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How to determine the maximum fire water storage as per NFPA codes and standards?

Question asked by on Apr 3, 2019
Latest reply on Apr 4, 2019 by

Hi. I have a question about the maximum fire water storage in a particular case as below:


In a case of fire water supply for a power plant, I think that one should refer to the below clause of NFPA 850:

6.2.1* The water supply for the permanent fire protection installation should be based on providing a 2-hour supply for all of the following:
(1) Either of the following, whichever is greater:
(a) The largest fixed fire suppression system demand
(b) Any fixed fire suppression system demands that could reasonably be expected to operate simultaneously
during a single event [e.g., turbine underfloor protection in conjunction with other fire protection system(s) in the turbine area, coal conveyor protection in conjunction with protection for related coal handling structures during a conveyor fire, adjacent transformers not adequately separated according to 5.1.4]
(2) The hose stream demand of not less than 500 gpm (1893 L/min)
(3) Incidental water usage for non–fire protection purposes

However, there are some fire water supply requirements in other NFPA codes and standards. For example, as per the table 12.8.6 of NFPA 13 there are some particular cases of sprinkler system which require more than 2 hours of water supply, e.g. ESFR standard sprinklers more than 25 in design area. One might think that the odds of such storage being provided in a power plant is negligible, and I do agree that, but if there is a storage in a power plant requiring more than 2 hours water supply, which NFPA standards one should follow?    


Any thought on this will be appreciated.