhorse” and help support this great forum

And when you have more “ unique conditions”

Just make them harder!!!!


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## RLGA (Jun 29, 2018)

IndianaJonesy said:


> Correct.
> 
> 
> 
> ...


Just keep in mind that the requirement is "equivalent thickness" and not actual thickness. If the brick has holes, you'll have to calculate the thickness as if the brick was squished from the long sides to remove the holes. If the brick is solid (i.e., no holes), then there is no question that the brick exceeds the minimum equivalent thickness.


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## JPohling (Jun 29, 2018)

If you cant get the brick to calc out you can easily build a 1 hour shaft wall from one side only right up against the brick.


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## Francis Vineyard (Jun 29, 2018)

Has been your experience designers prefer not to reference IEBC Resource A Guidelines on Fire Ratings of Archaic Materials and Assemblies, and instead find UL assemblies?


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## Tim Mailloux (Jul 11, 2018)

Maybe I'm missing something here but the solution seems very simple. Build a 1 hour rated shaft wall in front of the existing brick veneer. The shaft wall can build from one side and many UL design assemblies are out there.


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## sergoodo (Jul 12, 2018)

RLGA said:


> I assume you need the 1-hour because of the incidental accessory occupancy requirements per Table 508.2.5 and that the building is not sprinklered.
> 
> What is the thickness of the brick veneer? If the veneer is solid, then an equivalent thickness of 2.7 inches is enough to provide a 1-hour rating per Table 721.4.1(1).



...and most likely shaft wall expense not required.  Just show rating calculation of existing wall using IBC presciptive method.


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## Tim Mailloux (Jul 12, 2018)

In my experience a rated wall is required to provide a rating from exposure to fire on either side of the wall.


So playing devil’s advocate here,  while the existing brick veneer finish in this case may provide a 1 hour rating per the IEBC prescriptive method, the brick is probably not self-supporting and the other side of the wall, the existing structural backup wall which laterally supports the existing brick veneer may not provide the required rating. If the backup wall side is exposed to a fire it may be compromised and take the rated brick finish with it.


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