LED lighting: metrics and standards

This is an extract from an article entitled "Lighting community outlines challenges for LED industry". The article reports from the "LEDs: Meeting the Design and Performance Challenges" conference, which was held in London, UK, in late January 2004.

Kevin Dowling, vice-president of strategy and technology at the specialist LED lighting company Color Kinetics, described a metric for comparing the relative costs of different lighting technologies. The "cost of light" metric encompasses not only the cost of the light source and fixtures, but also the cost of maintenance and electricity over the lifetime of the light source.

Although incandescent lamps have a very low cost and high lumen output compared with LEDs, the LED source has a much longer lifetime and consumes far less power. In fact, typical LEDs already have a lower "cost of light" than incandescent and halogen sources, according to Dowling, although this is not widely appreciated. "Most Color Kinetics installations are not driven by energy savings, although the benefits are still there," he said.

Speakers and panelists kept returning to the issue of standards. Richard Hall of Thorn Lighting commented: "There is a very high need for standardization to allow luminaire [lighting fixture] manufacturers to manage their customers' expectations." In fact, a number of standards are being developed by the CIE, the International Commission on Illumination, relating to areas such as the measurement of LED flux, color rendering index, and other properties.

In some respects, LEDs will need to fit in with existing standards. "There are a number of internationally recognized standards, for example covering transport-related lighting applications, and LEDs will have to adapt themselves to fit around these," said Jonathan David. With regard to photobiological safety, Telectra's Oliver pointed out that the regulations covering laser eye safety also cover LEDs.