Heavy Timber Mezzanine in Type 2B

[John A. Benton]

FBCB 2020

I have an existing mercantile building that is Type 2B, fully sprinkled. It has an existing steel frame mezzanine. I want to add another mezzanine that is heavy timber for the columns and framing and nominal 2x wood decking. It is a boat sales building; the client wants the new mezz. to look like a dock. To maximise space, I want to use Section 505.2.1 Exception 2. which states:

1. The aggregate area of mezzanines in buildings and structures of Type I or II construction shall be not greater than one-half of the floor area of the room in buildings and structures equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1 and an approved emergency voice/alarm communication system in accordance with Section 907.5.2.2.

My questions:
Can I even use heavy timber for this condition?
If so, does it have to be fire treated wood?

Thanks!

 

[mtlogcabin]

Yes under the 2018 IBC
603.1 Allowable materials.
Combustible materials shall be permitted in buildings of Type I or II construction in the following applications and in accordance with Sections 603.1.1 through 603.1.3:

Exceptions:

19. Heavy timber as permitted by Note c to Table 601 and Sections 602.4.3 and 705.2.3.1.
Table 601 note c
c. In all occupancies, heavy timber complying with Section 2304.11 shall be allowed where a 1-hour or less fire-resistance rating is required.

 

[John A. Benton]

I saw Note c Table 601 but thought it only applied to roofs not floors. I did not see 2304.11. Thank you!