About how long can one keep the flame lit on a Zippo lighter?

Ive heard that plastic disposable lighters should not be held on for more than ten seconds, however Zippo's much more rugged construction seems to allow a flame to burn for a much longer time frame and could second as a mini lantern or even an emergency candle. Is there an official limit expressed by Zippo as to how long one can hold the flame without causing permanent damage or any other malfunction? If there is none, then what is the longest time anyone has left their Zippo lighter on for?|||ive used mine as a candle before and i let it burn till it ran out of lighter fluid, but it wasnt full, the only thing is the lighter was really hot and i burnt myself...and my friends|||I expect a Zippo lighter would stay lit until it ran out of fuel. They are proven to be very hardy. How long that would be depends on how much fuel was in it.