Lark Spectral Lighting Tool Reaches New Milestone
By Marty Brennan, AIA, WELL AP, Associate Principal
ZGF, in collaboration with Dr. Mehlika Inanici and the University of Washington, has reached a new milestone with its peer-reviewed analytic toolset for designers and practitioners to analyze, understand, and design the circadian environment. The updated release of Lark Spectral Lighting v1.0, a plug-in for Grasshopper, comes after seven years of beta testing and development since its debut at the 2015 Building Simulation Conference in Hyderabad, India.
Lark was the first open source software to help designers simulate non-visual light that entrains the human circadian system. The premise was simple: humans are wired for blue light-rich days and dark nights. Light exposure has been shown to impact sleep-wake cycles, alertness, productivity, and overall health and wellbeing.
Every light source and material used in indoor environments can either support or disrupt our circadian rhythm. Therefore, designers need to be able to visualize and quantify this interaction of light and biology for improved health outcomes. Lark helps architects, lighting designers, and researchers investigate circadian light metrics within a daylighting workflow rooted in the context of the built environment. The tool allows users to define the color of skies, glazing, and building materials based on spectral data and computes the impact of design strategies on the non-visual circadian light.
Lark’s nine-channel method for daylit scenes has since been validated for color accuracy at the 2019 Building Simulation Conference in Rome, Italy, and for prediction of indoor daylight at the 2021 conference in Bruges, Belgium.
ZGF has applied the research across multiple innovative healthcare projects, including the Swedish Medical Center Behavioral Health Unit, Children’s Hospital of Philadelphia Medical Behavioral Unit, and most recently, the Cincinnati Children’s Critical Care Building Expansion.
The success of these spectral lighting projects came through broad, multidisciplinary collaborations with daylighting specialists, architects, interior designers, computer vision experts, neuroscientists, sleep medicine specialists, lighting designers and manufacturers, biologists, nurses, UI designers, facilities engineers, spectrometer manufacturers, and neonatologists.
Beyond healthcare projects, Lark can be used to test circadian light in any indoor environment with applications for schools, workplaces, and homes.
Coming Soon
Lark v2.0 will be released in summer 2022 by a team of researchers at Oregon State University and Eindhoven University of Technology, followed by Lark v3.0 in fall 2022 as part of ZGF’s and University of Washington’s ongoing partnership through the Applied Research Consortium (ARC).
We’d like to thank McNeel for hosting the Grasshopper plug-in for Rhino and the global community of light health researchers that have peer-reviewed and published results of Lark’s three- and nine-channel simulation workflows.
More information about Lark is available at the following sites:
White Paper: Cincinnati Children's Neonatal Care Spectral Lighting System
Improving Outcomes for Cincinnati's Tiniest Patients
Post-Occupancy Evaluation: Swedish Medical Center Ballard Behavioral Health Unit
GB&D Magazine Features ZGF’s Circadian Lighting Approach
