According to NFPA 13, Standard for the Installation of Sprinkler Systems, the maximum floor area on any single floor that can be protected by one sprinkler system riser for an Ordinary Hazard occupancy is 52,000 ft² (4831 m²). This limitation is established to ensure that a single system is not responsible for an excessively large area, which could challenge its hydraulic capacity and overall effectiveness during a fire. The standard sets these limits based on the anticipated fire severity and rate of spread associated with each hazard classification.

A. 25,000 ft² (2,320 m²) is the maximum area for an Extra Hazard system designed using the pipe schedule method, not for an Ordinary Hazard system.

B. 40,000 ft² (3,720 m²) is the maximum area for a hydraulically calculated Extra Hazard system or for high-piled storage occupancies.

D. 70,000 ft² (6,503 m²) is not a standard maximum area limitation for any of the primary hazard classifications defined in NFPA 13.

1. National Fire Protection Association (NFPA). (2022). NFPA 13: Standard for the Installation of Sprinkler Systems. Quincy, MA: NFPA. Chapter 9, Section 9.2.2, Table 9.2.2.1 "System Protection Area Limitations".

2. National Fire Protection Association (NFPA). (2019). NFPA 13: Standard for the Installation of Sprinkler Systems. Quincy, MA: NFPA. Chapter 11, Section 11.2.2, Table 11.2.2.1 "System Protection Area Limitations".

3. Isman, K. E. (2017). Layout, Detail & Calculation of Fire Sprinkler Systems (3rd ed.). CRC Press. Chapter 3, "System Protection Area Limitations," p. 29. (This academic text directly references and explains the requirements of NFPA 13, Table 8.2.1 in the 2016 edition, which contains the same values).

4. Oklahoma State University. (n.d.). Fire Protection & Safety Technology Courseware, FPST 3333 - Fire Sprinkler Systems. Stillwater, OK: OSU College of Engineering, Architecture and Technology. Module on "System Area Limitations," which cites the 52,000 ft² limit for Ordinary Hazard from NFPA 13.