If a fire sprinkler systems is designed for "life safety" purposes, should not a primary and standby fire pump be provided? Why are standby pumps not required to improve reliability for these systems?
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9 Comments
James Phifer
2/2/2021 09:14:28 am
Just my opinion, but I think the Fire Department Connection serves at a secondary supply. The Fire Department will not rely on the pump, and will always hook up to the FDC anyway.
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Matt
2/2/2021 09:15:15 am
NFPA guidance provides a minimum reasonable standard of protection. If the prescribed maintenance is followed, then historically there is a very low failure rate. Many owners do provide a backup pump if they feel that the cost is justified.
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Brian Gerdwagen FPE
2/2/2021 09:17:48 am
It is a long answer.
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Casey Milhorn
2/2/2021 09:20:26 am
James nailed it. The FDC serves as the "backup". You will see two pumps provided in hi-rise buildings a lot of times, when the height of the building exceeds the pumping capacity of the responding fire department. For example, locally that height is 250'. We are required to provide two fire pumps in parallel when buildings are over 250'. One fire pump is the main, with the other being secondary.
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Casey Milhorn
2/2/2021 09:28:53 am
And to add to that, in almost all scenarios a bypass is installed around the pump that will allow city pressure to be supplied to the system(s). In pretty much all scenarios, other than the higher floors of hi-rises, the city water does provide some benefit. I don't remember the exact stat, but I believe almost all activations of fire sprinkler systems during a fire event involve only 1 to 2 heads. We actually had a small wet system on test overnight one time, with the valve shut off, and 1 head activated at a fire created by construction debris and it extinguished the fire with only test pressure and water.
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CJ Bonczyk
2/2/2021 09:47:49 am
The fire sprinkler system is a critical component in life safety of a building. IBC provides many exceptions to when a building is "fully sprinklered". Reductions in rated separations, reductions in fire hydrant flow demands, increased egress travel distances and increased building heights and areas are allowed due to this capability. These exceptions are allowed with the exception that, the sprinkler system will suppress the fire to a point in which that occupants can safely evacuate the building and the the fire will be controlled until the fire department arrives to fully extinguish it.
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Jesse
2/2/2021 09:54:12 am
Lots of great answers here. The short answer is that the local fire department is effectively the backup to the stationary fire pump.
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Jesse raises a good point. In some regions of the world two fire pumps are considered critical especially for high risk environments with significant values at risk to cover impairments.
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Franck
2/2/2021 11:14:43 am
As indicated by Graham and others, some other countries have other requirements and some insurance companies ask for more (based on insured values, not life safety).
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