Product category:
Compliance Engineering
News Release from: UL International (UK)
Edited by the Electronicstalk Editorial
Team on 24 May 2007
Setting the standard for LED lighting
safety
Safety standard will address light emitting diodes used as light sources in luminaires designed for sale in the North American market.
Underwriters Laboratories is leading the development of a safety standard for light emitting diodes used as light sources in luminaires designed for sale in the North American market As a first step, UL has recently released the document UL8750 titled "Outline of investigation for light emitting diode light sources for use in lighting products", which will be used as the main document within the certification organisation for all investigations of the LED light sources used in UL listed lighting products
This article was originally published on Electronicstalk on 23 Mar 2005 at 8.00am (UK)
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LED technology is the most innovative and fastest growing in the lighting sector.
The use of LEDs in general lighting is expected to explode in the next few years, causing a huge impact in the sector.
In spite of not being new, during decades the use of LEDs has been limited to indicator and signalling purposes.
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More recently, as LEDs technology evolves, the quality and durability of the lights has increased, permitting to broaden the field of applications.
Manufacturers offer increasing number of LEDs lighting products in their catalogues providing higher levels of illumination, which will make them shortly, the most common light source in the market for general lighting applications.
The fact that these products provide a longer life cycle and that they require minimum maintenance, makes them very attractive to lighting manufacturers.
Other very interesting features are their high potential of energy saving, their resistance to environmental changes and their flexibility in terms of colouring and beam control.
To date UL has evaluated LED lighting systems and components for a variety of applications, including: exit luminaires, signs and sign retrofit applications and general lighting.
These systems and components are covered under various UL categories relative to their application.
Some of the categories are signs, sign accessories, sign conversion retrofit kits, luminaires, under-cabinet luminaires, lamp adapters and miscellaneous lampholders.
UL is now working on a set of specific requirements to ensure that LEDs used any type of lighting products achieve the same levels of acceptance and consumer confidence as traditional lighting technologies.
Therefore, LED manufactures must consider three important potential safety issues when designing their products.
First, two kinds of applications are considered for risk of shock: 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, whereas 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 location, which further limits the maximum open circuit voltage to 15V AC or 30V DC.
In terms of 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).
Although using a Class 2 power supply reduces the risk of fire by limiting the available electrical energy, there is evidence that these systems may exceed 90C (the maximum permitted by the building code in the USA on combustible surfaces) due to the thermal energy dissipated by the LED in converting electrical energy to light.
Therefore, it is necessary that LED luminaires are 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.
In terms of 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 not 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.
During the first quarter of 2007, UL will form a balanced standards technical panel (STP), consisting of all the stakeholders involved: manufacturers, testing and standards organisations, supply chain, electrical and building code inspectors, government, consumer, general interest, commercial/industrial users.
The panel will work on the drafting and publishing of an ANSI compliant LED standard by using UL's OOI document as a starting basis.
All UL customers are able to download the OOI free of charge by visiting UL's standards portal.
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