Interpretation #7914

Original Request

Code Version: 2014
Code: BUILDING
Code Description
Chapter
Section: 508, 903
Topic: Mixing fire sprinkler systems

Question

1. With a Type IIIA, 5-story building, can we have R-2 occupancy on floors 1-3 with an NFPA 13R system, and I-1 occupancy on floors 4 and 5 with an NFPA 13 system? 2. Considering that the structural ratings will meet the requirements for both occupancies, will we be allowed to take the sprinkler height increase to 5 stories for the I-1 occupancy to bring the entire building into current compliance? 3. Considering the NFPA interpretation below regarding use of mixed systems and their compliance with the proper occupancy separations, and considering Section 903.1.1 ?STANDARDS. Sprinkler systems shall be designed and installed in accordance with Section 903.1.1.1, unless otherwise permitted by Sections 903.3.1.2 and 903.3.1.3?, where Table 508.4 for occupancy separations between R-2 and I-1 refers to footnote S, which refers to 903.3.1.1, does the code consider NFPA 13R a fully-sprinkled building, and would it allow the NFPA 13R on floors 1-3, R-2 occupancy in conjunction with NFPA 13 on floors 5-4, I-1 occupancy?

Answer Published 11/22/2016 at 11:28 AM

No. Please see the attached commentary

Commentary

While it is true there may be situations where the mix is permissible such as hotel residential areas vs. assembly or commercial areas, in this case the increase in height is based on the entire building being sprinklered per the required NFPA system. In the case of the I-1 Occupancy, the height increase is based on a NFPA 13 system. The reference to Section 903.3.1.1 is not a "generic" reference, but specifically requires a NFPA 13 system. If a 13R system is permitted, the reference would be to 903.3.1.2. In addition, the use of a 13R system is limited to four stories. This building is 5 stories. The answer is to provide a NFPA 13 system throughout the building.