The Broad, USA

Through a clever and regulated combination of artificial and natural  light, darc awards / architectural winner Arup has developed an efficient lighting scheme that is both inviting for The Broad museum’s visitors and sensitive to its artworks.

Often called ‘the veil and the vault’, Los Angeles’ The Broad museum merges public exhibition space and archive/storage that will support The Broad Art Foundation’s lending activities. The building’s architecture, designed by Diller Scofidio + Renfro (DS+R) in collaboration with Gensler, is characterised by a finely honed geometry derived from the solar path in LA. The entire envelope, including the carefully calibrated veil and skylights, serve as a light filtration device, bringing controlled and diffused natural light into the galleries.

Rather than relegate the archive/storage to secondary status, ‘the vault’ plays a key role in shaping the museum experience from entry to exit. Hovering midway in the building, its heavy opaque mass is always in view. Due to this positioning, its carved underside shapes the lobby below and public circulation routes, while its top surface becomes the floor of the exhibition space. The vault is enveloped on all sides by the so-called ‘veil’ – an airy, cellular exoskeleton structure that spans the entire gallery, allowing filtered natural daylight to penetrate the building’s interior space. Moving to the upper level, visitors are drawn upwards via escalator, tunnelling through the archive, arriving onto an acre of column-free exhibition space bathed in diffuse light. This 23ft high space is fully flexible to be shaped into galleries according to the needs of exhibits. Upon leaving the exhibition space, visitors take a  return trip through the vault via a winding stair that offers glimpses into the vast holdings of the collection.

Tasked with the museum’s lighting design, Arup has recently been awarded the Best Interior Lighting Scheme at the darc awards / architectural for its work on The Broad museum.

Working with the architects and the Broad to create a sustainable public space, Arup used energy saving strategies including the configuration of the architectural ‘veil’ as an external shading device, harvesting daylight through the gallery spaces, and use of low energy LED light fixtures. The museum was recently awarded a LEED Gold certification, the first major art museum in Los Angeles, and one of only a handful of museums nationwide to achieve this world-recognised status.

Collaborating closely with the architects, Arup’s lighting experts devised a way to utilise daylight while ensuring the artwork was protected. The team’s approach has created an original skylight design that eliminates direct sunlight whilst controlling the amount of diffuse and reflected light that enters the space. Applying a passive daylighting approach means that daylight levels in the galleries will vary with the season, time of day and weather, altering the ambience of the interior on each occasion a visitor comes to the museum.

The top floor gallery is illuminated by expansive north-facing skylights and a fully-shaded glazed south wall. The 300+ skylights are configured to allow filtered daylight through while preventing direct sunlight, creating a uniform ambience across the space. The natural daylight passing through the north canted light slots of the veil’s roof section create a uniform but dynamic light right through the 23ft depth of the upper gallery.

An appreciable amount of daylight occurs outside museum open hours. Daylight in the gallery at these times could be considered unnecessary exposure of art to light. In addition, some exhibitions may require reduced light levels, either for conservation reasons (e.g. works on paper) or for display reasons (e.g. video works). Working closely with The Broad and DS+R, and drawing on previous museum experience, Arup introduced black-out blinds installed on the exterior of the skylights. These can move between full deployment during closed hours to a pre-set position during open hours, giving the museum maximum flexibility to exhibit any medium of art.

For the artificial lighting, Arup assisted with the development of custom track mounted LED wallwashers which are used to uniformly illuminate the 23ft gallery walls. Arup worked with manufacturer Litelab to ensure the lighting complied with California’s Title 24. Several fixture reviews were carried out to evaluate the performance of the custom luminaires in terms of light quality, distribution and levels of illumination. In addition, the ambient lighting that is provided to the ceiling coffers by the skylights during the day is supplemented at night by fluorescent light fixtures carefully positioned within the coffers.

Interior photocells measure the levels of daylight within the space, which trigger the track lights to brighten when daylight levels are insufficient. This means that when daylight levels drop, the artificial lighting slowly brightens so that the combined illuminance is equal to a value set by the museum for that space. An exterior photocell tracks the daylight levels on the roof, and energises the fluorescent lights after dusk.

With all the lighting elements carefully considered, a control system was put in place to ensure all the lights worked together creating a uniformly lit space at all times. With the photocells communicating with the track lighting and fluorescent lighting, an automatic system was installed. An astronomical 365-day timeclock allows the lighting to be automatically controlled, primarily used to turn the lighting off during the museum’s closed hours. This helps to preserve the artwork and reduce the museum’s energy emissions creating a sustainable gallery.

After completion and commissioning of the lighting systems, Arup gave the museum a ‘Lighting Handbook’. This guide sets out how the daylight system can be configured to work with any type of exhibition on a month by month basis. This ensures that museum staff and curators fully understand the lighting strategy and how to work with it so the lighting always complements the artwork.

“Arup has been an amazing partner in the building of The Broad,’’ commented Joanne Heyler, founding director of The Broad. ‘‘They understand the sensitivities of building a space for a collection of contemporary art and helped develop efficient and innovative solutions for the physical and aesthetic needs of the institution.”

A stunning and intelligent project, The Broad museum has received global recognition for its beautiful galleries and critical acclaim from architects and museum professionals for its sophisticated lighting solution.

Pic: Hufton + Crow

www.arup.com

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