When light shines through the pathway of moving fan blades it creates a constant dimming and brightening of the light. This phenomenon is known as strobing. At the very least strobing is an annoyance; but more importantly, strobing can cause your facility's occupants to experience dizziness and confusion.
How to Avoid Strobing with HVLS Fans
1. Maximize horizontal separation between the blade and light
2. Increase vertical distance between the light and the blade
The smaller the distance between the light and the blade, the higher concentration and frequency of strobing.
(Measurement A in diagram)
3. Minimize light/fan overlap when separation isn't possible
The closer the light is to the center of the fan, the higher the frequency of strobing.
Different kinds of light sources cause more or less strobing. Single-point fixtures and lamps beam light in a more conical shape which is more susceptible to strobing. On the other hand, longer fluorescent tubes are less vulnerable.
Recessed lights are particularly at risk for strobing. It can be very difficult to prevent strobing with recessed lights because they are actually slightly higher than the ceiling. Maximizing the space between the lights and the fan is critical with recessed lighting.
If you have a minor strobing problem and don't want to change the configuration of your HVLS fan or lighting system, try adding more ambient light to your space. This can minimize the strobing effect to the point where it does not negatively impact workers in the building
The Bottom Line
To prevent strobing in your facility, carefully consider your current lighting layout before you install your HVLS fans. It's much easier to place your HVLS fans wisely and never have to worry about strobing than to have to fix a strobing problem after installation.
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