In the old days, the secondary containment around flammable liquid storage tanks could be a single system in which all the storage tanks sat. Today, that is NOT the case. Both NPFA 30 and IFC Chapter 57 require secondary containment to be designed so that an LOPC from one tank cannot affect the other tanks around it. They use the word “subdivided” to specify this.
Old secondary containment design vs. New secondary containment design
