Mezzanine and 508.2.4 Separation of occupancies for discourse

[sergoodo]

Any passionate disagreement with the following?

I interpret 2015 IBC occupancy separation not required for the following 10,000sf building:
Building Area Summary
9,000sf S2 occupancy ground level
1,000sf accessory B occupancy ground level
<0> mezzanine accessory B occupancy (1,000sf fire area)

 

[RLGA]

Sprinklered or nonsprinklered? What construction type? If sprinklered Type VB, no problem, you can have nonseparated occupancies with Group B being the most restrictive. If the mezzanine is truly a mezzanine per Section 505, then it will not contribute to building area, so the Group B floor level area would be within the 10% permitted for an accessory occupancy, thus also not requiring separation.

 

[sergoodo]

Sprinklered or nonsprinklered? What construction type? If sprinklered Type VB, no problem, you can have nonseparated occupancies with Group B being the most restrictive. If the mezzanine is truly a mezzanine per Section 505, then it will not contribute to building area, so the Group B floor level area would be within the 10% permitted for an accessory occupancy, thus also not requiring separation.

Thanks RLGA,

Type IIB, non-sprinklered with true mezzanine. What is your opinion on IBC mezzanine sf and occupancy separation? Know of any revision discussion history with IBC committees?

 

[RLGA]

Type IIB has an allowable area of 23,000 sf for Group B (most restrictive), thus you can use the nonseparated occupancies method. The Group B mezzanine must be within the Group S-2 to get the 1,000 sf area (can’t be more than 1/3 the area in which it is located) but it can be enclosed if the occupant load is no more than 10 (at 1,000 sf of area and an OLF of 100 sf/occ., that should not be a problem). There is no required occupancy separation between the mezzanine and the Group S-2.

 

[sergoodo]

For a more restictive F-1 occupancy looks like Non Sprink / non sep B occ office mezzanine is limited by comibined fire area 24k sf.

Any debate about 20k sf F1 + 2k sf B + 1.9k sf B mezz building being compliant w 2015 IBC non sprink / non sep with a total of 23.9k sf type IIB ? Note: site would allow for max area inceaae.

 

[RLGA]

Note: site would allow for max area inceaae.

I assume you mean by frontage increase.

To answer your question, no, that would not comply with Section 903.2.4, Condition 1, which limits an F-1 fire area to 12,000 sq. ft. Condition 3, to which you're referring, applies when a building has multiple fire areas of less than 12,000 sq. ft. each but has an aggregate F-1 fire area over 24,000 sq. ft.

 

[sergoodo]

I assume you mean by frontage increase.

To answer your question, no, that would not comply with Section 903.2.4, Condition 1, which limits an F-1 fire area to 12,000 sq. ft. Condition 3, to which you're referring, applies when a building has multiple fire areas of less than 12,000 sq. ft. each but has an aggregate F-1 fire area over 24,000 sq. ft.

Thanks RLGA. With that clarification of condition 3; enlightenment of the hard limit for the accessory use and occupancy separation found. Reasonable and not a gray area.