Playing catch up with global daylight standards
Athough US researchers are starting to discover new links between daylight and human health, Europe and the UK have a history of recognizing and protecting the need for light. A long history.
In 1832, England adopted the Right to Light. The doctrine confers historic easements on the level of light and air to building windows after 20 years. Neighboring construction that reduces protected light must mitigate its design or risk fines or possibly an injunction to halt construction.
The measure has produced a field of experts who assess site conditions and devise optimal plans for existing and new development. Consultants provide site specific studies and models offering ways to design developments that avoid or reduce loss of light.
In the European Union, since 1992 health and safety regulations have required that “every workplace shall have suitable and sufficient lighting” and that this lighting “shall, as far as is reasonably practicable, be by natural light.”
The International Organization for Standardization (ISO) has similar provisions. ISO standard 2014a covers methods of calculating daylight for both existing buildings and the designs of proposed construction.
In countries without specific daylight codes the EU has promoted using voluntary environmental rating systems like LEED, BREEAM and Greenstar that include building daylight standards.
After years of patchwork standards and legislation, in 2019 the EU passed EN 17037.
This legislation raised the bar on indoor median Average Daylight Factor (ADF) 1.5 times higher than previous recommendations. In turn this has raised concern in cities like London on how to meet these standards in urban dwellings.
But while the rest of the world debates the fine points of density, human health and required levels daylight, the US is only entering the discussion.
US safety leader Underwriters Laboratories (UL) has started with DG 24480 a first-of-its kind electric lighting guideline. The report’s preface states, “current building practice does not provide daytime lighting levels that are bright enough to support circadian entrainment of its occupants.”
DG 24480 offers detailed specifications for specialty indoor lighting, concluding that “providing lighting for a circadian entrainment is a new but important application area.” That’s true but it falls short of a full solution.
Economically and environmentally it’s out of touch and unsustainable to assume electric light will be adequate to sustain urban dwellers’ health. This was true even pre-pandemic and the new work-from-home paradigm.
As City leaders pursue a Seattle Green New Deal, we’ll know it’s for real if it addresses daylight building standards the rest of the world has long acknowledged as the most effective, environmentally sound and energy efficient way to promote human health.
Next week: What are Seattle standards for daylight?
