This is what anti-siphon valves are used to prevent: they are valves that open only when sufficient suction is present in the fuel line leaving the tank. Thus, when the line breaks or the pump fails, the valve will close.
> or it can be a few floors about the tank, too high to suck fuel from the tank so it has to be pushed up from below.
True, it has to be pushed up then. Alas, you can have a sequence of suction pumps. Note that otherwise you'd need to have high-pressure fuel piping, which might cause more problems than the possibility of feeding a fire indefinitely.
This is what anti-siphon valves are used to prevent: they are valves that open only when sufficient suction is present in the fuel line leaving the tank. Thus, when the line breaks or the pump fails, the valve will close.
> or it can be a few floors about the tank, too high to suck fuel from the tank so it has to be pushed up from below.
True, it has to be pushed up then. Alas, you can have a sequence of suction pumps. Note that otherwise you'd need to have high-pressure fuel piping, which might cause more problems than the possibility of feeding a fire indefinitely.