UL initiates safety certification for LEDs and fixtures

Of all the revolutionary technologies under development in the lighting world, LEDs are without doubt the one that will most radically change the market in the foreseeable future. While the technology is not new -- in fact LEDs have been used as indicator lights for decades -- improved chip designs and materials have allowed for brighter and longer-lasting light sources that can be used in a broad spectrum of applications.

Today, many manufacturers offer LED-powered luminaires in their catalogs. As these devices become more powerful we will very likely see this technology evolve into one of the main light sources used in general lighting applications. The fact that these products have very long lifecycles and require little maintenance makes them very attractive alternatives for product designers, who also value the potential for energy savings, resilience to environmental changes and flexibility in terms of coloring and beam control.

In order to ensure that this new technology enjoys the same level of acceptance and consumer confidence as other lighting technologies, UL is working on a set of requirements meant specifically for this technology.

Considerations for manufacturers
LED manufacturers need to consider the following when designing their products:

Risk of shock: For this purpose, two kinds of applications are considered: LEDs supplied by a Class 2 supply and those that are either line connected or otherwise connected to a non-Class 2 supply. The first group does not present a shock hazard due to the voltage and current limitation, while the second one will need to comply with standard insulation and accessibility requirements. The only additional concern even for Class 2 supplies is for devices used in wet locations. This further limits the maximum open circuit voltage to 15 VAC or 30 VDC.

Risk of fire: When dealing with risk of fire, many different aspects will impact the performance of a fixture, including but not limited to: proximity between the LEDs, diffuser design and material, type of enclosure, installation, etc. While using a Class 2 power supply reduces the risk of fire by limiting the available electrical energy, we do have evidence that these systems may exceed 90 degrees C (the maximum permitted by the building code in the US on combustible surfaces) due to the thermal energy dissipated by the LED in converting electrical energy to light. Therefore we believe that LED luminaires need to be designed to take this into account and to undergo temperature testing to ensure all components within the luminaire and the outside surfaces are operating within their specified temperature ratings.

Biological hazards: Issues like retinal damage and other health issues that could arise from exposure to these light sources are always a concern, but currently there is no conclusive research that proves that there is a significant risk involved with using this technology. As with any light source, using a diffuser may mitigate personal injury risks from the electromagnetic radiation it produces.

UL's involvement with LEDs
Towards the end of this month, UL will officially publish UL 8750 titled "Outline of Investigation for Light Emitting Diode Light Sources for Use in Lighting Products." Upon release of the document, the OOI will be used as the main document within UL for all investigations of the LED light sources used in UL Listed lighting products.

We would like to emphasize that as a result of the feedback that we received from industry, the Requirements will be conceived as a horizontal Standard, and therefore the assembled device will still be evaluated for Listing to the appropriate end product standard.

For example, the LED light source in an LED luminaire will be evaluated to the Outline of Investigation. Meanwhile, the LED luminaire, as a complete product, will be evaluated according to the Safety Standard for Luminaires, UL 1598.

Similarly, an LED light source used in a portable LED luminaire will be evaluated to the Outline of Investigation and the portable luminaire will be evaluated to the Safety Standard for Portable Luminaires, UL 153.

Standards Technical Panel
During the first quarter of 2007, UL will form, with the support of the LED industry, a balanced Standards Technical Panel (STP) consisting of: Producers, Testing and Standards Organizations, Supply Chain, AHJ (Authorities Having Jurisdiction; in the case of LEDs, that would be electrical and building code inspectors), Government, Consumer, General Interest, Commercial / Industrial Users. The panel will work on drafting and publishing an ANSI Compliant LED standard (using the OOI as a starting document) for products designed for sale in North America.

At this point in time, people that are interested in participating in the standards process should communicate with us at [email protected], letting us know, to the best of their knowledge, the interest group that they represent. Please keep in mind that in order to ensure that the group is balanced according to the ANSI guidelines, we may not be able to accommodate every request.

As we move forward, UL will endeavor to ensure that our activities meet industry's needs and maintain communications with all interested stakeholders through our website at www.ul.com/lighting/ledsummit.

If you should have any questions, please do not hesitate to contact Eli Puszkar, General Manager of the lighting Strategic Business Unit at UL, at [email protected].

About UL
Underwriters Laboratories Inc. (UL) is an independent, not-for-profit product safety certification organization that has been testing products and writing Standards for Safety for more than 109 years. UL tests more than 18,000 types of products annually, and more than 19 billion UL Marks appear on products each year. Worldwide, UL's family of companies and its network of service providers include 60 laboratories, and testing and certification facilities.