Why Can People See Light Beacons From Far Distances?|
Article - February 7, 2016 By LarsonElectronics.com
Why Can People See Light Beacons From Far Distances?
The distance at which a flashing beacon can be seen strongly relies on the following factors: power supply and type of lighting technology applied to the fixture. For example, a compact beacon that utilizes a set of powerful lithium-ion batteries and LEDs can be seen up to three miles away (generally speaking).
Are these the only factors that dictate the performance of light beacons? How does color and installation methods affect visibility in far distances? Read on to find out why people can see flashing beacons from remote distances.
Beam Projection versus Visibility
Digging deeper into this topic, it is common knowledge that shining a flashlight in a dark, open space will not generate the same results. At best, you will only be able to see the beam from a distance of roughly 20 feet. Theoretically, both luminaries (a flashing beacon and a handheld flashlight) could use powerful batteries and LEDs, which would mean that they should be able to operate and perform in the same manner. But in reality, the difference is what individuals see from a distance. Yes, light beams can reach great distances, but this is not what can be seen from great distances. Instead, it is the source of the beam from the fixture’s bulb that makes it visible.
The color of the lens is crucial to beacon visibility, with white being the most visible in nighttime conditions. Contrary to popular belief, white beacons can outperform yellow and green lenses in snowy and rainy environments. Rescue workers prefer to use white beacons due to its brilliant properties. By comparison, using a green or yellow beacon in the woods greatly hampers its ability to be seen from far distances, because it blends in with nearby leaves, trees, dirt, grass and bushes. If distance is your top priority, avoid blue, which blends in with water, and thus, should not be used in marine applications.
Below are the effects of lens color on intensity levels of flashing beacons:
• Clear- 100% (no effect)
• Yellow- 93%
• Amber- 70%
• Red- 23%
• Blue- 24%
• Green- 25%
Factors that Affect Beacon Visibility
In addition to the light source and lens color, there are other factors that increases remote visibility for flashing light beacons. One of these is the setting applied during operation. Many people assume that steady mode (constant illumination) is the most effective option, because it allows individuals to track down the source of light faster and with greater accuracy. Unfortunately, this is far from true, as steady projection that goes unnoticed has a higher chance of remaining unnoticed over time. Rescue workers prefer flashing modes because the “pulsing” beam is detected easily by individuals. Human eyes are designed to detect changes (including changes in lighting conditions) in everyday environments. Because of this, the flashing effect ensures that nearby lighting conditions are always fluctuating, which can streamline detection.
To increase visibility during operation, choose a beacon that emits light in all directions. Moreover, air should be able to move freely around the unit to prevent the accumulation of heat. It is vital to consider that light travels in straight lines or paths. Hence, the luminaries would be most effective if strategically positioned in the line of sight of observers. To ensure functionality, shock and vibration should be avoided, especially for beacons that rely on bulbs with filaments.
How to Use Personal Flashing Beacons
How you use personal flashing beacons greatly affects their effectiveness in outdoor environments. For runners, hikers or teams carrying out emergency services, it is best practice to mount the beacons on top of a person’s head. This ensures that people behind them does not get blinded by the light. Blinding nearby individuals is incredibly dangerous in the wilderness, because such occurrences may cause hinder an individual’s ability to focus on their environment. When using the light beacon as a marker for temporary campsites or starting lines (for trail runs), it is recommended to mount the unit for maximum exposure.