Cooling towers are heat rejection devices which extract waste heat to the atmosphere through the cooling of a water stream to a lower temperature. Cooling towers vary in size from small roof-top units to very large hyperboloid structures that can be up to 200 metres (660 ft) tall and 100 metres (330 ft) in diameter.
|H < 45m||1 level of low intensity obstruction lights shall be used|
|45m < H < 105m||2 levels of obstruction lights shall be used: top level with medium intesity, intermediate with low intensity|
|105m < H < 210m||4 levels shall be used: top with medium intesity, 1stintermediate with low intensity, 2nd intermediate with medium intensity, lower level with low intensity|