4.13 Sprinkler & Standpipe Flow Rate and Required Pressures (effective 7/23/09)

Reference: 2007 CBC, Sections 403, 903 and 905; 2002 NFPA 13, Sections 6.1, 8.15.1.2 and 15.1, and Table 11.2.3.1.1; 2003 NFPA 14, Chapter 7

Purpose: To establish uniformity in requirements for sprinkler system and hose valve flow and pressure requirements when supplied by a fire pump.

SPRINKLER SYSTEMS:
The San Francisco Fire Department's position on sprinkler system flow and pressure requirements is contained in 2007 CBC Section 403.2 and 903.3.1.1; and 2002 NFPA 13, Sections 6.1, 8.15.1.2 and 15.1, and Table 11.2.3.1.1.

Minimum Requirements - When a sprinkler system is supplied by a fire pump that takes suction from the City main and a fire water storage tank, the sprinkler system demand (including the hose allowance) shall be met while taking suction from the tank with the water level at the vortex plate.

Maximum Static Pressure - The maximum static pressure shall be at pump churn pressure, with the fire pump taking suction from the City main.

STANDPIPE:
The San Francisco Fire Department's position on fire hose requirements for standpipes supplied with a fire pump is contained in of 2003 NFPA 14 Chapter 7.

Minimum Pressure - The minimum pressure for a 3" hose valve shall be 100 psi at the valve outlet while flowing 250 gpm through the fire pump and valve. The minimum pressure while flowing the required standpipe flow (500 gpm from the hydraulically most remote standpipe and 250 gpm from each additional standpipe, up to a maximum of 1000 gpm for a fully sprinklered building) shall be 75 psi at any valve outlet while flowing 250 gpm through each valve. Therefore, the minimum hose valve outlet pressure at 250 gpm total standpipe flow is 100 psi, and the minimum hose valve outlet pressure at the maximum standpipe flow is 75 psi.

When the standpipe is supplied by a fire pump that takes suction from the City main and a fire water storage tank, the minimum residual pressure and maximum static pressures at the hose valve outlet shall be based on the fire pump taking suction from the City main.

EXCEPTION:

• For buildings 200 feet or more in height, the minimum residual pressure at the hose valve outlet shall be met with the primary fire pump taking suction from the fire water storage tank with the water level at the vortex plate.

The minimum pressures and maximum static pressures shall be confirmed by field test.

PRESSURE REDUCING VALVES:
Pressure reducing valves are required when the hose valve outlet pressure exceeds 150 psi static pressure while at the maximum pump pressure, or when hose valve outlet pressure exceeds 125 psi residual while flowing 250 gpm through the fire pump and hose valve.

Valves approved for this use shall be listed for use as a hose valve pressure reducing valve under flow and no flow conditions.

Factory set valves shall be properly labeled indicating the pressure setting and the intended floor for installation. The set pressure shall be confirmed by field test.

Valves that can be field set or field adjusted shall be labeled indicating the proper setting to obtain the required outlet pressure. The set pressure shall be confirmed by field test.