Accessory space

[DwightB]

I'm dealing with a local AHJ, my client is adding an 8,000 sq ft building to become part of a 24,000 sq ft business. 22020 IBC says 311.1.1 that an S-1 storage room or space that is an accessory to another occupancy shall be classified as a part of that occupancy. The client is a business, and I want to call the entire building B occupancy, the AHJ goes to a previous code that states the limit for accessory space is 100 sq ft. Is he wrong to drop back to a previous code for a tighter definition of my accessory space? This addition amounts to 35% of the total space. This is an office products supply business. They need room for printers to be delivered, regrouped for delivery and stored a short time until delivery.
AHJ wants to call it S-1. The addition is 5'-6" away with an access tunnel. AHJ says that I must have a 2-hour rating on the new wall where there are facing surfaces and 1-hour rating on the existing wall (this puts the dividing line between them on the face of the new wall.) Is he right?

 

[RLGA]

As to the first part of your post, they can only fall back on a previously adopted code if they bring forward that limitation as a local amendment to the current code. However, Section 311.1.1 is intended for storage spaces that occupants use for the main occupancy. It sounds like you have a business that sells office supplies and a distribution area for the supplies sold, received, and distributed. These sound like two different functions. The occupants on the business side do not go into the storage side to retrieve something that a normal business storage room would store (e.g., papers, pens, office Christmas tree, extra chairs, etc.). With that understanding, I agree with the AHJ that it is a Group S-1 occupancy.

Regarding the second part, I need help understanding what you are trying to describe. Can you attach a drawing or sketch?

 

[classicT]

Sounds like some confusion here, but I agree with Ron that it sounds like this new space is not an accessory space, but will have its own classification. Given the description, it is seemingly correct to classify that space as an S-1 occupancy.

Do you have some more information related to construction type?

 

[DwightB]

This is IIB construction, noncombustible, unprotected, non-sprinklered. It's not a retail store where you go get paper and rubber bands and/or a printer. This is an office "technology center" where commercial customers buy printers by the dozens for major offices. There are 6 or 8 offices for personnel who handle orders and sales, and space for equipment to arrive on pallets that are broken down into client orders and regrouped for delivery to clients. This addition is the space for that arrival of equipment, repackaging and delivery to client. It is not a warehouse. I agree with RLGA, 2020 code specifically left out the 100 sq ft limit for accessory space for a reason and it seems unreasonable for the AHJ to say my accessory space is too big because back in 2015 the limit was 100 sq ft. The new addition in question is "Area 5" on the attached pdf.

 

[DwightB]

Here is the full building:

 

[RLGA]

It's not a retail store where you go get paper and rubber bands and/or a printer.

Then why does your floor plan label the existing areas as Group M occupancies? A Group M occupancy is for selling goods and merchandise accessible to the public.

I believe "Area 5" is a Group S-1, regardless of what other occupancy groups are present or existing.

 

[Paul Sweet]

At a quick glance it looks like it exceeds the 17,500 SF (plus open perimeter increase) area limit for unsprinklered S-1, which is the more restrictive occupancy, in IBC Table 506.2. Since it doesn't comply with the exception #1 to IBC 705.3, exterior walls have to be fire-resistance rated in accordance with Tables 601 and 602.

 

[classicT]

Agree with Ron. I am not sure how Group M came into play with this building. I'd say that you are mixed use Group B and S-1. Given Type II-B, this should not be a problem if the building is sprinklered (NFPA 13). If not sprinklered, your likely running up against the allowable building area.

Also, I think you have some confusion about accessory spaces. There is two different provisions concerning accessory occupancies and I think you are blending them thinking that one changed to the other. Both exist, and they are very different in application.

First,

508.2 Accessory Occupancies​

Accessory occupancies are those occupancies that are ancillary to the main occupancy of the building or portion thereof. Accessory occupancies shall comply with the provisions of Sections 508.2.1 through 508.2.4.​

508.2.3 Allowable Building Area​

The allowable area of the building shall be based on the applicable provisions of Section 506 for the main occupancy of the building. Aggregate accessory occupancies shall not occupy more than 10 percent of the floor area of the story in which they are located and shall not exceed the tabular values for nonsprinklered buildings in Table 506.2 for each such accessory occupancy.​

Second,

311.1 Storage Group S​

Storage Group S occupancy includes, among others, the use of a building or structure, or a portion thereof, for storage that is not classified as a hazardous occupancy.​

311.1.1 Accessory Storage Spaces​

A room or space used for storage purposes that is accessory to another occupancy shall be classified as part of that occupancy.​

Note that the first option provides the maximum 10% provision; whereas the second option is specific to storage directly related to another occupancy. The latter being what Ron described as follows.

However, Section 311.1.1 is intended for storage spaces that occupants use for the main occupancy. It sounds like you have a business that sells office supplies and a distribution area for the supplies sold, received, and distributed. These sound like two different functions. The occupants on the business side do not go into the storage side to retrieve something that a normal business storage room would store (e.g., papers, pens, office Christmas tree, extra chairs, etc.). With that understanding, I agree with the AHJ that it is a Group S-1 occupancy.

I agree with Ron here.

As for the 10% provision, you are well over that limit as well.

Therefore, as I think the consensus is telling you, you have a building that should be classified B and S-1. Given the construction type (II-B) and presented area (24,000sf), I do not see this project moving forward without either fire walls or a NFPA 13 sprinkler system.

 

[classicT]

At a quick glance it looks like it exceeds the 17,500 SF (plus open perimeter increase) area limit for unsprinklered S-1, which is the more restrictive occupancy, in IBC Table 506.2. Since it doesn't comply with the exception #1 to IBC 705.3, exterior walls have to be fire-resistance rated in accordance with Tables 601 and 602.

I do not agree with this being an option. The buildings are connected, therefore there would need to be fire walls. The fire rated exterior walls presented are insufficient.

 

[DwightB]

Then why does your floor plan label the existing areas as Group M occupancies? A Group M occupancy is for selling goods and merchandise accessible to the public.

I believe "Area 5" is a Group S-1, regardless of what other occupancy groups are present or existing.

That was my error. We agreed later this should be B-Business.

 

[RLGA]

This is not the first time this "accessory storage" issue was being pushed beyond its intention. I have drafted a proposed change for the next cycle to add at the end of Section 311.1.1, "The aggregate area of accessory storage spaces shall not exceed 10 percent of the floor area of the story in which they are located."

This will keep it in line with the accessory occupancies provisions in Section 508.2, but not require the storage spaces to be included as part of the accessory occupancies when using Section 508.2.

 

[JPohling]

Area 5 is not a B occupancy. it is an S

 

[Jay Smith]

If the most restrictive occupancy is S-1 and the building has open frontage all around it (I checked a map), why wouldn't this all fit within the allowable area as one building and therefore no separation required at the walkway/tunnel? 17,500 + 13,125 = 30,625 SF allowable area.

 

[RLGA]

If the most restrictive occupancy is S-1 and the building has open frontage all around it (I checked a map), why wouldn't this all fit within the allowable area as one building and therefore no separation required at the walkway/tunnel? 17,500 + 13,125 = 30,625 SF allowable area.

I am unsure where the lot line is on the east side, but they can probably get enough allowable area to cover the entire building area without using fire walls. However, to avoid sprinklering the building, they must have fire barriers to keep any single Group S-1 fire area from exceeding 12,000 sq. ft. and the aggregate area of all Group S-1 fire areas from exceeding 24,000 sq. ft.

 

[DwightB]

At a quick glance it looks like it exceeds the 17,500 SF (plus open perimeter increase) area limit for unsprinklered S-1, which is the more restrictive occupancy, in IBC Table 506.2. Since it doesn't comply with the exception #1 to IBC 705.3, exterior walls have to be fire-resistance rated in accordance with Tables 601 and 602.

ok, If I'm a IIB construction and B occupancy, then as non-sprinklered, I'm allowed 23,000 sq ft on 2018 IBC (applies at this site), and 100% of perimeter is over 20' clear to PL or wall on site, so 75% increase gives me 40,250 sq ft. My total is 24,894 sq ft, so no sprinkler required.
Tabel 508.4 says B-S-1 occupancy, "N" no fire separation. Where am I wrong?

 

[DwightB]

If the most restrictive occupancy is S-1 and the building has open frontage all around it (I checked a map), why wouldn't this all fit within the allowable area as one building and therefore no separation required at the walkway/tunnel? 17,500 + 13,125 = 30,625 SF allowable area.

Seems right to me.

 

[DwightB]

I am unsure where the lot line is on the east side, but they can probably get enough allowable area to cover the entire building area without using fire walls. However, to avoid sprinklering the building, they must have fire barriers to keep any single Group S-1 fire area from exceeding 12,000 sq. ft. and the aggregate area of all Group S-1 fire areas from exceeding 24,000 sq. ft.

East property line is 25' away from building wall.

 

[classicT]

2018 IBC [F] 903.2.9 Group S-1​

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

1. A Group S-1 fire area exceeds 12,000 square feet (1115 m2).
2. A Group S-1 fire area is located more than three stories above grade plane.
3. The combined area of all Group S-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).
4. A Group S-1 fire area used for the storage of commercial motor vehicles where the fire area exceeds 5,000 square feet (464 m2).
5. A Group S-1 occupancy used for the storage of upholstered furniture or mattresses exceeds 2,500 square feet (232 m2).

 

[classicT]

or


Courtesy of https://www.buildingcode.blog/

 

[classicT]

View attachment 10360
or
View attachment 10361

Courtesy of https://www.buildingcode.blog/

@DwightB - Take note that this calculation is does not include the requirements of 903.2.9 that I also posted.

2018 IBC [F] 903.2.9 Group S-1​

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

1. A Group S-1 fire area exceeds 12,000 square feet (1115 m2).
2. A Group S-1 fire area is located more than three stories above grade plane.
3. The combined area of all Group S-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).
4. A Group S-1 fire area used for the storage of commercial motor vehicles where the fire area exceeds 5,000 square feet (464 m2).
5. A Group S-1 occupancy used for the storage of upholstered furniture or mattresses exceeds 2,500 square feet (232 m2).