LED retrofit codes, standards
Clients are asking lighting designers to help them save on energy costs. Replacing fluorescent, HID, or other lights with LEDs is in high demand.
LED lighting retrofits are becoming popular due to their energy and operational savings. LED retrofits can save 40% or more energy when compared with traditional light sources such as incandescent, halogen, and high intensity discharge (HID).
Resources such as the U.S. Energy Information Administration indicate that lighting accounts for approximately 26% of the energy use in commercial buildings. It is also widely known that buildings consume more than 40% of the energy in the United States, according to the U.S. Dept. of Energy.
The U.S. Energy Independence and Security Act of 2007 marked Jan. 1, 2014, as the date when 100-, 75-, 60-, and 40-W incandescent lamps can no longer be manufactured by U.S. companies. As a result, LED light sources are an attractive alternative to the lamps that have traditionally been used to replace incandescent lamps such as halogen and fluorescent lamps.
Why use LEDs?
Why are LED retrofits popular with clients? LEDs have a reduced environmental impact compared to other light sources. This is attributable to the energy savings from using LEDs as well as the longevity of LED light sources, resulting in many fewer lamp replacements over time. LEDs also do not contain hazardous materials such as mercury, which is used in fluorescent lamps.
LEDs emit virtually no ultraviolet (UV) rays or infrared (IR) heat radiation. This makes LED light sources ideal for venues where UV and IR are undesirable, such as in museums and art galleries. UV and IR can degrade sensitive materials found in these facilities.
LED light sources work well in applications where there is frequent on-off switch cycling. The life of fluorescent lamps is decreased when used with instant start ballasts and there is frequent switching. HID lamps have a restrike time delay (usually 2 to 20 min) when they are turned off so they can cool down before turning on again. This makes HID lamps ineffective for switch cycling applications. Conversely, there are no detrimental effects with frequent on-off cycling of LEDs, making them popular in spaces that use occupancy sensors for energy savings.
When turned on, LEDs are instant-on with full light output and do not require a warm-up period to reach full light output as many compact fluorescent lamps (CFLs) and HID lamps do. LEDs also perform well in cold temperatures whereas other light sources like fluorescent lamps have lumen degradation at lower temperatures.
The rated life of most LED light sources is higher than comparable light sources including halogen, HID, and most fluorescent lamps. Also, the lifecycle cost of LEDs is favorable compared with other light sources due to their long life and their energy efficiency.
LED retrofit options
There are several retrofit options with LED light sources. Popular retrofits include a self-ballasted LED screw-in A19 lamp or a LED PAR screw-in lamp. A typical LED A19 light source uses 13 W compared to a 60 W A19 incandescent lamp with similar lumen output. This comes out to a 78% reduction in energy usage.
The A19 LED light source in the above example has a typical life of 25,000 h compared to 1,000 h for a standard A19 incandescent lamp.
When comparing lifecycle costs, the low operational and maintenance costs of LED light sources make them very attractive compared to the A19 incandescent lamp. In our example, an incandescent lamp would have to be changed out 25 times before the LED lamp would need to be changed.
Another LED retrofit option is to replace T8 and T12 tubular (typically 4-ft linear) fluorescent lamps with tubular LED lamps. T8 and T12 lamps are omnidirectional, meaning that light is emitted in all directions out of the lamp. Omnidirectional light may not be desirable; reflectors in lighting fixtures are used to help provide a more uniform distribution of light.
Many of the early linear tubular LED retrofits had narrow beam angles, which presented issues with good lighting distribution.
Several manufacturers provide an LED retrofit kit complete with the LED driver and the tubular LED lamps. The conversion would involve removing the existing magnetic ballast, the fluorescent lamps’ lamp holders, and the fluorescent lamps themselves. Another option is a retrofit kit that is complete with LEDs and driver that come as an assembly and mount directly into the existing luminaire housing. One advantage of this style of retrofit kit is photometry is available for analysis.
Tubular LEDs can reduce energy usage by about 40% compared with standard 32 W T8 lamps with a normal ballast factor (0.88) while producing similar light level at the target area. However, most new tubular LED lamps have a wide beam angle (such as 160 deg) that has rectified this problem.
Another popular LED retrofit application is with street lighting and parking lot lighting. Many existing lighting fixtures in these applications use HID lamps such as high pressure sodium (HPS) and metal halide (MH).
Using LED lighting for streets and parking lots over HID lighting has many significant benefits. These include reduced energy usage and longevity, resulting in fewer lamp change-outs (saving high maintenance costs with tall light poles). LEDs also reduce risk from inadequately lit spaces when HID lamps are burned out (due to their shorter rated life) and areas become unsafe. LEDs also are flexible when it comes to controllability such as dimming or occupancy sensing, saving energy and helping comply with energy codes.
What are some of the code related considerations when retrofitting existing lighting fixtures with LED light sources? In most cases an existing lighting fixture is UL listed based on a particular lamp type (such as T8s). Most likely, the fixture that is being retrofitted does not have a UL listing with a retrofit LED light source.
It is important to check with the authority having jurisdiction (AHJ) to determine if luminaire retrofit kits require inspection and how compliance is established. In an online document, UL implies that modifying a fixture by replacing the existing lamps and ballasts in the field might negate the UL listing. AHJs may require that a LED retrofit kit be UL classified under the product category “Luminaire Conversions, Retrofit (IEUQ).” According to UL, “these products have been investigated to determine that, when used in accordance with the manufacturer’s instructions, they do not adversely affect the operation of the complete unit.”
A luminaire that is modified so it can no longer accept the original lamp should have a label affixed (provided by the retrofit kit manufacturer) indicating the luminaire has been modified and can no longer operate the originally intended lamp(s). The label is an easy way for the AHJ to identify whether a conversion retrofit kit meets the UL Classified Mark.
Some of these tubular LED linear light sources are able to use the existing T8 lamps’ electronic ballasts. This makes it easy to change out the linear T8 lamps without having to remove the existing ballast and installing a new LED driver.
REF: Consulting – Specifying engineer
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