rocker....
See this link:
Under "Location" it says:
"Heaters are always located at a safe distance 15 meters away from other hydrocarbon bearing equipment and preferably upwind; however, on some process it is permitted for reactors to be within this distance to prevent light volatile vapors from begin blown towards an open flame.
Space must be allowed for tube replacement for both horizontal and vertical heaters and this, together with ample access for mobile equipment, should be considered on piping layouts and drawings. Ample access is always needed for firefighting equipment with areas under or around heaters usually paved and curbed.
No low points in the paving or grading are permitted as these provide excellent sports for trapping hydrocarbon liquids which could be ignited by the open flames of the burners."
As I recall, the insurance people also may have a requirement for spacing on fired heaters.
With regard to storage tanks with Class I flamable liquids, NFPA-30 contains spacing requirements to other tanks, occupied buildings, property lines etc...
Please complete this thread and let us know what you decide ....
MJC