Fire Water Storage Capacity for Chemical Facility

[PharmaB]

I know this is a broad question but can anyone provide information on what is a recommended Fire Water Storage Capacity for a Chemical Facility. All I can find in the NFPA 22 code, 1-5.1 Water Tanks for Private Fire Protection is that "the size and elevation shall be determined by conditions at each individual property....."

Are there any guidelines available that recommend a storage capacity for chemical facilities or flammable storage facilities. We are reviewing a system that has 3 hours supply [2,700,000Litres] should the largest deluge system [15,000L/min] be activated assuming no top-up from the city water mains to the storage tank. The city water mains is considered a reliable supply and top-up flow is [9,000L/min].

Thanks in advance.

 

[SooCS]

For diesel engine driven firewater pump, I believe the required the fuel supply to last for about 8 hours (1 gal/hp fuel storage). Base on this, I assumed the water supply to last for 8 hours. The last project I had been involved many many years ago, had a firewater storage tank to last for an hour but is supplimented by a firewater pond with the size of olympic swimming pool. Therefore water supply was not a issue.

Best of luck.

 

[kieffer]

You need to use the highest fire protection system water demand and multiply it time the duration required for your type of occupancy. You can subtract the fill rate from the public if the public system is reliable and you have an automatic fill valve and no the fill rate. For example if your flow from the deluge system is 2000 gpm and the hose requirements are 500 gpm and your duration required for your occupancy is 3 hours then you need (2000 gpm + 500 gpm)x 3hr x60 min = 450,000 gallons. If the fill rate from the public is 1000 gpm and the supply is reliable and you have an automatic fill valve you can reduce your tank by 60x3x1000 = 180,000 gallons.

 

[DavidCR]

I´m not shure, but I reckon that NFPA does not include specific water system sizing for industrial facilities, but for power plants NFPA 850 (or 851)do. If you can give a glance to these, you will find a good approach to your case following NFPA philosophy, but I´m shure that you local AHJ must provide some local requirements.