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Volume 19 Articles

CAST Lighting logoGain a Tactical Advantage
on the Perimeter Fence Line
with LED Technology

David Beasoleil, Inventor & President of CAST Lighting, LLC.

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Up until now the tools available to protect the perimeter have been fences, guards, intrusion detection, CCTV, and streetlights. The most vulnerable time for an intrusion is usually at night and security experts all agree that adding light to any perimeter will greatly improve security. In almost all cases the only lighting solution available has been legacy pole mounted security lights designed for parking lot, street lighting and highway lighting, with fixtures typically installed twenty-five feet or more off grade and spaced one hundred feet apart. The problem with using legacy pole mounted streetlights is that they were never designed for perimeter security lighting, camera systems, on site security personnel and were never really designed around optimizing the human eye for security in a dark environment.

LED’s and Precision Optics… Change the Game

Most people believe LEDs save energy and last a long time which we completely agree with. When it comes to Illuminating a perimeter, the folks at CAST Lighting had a different idea altogether; which is to use light designed around the optimal range for the human eye, advanced CCTV systems and deploying disability glare as a tactical advantage against intruders.

Understanding The Human Eye

The human eye is amazing, it has a natural mechanism that adjusts the iris of the eye to open and close automatically to maximize what the eye can see during the day and night. When you walk outside during the day, the iris quickly adjusts and constricts to optimize your sight. If exposed to an excessive amount of light suddenly, the rods and cones of the eye go into protective mode and filter the light. You can recognize this as spots and mild disorientation until the eye has time to adjust. At night, the opposite happens, where there is little to no light. Surprisingly, to navigate your surroundings effectively at night, you don’t need as much light as you may think. With this knowledge the security lighting goal now becomes twofold. The first objective is to create the perfect interaction with the human eye for optimal performance; the second is to create the right light setting so CCTV cameras can capture the best image possible.

Chart 1.1 (click image to enlarge)
Chart 1.1 (click image to enlarge)

Uniformity Is Critical For Optimal Security Lighting.

At CAST Lighting, we found that the uniformity of light is far more important than the amount of light falling on the ground. When designing the proper lighting plan, you want to avoid contrasting brightness levels (which is common with legacy pole mounted fixtures) that create total darkness on the edges(what we call “black holes”) to full brightness (“light bombs,”) on the interior. The best practice is to have even and consistent light distribution across the entire viewing field so the eye can move seamlessly from one scene to another. This view is supported by the IESNA, where light uniformity refers to the evenness of light distribution on horizontal surfaces.

The Human Eye at Optimal Performance: Understanding Minimum to Maximum Ratios & Lux Levels

The human eye has an amazing ability to adjust to a wide range of light. For example, the brightest full moon (a harvest moon) is only .108 lux while the typical lux value on a sunny day at noon is 107,527 lux. Most 2-megapixel cameras, along with the human eye easily operate well between 2 to 4 lux. The optimal uniformity ratio for security lighting is 4:1 minimum to maximum horizontal illumination, i.e. the light falling on the ground. Take note: 10 lux divided by 2.5 lux equals the 4:1 ratio. The CAST Perimeter® Security Lighting system delivers the right light lux level for both effective camera imaging and optimal eye performance at night with the added benefit of greatly reduced glare for both. This achieves the main objective of producing a more secure site condition.

Horizontal & Vertical Illuminance

Most lighting designs use the common horizontal lux or foot-candle light distribution plot to design any lighting system layout. This plot is essentially a scaled numeric rendering displaying in a grid format showing the light that will fall on the “horizontal” ground surface using a chosen lumen fixture, beam spread, fixture spacing, and mounting height. So, imagine turning on the lights in your office. The light that hits the ground is the horizontal ground surface or illuminance. Vertical illuminance is the light that reflects off walls and lands on objects or a person’s face. Up until now, vertical illuminance was disregarded because pole mounted solutions only pointed light in a downward direction, but security lighting experts, began carefully exploring this as a valuable security tool and an advantage. According to the IESNA, “one lux of vertical illuminance is sufficient to obtain a 90 percent probability of correct detection of an approaching person (but not facial recognition).” The 2003 IESNA findings reported, “Facial recognition can be made at levels as low as 2.5 lux. The IESNA Security Lighting Committee recommends that for facial identification the minimum vertical illuminance should be 5.0 lux.” One inherent flaw when using pole-mounted fixtures, mounted 25 feet or higher and typically spaced 100 or more feet apart is the difficulty projecting vertical illuminance on faces for identification, to read body language, to identify those who are familiar or threatening, and for security camera image capture. The CAST Perimeter® lighting solution resolves this issue by placing fixtures typically 10 to 12 feet off grade with spacing of 20 to 30 feet apart. This provides a light closer to the subject and better, more directed light that delivers both horizontal and vertical illuminance to enhance both camera imaging and on-site security detection.

Tactical Glare & Safe Glare-Free Observation

Special Forces use stun grenades – or flash bang grenades – to blind, deafen, and disorient combatants. Local police use light to blind possible threats during evening traffic stops, and we all know how annoying high beams are at night for oncoming traffic. Blinding glare is a tool that disables assailants and can be deployed tactically to YOUR perimeter security advantage, too. CAST Lighting has developed the perfect tool to do just that.

With the introduction of the 3rd generation CAST Perimeter® security light, our experts have taken precision optics, specific illuminance values; minimum to maximum ratios, electrical efficiency, and security lighting to create a whole new level of lighting that can be used as a tactical advantage. By strategically positioning a precision beam angle and accompanying glare shroud and mounting on top of a fence, this next generation of lighting is something truly extraordinary. We have produced, for the first time, a tactical blinding glare solution in what we call the “glare zone” for the intruder as well as a “glare-free observation zone” for on-site security guards.

Here’s how it works: (See Chart 1.1) The glare zone runs from 22 feet to 45 feet from the fence depending on the mounting height of the fixture. Intruders that approach the fence enter the glare zone and are quickly exposed to blinding disability glare, which will likely deter their intrusion. At the same time, guards can monitor this activity from the glare-free observation zone and can see clearly through the light providing a tactical advantage for guards to remain virtually out of sight while observing anyone in the glare zone. Essentially, the glare-free observation zone is the equivalent to a sun visor, allowing guards to see more clearly without being exposed to blinding glare.

Security Leverage: Integration with Intrusion Detection Systems

The CAST Perimeter® Security Lighting system can be integrated to work in unison with most modern intrusion detection systems to create effective zones of protection. During an intrusion, CAST Perimeter® lights can be triggered to operate for a specific duration or setting coinciding with the specific detection zone. The lighting can be set for a host of activities when an intrusion occurs such as: Turning on, Turning off, Blinking, Dimming or brightening, and Switching from IR to white light.

Using Light to Disorient & Disable: Your Tactical Advantage

Light is powerful. Perhaps the one sense criminals rely on most heavily on is vision. Once someone is blinded by light, it takes up to two full minutes for the eye to naturally adjust, and you would recognize it as “stars”, “dots” or “artifacts” which are still visible after turning away from bright glaring light.

The CAST Perimeter® system can be fitted with a relay that will cycle from full-on to total darkness every 45 seconds, essentially never allowing an intruder’s eye to fully reset, causing extreme visual disorientation! This feature can be activated via a simple dry contact or power signal provided by any intrusion detection system and can be adjusted by the end user for cycle time and duration settings. This is an inexpensive and extremely effective feature that uses light in a whole new way to stop an intruder from carrying out their intended act.


As evidenced, security lighting can be used as a tactical advantage by adding low voltage, low cost, easy to install LED lighting mounted on top of the fence. The results help detect and deter intruders by changing a dark environment into a lit environment. With the integration of other perimeter security solutions, now you can provide a multiple security solution platform that works seamlessly together, creating a stronger perimeter solution to impact an intruders ability to breach a perimeter.

CAST Lighting logo For more information regarding Perimeter Security Lighting and the products, visit:

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