Forum for Illumination Research, Engineering, and Science (FIRES)

FIRESThe ability to control fire is considered one of the most important factors in expanding and developing our human ancestors’ societies. The societal importance of fire required larger and larger groups to work together in order to maintain and sustain the fire; individuals had to work together to find fuel for the fire, maintain the fire, and complete other necessary tasks. Ultimately, fire had a significant influence on the development of language and the size and social interactions of communities.

The Forum for Illumination Research, Engineering, and Science (FIRES) is the IES online space for our lighting community to openly share and discuss the latest research and innovations in illumination engineering and science. As a space for the free dissemination of knowledge and exchange of ideas, FIRES is intended to foster relationships between individuals and larger institutions, and reignite the emphasis on science and engineering in the lighting industry. Through FIRES, we hope to have a significant influence on the development and advancement of lighting.

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The views expressed in articles published on FIRES do not necessarily reflect those of IES or represent endorsement by the IES.

Figure 1.

Circadian Lighting: a Neuroscientist’s Perspective

By Douglas Steel, Ph.D., NeuroSense

The purpose of this article is to evaluate from a biological standpoint the rationale for the establishment of a Circadian Lighting standard put forward by UL under the direction of Dr. Mark Rea of the Lighting Research Center at Rensselaer Polytechnic Institute. This critique is limited in scope but also applies to utilization of the Circadian Stimulus (CS) calculator also developed by the LRC. Read More

Figure 1.

Circadian Lighting: An Engineer’s Perspective

By Ian Ashdown

Whether you call it “circadian lighting,” “biologically effective lighting,” or some other name, the principle is the same: the color and intensity of light can be used to regulate the timing of our biological clocks, or “circadian rhythms.” For architects and lighting designers, this is an opportunity to provide healthy and comfortable environments for building occupants. Read More

An Intuitive Metric for Lumen Maintenance

An Intuitive Metric for Lumen Maintenance

By Eric Bretschneider

For better or for worse, the lighting industry commonly associates the lifetime of LEDs and LED-based lighting products with L70 – the amount of time for the lumen maintenance of an LED-based device to reach 70% of its initial value. Admittedly, the failure of other components, particularly those that provide power to LEDs, are more likely to determine the overall lifetime of an LED-based component or luminaire. However, only lumen maintenance is considered here. Read More

Figure 1: An example of the stroboscopic effect, measured with a short duty cycle and 100% modulation

Concerns in the Age of the LED: Temporal Light Artifacts

By Dr. James M. Gaines

Flicker and stroboscopic effect are presently hot topics in lighting, along with other subjects like blue light (subject of a recent FIRES article). A National Electrical Manufacturers Association (NEMA) standard, NEMA 77, addresses measures for temporal light artifacts (TLA), which is an umbrella term covering both flicker and stroboscopic effect (as well as phantom arrays. The NEMA metrics for flicker (short-term flicker indicator, Pst) and stroboscopic effect (Stroboscopic Visibility Measure, SVM) are both based on experiments done with many human observers, to measure average human sensitivity to flicker and stroboscopic effects. Read More

The Lighting Design Objectives (LiDOs) Procedure

By Christopher Cuttle, MA, PhD, FCIBSE, FIESANZ, FIESNA, FSLL

This procedure is based on the concept that there is real advantage to be gained from changing the illumination metrics used for specifying, measuring and predicting lighting applications so that they relate to people’s responses to visible effects of lighting in indoor applications. Read More

A Reality Check on Blue Light Exposure

By Eric Bretschneider, Ph.D

How often do we hear about the dangers of blue light from LEDs? Such discussions inevitably include statements about “the intense blue peak” in LED lighting and the potential for damage from the massive amounts of blue light present in LED lighting.

The whole argument sounds plausible enough when we look at the spectrum of a typical white LED. The spectrum below is for a typical white LED with a CCT of 4,000 K at levels that approximate a typical commercial or retail environment (400 lux). The isolated peak in the blue clearly stands out, but does it really represent a massive dose of blue light? Read More

Melanopic Green The Other Side of Blue

By Ian Ashdown, P. Eng. (Ret.), FIES
Senior Scientist, SunTracker Technologies Ltd.

Numerous medical studies have shown that exposure to blue light at night suppresses the production of melatonin by the pineal gland in our brains and so disrupts our circadian rhythms. As a result, we may have difficulty sleeping. It is therefore only common sense that we should specify warm white (3000 K) light sources wherever possible, especially for street lighting.

True or false? Read More

The Science of Light and Health: How to Interpret the Claims That Underlie Medical and Wellness Effects

By Douglas Steel, PhD
Founder and Chief Scientific Officer of NeuroSense

These are transformational times for the lighting industry. The cost of LED-based products has dropped dramatically. At the same time, increased sophistication and capabilities of tunable LED arrays, controls, and sensors now enable the commissioning of platforms that can precisely control light intensity, correlated color temperature, and relative spectral content. Read More

Lighting and the Internet of Things

By Robert F. Karlicek, Jr., Ph.D.

The Internet of Things (IoT) is a hot topic these days, driven by the explosion of low-cost sensors, microprocessors, and wireless communications to provide new types of services for consumers and businesses. Read More

Figure 3 – Infrared “smudge” (see text for explanation).

The Science of Near-Infrared Lighting: Fact or Fiction

By Ian Ashdown, P. Eng. (Ret.), FIES, Senior Scientist, SunTracker Technologies Ltd.

There is a common-sense argument being presented in the popular media that since humans evolved under sunlight, our bodies must surely make use of all the solar energy available to us. Given that more than 50 percent of this energy is due to near-infrared radiation, we are clearly risking our health and well-being by using LED lighting that emits no near-infrared radiation whatsoever. Read More

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