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UL wall listing for 2 different ratings

R

Robert

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Jan 29, 2016
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Pinole, CA
I have an exterior wall that needs to be 1 hour rated due to distance from property line, but needs 2 hour rating due to supporting construction (the floor/clg. assembly it is supporting is 2 hour rated). Question: Does the 2 hour rating only apply to the interior face?
 
Not my area

But are you sure the interior wall, entire wall has to be two hour?

If so, than seems like the entire wall has to be two hour inside/ outside.
 
It is implied (although not stated very well) in the code that construction type fire rating is from the inside (protected from itself) and exterior walls/ FSD is from the outside (protected from others).....Fire barriers get protected from both sides, so I would deduce that the supporting structure does as well...But I am a big fan of passive protection.
 
Robert said:
I have an exterior wall that needs to be 1 hour rated due to distance from property line, but needs 2 hour rating due to supporting construction (the floor/clg. assembly it is supporting is 2 hour rated). Question: Does the 2 hour rating only apply to the interior face?
Click to expand...


Ok my non knowledge of IBC answer


So the exterior wall has to be one hour, problem solved.

The ceiling/ floor assembly is two hour, NO Sprinkler system???

So, I am thinking the wall does not have to be two hour on the inside, You just have to meet IBC where the two hour ceiling/ floor assembly meets the one hour wall.


I wait to be corrected, and schooled on this answer.
 
It is my understanding that (per CA Building Code) Section 705.5 may be the appropriate reference for this question. If the FSD is less than or equal to 10 feet, the exterior wall shall be rated for exposure to fire from both sides. Greater than 10 feet to FSD, interior only. This should be sufficient to maintain the integrity of the horizontal assembly, unless I'm missing something.
 
Thanks, I probably should have simplified my question. Does supporting construction need to be rated on both sides? I would think an interior wall would require it and be easy to accomplish but my confusion is the exterior wall. I tend to agree with Steveray that ratings are from the inside (except FSD on exterior walls). My resulting wall will end up being one hour on the exterior face (FSD), and 2 hours on the interior face (supporting construction). Now the other reason I posted this is that the plan checker is asking for a UL listing. I've never seen a UL for asymmetric conditions...1 hour exterior/2 hour interior. Any thoughts? Maybe I need to give him two UL listings, one for each condition.
 
Robert said:
Thanks, I probably should have simplified my question. Does supporting construction need to be rated on both sides? I would think an interior wall would require it and be easy to accomplish but my confusion is the exterior wall. I tend to agree with Steveray that ratings are from the inside (except FSD on exterior walls). My resulting wall will end up being one hour on the exterior face (FSD), and 2 hours on the interior face (supporting construction). Now the other reason I posted this is that the plan checker is asking for a UL listing. I've never seen a UL for asymmetric conditions...1 hour exterior/2 hour interior. Any thoughts? Maybe I need to give him two UL listings, one for each condition.
Click to expand...

Once again not my area

Is the plan checker requiring the actual interior wall to be two hour???

Or did you submit it as two hour???


Where is RLGA when you need him.
 
cda said:
Once again not my area

Is the plan checker requiring the actual interior wall to be two hour???

Or did you submit it as two hour???


Where is RLGA when you need him.
Click to expand...
Yes...any wall that is supporting the floor above (hence "supporting construction") needs to be the same rating as the floor/clg. assembly. I submitted the wall as 1 hour on the exterior face and 2 hours on the interior face. He is asking for a UL listing. I've just never run into a situation where a wall has different exposures and then needing to find a UL listing for it.
 
Ok trying to learn

Do the interior two hour

Submit a one hour design for the exterior

Use the exterior side of the two hour wall as the interior side of the exterior wall.

I think you are allowed to over design??

Where is RLGA when you need him
 
Regarding the exterior wall and the difference in rating requirements from the exterior to the interior membrane.... A UL rating is a listed rating that consists of the entire wall "system" (interior and exterior covering, framing, insulation.. all of it) eliminating or adding to that "system" modifies the listing although there are some specific allowances thereto which can be found in the Gypsum Associations handbook or similar references but they have to be specified per the individual listing to be used in that specific wall type. There aren't listings for asymmetrical walls the more restrictive (higher rated wall) would typically be constructed thus meeting the requirements of both, at least that's what I've seen.

The code doesn't specify side of exposure in regards to supporting construction just like it doesn't specify the type of rated wall that is providing the support as it could be any of the rated wall types (Exterior Wall, Fire Wall, Fire Partition or Fire Barrier). The code just indicates that all supporting construction shall be of at least the same rating not knowing which wall type, or more likely, combination of them is serving that purpose. I think the misconception is that if you are required to have a 1-hour rated wall with exposure from one side you just build the exposure side of the wall to meet the requirement which isn't the case. If the 1-hour listing is a two sided assembly then to get the 1-hour rating on either side you build the whole wall per the listing or find a listing that is one sided to avoid that.

The first 40 pages of the Gypsum Association Design Manual provides some great information for those wanting clarification on these issues.

SIGS
 
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Robert said:
Thanks, I probably should have simplified my question. Does supporting construction need to be rated on both sides? I would think an interior wall would require it and be easy to accomplish but my confusion is the exterior wall. I tend to agree with Steveray that ratings are from the inside (except FSD on exterior walls). My resulting wall will end up being one hour on the exterior face (FSD), and 2 hours on the interior face (supporting construction). Now the other reason I posted this is that the plan checker is asking for a UL listing. I've never seen a UL for asymmetric conditions...1 hour exterior/2 hour interior. Any thoughts? Maybe I need to give him two UL listings, one for each condition.
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Your question is: does an exterior wall supporting a 2 hour assembly need to be rated from the interior only.

At least in our code, yes. The only time you would rate something on both sides is an interior load bearing wall. If you think about it practically, you are protecting one occupancy from another. This is what generates the 2 hour rating. Now, because we don't want the 2 hour separation to be compromised due to a structural failure, everything supporting the separation needs to be rated as well based on the risk, which is the occupancy.

I've always found that once you understand what is driving the requirement for the fire rating (the reason why it needs a rating), it helps me understand what else needs to be rated and how. It sounds like you are on the right path and just looking for confirmation.
 
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tmurray said:
Your question is: does an exterior wall supporting a 2 hour assembly need to be rated from the interior only.

At least in our code, yes. The only time you would rate something on both sides is an interior load bearing wall. If you think about it practically, you are protecting one occupancy from another. This is what generates the 2 hour rating. Now, because we don't want the 2 hour separation to be compromised due to a structural failure, everything supporting the separation needs to be rated as well based on the risk, which is the occupancy.

I've always found that once you understand what is driving the requirement for the fire rating (the reason why it needs a rating), it helps me understand what else needs to be rated and how. It sounds like you are on the right path and just looking for confirmation.
Click to expand...


So will the interior and exterior be a two hour assembly???

Or what is the answer to the one hour/ two hour question
 
cda said:
So will the interior and exterior be a two hour assembly???

Or what is the answer to the one hour/ two hour question
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That is the question....I have an asymmetric condition...one hour on the exterior, 2 hour on the interior. And plan checker wants a UL for this condition. Tmurray is using the same logic I am about the 2 hour protection on the interior, being that is where the occupancy separation is. I may have to give the plan checker 2 UL listings for 2 conditions....the 1 hour (from the exterior) and 2 hour (from the interior). I will look at the GA manual as Mark suggested. Thanks for your replies.
 
Robert said:
That is the question....I have an asymmetric condition...one hour on the exterior, 2 hour on the interior. And plan checker wants a UL for this condition. Tmurray is using the same logic I am about the 2 hour protection on the interior, being that is where the occupancy separation is. I may have to give the plan checker 2 UL listings for 2 conditions....the 1 hour (from the exterior) and 2 hour (from the interior). I will look at the GA manual as Mark suggested. Thanks for your replies.
Click to expand...


Ok back to my non IBC knowledge,,,,


You can fab it!!!!!!!!!!!

IBC 2015



Check

722 somewhere in 722 for the interior


Maybe 722.2.1.4

Exterior

722.6.2.2
722.6.2.3
 
Reviving this post to share what plan checker has said about my listed wall assembly which is 1 hour exterior (FSD from property line) and 2 hour interior (supporting construction of 2 hour floor/clg)........ "You have provided a 2-hour wall with listing UL #408. This assembly is only listed on the interior side and supporting construction must be by 2-hour wall assemblies listed from both sides. The CBC does not recognize wall ratings from only the interior or exterior side.".....so at the risk of oversimplifying....no wall assemblies allowed that are asymmetric.
 
Robert said:
Reviving this post to share what plan checker has said about my listed wall assembly which is 1 hour exterior (FSD from property line) and 2 hour interior (supporting construction of 2 hour floor/clg)........ "You have provided a 2-hour wall with listing UL #408. This assembly is only listed on the interior side and supporting construction must be by 2-hour wall assemblies listed from both sides. The CBC does not recognize wall ratings from only the interior or exterior side.".....so at the risk of oversimplifying....no wall assemblies allowed that are asymmetric.
Click to expand...


He who holds the Codes, Makes the Rules.

Anyway, not my area, but I could see if a column is required two hour protection, that protection would have to encapsulate / wrap it.
 
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