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Changing occupy reduce wall assembly fire rating

ExchangeOR

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Joined
Oct 1, 2025
Messages
6
Location
Oregon
Wow! Great forum rich with knowledge and insight.

I have a commercial property that I am making repairs to. Structure is stuck built from the 1960s. Type V.
South wall (parallel to lot line) is > 3’ and < 5’ from said property line.

Historic occupancy was A.

Building official is requesting a 2hr fire rated wall assembly. Looking at IBC tables 601 & 602,I deduce that this is due in part to the no longer accurate occupancy.

Is this correct and if I change occupancy to B or R or S can I go to 1hr or less?

Thanks for helping a residential guy enter the commercial world
 
VA or VB construction?

Change in occupancy can trigger fire-resistance requirements.

Table 705.5 says that an S-1 occupancy with a fire separation distance of less than 5 feet shall have a 2-hour rated exterior wall. A, B, R, and S-2 would require a 1-hour rated wall.

If the fire separation distance is greater than 5 feet, a 1-hour rated wall is required for all occupancies other than H.

No rating required after 30 feet unless required by 601.

Oregon doesn't appear to modify these requirements at a state-level.
 
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Thanks pros :

I assume VB construction

If “Table 705.5 says that an S-1 occupancy with a fire separation distance of less than 5 feet shall have a 2-hour rated exterior wall. A, B, R, and S-2 would require a 1-hour rated wall.”

Then I shouldn’t be required to upgrade current A occupancy to 2 hrs, correct?

…Just 1hr. Is that 1hr from the inside, outside , or both?

Building inspector is saying that due to the extent of the repair I have to upgrade. Is there a % threshold I can stay under & just put it back like it has been for the last 70yrs?

Thanks for the immediate feedback and keen insights…
 
Building inspector is saying that due to the extent of the repair I have to upgrade. Is there a % threshold I can stay under & just put it back like it has been for the last 70yrs?
Did they provide a code section to justify their request?
 
I believe exterior walls require rating from both sides. Are you, or have you, considered adding sprinklers? That may (or may not) change the equation. If you're considering sprinklers (for insurance or other reasons) you may be able to present the use of sprinklers as an AMM or modification.
 
They did not provide a code section to justify the request. I’m hoping to do my research and respectfully point to code sections that let me keep fire wall assembly to 1hr or non required (not because I don’t respect fire life and safety, just because it adds hard costs, adds Sheetrock to the exterior of my structure in a wet climate and has not had it since the structure was built).

Can you point me to code other than table 601,602 & 705.5 ?

What code triggers “code upgrades” (In this particular instance fire rating of wall assembly) or is it subjective?
 
I had a knee jerk reaction to sprinklers, but it might actually be cost effective in the face of overly strict fire wall assembly measures
Check with your insurance company too. You might be pleasantly surprised at how much better your rate could be with the addition of sprinklers.
 
Can you point me to code other than table 601,602 & 705.5 ?
What version of IBC are you using? I don't see a Table 602 in current IBC.
What code triggers “code upgrades” (In this particular instance fire rating of wall assembly) or is it subjective?
If the Existing Building Code is applicable (I think it would be, but correct me if I'm wrong), there are a few possibilities. IEBC chapter 4 applies to repairs (no change in occupancy or use, no alterations). If all you're doing is repairs, look at this chapter. IEBC 403.1 states "Repairs shall be done in a manner that maintains the level of fire protection provided". I believe repairs alone wouldn't trigger what the Building Official is asking for.

If you're altering the space, then Chapters 6 thru 9 kick in. Depending on the extent of the alteration (I assume this would be Level 3 based on what you've described), sprinklers and fire-resistant upgrades may be required at the area of alteration. See IEBC 802.6.

Change of Occupancy would trigger IEBC 1011. See steveray's post, #3, above. An increase in relative hazard would trigger the need for the exterior walls to be fire-resistant as required by the IBC. See IEBC 1011.7.1.

Local amendments could also trigger stuff. Perhaps the city has amended parts of code and increase what's required (assuming that's something that your state allows).

If the IBC applies and not the IEBC, then yeah, you'll probably have to either make those walls fire rated and/or add sprinklers. IBC doesn't really touch on existing buildings. If the building is considered "existing" as defined in code, then IEBC likely applies instead.
 
Thank you Arwat23 & others !

You have jumpstarted my research

I must have been using an old version of the IBC (see attached).

Now working from 2021

Thank you for directing me to the IEBC!!! Might be my savior.

“”IEBC 403.1 states "Repairs shall be done in a manner that maintains the level of fire protection provided". I believe repairs alone wouldn't trigger what the Building Official is asking for.””

I could have elected to replace and sister some questionable studs, I instead chose to reframe the entire 20’ wide 16’ tall 2x6 stud wall (exterior, non load bearing). I am reducing the use (number of humans present) and lowering the level of hazard (was assembly space, will become office, storage or apartment)…

Will sort out if I am held to IBC or IEBC
 

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Wow! Great forum rich with knowledge and insight.

I have a commercial property that I am making repairs to. Structure is stuck built from the 1960s. Type V.
South wall (parallel to lot line) is > 3’ and < 5’ from said property line.

Historic occupancy was A.

Building official is requesting a 2hr fire rated wall assembly. Looking at IBC tables 601 & 602,I deduce that this is due in part to the no longer accurate occupancy.

Is this correct and if I change occupancy to B or R or S can I go to 1hr or less?

Thanks for helping a residential guy enter the commercial world
Yeah, that 2-hr wall is coming from the change in occupancy and the fact you’re under 5 ft from the line. If you switch to B, R, or S, you can usually get it down to 1 hr in that distance range, but it depends on what code year your AHJ is using
 
Thanks pros :

I assume VB construction

If “Table 705.5 says that an S-1 occupancy with a fire separation distance of less than 5 feet shall have a 2-hour rated exterior wall. A, B, R, and S-2 would require a 1-hour rated wall.”

Then I shouldn’t be required to upgrade current A occupancy to 2 hrs, correct?

…Just 1hr. Is that 1hr from the inside, outside , or both?

Building inspector is saying that due to the extent of the repair I have to upgrade. Is there a % threshold I can stay under & just put it back like it has been for the last 70yrs?

Thanks for the immediate feedback and keen insights…

Do not start by looking in the IBC. It's an existing building, so you start by looking in the IEBC (which Oregon has adopted). You follow the IEBC, and from there you only look in the IBC if the IEBC sends you there. Since you want to change the occupancy classification, read IEBC chapter 10, and especially section 1011.7. IEBC Table 1011.7 classifies A and B occupancies as the same degree/level of hazard.

1759409248213.png
 
They did not provide a code section to justify the request. I’m hoping to do my research and respectfully point to code sections that let me keep fire wall assembly to 1hr or non required (not because I don’t respect fire life and safety, just because it adds hard costs, adds Sheetrock to the exterior of my structure in a wet climate and has not had it since the structure was built).

Can you point me to code other than table 601,602 & 705.5 ?

What code triggers “code upgrades” (In this particular instance fire rating of wall assembly) or is it subjective?
Remind the building official that Oregon Administrative Rules has a cite it write it requirement since 2006.Check chapter 34 in the OSSC. What year was this built?
 
Thank you for directing me to the IEBC!!! Might be my savior.

“”IEBC 403.1 states "Repairs shall be done in a manner that maintains the level of fire protection provided". I believe repairs alone wouldn't trigger what the Building Official is asking for.””

A Change of use and occupancy is not a "repair." Be sure you read and understand chapter 10 of the IEBC.c

Will sort out if I am held to IBC or IEBC

The IEBC applies. The IBC applies only when the IEBC sends you there, and then only to the specific section or chapter referenced in the IEBC.

1759426308891.png
 

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Big thanks Yankee Chronicler for chiming in and adding MUCH clarity !

I called the state building code division this morning to continue to gain clarity after gathering some great input from the members of this forum. Thank you steveray, arwat23, and Joe.b !
In got a call back from a very knowledgeable and helpful individual (he must be a member here)
The building code specialist that I spoke with was just as surprised as I was that an existing structure, undergoing repairs (structural and non structural) to return it to original form was being requested to change and increase the fire rating of the wall assembly.
Said that my repairs should be governed by chapter 34 of the 2022 IBC. In his words Chapter 34 is the IEBC stuffed into the IBC so they don’t have to buy a separate book .

He quoted 3404.1, but said that since I was NOT making alterations, just repairs to return to original form that I should not be required to change or upgrade the fire rating of the original wall.

Not I have to tactfully and respectfully engage the local building inspector…any tips so it doesn’t come across as “I think you are mistaken? “

Another point, I suppose, is that if I were to change the occupancy rating in the future, (business or apartment) that COULD trigger upgrades, so I might want to pursue a 1hr fire rating of the wall assembly or installation of sprinklers now, so that I am ready for that future requirement.

Does anyone know if the addition/ presence of sprinklers would cancel out and remove a 1hr fire rating requirement? And what code path I would take to get there?
 
I believe exterior walls require rating from both sides. Are you, or have you, considered adding sprinklers? That may (or may not) change the equation. If you're considering sprinklers (for insurance or other reasons) you may be able to present the use of sprinklers as an AMM or modification.

Exterior walls require a fire-resistance rating from the inside only, unless the fire separation distance falls below some magic number that I don't recall off the top of my head.
 
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