There are some safety standards avialble such as the oil industry safety directorate ( OISD) which say that the safe distance between heatetr and class A storage tank ( flash point below 23 deg centigrade) should be atlest 90 meters.
onshore
What should be the basis for design pressure for a Atm crude oil tank 30 m dia which is having breather valves? should the pressure at whihc the breather valve operates be considered?