Why do most experts recommend the use of aqueous film-forming form (AFFF) to extinguish crude oil fires inside a bulk storage tank?

The multiple components of crude oil are seperated by a process called fractionation (factional distillation) at petroleu, refineries.

1.  Rank ( or arrange) the following petroleum products according to their increasing risk of fire and explosion at room temperature, and provide the technical basis for the ranking:  Asphalt, aviation gasoline, transmission fluids, propane and kerosene.

2.  Why do most experts recommend the use of aqueous film-forming form (AFFF) to extinguish crude oil fires inside a bulk storage tank?

your response must be at least 200 words in length.  Must be referenced and cited.