The Myth of the Irrelevant Lighting Designer

Kevin Willmorth has a long and interesting article on his blog in which he argues for the recognition of professional lighting designers and what a professional lighting designer is and is not.  The post echoes Chapter 1 of Designing With Light, and many of the things I’ve written here, including promoting the lighting design profession, the value of professional lighting design, the need for projects to use a professional lighting designer (here, here and here),  those other than professional lighting designers making design decisions, and poor documentation of LED products by manufacturers, among other topics.  I don’t have much to add to Kevin’s post, except to say that it’s well worth reading.

IES Lighting Terms and Definitions Now Online

ANSI/IES RP-16 Nomenclature and Definitions for Illuminating Engineering has long been one of the two major documents defining terms related to lighting design (the other is CIE ILV: International Lighting Vocabulary).  RP-16-10 (the 2010 version of the Recommended Practice) is now available online as a searchable database.  From the first page you can click on terms to see the definition and you can also search by keyword.  If you don’t already own RP-16 bookmark this now!

IES Disagrees With AMA on Night Time Outdoor Lighting

Last year the AMA issued Policy H-135.927 Human and Environmental Effects of Light Emitting Diode (LED) Community Lighting, which recommended, among other things, that LED outdoor lighting should have a CCT of 3000 K or below.  The AMA made this recommendation thinking that lower correlated color temperatures contain less blue light, which can disrupt circadian rhythms.

Today the IES issued a Position Statement disputing that recommendation, noting that CCT

is inadequate for the purpose of evaluating possible health outcomes; and that the recommendations target only one component of light exposure (spectral composition) of what are well known and established multi-variable inputs to light dosing that affect sleep disruption, including the quantity of light at the retina of the eye and the duration of exposure to that light. A more widely accepted input to the circadian system associated with higher risk for sleep disruption and associated health concerns is increased melanopic content, which is significantly different than CCT. LED light sources can vary widely in their melanopic content for any given CCT; 3000 K LED light sources could have higher relative melanopic content than 2800 K incandescent lighting or 4000 K LED light sources, for example.

Follow the link to read the entire Position Statement.  Blue light hazard, light’s impact on circadian rhythms and overall health, and related topics are a hot area of research.  We’re learning more all the time, but we don’t yet know enough to apply circadian lighting to every situation.  Outdoor and street lighting are among the areas where research is not yet conclusive.

A New Report on LED Color Shift

Like other lighting technologies, the color or chromaticity of light emitted by an LED can shift over time.  To address the challenge of developing accurate lifetime claims, DOE, together with the Next Generation Lighting Industry Alliance, formed an industry working group, the LED Systems Reliability Consortium (LSRC).  A new LSRC report, LED Luminaire Reliability: Impact of Color Shift, focuses on chromaticity. The purpose of the new report is not to define limits for specific applications, but rather to enable a better understanding of how and why color shifts, and how that impacts reliability.  Download it and take a look.