for the fixed roof crude oil storage tanks,the AFFF foam solution application rate shall be 4.1L/m2/min for 55min when use type II foam chambers as the primary protection means according to NFPA 11 requirements.
and at the same time, 2 pieces hose streams shall be used for supplementary protection, with 189L/min for 30min for tanks which diameter are bigger than 30m.
but, I want to know, whether these 2 pieces hose streams are used for extinguishing the small spill fire in diked area (storage tank farm) or just supplementary protection for the tank and another stream of foam consumption for diked area will be added into the calculation?
for the diked area(storage tank farm),how to decide the area of spill fire?if the total area of tankfarm is used, the foam consumption is very large.
and how to calculate the foam consumption for non-diked area,how to decide the area of spill fire in non-diked area?
anybody has the calculation reports?pls share it, thanks a lot.