Question separate buildings or not

[Apurva Dave]

I have new building Not high rise consists of four floors and parking garage.
The first floor is residential and assembly mixed while second to fourth floors are all residential units.

All Four floors are above the parking garage and they are construction III and the parking garage is construction II.
So their is 3 hours rating firewall between roof of parking and above floor that is construction III. Their is also firewall between parking floor roof to the foundation.

Our building department says parking and the four floors are separate buildings per IBC 2018 code. Would this be correct or incorrect?

 

[cda]

Technically yes

WHY

 

[Mark K]

The structural provisions address this situation and consider this as one building. Because of the different types of construction there are some special rules defining the interaction of the upper and lower half of the building.

Would you consider a basement a separate building from the floors above?

What is the argument that they are separate buildings? Provide code references.

What of a one story building with different occupancies?

 

[Mark K]

Talk to your structural engineer and ask him how similar buildings have been treated in various jurisdictions.

 

[steveray]

Correct....Somewhere in Chapter 4 I believe...

 

[tmurray]

The structural provisions address this situation and consider this as one building. Because of the different types of construction there are some special rules defining the interaction of the upper and lower half of the building.

Would you consider a basement a separate building from the floors above?

What is the argument that they are separate buildings? Provide code references.

What of a one story building with different occupancies?

I think the original poster is referring to whether the building can be considered two different buildings in relation to fire safety provisions, not structurally.

 

[Apurva Dave]

I think the original poster is referring to whether the building can be considered two different buildings in relation to fire safety provisions, not structurally.

I am trying to see if NEC 2017 section 225 would apply or not. Whats more strange is that parking level has stairs which leads to the inside of first floor. Also has vestibule where first floor of east and west can walk thru each other.

Is it stll separate buildings given above situation?

 

[Apurva Dave]

Technically yes

WHY

I am trying to see if NEC 2017 section 225 would apply or not. Whats more strange is that parking level has stairs which leads to the inside of first floor. Also has vestibule where first floor of east and west can walk thru each other.

Is it still considered separate building by ibc 2018?

 

[tmurray]

There are permitted penetrations through assemblies acting as firewalls to allow communicating access from one side to the other. That in and of itself is not so strange.

 

[steveray]

By building code...kinda sorta yes.....For the purposes of NEC 225 I believe the intent is truly detached buildings or structures...But I am not the smartest NEC guy I know....

 

[fatboy]

I don't think the NEC cares what the IBC says in regards to separate buildings. I would say it is a single building/stricture for NEC purposes. JMHO

I tried the argument with the Colorado State Inspector Supervisor years ago the townhouses were separate "structures", so for the purposes of 1-4 family dwelling inspectors, a group of 6 townhouses, were six separate structures, not a 6-plex.

Didn't fly for a second.

 

[classicT]

From the other thread....

If you are going from one construction type to another, in a stacked configuration, then yes, they are separate buildings.

510.2 Horizontal Building Separation Allowance
A building shall be considered as separate and distinct buildings for the purpose of determining area limitations, continuity of fire walls, limitation of number of stories and type of construction where all of the following conditions are met:

1. The buildings are separated with a horizontal assembly having a fire-resistance rating of not less than 3 hours where vertical offsets are provided as part of a horizontal assembly, the vertical offset and the structure supporting the vertical offset shall have a fire-resistance rating of not less than 3 hours.
2. The building below the horizontal assembly is of Type IA construction.
3. 
   Shaft, stairway, ramp and escalator enclosures through the horizontal assembly shall have not less than a 2-hour fire-resistance rating with opening protectives in accordance with Section 716.
   
   
   Exception: Where the enclosure walls below the horizontal assembly have not less than a 3-hour fire-resistance rating with opening protectives in accordance with Section 716, the enclosure walls extending above the horizontal assembly shall be permitted to have a 1-hour fire-resistance rating, provided:
   1. The building above the horizontal assembly is not required to be of Type I construction;
   2. The enclosure connects fewer than four stories; and
   3. The enclosure opening protectives above the horizontal assembly have a fire protection rating of not less than 1 hour.
   4. Interior exit stairways located within the Type IA building are permitted to be of combustible materials where both of the following requirements are met:
      
      4.1. The building above the Type IA building is of Type III, IV, or V construction.
      4.2. The stairway located in the Type IA building is enclosed by 3-hour fire-resistance-rated construction with opening protectives in accordance with Section 716.
4. The building or buildings above the horizontal assembly shall be permitted to have multiple Group A occupancy uses, each with an occupant load of less than 300, or Group B, Group I-1, Condition 2 licensed care facilities, M, R, or S occupancies.
5. The building below the horizontal assembly shall be protected throughout by an approved automatic sprinkler system in accordance with Section 903.3.1.1, and shall be permitted to be any occupancy allowed by this code except Group H.
6. The maximum building height in feet (mm) shall not exceed the limits set forth in Section 504.3 for the building having the smaller allowable height as measured from the grade plane. Group I-1, Condition 2 licensed care facilities shall be permitted to use the values for maximum height in feet for Group R-2 occupancies.