In the past, high intensity discharge (HID) lamps were the standard used by companies that needed illumination over a wide target area. This type of lamp came with several drawbacks that were eventually addressed with the introduction of 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.
The main difference between HIDs and LEDs is the way they generate light during operation. The sealed HID lamp contains various gases that determine the type of HID unit, the three most common being metal halide, mercury vapor, and high pressure sodium. 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.
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 become 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 is omnidirectional and uses reflectors to direct beams toward a target. The reflector component, which is essential for HID, can only reach a maximum efficiency rate of 95 percent, as five percent of the light is absorbed or converted to heat.
Maintenance is another major disadvantage for HID high mast lights. 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 to maintain light quality.
Benefits of LED High Mast Lighting
LEDs represent the present and future 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 them 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 commercial and industrial outdoor sites and very out of reach.
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 and certain variants are also dimmable.
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.
All of the factors above, from its solid-state build to its long lifespan and ability to retain light output, equate to lower maintenance and repair costs.Clearly the question of LED vs HID is no longer an issue, the benefits of LED lighting for all applications, especially in high mast light, far outweigh that of high intensity discharge.