2021 NFPA 101 vs 2021 IBC - separated mixed use

[Nicole Brooks]

This is a question for multi-tenant mixed use buildings. The tenancy is usually, Business, Mercantile, Factory 1 or Storage 1 (per IBC) and Business, Mercantile, Storage Low/Ordinary and Industrial General Purpose (per NFPA 101). Each individual tenant is separated by a 2hr wall as standard practice. However, within each tenant space, there is usually Business and either Storage 1 (Storage Low/Ordinary or Factory (Industrial). I would say 85% of our tenants are Business and Storage 1. None of the AHJ that's I've worked in require a fire rated separation between these two spaces within a tenant space. Some have required a smoke partition per NFPA 101 8.7.1.2 (below). Per IBC table 508.4, if the building is sprinklered then no separation between B, S-1,F-1, or Mercantile is required. Per NFPA 101, most of the combination of these occupancies are eligible for a 1hr reduction due to the sprinkler system, but as per the notes under table 6.1.14.4.1 *Minimum Fire Resistance Rating. The fire resistance rating is permitted to be reduced by 1 hour, but in no case to less than 1 hour, where the building is protected throughout by an approved automatic sprinkler system in accordance with 9.7.1.1(1) and supervised in accordance with 9.7.2., so some mixes require a 1hr rating. I am confused as to why the AHJ's don't require a 1hr rating between say Business and Storage 1 (storage low/ordinary hazard). Is is because they see the tenant's as the separated mixed use and inside the individual tenants it is considered non-separated?

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8.7.1.2​

In new construction, where protection is provided with automatic extinguishing systems without fire-resistive separation, the space protected shall be enclosed with smoke partitions in accordance with Section 8.4, unless otherwise permitted by one of the following conditions:

• (1)
  Where mercantile occupancy general storage areas and stockrooms are protected by automatic sprinklers in accordance with Section 9.7
• (2)
  Where hazardous areas in industrial occupancies are protected by automatic extinguishing systems in accordance with 40.3.2
• (3)
  Where hazardous areas in detention and correctional occupancies are protected by automatic sprinklers in accordance with 22.3.2

 

[Nicole Brooks]

I'll answer my own question:

6.1.14.1.3*



Where incidental to another occupancy, areas used as follows shall be permitted to be considered part of the predominant occupancy and shall be subject to the provisions of the Code that apply to the predominant occupancy:

• (1)
  Mercantile, business, industrial, or storage use

 

[Yankee Chronicler]

The IBC also allows for non-separated mixed uses. See IBC 504.2, 506.2.2, 508.3.2 and 508.4.2

You can combine separated and non-separated