Yeah, it would be unusual to see aircraftwarning structure lighting on most tank farms. I have seen some near airprorts, which often have a nearby or even on-site tank farm for jet fuel and avgas. Because they're so close to the airport, as Eric noted, lighting is required there in many cases.
Mike Lehman
Urbana, IL
Generally, you only need obstruction lights on structures more than 200 feet above ground level, unless is it close to an airport.
http://www.faa.gov/documentlibrary/media/advisory_circular/ac%2070%207460-1k.pdf
"No soup for you!" - Yev Kassem (from Seinfeld)
Hello I am building an oil tank farm and I could use a little help, like I have six tanks, do I place a air craft light on top of each tank or just the tallest tank? And more questions.