According to NFPA 14, Standard for the Installation of Standpipe and Hose Systems, the minimum hydraulic demand for a Class I standpipe system is 500 gpm for the most hydraulically remote standpipe. An additional 250 gpm is required for each additional standpipe, up to a specified maximum. For a building that is fully protected with an automatic sprinkler system in accordance with NFPA 13, the total standpipe demand is capped at a maximum of 1,000 gpm. Although the calculated demand for four standpipes would be 1,250 gpm (500 + 250 + 250 + 250), the presence of a complete sprinkler system limits the required flow to 1,000 gpm.

A. 750 gpm (2,840 L/min): This flow rate represents the demand for only two standpipes (500 gpm for the first + 250 gpm for the second) and does not account for all four.

C. 1,250 gpm (4,731 L/min): This would be the correct demand for four standpipes in a building that is not fully sprinklered. The sprinkler protection reduces the maximum required flow.

D. 1,500 gpm (5,678 L/min): This flow rate exceeds the maximum allowable demand for a Class I system, regardless of whether the building is sprinklered or not.

1. NFPA 14, Standard for the Installation of Standpipe and Hose Systems, 2019 Edition.

Section 7.10.1.1.1.1: "For Class I and Class III systems, the minimum flow rate for the hydraulically most remote standpipe shall be 500 gpm (1893 L/min)."

Section 7.10.1.1.1.2: "For each additional standpipe, a flow of 250 gpm (946 L/min) shall be added to the demand."

Section 7.10.1.1.2: "The total demand shall not be required to exceed 1000 gpm (3785 L/min) for buildings that are sprinklered throughout in accordance with NFPA 13..."

Section 7.10.1.1.3: "The total demand shall not be required to exceed 1250 gpm (4731 L/min) for buildings that are not sprinklered throughout..."