Lighting
Lighting was a very important aspect of the design for the new LightHouse space. The right type of lighting is crucial to utilizing the remaining sight of the visually impaired. There are many types of vision loss, and many (but not all) people with low vision need very high light levels to make the most of their visual acuity. Low-vision users need a comfortable environment with soft, low-glare lighting.
Lighting consultants at Auerbach Glasow researched recommended light levels for the visually impaired to use as a starting point in the project. American Society of Heating, Refrigerating, and Air-conditioning Engineers/Illuminating Engineering Society (ASHRAE/IES) 90.1, Energy Standard for Buildings Except Low-rise Residential Buildings, allows a higher-than-typical lighting density for the visually impaired, but surprisingly, these light levels apply to spaces “in a facility for the visually impaired (and not used primarily by the staff).” At the LightHouse, the majority of the staff are also visually impaired, but this code excludes them. While certainly well-intentioned, it nonetheless perpetuates the assumption blind and low-vision people are not active participants in the workforce.
In California, light levels are often limited by the stringent wattage limits in the California Energy Code (California Code of Regulations, Title 24, Part 6). Initially, Auerbach Glasow designed the project to maximize light levels while staying within the wattage limits. This design was then vetted with LightHouse low-vision staff in an extensive lighting mockup, where all 28 fixture types in the project were set up for users to review. The results of the mockup revealed a code-compliant approach would not lead to a visually accessible space for low-vision staff and clients. The code-compliant design maximized brightness, but to minimize wattage, each individual fixture had a higher level of brightness at the lens. The mockup participants noted that this caused uncomfortable amounts of glare for those users with low vision.
It was clear the team needed to redesign the lighting in a way that was user-compliant rather than code-compliant. Given so many of the staff at the LightHouse are blind or have low vision, this was truly a matter of creating an equitable and accessible workspace, which is mandated by the Americans with Disabilities Act (ADA). Working closely with plan examiners and advocates in the San Francisco Mayor’s Office on Disability, the LightHouse applied for a disabled-access accommodation allowing the project to be exempted from the wattage limits imposed by Title 24. The project was still required to meet all other energy code requirements, such as stepped dimming in daylight zones, occupancy sensors, and full dimming capability throughout. The resulting design allows the space to be very bright, while keeping a lower level of brightness at each fixture to control glare. Comparing the code-compliant version with the final version, it was calculated this design incorporates 25 percent more fixtures and wattage in circulation areas, with 50 percent more in offices.
Acoustics
Another common misconception is the idea as one sense is lost, others become stronger. People who are blind or have low vision are sometimes thought of as having better hearing, but this is a myth. Rather, blind people are often better listeners who focus more on sound in the absence of visual distractions.
Bashin challenged the design team to create a space emphasizing the right types of sound. Rather than absorbing or blocking out all sound, he wanted the space to be warm and lively. Some of this was achieved through architectural moves—for instance, the polished concrete circulation ring enables people to hear others’ cane taps and the click of guide dogs’ toenails, and the new grand stair was designed to be as open as possible. It allows sounds to travel from one floor to another so occupants have a sense of activities happening elsewhere in the space. Other aspects required deeper analysis. The architects worked with acoustic designers at Arup, who created three-dimensional acoustic models of key spaces in the LightHouse to test them out prior to construction.
During the testing process, the LightHouse stakeholders sat in a spherical array of speakers and listened to the effects of iterative changes in room surfaces for acoustic control within a space, as well as acoustic separation between spaces to block out unwanted noise. They assessed the finishes in the reception area and determined what was the most comfortable ratio of absorptive surfaces for sound control and reflective surfaces for liveliness.
The study showed secondary acoustic windows were needed in important spaces along the Market Street façade to keep noise from streetcars from disrupting activities in the boardroom and multipurpose room. It was also determined a higher degree of acoustic separation was necessary between private offices so office occupants would not hear their neighbors, meaning partitions with
a noise isolation class (NIC) of 42 were specified. At the office front, however, too much sound separation would have led to an office occupant not knowing about activities happening outside, so a lower NIC of 30 was specified. The 9.5-mm (3/8-in.) laminated glass and acoustic door seals achieve this NIC 30 performance, reduce distracting noises, and allow a sense of activity and liveliness to pass through.
