Foam Storage Tank

It is rectangular in shape or cylindrical depending on the design which is used to store foam concentrate in chemical forms like AFFF (Aqueous Filming Forming Foam), AR AFFF (Alcohol Resistant Aqueous Filming Forming Foam) depending on the specific fire design but in this case it is liquid fire so AFFF is in the storage tank. The foam pump is on to mix the chemical with water to fight fire.

Foam Tank

Foam Pump