As specified by Annex 14 of ICAO regulations, Low Intensity Obstruction Lights (LIOL) should be used to warn the presence of obstacles up to 45m height, such as telecommunication towers, wind turbines, chimneys, cranes, buildings and other structures.
Low Intensity Obstruction Lights are the simplest devices according to ICAO standards and they have the following characteristics and uses:
- LIOL Type A (intensity >10cd, red steady burning) can be used alone;
- LIOL Type B (intensity >32cd, red steady burning), can be used either alone or in combination with medium intensity obstacle lights Type B, Type AB or with high intensity obstacle lights Type AB;
- LIOL Type E (intensity >32cd, red flashing), can be used either alone or in combination with medium intensity obstacle lights, Type B. Flashing rate will be set at the same rate of other flashing beacons installed on the structure.