This month, we will explore the role that lighting controls play in illumination of art at the Barnes Foundation. Lighting design by Fisher Marantz Stone. Photography by Michael Moran/OTTO, Tom Crane and Fisher Marantz Stone. Lighting controls by ETC.
Capped by a glass box roof, the aperture in the LightCourt directs reflected daylight into the north-facing galleries.
Exterior windows in all galleries have 14% transmission glass as the first element of daylight control. Each window also has a 5% transmission motorized solar shade and an opaque shade to shield the art from direct sunlight; both are controlled by a centralized lighting system. The control system responds to photocell readings, allowing the use of daylight to be maximized, and electric light to supplement as required within conservation illumination levels.
Controlled daylight and electric gallery lighting permits both outdoor views and full spectrum art lighting throughout, while keeping within conservation illumination thresholds.
All second floor galleries have clerestories which provide screened daylight in tandem with indirect fluorescent lighting.
A series of scaled mockups were created to audition various clerestory heights and ceiling apertures to maximize daylight, maintain light uniformity across the walls and reduce glare.
The clerestory section is comprised of an exterior louver, high-performance glazing, motorized opaque shade, and an indirect 3500K digital ballast fluorescent cove. Individual wall-watching photocells control electric lighting in each Gallery.
A full-scale mockup, of a typical gallery, used loggers to measure the daylight over the course of a year to help set thresholds within the final control system.
On the gallery roof, a “suite” of 4 miniature windowed rooms, each equipped with a photocell, measures the real-time daylight and operates the solar shades in corresponding galleries.
Lighting for the new galleries utilizes less than half of the lighting power density otherwise consumed by a standard track lighting solution. The control strategy further reduces the electric load by up to 40% in clear sky conditions.
The exterior volume of the LightCourt roof houses a photovoltaic array which provides 8% of this LEED Platinum project’s electricity.