ICAO Annex 14 regulation, for marked structures (painted with white / red horizontal bands), prescribes the use of Aircraft Warning Lights with night-time operation only.
Appendix 6-2 of the standard indicates the use of two types of obstacle warning lights: medium intensity flashing red (MIOL-B 2.000cd) and low intensity fixed red (LIOL-B 32cd). Medium intensity AWL should always be placed on the top of the structure, and the underlying levels must respect the alternation between medium and low intensity beacons.
For example, for a structure with a total height of 90 meters must be installed: MIOL-B beacons on top and LIOL-B beacons on the second (and last) level; or, for a building with a height of 110 meters it will be necessary to use 4 levels of lights: the one at the top and the second one with medium intensity lights and the third one and the lower one with low intensity lights.
However, if an aeronautical study or the civil aviation authority institution under which the control of the structure in question is to require the use of other lights or other configurations, the requirements must be respected by way of what the ICAO Standard Annex 14 establishes .