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Assembly space on 7th floor of B occupancy building

A

APrince125

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Joined
Jan 22, 2021
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14
Location
Philadelphia
We have on a project a conference room on the 7th floor that is 868 SF in a B occupancy building. The building is a 7 story high-rise office building with a penthouse on the 8th floor. The building was built in 1969 and is a gut renovation of the whole building. Would placing 1 hour rated walls be enough or would this not even be allowed to be placed on the 7th due to IBC 2018 limiting A-3 to the 6th floor?

It doesn't seem like we can easily cut out 120 SF to make it below 750 SF to be an accessory space.
 
What will the space actually be used for??

Details

Type of seating/ room set up ?
 
APrince125 said:
Sorry 26 seats around the table, not 23.
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What is the OL of the room?

You obviously are aware of IBC Section 303.1.2, Condition #2... but what about Condition #1? Is the total OL of the room less than 50?

303.1.2 Small Assembly Spaces
The following rooms and spaces shall not be classified as Assembly occupancies:
  1. A room or space used for assembly purposes with an occupant load of less than 50 persons and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy.
  2. A room or space used for assembly purposes that is less than 750 square feet (70 m2) in area and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy.
 
classicT said:
What is the OL of the room?

You obviously are aware of IBC Section 303.1.2, Condition #2... but what about Condition #1? Is the total OL of the room less than 50?

303.1.2 Small Assembly Spaces
The following rooms and spaces shall not be classified as Assembly occupancies:
  1. A room or space used for assembly purposes with an occupant load of less than 50 persons and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy.
  2. A room or space used for assembly purposes that is less than 750 square feet (70 m2) in area and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy.
Click to expand...
Is that still allowed though if for example if they remove the current table and chairs and change the room layout down the road? I could call for a 49 person max occupancy sign to be placed in the room if that would cover it.
 
APrince125 said:
Is that still allowed though if for example if they remove the current table and chairs and change the room layout down the road? I could call for a 49 person max occupancy sign to be placed in the room if that would cover it.
Click to expand...


The building offical is allowed to reduce the occupant load

So show the table

Show the chairs around it

Maybe label occupant load at 40

Call it a B occupancy on your plans for that room
 
Thought it read different

Check against the IBC you have

1004.1.2 Areas Without Fixed Seating​




The number of occupants shall be computed at the rate of one occupant per unit of area as prescribed in Table 1004.1.2. For areas without fixed seating, the occupant load shall be not less than that number determined by dividing the floor area under consideration by the occupant loadfactor assigned to the function of the space as set forth in Table 1004.1.2. Where an intended function is not listed in Table 1004.1.2, the fire code officialshall establish a function based on a listed function that most nearly resembles the intended function.

Exception: Where approved by the fire code official, the actual number of occupants for whom each occupied space, floor or building is designed, although less than those determined by calculation, shall be permitted to be used in the determination of the design occupant load.
 
APrince125 said:
Is that still allowed though if for example if they remove the current table and chairs and change the room layout down the road? I could call for a 49 person max occupancy sign to be placed in the room if that would cover it.
Click to expand...
If the table is a permanent fixture, you can count the seats; however, most typically the table is not built in. You would therefore use an OLF of 15-net. 15x50=750 (hence Condition #2).

What you may be able to do, is justify that the table is built in and can therefore be deducted from the area (per net area measurements). Table would need to legitimately be built in though.
 
If the story is 23,383 sq. ft. and the conference room is 868 sq. ft., that just under 4% of the floor area. Call it an accessory occupancy per 508.2. Per Section 508.2.2, an accessory occupancy is only limited to the height of the main occupancy.

Side comment: the 2018 IBC does not indicate a limitation to 6 stories anywhere for Group A-3--it is 4 stories for Types IV, IIIA, and IIA, and then it jumps to 12 stories for Type IB. Even Group B is limited to 6 stories unless Type IB construction is used, then it is limited to 12 stories, also. So, what construction type are you using?
 
RLGA said:
If the story is 23,383 sq. ft. and the conference room is 868 sq. ft., that just under 4% of the floor area. Call it an accessory occupancy per 508.2. Per Section 508.2.2, an accessory occupancy is only limited to the height of the main occupancy.

Side comment: the 2018 IBC does not indicate a limitation to 6 stories anywhere for Group A-3--it is 4 stories for Types IV, IIIA, and IIA, and then it jumps to 12 stories for Type IB. Even Group B is limited to 6 stories unless Type IB construction is used, then it is limited to 12 stories, also. So, what construction type are you using?
Click to expand...

Even if it is an accessory occupancy I would still need to calculate the occupant load at the A-3 correct?

As for IBC 2018 the building is construction type 1B and I am using the New Jersey addition which limits A-1,3,& 4 to 6 stories sprinklered and A-2 to 4 stories sprinklered.
 
classicT said:
If the table is a permanent fixture, you can count the seats; however, most typically the table is not built in. You would therefore use an OLF of 15-net. 15x50=750 (hence Condition #2).

What you may be able to do, is justify that the table is built in and can therefore be deducted from the area (per net area measurements). Table would need to legitimately be built in though.
Click to expand...

The table is a furniture piece but is hardwired into electrical feeds in the floor for power & data so its not going anywhere unless they disconnect everything.
 
APrince125 said:
Even if it is an accessory occupancy I would still need to calculate the occupant load at the A-3 correct?

As for IBC 2018 the building is construction type 1B and I am using the New Jersey addition which limits A-1,3,& 4 to 6 stories sprinklered and A-2 to 4 stories sprinklered.
Click to expand...
You would need to calculate the occupant load as an unconcentrated assembly.

You might want to check to make sure NJ did not also amend Section 508.2.2.
 
classicT said:
If the table is a permanent fixture, you can count the seats; however, most typically the table is not built in. You would therefore use an OLF of 15-net. 15x50=750 (hence Condition #2).

What you may be able to do, is justify that the table is built in and can therefore be deducted from the area (per net area measurements). Table would need to legitimately be built in though.
Click to expand...
The 1/15sf factor that applies to a conference room is called 'Assembly tables and chairs'....don't you think the area of the table or tables is factored into that calculation?

If you were to deduct the area of the table from the room due to it being 'fixed' I would then argue the remaining area left over would fall under the more restrictive 1/7SF Assembly concentrated (chairs only - not fixed) load factor.
 
APrince125 said:
Even if it is an accessory occupancy I would still need to calculate the occupant load at the A-3 correct?
Click to expand...

APrince125 said:
Even if it is an accessory occupancy I would still need to calculate the occupant load at the A-3 correct?

As for IBC 2018 the building is construction type 1B and I am using the New Jersey addition which limits A-1,3,& 4 to 6 stories sprinklered and A-2 to 4 stories sprinklered.
Click to expand...

Occupancy classifications / use groups (chapter 3) don't have occupant load factors. Occupant load factors are based on the 'function of space' listed in chapter 10. You can have a small conference room under 750SF that is part of the B occupancy, but it would still use the assembly tables and chairs 'Function of Space" occupant load calculation.
 
You can get creative with occupant load, I see it all the time. But why be creative when an approved option is available to you? I think RLGA has it, but in using the accessory provisions you need to make sure everyone understands the 10% is aggregate. If other large conference rooms (or any other accessory use space) are proposed they would add to the area limitation, either now or in the future. At 4% you are probably ok but it is worth mentioning. In a full gut and remodel you have the opportunity to know and control the total areas used on each floor, but in existing individual retrofit T/I's or remodels, controlling or even finding out the aggregate accessory spaces can be a challenge. Story limitations for an accessory occupancy mixed use strategy follow the main occupancy of the building.
 
APrince125 said:
a large table that takes up most of the space and has 23 seats around it
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That is a table that is not going to be removed from the room very easily in order to make room for more than 50 people. As an AHJ I would permit a reduced occupant load for that room. Conference rooms function similar to a classroom IMHO so a 20 net sq ft factor would be less than 45 OL for that room
 
Tim Mailloux said:
The 1/15sf factor that applies to a conference room is called 'Assembly tables and chairs'....don't you think the area of the table or tables is factored into that calculation?

If you were to deduct the area of the table from the room due to it being 'fixed' I would then argue the remaining area left over would fall under the more restrictive 1/7SF Assembly concentrated (chairs only - not fixed) load factor.
Click to expand...
Generally speaking, I agree. However, I am trying to help the poster by providing an idea on how to move forward.

As an example, if I was told that the table in the image below was being placed in the conference room and permanently connected by electrical systems, I would personally feel comfortable deducting the area of the table and calculating the remaining net area at an OLF of 15. Is this a perfect interpretation of the code... no, probably not. But it is something that I think many BO's would be willing to accept.

1615993305810.png
 
The ahj can reduce the occupant load

868/ 15= 57

So mark it as 49 or less

8 people less


C'MON MAN!​

 
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