7 minute read
New Life for an Old Warhorse
Cover Image: U.S. National Archives and Records Administration, Group 18, Records of the Army Air Forces, 1941. Public domain.
By Daniel Frering, Jennifer Brons, and David Pedler
Light and Health Research Center at Mount Sinai
In 2020, the General Services Administration (GSA) began transforming Building 48 on the Denver Federal Center campus in Lakewood, Colorado, into a modern office facility for the Department of the Interior’s Interior Business Center. The building was originally constructed in the early 1940s as part of the sprawling World War II-era Denver Ordnance Plant and repurposed as the Denver Federal Center in 1947. Vacant since 2013, Building 48 was a 150,000-square-foot, single-story, brick-exterior facility with a very limited number of small windows prior to its renovation.
In the summer of 2020, the contract to modernize Building48 was awarded to a design-build team that included the architectural firm CannonDesign, the engineering firm RMH Group, and builders Centerre Construction. When the project’s concept phase kicked into gear in late 2020, the country was mired in the confusion and lockdowns of the COVID-19 pandemic’s early stages.
With millions of government employees working from home in isolation and the widespread availability of effective vaccines on the horizon, the team decided that the design of Building 48 should focus on creating a dynamic environment that would encourage people to return to the office and feel good about being there. In terms of the work experience, the design team emphasized the need for collaborative spaces where people could gather in a workplace that supported their health, productivity, and comfort.
The broader design goal for Building 48 was to achieve the status of a high-performance green building by creating a modern, sustainable net-zero energy office space that would be powered exclusively by electricity and meet requirements for LEED Gold and SITES Silver certifications. Both daylighting and electrical lighting systems were designed to support the health of the human circadian system following design principles outlined in UL 24480, Design Guideline for Promoting Circadian Entrainment with Light for Day-Active People, and the GSA’s P100 Facilities Standard for the Public Buildings Service.
The Design Process
Because Building 48 is large with a deep floor plate, the design divided the space into a series of "neighborhoods,” each anchored by an open office and areas for informal collaboration and surrounded by enclosed private offices, huddle spaces, and conference rooms.
Providing daylight in the design was a top priority, both for its circadian health benefits and to provide views that make the occupants feel connected to the outdoors. This was achieved by distributing large, 10–12 feet tall windows (Figure 1) and skylights throughout the open areas, being careful to reduce glare from direct sunlight. Glazing was also provided in interior enclosed spaces to permit daylight penetration from the open areas, again while reducing glare. For the electric lighting, the design initially employed luminaires that were evaluated and selected using the unified glare rating specified in the P100 Facilities Standard.
Although UL 24480 was not incorporated in the initial plan, after consultation with the stakeholders, the GSA opted for its inclusion once the design development phase began in 2021. The process was carried out in three primary steps using the circadian stimulus (CS)1, 2 metric employed in UL 24480 with the assistance of lighting design software that accounted for all light sources implemented in the design.
First, in contrast to the prior P100 practice of assessing only horizontal illuminance levels (ensuring a minimum 30 footcandles on work planes) throughout the building, UL 24480 required the assessment of vertical illuminance levels to ensure that the design choices (e.g., luminaires, spectral power distribution, spatial distribution) would provide sufficient light for the circadian system (a CS value of at least 0.3 for a minimum of two hours per day) at the occupants’ eye level.
Step two incorporated photometric analysis of the building’s entire lighted environment using the Light and Health Research Center’s online CS Calculator (2.0) based on specifications provided by the luminaire manufacturers. Because the windows and skylights included spectrally neutral glazing, the analysis also incorporated the CIE daylight spectral data available in the calculator’s source files.
Finally, for step 3, the team followed UL 24480’s iterative design process of checking whether the design met the desired criteria and repeating steps 1 and 2, if necessary, to ensure that it did.
The project’s results are impressive by any yardstick, as suggested by the renderings of the workspace (Figures 2 and 3), though final determinations of the project’s success will ultimately be made by the people who began working there in August 2024. But the success of Building 48’s transformation as a collaborative project is widely regarded as a success by the design team, stakeholders, and visitors alike.
Takeaways
1. Start early in the design process. If the team holds off on circadian-effective lighting design considerations until the time comes to select luminaires, which typically occurs quite late in the design process, it will be more difficult to ensure the integrity of the system without following through on UL 24480’s iterative design process.
2. Teamwork pays off. Integrating the efforts of a design-build team from the project’s beginning will ensure that everyone is working together to resolve potentially conflicting plans that might cloud the shared vision for the building’s lighted environment. It is important to involve all decision-makers who will influence the final design. Those who decide on interior design and furniture options, for example, will make important choices (e.g., localized lighting, furniture height and finishes) that can dramatically impact the circadian effectiveness of the design.
3. Standards and recommendations may conflict. The entire team will inevitably be compelled to follow requirements (e.g., P100, state energy code) and recommended practices (e.g., IES, CIE) that may conflict with other design elements. Again, working together as an integrated team will help to identify and resolve such conflicts early on in the design process.
4. Don’t be afraid to ask for help. Once the incorporation of UL 24480 into the design for Building 48 was embraced, the daunting question faced by the design team was, “What do we do now?” With long-standing expertise in the science of light and educational outreach, the Light and Health Research Center was happy to assist with a one-hour session that explained the UL 24480 process, resolved the team’s questions and concerns, and generally made them feel comfortable moving forward with the implementation process. (The GSA has many resources that can help you through the design process.)
5. Daylight is the circadian system’s friend. The team inherited a blank canvas that permitted creative daylight penetration with skylights and large windows, a luxury that is not routinely afforded to those tasked with building redesigns. But it is essential that daylight be considered as part of any lighting design that is crafted to support the circadian system and thereby promote the health and well-being of occupants and visitors. When a design heavily relies on daylight for meeting CS requirements, however, the designer must take a very conservative approach to modeling the space because daylight can be so variable, seasonally and across the floor plate.
References
1. Rea MS, Nagare R, Figueiro MG. Modeling circadian phototransduction: Retinal neurophysiology and neuroanatomy. Frontiers in Neuroscience. 2021;14:10.3389/fnins.2020.615305. doi:
2. Rea MS, Nagare R, Figueiro MG. Modeling circadian phototransduction: Quantitative predictions of psychophysical data. Frontiers in Neuroscience. 2021;15:10.3389/fnins.2021.615322. doi:
