Level 2 or Level 3 Alteration or Change of Occupancy

[Kmarie039]

Hi All! I am new to this forum but have found it helpful over the last two years as I started my own firm to clarify code issues.

I have an existing 'B' occupancy and F-1 occupancy building, Type IIB building. There is a 3-hour fire barrier separating the original building (non-sprinklered, 9,752SF + 2,500 sf basement) and an addition that was put on in 2022 (sprinklered, 23,800sf). Currently all F-1 operations are in the addition area where it is fully sprinklered. We are reconfiguring their office space as it's outdated and they need more room.
The client just mentioned to me they are now going to move a portion of their F-1 operations over to our non-sprinklered side of the building because they are growing fast and need the space. Originally I was classifying this as a Level 2 alteration but with the F-1 occupancy moving into the space will this be a change of occupancy? or potentially make a Level 3 since I'm touching more space?
I'm mainly wondering if it will trigger applying Chapter 9 in needing a sprinkler as I'm over the allotted sf numbers for an F-1.

Thanks!

 

[steveray]

It would be COO putting the F1 on the other side of the wall...Not Level 3 unless you are doing 50% of the building...<10,000 fire area might be OK for no sprinklers in an F1. Are you sure it is a fire barrier and not a fire wall?

And Welcome to THE Forum....

 

[Yankee Chronicler]

Two separate questions.

If the non-sprinklered original building was completely a B occupancy and they are moving some of the F-1 into it, yes, it is clearly a change of occupancy for that portion of the building.

If the original building wasn't sprinklered and there is a 3-hour fire wall, you actually have two buildings -- or could have. How was the addition treated when it was built? Was it permitted as a separate building, or was it treated as an addition? Does it have a separate certificate of occupancy? This is an important question, because a "building" is not considered to be sprinklered unless the entire building is sprinklered. Unless the owner plans to add sprinklers to the original building, it's going to be critical to maintain the integrity of that fire wall so they can continue to have the original building unprotected.

Beyond that, I'm confused. The office space is in the original building and they need more office space -- so they are moving part of the F-1 occupancy into the B portion of the building -- which already needs more office space? How does that work?

IMHO, before proceeding you need to determine whether you are dealing with one building or two buildings.

 

[RLGA]

IMHO, before proceeding you need to determine whether you are dealing with one building or two buildings.

This^

Additionally, how much area does each of the occupancy groups currently occupy on each side of the 3-hour assembly, and how much will they occupy per the proposed plan?

 

[Kmarie039]

Two separate questions.

If the non-sprinklered original building was completely a B occupancy and they are moving some of the F-1 into it, yes, it is clearly a change of occupancy for that portion of the building.

If the original building wasn't sprinklered and there is a 3-hour fire wall, you actually have two buildings -- or could have. How was the addition treated when it was built? Was it permitted as a separate building, or was it treated as an addition? Does it have a separate certificate of occupancy? This is an important question, because a "building" is not considered to be sprinklered unless the entire building is sprinklered. Unless the owner plans to add sprinklers to the original building, it's going to be critical to maintain the integrity of that fire wall so they can continue to have the original building unprotected.

Beyond that, I'm confused. The office space is in the original building and they need more office space -- so they are moving part of the F-1 occupancy into the B portion of the building -- which already needs more office space? How does that work?

IMHO, before proceeding you need to determine whether you are dealing with one building or two buildings.

The original is a pre-fab metal building and they were only taking up 1/3 of it currently for office space. They have 2/3 left that they are expanding their office into and want to bring the F-1 into.

The addition drawings from a previous architect state the building is separated by a 3-hour fire barrier, UL 263 assembly.

 

[Kmarie039]

This^

Additionally, how much area does each of the occupancy groups currently occupy on each side of the 3-hour assembly, and how much will they occupy per the proposed plan?

The 3-hour fire barrier (UL263) sprinklered side houses all F-1, 23,800sf. The non-sprinklered B space is just under 10,000 sf w/ a 2,500sf basement. About 7,100sf will be remodeled office. They want to use the remaining 2,600sf to expand F-1 back into the original building.

 

[Yankee Chronicler]

The original is a pre-fab metal building and they were only taking up 1/3 of it currently for office space. They have 2/3 left that they are expanding their office into and want to bring the F-1 into.

The addition drawings from a previous architect state the building is separated by a 3-hour fire barrier, UL 263 assembly.

Okay. But a fire wall creates two "buildings." When the firewall and the addition were constructed, was the addition permitted and received a certificate of occupancy as a separate building on the same site, or was it permitted as an addition to make the one building into a larger building?

If it was permitted as one building -- how did they get away with only installing sprinklers in the addition? If it is one building, is it classified as separated mixed uses or non-separated mixed uses?

[Edit] My error. I read "fire wall" but you wrote "fire barrier." If the separation is a fire barrier, then it is one building, not two. But if only the new part is sprinklered, then the code regards the building as non-sprinklered. You only get to take credit for sprinklers if the entire building is protected.

The addition (the current F-1 space) is approximately 2-1/2 times the area of the original B area. The 2,600 s.f. of office being changed to F-1 is clearly a change of occupancy. Wisconsin has adopted the IEBC, so you need to look at Chapter 10.

 

[Kmarie039]

Okay. But a fire wall creates two "buildings." When the firewall and the addition were constructed, was the addition permitted and received a certificate of occupancy as a separate building on the same site, or was it permitted as an addition to make the one building into a larger building?

If it was permitted as one building -- how did they get away with only installing sprinklers in the addition? If it is one building, is it classified as separated mixed uses or non-separated mixed uses?

[Edit] My error. I read "fire wall" but you wrote "fire barrier." If the separation is a fire barrier, then it is one building, not two. But if only the new part is sprinklered, then the code regards the building as non-sprinklered. You only get to take credit for sprinklers if the entire building is protected.

The addition (the current F-1 space) is approximately 2-1/2 times the area of the original B area. The 2,600 s.f. of office being changed to F-1 is clearly a change of occupancy. Wisconsin has adopted the IEBC, so you need to look at Chapter 10.

Yankee Chronicler,

This is the conclusion I was coming to myself, but started second-guessing some things. I believe it is being considered one building. Would anyone have any guidance on how to take a UL263 3-hour assembly and create it into a fire wall? I have no experience with this.

 

[steveray]

You don't get to exceed 24,000 in F1 so FB is out it would seem...To be a fire wall it would have to be structurally independent. There is a FW alternative to be a FB in the IEBC 1011.6ish, but not for beating sprinklers...

[F]​

An automatic sprinkler system shall be provided throughout all buildings containing a Group F-1 occupancy where one of the following conditions exists:

1. 1.A Group F-1 fire area exceeds 12,000 square feet (1115 m2).
2. 2.A Group F-1 fire area is located more than three stories above grade plane.
3. 3.The combined area of all Group F-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).

 

[Yankee Chronicler]

Wisconsin is still on the 2015 ICC codes. Irrespective of fire areas by occupancy, we also have to look at building area. For a non-sprinklered F-1 of Type II-B construction, the maximum allowable area is only 15,500 s.f. but it jumps to 62,000 s.f. for one story, sprinklered. For mixed uses, you have to look at section 508. With all the F-1 on one side of a 3-hour fire barrier, it was obviously a case of separated mixed uses. That falls under IBC 508.4. Once you move some of the F-1 to the same side of the fire barrier, you now have a non-separated mixed use. That's IBC 508.3.

Just to further confuse the issue, Table 508.4 says that there is no requirement for a separation between B and F-1. This suggests that the reason for the 3-hour fire barrier was to completely separate the F-1 occupancy from the B so they wouldn't have to sprinkler the B portion. Once you move some of the F-1 into the original portion of the building, you're going to have to perform the allowable area analysis all over again, starting from scratch.

 

[steveray]

Hunh...Maybe the addition should not have been approved....The new F needed sprinklers by FA no doubt

1102.2​

An addition shall not increase the area of an existing building beyond that permitted under the applicable provisions of Chapter 5 of the International Building Code for new buildings unless fire separation as required by the International Building Code is provided.

Exception: In-filling of floor openings and nonoccupiable appendages such as elevator and exit stairway shafts shall be permitted beyond that permitted by the International Building Code.
INSIGHTS (1)

1102.3​

Existing fire areas increased by the addition shall comply with Chapter 9 of the International Building Code.

 

[Kmarie039]

You don't get to exceed 24,000 in F1 so FB is out it would seem...To be a fire wall it would have to be structurally independent. There is a FW alternative to be a FB in the IEBC 1011.6ish, but not for beating sprinklers...

[F]​

An automatic sprinkler system shall be provided throughout all buildings containing a Group F-1 occupancy where one of the following conditions exists:

1. 1.A Group F-1 fire area exceeds 12,000 square feet (1115 m2).
2. 2.A Group F-1 fire area is located more than three stories above grade plane.
3. 3.The combined area of all Group F-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).

Wisconsin is still on the 2015 ICC codes. Irrespective of fire areas by occupancy, we also have to look at building area. For a non-sprinklered F-1 of Type II-B construction, the maximum allowable area is only 15,500 s.f. but it jumps to 62,000 s.f. for one story, sprinklered. For mixed uses, you have to look at section 508. With all the F-1 on one side of a 3-hour fire barrier, it was obviously a case of separated mixed uses. That falls under IBC 508.4. Once you move some of the F-1 to the same side of the fire barrier, you now have a non-separated mixed use. That's IBC 508.3.

Just to further confuse the issue, Table 508.4 says that there is no requirement for a separation between B and F-1. This suggests that the reason for the 3-hour fire barrier was to completely separate the F-1 occupancy from the B so they wouldn't have to sprinkler the B portion. Once you move some of the F-1 into the original portion of the building, you're going to have to perform the allowable area analysis all over again, starting from scratch.

I have always found the mixed-use portion of the code highly confusing, specifically 508.3 and Table 508.4. due to the fact that you still need to reference 903 and it doesn't mention it in those specific sections.

Unfortunately, by performing the area analysis as a whole, I'm brought back to sprinkler the building or provide a fire wall.

 

[Kmarie039]

Hunh...Maybe the addition should not have been approved....The new F needed sprinklers by FA no doubt

1102.2​

An addition shall not increase the area of an existing building beyond that permitted under the applicable provisions of Chapter 5 of the International Building Code for new buildings unless fire separation as required by the International Building Code is provided.

Exception: In-filling of floor openings and nonoccupiable appendages such as elevator and exit stairway shafts shall be permitted beyond that permitted by the International Building Code.
INSIGHTS (1)

1102.3​

Existing fire areas increased by the addition shall comply with Chapter 9 of the International Building Code.

I agree, other than this addition was only done a couple of years ago. I have the drawings from when it was done and it may be one of the worst code summaries I have come across. It gives no path to how they came to their conclusion. Technically, it does appear to meet code, but I feel it could have been done better. I'm sure as always cost played a significant role over what makes sense for long term growth.

 

[Yankee Chronicler]

Unfortunately, by performing the area analysis as a whole, I'm brought back to sprinkler the building or provide a fire wall.

I think I see what they did. The mixed use provisions call for using a sum of ratios. If the entire building were not sprinklered, the ratio for the original building would be 9,800/23,000 = 42.6%. The addition would have been 23,800/15,500 = 154%. The sum exceeds 100%, so this was not allowed. BUT ...

2015 IBC section 901.7 allowed them to create a 3-hour fire barrier to split off the addition into a separate fire area:

901.7 Fire areas. Where buildings, or portions thereof, are
divided into fire areas so as not to exceed the limits established
for requiring a fire protection system in accordance
with this chapter, such fire areas shall be separated by fire
barriers constructed in accordance with Section 707 or horizontal
assemblies constructed in accordance with Section
711, or both, having a fire-resistance rating of not less than
that determined in accordance with Section 707.3.10.

By treating the addition as a separate fire area, the ratio changed to 23,800/62,000 = 38.4%. 42.6 + 38.4 = 81%. That's less than 100%, so it passed muster as separated mixed uses.

Personally, I would not have allowed that. The basic rule under the IBC and under NFPA 13 is that if the entire building isn't sprinklered, the building isn't sprinklered. But, apparently the AHJ allowed this to be built. Your problem now is that you want/need to move some F-1 into the 9,800 s.f side that was previously all B.

Consider doubling down on the analysis. The addition was apparently approved on the basis on separated mixed uses, even though otherwise there is no separation required between B and F-1. (Table 508.4). Can we assume that the 23,800 s.f. side will remain all F-1? If so, that part of the analysis remains unchanged. But you will be introducing some F-1 into the B side, so treat that portion of the building as non-separated mixed uses and analyze it as such under 508.3 and 508.3.2. This says:

508.3.2 Allowable building area and height. The allowable
building area and height of the building or portion
thereof shall be based on the most restrictive allowances
for the occupancy groups under consideration for the type
of construction of the building in accordance with Section
503.1.

Going back to Table 506.2, in construction type II-B a non-sprinklered B occupancy is allowed 23,000 s.f but a non-sprinklered F-1 is only allowed 15,500 s.f. The F-1 is the more restrictive. 9,800/15,500 = 63.2%. The addition was 38.4%. 63.2% + 38.4% = 101.6%. That's more than 100%, so it's not allowed. But it's very close.

Can you separate the new F-1 portion of the original building from the expanded B portion of the original building with a fire barrier? If so, you can then analyze the overall building as three fire areas, and that will probably make it work without adding sprinklers in the original building. It will have to be a 3-hour fire barrier, per Table 707.3.10, but that's not impossible.

 

[Kmarie039]

Thank you all for your responses and insight. Client has decided to fully sprinkler as it also seems to be the most cost effective approach to allow us a type IIB, F-1 62,000sf building with non-separated B-occupancy. It would also allow us to punch openings in the existing 3-hour fire barrier for more connection between the spaces.

In adding a 1,000-1,300sf break room that is over 50 persons (so can't be considered a 'B' and would need to be A-3) would my next best option be 508.3.2 and treat it as an accessory occupancy (under 10%)? Our facility is 36,400sf in total so still under the 38,000sf limit for an A-3, IIB building.

 

[steveray]

would my next best option be 508.3.2 and treat it as an accessory occupancy (under 10%)?

508.2.3?...Maybe....

 

[Kmarie039]

508.2.3?...Maybe....

What do you see as a possible problem?

 

[steveray]

What do you see as a possible problem?

I believe I was just correcting your code section.....3.2 vs. .2.3