The ≥150 Hz requirement has been challenged by a number of companies and Energy Star stakeholders.
If accepted, the proposed change will result in a new version of the specification, Version 1.1. The effective date of the specification, August 31, 2010, would remain unchanged. The letter says:
“The performance requirements laid out in the Energy Star specification for Integral LED Lamps (V1.0) are intended to ensure that qualified products are energy efficient and meet user performance expectations. One of the requirements contained in the criteria document is for minimum LED operating frequency. This requirement was intended to mitigate potential health and safety problems caused by visible flicker. Feedback from industry stakeholders on earlier drafts of the integral LED lamp criteria was minimal and inconsistent, suggesting alternative frequency requirements ranging from 100 Hz to 500 Hz.
“In the final criteria published December 3, the minimum LED Operating Frequency requirement was increased from the previously proposed 120 Hz to 150 Hz in an effort to address stated industry concerns. However, subsequent industry feedback has indicated significant concerns exist about this higher requirement, citing cost and design implications, and the exclusion of products using AC-driven LEDs. Further, several stakeholders state the requirement as written is inadequate to prevent visible flicker and potentially should address modulation depth, waveforms, duty cycle, and other characteristics, in addition to frequency.
“EPA seeks to address this issue in close cooperation with the Department of Energy, industry and standard-setting organizations to achieve the following objective: Energy Star qualified lamps do not exhibit visible flicker during full output or dimmed operation.
“An IEEE working group including leading human factors experts is working to develop Recommended Practices of Modulating Current in High Brightness LEDs for Mitigating Health Risks to Viewers, but the results of this work likely will not be available until next year.
“To avoid delays in the implementation of the Energy Star specification for Integral LED Lamps, we propose reverting back to a ≥120 Hz requirement, pending the completion of further research on this topic.
“Stakeholders are advised that EPA intends to again address visible flicker concerns once industry consensus measurement methods and recommended performance thresholds are available. If additional changes are warranted, they will be proposed and finalized through a stakeholder process, allowing adequate time for transition.”