Obstruction lighting marks structures that may endanger aircraft and helicopters – chimneys, masts, telecommunication towers, tall buildings, cranes and wind turbines – at night and, for very tall structures, also by day. Below we explain in plain language what the current rules say and which lights to choose.
Which rules apply?
The international standard is ICAO Annex 14 – Aerodromes, Volume I, Chapter 6. It defines the colours, light intensities and flash characteristics of obstruction lights. Most national regulations either adopt Annex 14 directly or refer to its tables.
In Poland, the Regulation of the Minister of Infrastructure of 12 January 2021 on aviation obstacles (Journal of Laws 2021, item 264; consolidated text 2025, item 903), amended in 2024 (Journal of Laws 2024, item 1540), refers directly to the ICAO Annex 14 tables. Always check the requirements of the aviation authority in the country where the structure is located.
Obstruction light types according to ICAO
| Intensity | Type | Colour / mode | Intensity (approx.) | Use |
|---|---|---|---|---|
| Low | A | red, steady | min. 10 cd | fixed obstacles below 45 m of small size, where Type B would be too bright |
| Low | B | red, steady | min. 32 cd | fixed obstacles below 45 m; intermediate levels on taller structures; combined with medium-intensity Type B |
| Low | E | red, flashing | min. 32 cd | intermediate levels on wind turbines from 150 m |
| Medium | A | white, flashing | 20,000 cd day / 2,000 cd night | day and night marking of structures from 45 m, instead of painted bands |
| Medium | B | red, flashing | 2,000 cd | night marking of structures 45–150 m; wind turbine nacelles |
| Medium | C | red, steady | 2,000 cd | night marking of structures 45–150 m where flashing light is undesirable (e.g. near buildings) |
| High | A | white, flashing | 200,000 cd day / 2,000 cd night | buildings and other structures from 150 m – day and night marking instead of painted bands |
| High | B | white, flashing, sequenced | 200,000 cd day | per ICAO: towers supporting overhead wires. Rarely used in practice – such towers are usually battery-powered and these lights need a lot of energy, so the towers are painted instead. |
Intensity values are approximate. The exact values for each type are given in the ICAO Annex 14 tables.
From what height and which lights?
Obstacles below 45 m
Low-intensity Type A or B lights are installed at the top. On large structures, lights are also spaced horizontally.
Obstacles from 45 m
Medium-intensity Type C lights, or Type B alternating with low-intensity Type B lights, are used. Further light levels are spaced at intervals of no more than 52 m.
Structures from 150 m
Instead of red-and-white painted bands, daytime marking with high-intensity Type A lights can be used, subject to approval of the changed marking.
Chimneys
A chimney is marked like any other obstacle – according to its height. The top level of lights is installed slightly below the chimney top, so that smoke and soot do not obscure the light or damage the fittings.
Wind turbines
- On the nacelle – a medium-intensity Type B light.
- Turbines from 150 m – additionally at least three low-intensity Type E lights at mid-height and a backup Type B light that switches on automatically in case of failure.
- Turbines located within 900 m of each other must flash simultaneously – hence GPS synchronisation.
- Since 2024, similar rules in Poland also cover offshore wind turbines (synchronisation within 1,852 m).
Which COLOZUZ light for which structure?
| Structure / requirement | COLOZUZ light |
|---|---|
| Obstacle below 45 m – low-intensity Type B (or A) | N-50 |
| Obstacle from 45 m – medium-intensity Type B or C | C-100K or the economy C-100Eco |
| Wind turbine – Type B with GPS synchronisation | C-100G |
| Day/night marking – Type A/C | C-100D Dual |
| Structure from 150 m – high-intensity Type A | C-100H |
N-50, C-100K and C-100Eco are available in 230VAC mains or DC (off-grid) versions. All our lights are powered directly, with no additional power supply boxes.
Frequently asked questions
From what height is obstruction lighting required?
It depends on the location of the structure (e.g. its distance from an airport) and on the aviation authority's decision. Near airports even small structures may require marking; elsewhere the key thresholds are 45 m and 150 m.
Is red-and-white paint enough?
Paint is daytime marking only. At night, lights are required. For structures from 150 m, painting can be replaced by white high-intensity lights.
How much does obstruction lighting cost?
The cost depends on the height of the structure, the number of light levels, the required light types and the power supply. Contact us – we will select the right lights for your structure.
This information is general. The applicable regulations and the requirements of the competent aviation authority for a specific structure are binding.