Water Requirements for Storage Tank Farm Bund Area

[Clamont]

When trying to calculate the water requirements for a storage tank farm containing Atmospheric Storage tanks how do you consider the bund area? Can you calculate just the requirements of water for the storage tanks based on the flow rates in NFPA 15 and assume that some of this water can be diverted away from the tanks (through the hydrants) and to any potential pool fire in the bund area?

The only place I have seen in NFPA 15 which may cover this would be "Flammable and Combustible Liquid Pool Fires" however I do not think this would apply to a bund area as the flow rates are very high.

 

[stookeyfpe]

No fire flow requirements exist in either NFPA or API standards or Recommended Practices for petroleum storage terminals. You can find some guidance in API RP 2021.

 

[chicopee]

What's in the tanks and which code are you using to determine the water requirements? You should also contact your fire insurance carrier for guidance. I suppose that you are looking at water based foam as an extinguishing agent so would that be the nature of your inquiry? and if so contact the foam supplier for assistance. Water by itself can be a real concern from a contamination standpoint but then you have not identified the products in the tanks. I know that the NFPA talks about wetted surfaces to determine emergency venting of on flammable and combustible liquid tanks so perhaps there is a parallel in your quest.

 

[DavidCR]

NFPA 15 is only for fixed spray systems, in your threads you have not described what type of installation, how critical, how important, insurance condition, etc. You mention several types of product. If this an important risky place you should include a good quantity of water including proccess equipment and not only tanks.

Tanks could be protected by NFPA 15 and NFPA 11 equipments that might use less water than other areas that require handlines or fixed monitors. If you follow NFPA 30 and all distances and dikes are OK you need very little of fire water. (One may interpret that NFPA considers that if all things are relatively safe and OK, the possibility of letting it all burn down is not out of the code, the NFPA does not obligate everyone to have a tank farm with a suppression system for a big fire, it requires only a reasonable minimum protection).

The answser is not easy followin API RP 2001, RP 2030.

If this is for a refinery or similar, in general for this RP2001, it says a "should" for duration of 4-6 hours.

If your protection is based on fixed systems the water follwing API RP 2001, RP 2030, comes from NFPA 13,15,11,etc., also you have to consider handlines, monitors you may require that may use 0.1-0.5 gpm/ft2 of protected equipment area for some recommended time that may go from 2 to 6 hrs.

As an example, for power plants, NFPA 850 asks for simutaneous water/foam fixed equipment plus 500gpm for 2 hrs. But in case of oil industry this 500gpm will not be enough.