A view on daylight planning in America

By Megan Kruse and Edward Clark

A UK survey updated in 2020 found that 16 countries had national daylight regulations including seven with Right to Light laws. Conspicuously, the US is not one of them...

In the 1950’s, a US landmark legal decision rejected this common law provision. Since then American cities have determined how or if daylight protection is considered in local design. Most have prioritized the efficiencies of dense urban housing, office space and mass transportation over focus on environmental and human health impacts.

But that’s changing. A decade of unchecked density and rising awareness of health risks have prompted new urban towers to promote access to daylight as the ultimate amenity. Unfortunately, daylight access is only considered and optimized for the new buildings. This unilateral approach is leaving neighbors of new developments in the dark.

Seattle is among the country’s fastest growing cities. Here, downtown neighbors have begun pressing the case for daylight preservation standards. As an urban livability advocate and sustainable design professional involved in this effort, we see the following themes driving the daylight discussion and preservation movement.

Circadian Health

Recognition of daylight’s function in regulating circadian rhythms has sparked international research on its role in heart disease, diabetes, cancer dementia and more. In Seattle, scientists are analyzing the connection between low levels of daylight and the severity of autoimmune diseases such as MS, a condition found in the overcast Pacific Northwest at triple the national rate.

Likewise, poor mental health has been associated with lack of sustained sun exposure, most notably in Seasonal Affective Disorder (SAD), and its lesser form, winter depression common here and other northern cities.

COVID-19

The pandemic has made access to daylight more urgent as millions worldwide are forced indoors and dependent on daylight available from their windows.

Prompted by the sudden work from home phenomenon now considered a long term trend, the Rensselaer Institute conducted a daylight survey last spring. It found those working from home who had access to “somewhat to very bright light” experienced fewer sleep disturbances, less anxiety and depression, and increased happiness.

Beyond Circadian health benefits, scientists have confirmed sunlight’s ultraviolet, antibacterial properties to kill viruses including Covid-19 on surfaces. They foresee sunlight will be key in post-pandemic building design.

The pandemic has also caused urban centers to see a dramatic loss of population as occupants seek more space in a healthier setting. If we hope to restore our cities, the quality of the urban environment must be improved.

Designing Green Development for the inside and out

Fortunately, the push for urban density has come with a renewed interest in the environment and public health.

Green certified buildings once aimed at energy savings and conservation now seek to incorporate health and wellness benefits associated with access to daylight, fresh air and access to nature through biophilia design strategies.

Commercial developers advertise these green building features as maintaining a happier, healthier workforce with higher productivity. Residential towers have followed suit making daylight and views central to their marketing campaigns.

While desirable, green certification standards only apply to the building certified without considering its impacts to adjacent buildings. Hence a development proposed recently under Seattle’s Living Building Challenge is under fire by neighbors. They say the bonus height and floor ratio it received for meeting green standards exceeds current zoning and substantially reduces their access to daylight.

Introducing light literacy and analysis to Design Review

After years of frenzied building activity, Seattle has reached the stage where small urban infill lots are slated to hold towers over 150 metres. High land and construction costs and small building envelopes leave little room or incentive to provide creative, equitable lighting solutions for dense urban neighborhoods.

Even with incentives or directives, there’s no standard or framework to analyze daylight. Environmental review happens after design review where project designs are set . Both reviews briefly consider glare or shadows a building may cast but not the absolute loss of daylight to existing buildings. This allowed the recent permit approval for a tower that daylight modeling shows will reduce up to 100% of existing daylight to residents of two adjacent buildings.

Heading for the Light

To paraphrase Thomas Fuller, daylight planning in the US may be in the ‘darkness before the dawn,’ however, the horizon is in sight.

The pace of progress will be determined by the success of individual permit appeals and other factors in play. Among them is federal government recognition of daylight’s role in health. Another is support from local politicians who embrace Green New Deal policies but have been slow to check big developments that feed the City budget. But there is movement in these areas. “High land and construction costs and small building envelopes leave little room or incentive to provide creative, equitable lighting solutions for dense urban neighborhoods. ”

Government recognition

Removed from local zoning, the federal government is laying the foundation for daylight preservation by confirming its role in human health.

To-date, two of America’s preeminent health organizations have acknowledged daylight’s role in healthy urban housing and development. The Center for Disease Control (CDC) website3 states “housing environment constitutes one of the major influences on health and wellbeing” and cites daylight in three of nine housing elements crucial to “fundamental physiologic needs.”

In 2019, the National Institutes of Health (NIH) issued a technical bulletin4 reviewing EU EN17037. It said, “Daylighting has proven to be beneficial for the health and well-being of building occupants.” Concluding, “With the increased awareness of healthy design in the US, similar requirements may be adopted here in the future.” The US General Services Administration, the largest landholder and building operator in the US has actively funded and participated in light and health research. It also issues publications encouraging the use of daylight in building design.

At the Washington state level, two legislators representing Seattle’s urban core have offered their support for Daylight for All legislation to introduce daylight as a required element in the state’s Growth Management Act. Additionally, the City Council Member representing downtown Seattle has agreed to study daylight in future livability legislation.

Standardizing daylight analysis and measurements

The immediate need is to develop a common literacy and understanding of daylight at all levels of planning and establish metrics for analysis applied consistently across jurisdictions. For this we’ve looked to pioneering work in the UK and EU. “The immediate need is to develop a common literacy and understanding of daylight at all levels of planning and establish metrics for analysis applied consistently across jurisdictions. For this we’ve looked to pioneering work in the UK and EU. ”

Coalescing around daylight measurements, methods and standards will propel urban daylight into wider global consideration. It will greatly reduce the learning curve for decisionmakers and reduce the burden for practitioners.

The holy grail will be achieving consistent results and establishing a set of minimum daylight thresholds to evaluate daylight at the street level and on adjacent building facades. Consistency can be achieved by applying pertinent variables including annualized climate data and a building’s function for work or residential occupancy.

Looking to the horizon

The world is at an historic inflection point, with cities being challenged and redefined by a global health crisis. In Seattle and elsewhere, an extended development boom has sacrificed daylight relevant to the pandemic’s impacts and to the long term quality of the urban human habitat.

Global practitioners already have the tools and knowledge to quantify and illustrate daylight loss. We hope sharing our experience will add data points for consideration in creating standards for a sustainable and bright future.

References:

https://www.designingbuildings.co.uk/w/images/1/1d/David_Strong_(1of2)The_Daylight_Factor_TSB-BRE_ paper_v_3.pdf

https://www.lrc.rpi.edu/resources/newsroom/pr_story.asp?id=464

https://www.cdc.gov/nceh/publications/books/housing/cha02.htm

https://www.orf.od.nih.gov/TechnicalResources/Documents/Technical%20Bulletins/19TB/Daylighting%20%E2%80%93%20European%20Standard%20EN%2017037%20October%202019-Technical%20Bulletin_508.pdf

Authors:

Megan Kruse is a communications consultant who works on urban livability issues and resides in downtown Seattle.

Edward Clark is director of Circa Dies, a sustainable design consultancy experienced in IES, WELL AP, LEED AP, RESET and AP. He was formerly in-house consultant for ZGF Architects LLC, an award winning North American design firm.