PNNL

Patients in mental health facilities can experience disorientation and disrupted sleep, especially if they remain indoors much of the time. But this is changing. More behavioral health architects are designing lighting environments to improve the well-being of patients and staff.

Through the Department of Energy’s GATEWAY program, researchers from PNNL evaluated the performance of light-emitting diode (LED) lighting systems at the newly renovated Swedish Hospital Behavioral Health Unit in Seattle. The resulting insights can help lighting fixture and control manufacturers.

Sunrise, Sunset

In the 22-bed mental health facility, adult patients typically stay from a couple of weeks to a month. Hospital patients often lose track of the time of day, but they need that orientation to provide a sense of normalcy.

When ZGF Architects designed the building interior, they paid special attention to lighting. They wanted to create an environment that connected staff and patients to nature, as well as addressing the behavioral health aspects of lighting. By varying the intensity and spectrum of light, they designed a system that mimicked a warm sunrise, a brightening and cooling of light by early morning, peaking by noon, and a sunset in the evening. This pattern provides visual cues to wake and energize patients, then calms them as they prepare for bedtime.

Lighting professionals installed 34 white-tunable LED ceiling downlights in the corridors and in dining and activity spaces. The lights operated automatically on a daily schedule, cycling between warm, cool, bright, and dim. Hospital staff could also dim the lights further.

ZGF Architects and Swedish Hospital invited DOE to document how the lighting system was being used in a healthcare facility. PNNL evaluated the lighting in May and September of 2016.

When Control is a Good Thing

PNNL researchers measured the light output and interviewed staff at the facility, arriving at key conclusions.

First, the tunable LED systems can provide significant energy savings, but can also increase energy use, depending on the desired results. In the Seattle facility, the lighting was dimmed for long periods of the day and night, achieving an annual energy savings of 41 percent if compared with a non-tunable lighting system with the same number of lights.

But the lights were set at their brightest levels for a full six hours, from 8 am to 2 pm, to stimulate wakefulness. In contrast, a standard lighting system, designed for tasks like reading, would use half the number of lights. Thus, the tunable system in the mental health facility actually increased annual energy use by 19 percent when compared with a non-tunable system. Future studies are needed to determine whether the brightness and duration of time the lights were on could have been reduced further in the daytime, yet still provide the desired “wake-up” effect.

Second, giving the building occupants some degree of manual control increased energy savings. Nursing staff chose to reduce the brightness or turn off the downlights in the evening hours while leaving the less intense wall lights on, feeling that this configuration helped patients and staff. The lighting designers then programmed this approach into the automatic controls, which reduced energy use. The system can also be adjusted in the future to account for new research findings related to duration, brightness, and spectrum.

Third, the process of installing and testing lights in the user space, called field commissioning, remains a challenge. Initial PNNL measurements showed that the installed lights were set at the wrong intensity and spectrum. The electrical contractors had to re-tune them twice to achieve the correct levels for the study, leading to a decrease in energy use. A detailed specification of the desired control sequences and outcomes early in the design process could help identify potential shortcomings and make commissioning more efficient.

And fourth, understanding the medical effects of tunable lighting is still in the early stages. Patient behavior and perceptions were not evaluated in this study because of research limitations. Once there is more evidence of the optimal lighting outcomes in these kinds of environments, it will inform lighting standards, which will become more widely accepted in healthcare communities. “Using a collaborative team with backgrounds in lighting measurement, lighting effects on human circadian rhythms, and medical and psychological expertise would be ideal,” said PNNL researcher Andrea Wilkerson.

Other GATEWAY studies evaluated energy savings from tunable LEDs in a senior care center and in classrooms. The current study was the first DOE documentation of a tunable system designed to enhance well-being by simulating outdoor light conditions throughout 24-hour periods.

DOE’s Office of Energy Efficiency & Renewable Energy funded the research. For more information, read the report on DOE’s website.