Benefits of Switching from HID Lighting to LED High Mast Lighting
High mast lighting systems can be equipped with different types of lamps, depending on the preferences and requirements of the project or work site. Previously, high-intensity discharge (HID) luminaries were the standard used by companies that needed elevated illumination over a wide target area.
While effective, this type of lamp came with several drawbacks that were eventually addressed and rectified through the introduction of light-emitting diodes (LEDs). The promise of clean, energy efficient illumination with minimal maintenance has forced some businesses to rethink their lighting technology of choice for industrial towers.
HID Sources and Pitfalls
The main difference between HIDs and LEDs is the way they generate light during operation. For HIDs, an arc inside a gaseous, quartz glass capsule is responsible for light radiation. The hermetically sealed lamp contains various gases that determine the type of HID unit: metal halide (metal halide compounds, mercury and argon), mercury vapor (previously common in street lighting systems, with a lumens-per-watt rating range of 30-50 LPW) and high-pressure sodium (xenon and sodium-mercury gas, with sodium being the element that makes this luminary unique, contributing to its bright yellow, golden color).
Due to the way HID lamps generate light, the units are very fragile. Additionally, the bulbs contain harmful gases that could escape, should breakage occur. For rugged and hazardous environments, this is a huge risk. Although fragile, HID light towers can tolerate extremely cold temperatures better than LEDs. Lighting manufacturers usually offer HID assemblies with a color temperature range of 3,000K to 5,000K. This is rather limited, considering the color temperature scale visibly starts as low as 800K and peaks as high as 12,000K.
Perhaps the biggest drawback with using HID light towers is their warm up requirements. Operators must wait between 5-15 minutes for full light output. Moreover, the units are subject to cool down and warm up periods when restarting the system. The accumulation of time wasted waiting for the lamps to reach full output can get overwhelming. Over a month, businesses can lose around nine hours just waiting for the lamps to fully turn on (assuming two, 10-minute warm up times per day).
HID light, being omnidirectional in the way the lamps distribute light, use reflectors to direct beams toward a target. The reflector component, which is essential for HID units, can only reach a maximum efficiency rate of 95 percent, as five percent of the light is absorbed or converted to heat. Additionally, the more times the beam is reflected, the lower the efficiency rate of the unit. With this in mind, high-quality HID lamps with robust reflectors usually max out at 85 percent efficiency. By comparison, LEDs, do not use reflectors (though they can).
Maintenance is another major disadvantage for HID masts. With an average lifespan of 15,000-25,000 hours, operators must replace these units frequently, which can be challenging in rough work sites. In most cases, the ballast must also eventually be replaced, adding to the overall cost of maintenance. The degradation of HID lamps is not a straightforward process. As the lamps reach the end of their intended lifespan, they start to shift colors. For outdoor sites that need maximum illumination and clarity, operators will usually re-lamp the units at this stage in order to maintain light quality.
Benefits of LED Towers
LEDs represent the next era of lighting technologies for high mast systems. The solid-state lights are constructed of semiconductor materials that generate light via electroluminescence without the use of loose filaments or harmful gases. This makes then very durable, capable of standing up to rough treatment, vibration, direct contact and unpredictable elements. For light towers, this is a huge benefit, since the assemblies are used in outdoor sites.
Compared to HIDs, LEDs are not subject to a lengthy warm up period. They can provide instant illumination and toggling without affecting light performance. Color temperature capabilities of LEDs range between 2,700K and 7,000K. Certain variants are also dimmable (the lamps do not use a ballast – eliminating a major point of failure).
LEDs consume around 30 percent less energy than traditional lighting technologies. Again, for high mast lighting systems this is a key advantage – especially remote assemblies that run on a generator or batteries. With an average lifespan of 50,000+ hours, LEDs also last up to twice as long as HID models. Outside of its rated lifespan, the luminaries are usually still useful – since some high-quality LEDs are able to retain up to 80 percent of output after surpassing its general lifespan.
All of the attributes above, from its solid-state build to its long lifespan and ability to retain light output, equates to lower maintenance and repair costs. Although LED light masts are more costly to acquire during the early stages of ownership, over time, the lower cost of operation makes this option far more superior than HID light towers.