Fire Flow Requirments

[djcbgn]

Two methods for computing fire flow that I am familiar with are from the Uniform Fire Code (UFC) and ISO. I am working on a high rise project where the fire sprinkler designers used the NFPA (hydraulic method) for the design. Would it be valid to use the fire sprinkler capacity as the fire flow required for this building? IF we use the UFC method the required fire flow would be substantially higher than the sprinkler capacity even with the credit taken for a fire suppression system. I do not want to underestimate the fire flow needed since we will be using this to design the water mains for this site. I am leaning towards the UFC method since, in my opinion, the fire flow needed should exceed the fire sprinkler demand. It seems to make sense that you would need additional flow from adjacent fire hydrants to supplement the fire sprinkler system . Thank you.

 

[canman]

djcbgn - Out here in California, building fire flow requirements are based on the California Fire Code. The California Fire Code is the Uniform Fire Code with State of California amendments. The minimum required fire flow, at a residual pressure of 20 psi, is based on size of building, construction type, and in some cases reduction in fire flow if the building has a fire sprinkler system. Most City & County fire departments give anywhere from 0%-50% reducation if a building has a sprinkler system. If you are sizing the lines outside the building that serve hydrants you should follow the UFC not NFPA. NFPA is used to design the flow requirements of the system inside the building which is usually much lower then that outside. I hope this helps.

CANMAN

 

[cvg]

fire flow should never be completely based on sprinkler flows. If the fire starts on an exterior wall or roof - as in the case of a wildfire, the sprinklers may be completely useless.