How do you classify an "Important Building" for separation distances in Chapter 6 of NFPA 58? In the standard we don't define this term, and leave it up to the AHJ.
I do have a couple reasons some AHJ's have declared some buildings are an "Important Building":
1. Replacement Value
2. Human Occupancy
3. Value of the Contents
4. Vital Role in the function of the Business or it's Records
5. It's role in Emergency Operations
-Eric Nette, P.E.