Americans spend around 90 percent of their time indoors and we inherently know that lighting is a necessity for indoor environments. Lighting is often taken for granted, but did you know that it can have a direct impact on your health?
There is a growing focus on health in the built environment, from indoor air quality and the composition of building products, to promoting wellness at work. Lighting is one component of occupant health, which can affect productivity and both physical and mental health. A lighting strategy can also affect your ability to get work done. Various organizations, such as the Illuminating Engineers Society of North America, have set the minimum level of footcandles (fc) appropriate for a work surface in an open office environment at 30 fc, with a maximum recommended level at 50 fc.
Even with these guidelines, we still notice spaces that are not properly lit for a particular task. This can cause a number of physical effects such as eye fatigue and headaches. In healthcare environments, improper lighting can cause sleep disorders and even dementia.
In the Perkins+Will Washington, D.C., office, a team of designers sought to explore proper lighting in a corporate workplace setting. We hypothesized that our space was over-lit for our daily tasks, and used technologies in the office lighting control system to see if we could lower the electric lighting levels and take advantage of more natural light without negatively impacting employees.
The LEED Platinum office is located on the top floor of an eight-story office building in the West End neighborhood of Washington, D.C. The primary area of focus was the open office studio that is situated along the curved, all-glass east-facing façade. The studio is comprised of low, benching-style workstations and collaborative islands, and the finishes are primarily light in color. The eastern façade faces the street and an adjacent light-colored building.
Daylight not only eliminates the need for artificial lighting, but it also plays a role in biology. “When designing artificial lighting, it is important to mimic the spectrum and timing of natural lighting,” says Dr. Joan E. Roberts, Ph.D. and Professor of Chemistry at Fordham University. This natural spectrum plays a key role in the biological process of circadian rhythm. Roberts recommends providing blue visible light in the morning that moves toward red visible light throughout the day. This daily dark/light cycle allows for various necessary biological responses, but also directly impacts productivity and alertness – key factors in designing a workplace environment.
In the Perkins+Will study, we found that the eastern façade let in enough natural light to provide adequate light levels 20 to 30 feet into the floor plate at certain times of the year, eliminating the need for additional electric lighting along the perimeter. With the introduction of more daylight into the space, we used manual roller shades and monitor arms in order to mitigate any glare from direct sunlight on computer screens. This allowed us to bring daylight deeper into the building’s floor plate than the LEED-prescribed minimum of 15 feet from the perimeter.
Another finding was that we could reduce the overall lighting levels 30 to 50 percent in the open office area (not just at the perimeter), based on seasonal variations, and still maintain the recommended 30 footcandles on worksurfaces. We found that occupants working on computers were generally comfortable with much lower footcandle levels on their desks than those engaging in “heads down” or paper-oriented tasks. By providing adjustable task lights, people were able to supplement the general light levels for this type of work by bringing focused light directly to the worksurface. This allowed occupants to have control over their environment and gave them a choice in how much light they needed for a particular task.
This study was focused on a corporate workplace, but lighting is just as critical for employees in healthcare settings. In detail-oriented tasks such as medication dispensing, errors have been linked to lighting levels on the worksurface. When lighting levels are higher the error rates are reduced. Additionally, the benefit of a proper lighting strategy extends to the patients. Natural lighting in patient rooms can help them gain a better orientation and decrease confusion in some patients. It is associated with both a shorter length of stay and lower use of pain medications.
There are many lessons to be learned about lighting and health, but there are two points that should always be considered when designing a lighting strategy for a workplace:
1) Use daylight when you can (or fake it).
There are many benefits to maximizing the use and exposure to natural daylight, from reducing the demand on electric lighting and using less energy, to exposing ourselves to the healing process of circadian rhythm. When natural lighting can’t be used, the designer should investigate using color-changing LED technology to slowly shift from cooler, blue light in the morning to warmer, red light in the afternoon (or fluorescent lamps with different color temperatures) to gain similar benefits.
2) Tune in to the task.
The task should set the stage for any lighting strategy and the occupant should always be considered. Use guidelines from organizations such as the Illuminating Engineers Society, but evaluate your lighting strategy based on your physical space (architecture, interior finishes, etc.) and the task of the occupants. Over-lighting may have a negative impact on some settings, such as in a workplace environment, but it may also have a positive impact in others, such as in a healthcare workplace environment.
David Cordell leads the sustainability efforts of Perkins+Will’s Washington, D.C., office and has served as a project designer and technical coordinator there for over nine years. His projects have received multiple awards and have been published in Contract magazine, American Builders Quarterly, and Building Design + Construction. His experience includes working with a variety of client types on numerous LEED projects, several earning LEED Platinum certification. You can contact David at email@example.com.
Haley Russell is an interior designer in Perkins+Will’s Washington, D.C., office with over five years of experience in the industry, including a range of corporate and government projects with solutions that explore the connection between the human experience and spatial design. Furthering Perkins+Will’s commitment to social purpose and sustainability, Haley is a leader of the DC office’s social responsibility and sustainable design initiatives. You can contact Haley at firstname.lastname@example.org.
ANSI. American National Standard Practice for Office Lighting. New York: Illuminating Engineers Society of North America, 2004. Print.
EPA, “Report on the Environment: Indoor Air,” March 10, 2011, http://cfpub.epa.gov/eroe/index.cfm?fuseaction=list.listBySubTopic&ch=46&s=343
New York Times, “Companies Get Strict on Health of Workers,” March 25, 2013, http://www.nytimes.com/2013/03/26/business/companies-offer-workers-more-incentives-for-health-changes.html?_r=0
Roberts, Joan E., Ph.D. “Circadian Rhythm and Human Health,” http://www.photobiosci.info/Roberts-CR.html, 17 July 2013.
Roberts, Joan E., Ph.D. “Lighting for Maximal Health and Well-Being,” http://www.aging.ny.gov/LivableNY/ResourceManual/Design/IV1a1.pdf, 17 July 2013.
U.S. Department of Labor Occupational Health & Safety Administration (OSHA). “Occupational Health and Environmental Controls Guidelines.” 1926.56(a) table D-3 “Minimum Illumination Intensities in Footcandles.” http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10630, Web. 5 September 2012.
USGBC, “A Closer Look at Materials and Resources in LEED v4,” October 11, 2012, http://www.usgbc.org/articles/closer-look-materials-resources-leed-v4
U.S. General Services Administration (GSA). 2003 Facilities Standards (P100). “6.15 Lighting.” http://www.gsa.gov/portal/content/101308, Web. 5 September 2012.