ICAO-International Civil Aviation Rules
The obstacles marking is intended to reduce the risk of collision for aircrafts.
All fixed and mobile objects that are in a position to constitute a collision risk for planes in the vicinity of airports or heliports must be indicated.
The minimum recommendations for obstacle markings are included in Annex 14, Vol. I, Chapter 6 of ICAO.
These rules define what types of beacons are necessary for the signaling of obstacles, the minimum light intensity and their disposition respect to the height and the extension of the structure.
The light intensity of a beacon must never be less than 10 Cd according to the aforementioned ICAO standards.
The instructions for this purpose can be obtained from the airport authorities or from the air navigation services.