Separated mixed use requirements

[wsquiers]

We are designing an addition to an existing school. There are 2 existing structures: a 2 story elementary and single story gymnasium...both are type IIB unsprinkled building. We are adding a building in between the 2 and connecting them all with doors. The new building will house meeting rooms, a multi-purpose room, offices, storage and a kitchen. The school is catholic so the building will be used by both the school and the church. I'm having trouble determining the requirements for the building(s) based on it being a separated mixed use facility. Our preference is to have them all be considered as a single building with separate fire areas rather than as multiple buildings with fire walls between them...but there are a couple of issues I don't fully understand when making this decision and I'll try my best to be concise and clear:

If we make this a single mixed use building do all portions of the structure need to be brought up to current code, particularly the question of sprinkling: do we need to sprinkle all portions of the building if we combine them into a single building......or can we separate the entire structure into separated occupancies with some being sprinkled and some not sprinkled and installing fire barriers to separate them?

The other sticking point is what the make up of the fire barrier needs to be between A and E occupancies. Table 508.4 says there is no separation requirement between A and E occupancies (sprinkled or not). If the new addition is sprinkled and the existing elementary is not do we still not have fire separation requirement between them?

Any insight is appreciated.

 

[cda]

Which edition of ibc?

 

[cda]

Wow no seperation is required

Are you over your allowable area?

 

[cda]

I guess are you able to seperation the new from the old by two hour wall.

And if so what is the total sq ft of new??

 

[steveray]

707.3.9 Fire areas. The fire barriers or horizontal assemblies, or both, separating a single occupancy into different fire areas shall have a fire-resistance rating of not less than that indicated in Table 707.3.9. The fire barriers or horizontal assemblies, or both, separating fire areas of mixed occupancies shall have a fire-resistance rating of not less than the highest value indicated in Table 707.3.9 for the occupancies under consideration.

TABLE 707.3.9 FIRE-RESISTANCE RATING REQUIREMENTS FOR FIRE BARRIER ASSEMBLIES OR HORIZONTAL ASSEMBLIES BETWEEN FIRE AREAS

OCCUPANCY GROUP FIRE-RESISTANCE RATING (hours)
H-1, H-2 4
F-1, H-3, S-1 3
A, B, E, F-2, H-4, H-5,I, M, R, S-2 2
U 1

Thats where you get the hourly separation...Fire barriers can get you out of sprinklers but you will not get the 200% increase for Height and area....

 

[JBI]

Separated vs. Non-separated...
'Separated mixed use' uses the sum of the ratios to determine allowable area, while non-separated uses the 'most restrictive' approach.
The lack of a 'required' separation simply means that the sections could be considered separated despite no rating between and allows the 'sum of the ratios' approach.
HOWEVER, to consider them separate 'fire areas' (as suggested by the OP) then the proper rating MUST be provided.
That is a Chapter 7 application. Depending on Code cycle it is in a slightly different location in Chapter 7... 707 in 2015, 2012 and 2009 IBC, 706 in the 2006.
Between Group A and Group E a 2 hour separation is required to be considered separate fire areas.

 

[Builder Bob]

It opens a lot of issues when you start mixing old construction with new..... for instance, will the occupant load or arrangement of meeting rooms (assembly) above the level of exit discharge in the new addition require a sprinkler system? IF so, will the AHJ allow you to use fire barriers and only sprinkler a portion of the building?

I'm sorry, but it seems to me that fire walls would allow the new addition to be considered independently of the other structures as long as the MOE is can take care of itself.otherwise, sprinkler requirements might be a tad bit difficult, especially if the MOE is dependent upon existing conditions.