“Lighting designers, architects and building managers should consider how to effectively use electric lighting to supplement daylight to ensure every worker receives enough light during the daytime to support circadian health and wellbeing in the office environment,” Figueiro says.
Circadian wellbeing depends upon a person’s light exposure over 24 hours, not just the light received at the office. Even if a particular building provides ideal circadian-effective lighting, too much light after work can lead to circadian disruption. Nevertheless, office buildings may still provide the greatest opportunity for workers to meet their daily requirements for light exposure, especially in winter months.
Results in Action
Last year, the LRC research team applied the results of the previous studies by developing and then installing circadian- effective lighting, providing a CS of 0.3 or greater, in two additional federal buildings: the White River Junction VA Medical Center in Vermont and Turner-Fairbank Highway Research Center near Washington, D.C.
The LRC researchers demonstrated two basic strategies to achieve a CS of 0.3— overhead lighting and desktop lighting. For the desktop lighting, two types of light (a cool white and a blue light) were used to deliver a CS of 0.3 or greater at eye-level. Similar to the previous studies, Daysimeters were used to measure personal circadian light exposure. The LRC also collected data on the participants’ sleepiness and energy levels.
With help from GSA, the LRC collaborated with 37 volunteers at these sites. Participants completed a three-day protocol in summer 2016. Preliminary results using summer data from both buildings revealed that participants reported feeling less sleepy and more energized on days two and three after receiving the lighting intervention, compared to day one.
The LRC is performing similar studies in northern Europe at U.S. embassies in Reykjavi?k, Iceland, and Riga, Latvia, in a project funded by GSA and the U.S. Department of State. Preliminary results will be discussed at the LIGHTFAIR presentation on May 10 in Philadelphia. (See “Attend this Presentation at LIGHTFAIR International in Philadelphia”, below, for details.)
“Office workers in the far north, near the Arctic, experience a dramatic reduction in daylight during winter months, which can lead to decrements in sleep, mood, and general health and wellbeing,” says Donna McIntire-Byrd, U.S. Department of State. “We are interested in finding solutions by testing whether lighting can help mitigate these issues.”
Learn More
To help lighting professionals select light sources and targeted photopic light levels that will increase the potential for circadian light exposure in buildings, the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute, Troy, N.Y., developed a circadian stimulus, or CS, calculator, which can be used to determine CS for any combination of source type and light level in photopic lux. Access the CS calculator.
The LRC also has developed a portfolio of lighting patterns, along with CS guidelines and methodology, so CS may be used as the primary design component and applied to practical design solutions. Application of the CS metric as the primary design component could have far-reaching effects on sustainable lighting design as a means to enhance the health and wellbeing of office workers.
Attend this Presentation at LIGHTFAIR International in Philadelphia
Dr. Mariana Figueiro, Light and Health program director at the Lighting Research Center at Rensselaer Polytechnic Institute, will present, along with Bryan Steverson of the U.S. General Services Administration and Donna McIntire-Byrd of the U.S. Department of State, in a session titled “Circadian Light for Your Health: Light, Not Laughter, is the Best Medicine”. The session is part of LIGHTFAIR’s new Light & Health Forum and takes place Wednesday, May 10 at 10 a.m. Learn more about the Light & Health Forum, as well as other LIGHTFAIR events.
PHOTOS: Lighting Research Center at Rensselaer Polytechnic Institute