My email to "engineering" at state office of insurance commisioner, under whose wing state fire marshal's office cowers, which fire marshal's office was given accessibility, brought a reply that said, "not necessarily" if the non-paved surface is compacted and durable enough.
True to form, as I have noticed among state officials to whom questions of any substance are put, the answer was "maybe".
BTW I e-mailed a county ag extension agent a picture of a fruit tree that had dead-ringer signs of fire-blight and asked him if he thought it looked like fire blight.
His answer, "I can't tell from the picture," and he then went on to verbally describe, in hints of what to look for, exactly what the picture showed.
Message to me, "I don't go one millimeter out no limb fer nobody."