Reliability in
Obstruction
lighting

Obstruction lighting for stack

The number of lights per level depends on diameter of the stack: 3 lights are required per level if the diameter is less than 6 meters, 4 lights if the diameter is between 6 and 30 meters, 6 lights if the diameter is between 30 and 60 meters and 8 lights if it is above 60 meters

Stack without red and white stripes 45 to 105 meters high, lights operating day and night

Dual color medium intensity up to 6 meters below the top of the stack (red flashing at night, white flashing during daytime) Low intensity type B or FAA L-810(F) at mid level (red at night, off the day) Power cabinet and photocell at bottom

Stack with red and white stripes up to 45 meters high, lights operating at night only

Low intensity type B or FAA L-810 at the top

Stack with red and white stripes 45 to 105 meters high, lights operating at night only

Red medium intensity up close to the top of the stack Low intensity type B or FAA L-810(F) at mid level

In case of medium intensity, control cabinet and photocell oriented to the North should be present at bottom