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    Energy Star challenged over 150 Hz requirement for LED lamps

    Jan. 12, 2010
    The Energy Star criteria for Integrated LED Replacement Lamps includes a requirement for 150 Hz operation, which is now being challenged.

    The US Department of Energy (DOE) is facing a challenge to its Energy Star criteria for Integrated LED Replacement Lamps, which were published in December 2009 (see News) and are due to go into effect on August 31, 2010.

    DOE is already looking at the issue and consulting with technical experts, as described below (see "DOE response to queries").

    The issue concerns an item on page 7 of the criteria, and applies to all replacement lamps. It relates to LED operating frequency, which must be ≥150 Hz. Of course, mains voltage operates at a frequency of 50 or 60 Hz, depending on the country.

    The document says "This performance characteristic addresses problems with visible flicker due to low frequency operation and applies to steady-state as well as dimmed operation. Dimming operation shall meet the requirement at all light output levels."

    This requirement was, apparently, introduced at short notice just before the criteria were finalized. The previous draft version contained a requirement for ≥120 Hz. The 150 Hz requirement is being challenged by, among others, Lynk Labs Inc. (see press release).

    Mike Miskin, president of Lynk Labs, told LEDs Magazine that "increasing the frequency requires additional drive components to be added. This increases cost but also requires additional real estate on the product. Many lamps with small form-factors may not have the real estate to allow for the additional components." Since these lamps could not be made, they would effectively be excluded from participating in the Integral LED Lamp market, which "will contradict the very mission of DOE Energy Star," argues Miskin.

    Another company, Once Innovations, has filed formal requests with the DOE under the Freedom of Information Act (FOIA). The company has requested all information and documents used as the basis for changing the Energy Star requirement on operating frequency for integral LED lamps from ≥120 Hz to ≥150 Hz.

    Once's press release says that the change "was apparently based on a vague suggestion in a comment from NGLIA/NEMA regarding the possibility of visual flicker problems. That comment simply suggested that the issue be looked into further."

    In an earlier press release, Once said that hundreds of pages of research material showed "no evidence, other than speculative statistics, to support claims that luminous modulation over 100Hz is visible or harmful to human health."

    DOE response to queries

    The DOE Energy Star team is responding to queries about this issue as follows: "As stated in the criteria document, the intent of this requirement is to prevent visible flicker in qualified integral LED lamps, in support of the successful market adoption of high-efficiency light sources.

    "However, since publication of the final criteria document, DOE has been contacted by a number of industry stakeholders who have raised technical and market issues related to this particular requirement.

    "We are currently investigating these issues and engaging technical experts and the relevant industry standards organizations to resolve them. We will be mailing additional information on this issue to ENERGY STAR partners as soon as we are able. We anticipate resolution to take approximately 30-60 days."