Introducing the Design Guideline for Promoting Circadian Entrainment with Light for Day-Active People

Finally, the industry has a Design Guideline that we can use for specifying Circadian Entrainment on our jobs. But the DG doesn’t come from IES, it is published by Underwriters Laboratories (UL).  

This DG has been a long time coming.  In 2007 the National Institute for Health (NIH) first published data proving the important effects of the circadian system on health.  For 13 years the industry has had lots of discussion with very little results.  During those 13 years a handful of circadian experts have built lucrative practices advising manufacturers on the important role of circadian stimulus and health. Now that there is a Design Guide, manufacturers should be able to navigate their way without the cost of those consultants. 

We spoke to Brian Liebel of IES a few months ago and Brian explained that IES is working on an RP and emphasized the process of due diligence and the importance of having an ANSI, peer-reviewed document.  He declined to give a target date for the IES version.  

While the UL DG is not an ANSI document, the committee that developed it is wide and diverse with manufacturers, lighting designers, researchers, academia and a non-profit.   In addition, there were two cycles of public review in 2019.   The first public review from 10 APR to 12 JUN had 53 comments and the second review, from 6 SEP to 27 SEP (recirculation), had 39 comments.   Each comment was evaluated and considered.   

The document is available online.  Go to and enter the document number 24480 and click purchase ($402) or digital review (free.)

While the science behind the UL RP may not be perfect, it is a very good beginning point.   Think of Chemotherapy 30 years ago and contrast it to cancer treatment today.  The doses were so high and brutal, still it saved lives. Today’s chemo treatments are more precise, but that is because of what we learned over those 30 years.  Today’s UL Design Guideline may not be perfect and it probably won’t be the final version.    But, it’s already been 13 years, why not get started? 

For more information regarding the development process of the Design Guide, contact Joe Musso at 

10 Jan