There is no real standard for visual comfort in buildings, and the term is rarely used by design erofessionals. IES ( of which I am an active member ) last defined visual comfort in 1966, with a method that exemplifies the “engineered” approach to lighting, which is not particularly useful for designing real spaces for real people. By default, visual comfort is often defined by its absence, in spaces that are overlit or underlit, or have lighting with poor color rendering, glare, or poor controls. This applies to both electric lighting and daylighting.
Visual comfort is a result of a number of complex factors that work together in ways that vary greatly according to different environmental contexts. Good lighting designers intuitively understand that simply providing adequate illumination in terms of rigorously metered footcandles delivered to horizontal surfaces is not enough – that layers of light can be used to provide the richness of experience required for optimal visual comfort.
Many feel that visual comfort is too “subjective” and difficult to measure, but I believe that this is because we typically look only at single metrics or factors like glare or luminous flux, and not at the experience of people in the built environment as evidenced by their emotions and behavior. We can now measure this by aggregate rating systems rather than single metrics, and even more effectively with powerful new technologies that can track and analyze emotions and behavior.
Bear with me here as I go into a pretty strange but not at all implausible near-term scenario in which a rich palette of technologies (smart sensors, big data, cloud computing, machine learning, BIM ) combine to form a highly intelligent building system. Let’s take a typical commercial office space with a fair amount of ambient light delivered by ceiling troffers, some daylight, and high quality task lighting at desks. Lighting fixtures are equipped with occupancy and motion sensors, video cameras, audio sensors, and dimming and color tuning capability. Initial setpoints for light levels, dynamic circadian color shifting, and energy use are made with “best guess” defaults derived from pilot tests in a small area of the installation, generally accepted best practices, and input from users of the space. The control interface for the system includes an analytics engine that can read facial expressions, pupil dilation or contraction, gait, voice pitch and inflection, walking speed and direction, and many other behavioral and emotional data generated by building users and indicate whether people are satisfied, happy, angry, sad. Other indicators of general health are also detectable from these kinds of signals. If the lighting or HVAC needs to be adjusted automatically in certain zones, or messages sent to individuals suggesting adjustments, these can be generated and fed back into the system to determine the immediate effects of the adjustments. Defaults can be adjusted dynamically, and easily overridden based on real behavioral data, not rule of thumb engineering assumptions. As behavior and emotions in real time are monitored, they provide a level of feedback that is invaluable for fine-tuning the environmental conditions that most affect them, and that in turn affect productivity and health. The system should gradually evolve into an equilibrium that provides the best environmental conditions for occupants. And data from the system can be shared and imported into BIM models for future similar spaces.
This sounds totally creepy, as most of us aren’t consciously ready for this level of behavioral monitoring. For technology to be widely deployed in this way requires a broad ethical framework around the use of personal data, like health metrics, that simply doesn’t exist yet. Communications protocols and other technical issues (like data architecture and storage) are obviously huge concerns as well. But regarding security, we’re already quite used to adaptive systems that make decisions for us, and to relinquishing personal data to certain trusted providers in exchange for increased convenience. The technical and ethical concerns in the Internet of Everything are considerable but not insurmountable. Increasingly complex and powerful technology seems inevitable, but we need to remember that it works for us, not vice versa. We can use technology to increase security, trust, health, prosperity, and equality just as we can use it for less noble purposes, and we can use it to combat those less noble purposes.
Pioneering smart systems with lighting in buildings today can result in learning that can impact many things far beyond lighting, and tying system response to the things that matter most – our behavior and emotions- is something we’ve never really been able to do before. New and often unexpected combinations of technologies will create changes we haven’t even begun to imagine yet.
- The Illumitunity Convergence - January 15, 2019
- Yellow to Blue: the Recent History of Lighting and Color - December 7, 2015
- The Net-Zero Nonzero City - October 19, 2015
- Stores That Feel You - July 27, 2015
- The United States of Light - June 29, 2015
- Light People! - June 15, 2015
- Visual Comfort and Buildings that Feel - June 1, 2015
- Building for Light: Collaboration Between Architects and Lighting Designers - May 18, 2015