What Construction Type is this....

[fj80]

2012 IBC

We're in the very early pre-design phase of an approximately 106 unit apartment building. It will be five stories of wood-framed apartments (R-2), over a ground floor level of retail (probably concrete construction) (M - Mercantile), over 4 levels of underground parking garage (S-2). I thought the code limited us to four stories with wood construction but my boss says he knows five stories is allowed if we do a 1-hour rating on the exterior wall but he doesn't know what construction type it would be. So I'm on the hunt...

What construction type would this be and where do I figure that out in the code?

Also, where do I figure out the fire rating between the following uses:

1) The floor between ground floor retail level and apartments above.

2) The floor between parking garage and retail level.

3) Also, the site is very steep so there will be areas where apartment units are on the same level as the parking garage, so I need a fire rated wall between those two. Where would I find that requirement in the code?

Thanks in advance for any help.

 

[cda]

You do the easy ones.

Not for sure but thought it is three hours between retail and apartments

I take it you are doing full NFPA 13 everywhere??

 

[cda]

This is an 09 article, but may get you started

http://wooddesign.dgtlpub.com/2009/2009-12-31/pdf/technical_abstract.pdf

 

[fj80]

You do the easy ones.

Not for sure but thought it is three hours between retail and apartments

I take it you are doing full NFPA 13 everywhere??

I'm a bit out of my depth on this one, so I'm not sure about NFPA. I also need to figure out if FHA applies to this project. Anyone know what determines that?

 

[cda]

Well NFPA 13R is only good to four stories on R and/ or sixty feet

 

[cda]

http://www.thebuildingcodeforum.com/forum/threads/4-or-5-story-wood-framed-apt.13396/#post-150762

 

[cda]

http://www.thebuildingcodeforum.com/forum/threads/13r-open-garage.4076/#post-51336

 

[steveray]

IIIA can go 5 stories if you use the exception for FRTW..Grade plane will be really important on this one...Probably a 3 hr horizontal separation....Ch4 for pedestal buildings...

 

[classicT]

Table 508.4 (2015) for the required separation of occupancies.

Provided that your building is equipped throughout with a sprinkler system;
- 1hr for R-2 to S-2 - also see 406.3.4
- 1hr for R-2 to M
- 1hr for M to S-2

 

[fj80]

IIIA can go 5 stories if you use the exception for FRTW..Grade plane will be really important on this one...Probably a 3 hr horizontal separation....Ch4 for pedestal buildings...

Where do I find the exception for 5 stories using FRTW?

 

[cda]

See if this gives a little info

http://www.structuremag.org/?p=10934

 

[ADAguy]

Are you the developer or the architect?

 

[Yikes]

Where do I find the exception for 5 stories using FRTW?

CBC / IBC 602.4.1; as it relates to Table 601 for type IIIA construction; as it relates to Table 504.4 for R-2 occupancy Type IIIA construction, fully sprinklered, without area increase.

 

[fj80]

Are you the developer or the architect?

Architect

 

[RLGA]

Use Section 510.1 for the horizontal separation allowance between the first story (plus basements) and the four stories of residential. This requires a 3-hour horizontal separation with Type IA construction below and any construction type above; thus, creating two separate buildings. This allows the use of NFPA 13R for the upper four stories and a NFPA 13 system for anything below the 3-hour horizontal separation (this is permitted by NFPA).

The first story (lower building) has unlimited area and the upper building is limited in area by the construction type used. The upper building is allowed the number of stories permitted by construction type starting at the first story above the 3-hour horizontal separation; however, the height in feet for the upper building is measured from the grade plane. Thus, if using NFPA 13R for the upper building, four stories is permitted above the 3-hour horizontal separation, but the 60-foot height limitation is measured from the grade plane at the lower building.

Section 2304.3.3 only allows the use of wood frame construction supporting two floors and a roof--essentially a 3-story building. To go taller, that section permits it, but you must submit an analysis that shows that shrinkage will not be a problem and that building systems would not be affected by any shrinkage.