© 2021 ArtRatio S.L.
Art collections can reside in museums, corporations or private residences. The trend towards greener, healthier and more sustainable buildings requires architects to reconcile the need for increased daylighting with the need to protect the sensitive materials on display.
This article discusses the effects of natural daylight on works of art and showcases recent LEED-compliant museums.
There is an inherent trade-off that needs to be made when conserving and exhibiting art collections, which makes any museum especially difficult to certify against the US Green Building Council standard for “Leadership in Energy and Environmental Design”, or LEED v4 [Ref. 1].
Mandi Lew of New York-based Samuel Anderson Architects, winners of the LEED Gold award for the Allen Memorial Art Museum says: “Museums are inherently not energy efficient, because strict humidity and temperature control must be maintained at all times”.
As stated in BSI PAS 198 “Specification for Managing Environmental Conditions for Cultural Collections” [Ref. 3]:-
LEED v4 requirements for museums include credits for energy efficiency, water usage, waste recycling and daylighting as well as climatic requirements for visitors and staff.
To compound all of this, the requirements of the art collection itself must be placed centre-stage.
“Colours are Light’s Suffering and Joy”
Johann Wolfgang von Goethe
Abundant daylighting represents both an element of pleasure through the improved perception of fine details and colours on works of art and at the same time, due to deterioration, an element of pain.
Here is the chain of events [Ref. 8] that unfold when daylight on art collections is poorly managed:-
1. Sunlight entering the building facade through unfiltered windows can contain up to 55% infrared energy [Ref. 5] (i.e. heat).
2. This heat increases the ambient temperature in the vicinity of the collection and inside the objects, accelerating chemical reactions and increasing internal temperature gradients, which causes stress.
3. The increased temperature reduces the relative humidity (RH), causing embrittlement and cracking of composite objects containing hygroscopic materials of differing thermal coefficients of expansion.
4. The reduced RH also reduces the electrical conductivity of the air [Ref. 7], since dry air contains less water, allowing electrostatic charge to build up on insulative surfaces, e.g. glass / acrylic displays, since the charge has no natural dissipation mechanism to electrical ground.
5. An increase in electrostatic charge on nearby surfaces increases the risk of lift-off of friable media such as charcoal and graphite, found on drawings, sketches and other works on paper. It also increases the transfer of dust and other pollutants.
You can read more about the effects of light on fragile art and antiques on our blog article: Antique Art and the Light Spectrum.
The International Commission on Illumination (CIE), based in Austria recommend in their report [ref. 2], which we will refer to as CIE 157, that fragile works of art containing materials such as silk, paper and fugitive pigments should not receive more than 50 Lux at any time and should not be exposed to more than 15,000 Lux-Hours in a year.
Other international standards such as BSI PAS 198 [Ref. 3] and the CIBSE Lighting Guide 8 [Ref. 4] quote similar figures.
Assuming typical museum opening times of 3000 hours per year, even a minimal (but permanent) light level of 50 Lux would result in a total exposure of 150,000 Lux-Hours per year, which is 10 times the CIE recommended figure for the most sensitive of materials.
Furthermore, with the LEED v4 daylighting requirements [Ref. 1] awarding 2 points for the successful adoption of light levels of at least 300 Lux in 75% of regularly occupied floor areas, architects will realise that this level of light would restrict the most sensitive objects in a museum to a maximum of only 50 hours exhibition time in a year.
Other LEED v4 requirements related to light management include:-
a. Light Pollution Reduction
To increase night sky access, improve nighttime visibility and reduce the consequences of development for wildlife and people for all exterior luminaires located inside the project boundary.
b. Interior Lighting
To promote occupants’ productivity, comfort, and well-being by providing high-quality, personalised lighting control across at least 90% of occupant spaces and specific lighting quality (e.g. a Colour Rendering Index greater than 80).
These conflicting requirements can place stress on the architect, the project, the collection and ultimately the client.
The author’s own experience with a major UK university new-build library project in 2017 highlighted the complexities of balancing conservation issues surrounding fragile art collections against the daylighting and interior lighting requirements within the project goals of creating a Net Zero Energy (NZE) building.
We worked with the architects and the client to explore the issues and possible solutions. As one example, we saw first-hand how the importance of the special manuscripts collection at that institution dictated the architectural philosophy of how to manage light within the building facade, the daylight control systems, the quality and intensity of light sources and light filters, and even the expected popularity of the collection (and hence the expected light exposure that the collection would have to endure).
So, how have recent LEED-compliant projects resolved this issue? Let’s take a look at some examples:-
The Broad Art Museum (California, USA), designed by Diller Scofidio + Renfro won LEED Gold in 2016 for sustainable design practices. The design involves drawing natural light into the building using a calibrated veil structure and skylights which serve as a light filtration device, bringing indirect, filtered natural light into the galleries in a controlled way. This creates optimum conditions to view the art whilst simultaneously reducing light exposure. Furthermore, the third-floor skylights are digitally monitored to control the amount of northern light that is allowed in, whereby each skylight is fitted with blackout shades to enable the museum to eliminate natural light when needed.
Harvard Art Museums (Massachusetts, USA) worked with Renzo Piano Building Workshop and Payette to achieve LEED Gold in 2015, transforming the historic structure within Harvard Yard into a state-of-the-art, sustainable art museum facility. With 20% of all materials being recycled and 95% of waste being recycled, this project achieved a 25% saving in annual energy costs. The sloped glass roof system brings together the new-build and existing construction, maximizing natural light at the upper floors and at the central courtyard. Two shade systems control solar gain to facilitate maintenance of closely controlled environmental conditions.
This state of the art complex, designed by Architects Thomas Phifer and Partners’ features white, curved walls and more than 900 skylights, allowing swathes of natural light to complement the low-energy LED lighting, reducing the overall energy usage by 76 percent.
Architects often find themselves having to make trade-offs when exhibiting fragile art collections, both in corporate, institutional and private buildings.
What is paramount is that the collection is considered centre-stage, since the objects on display can deteriorate rapidly if the architecture team does not tailor the day-lit environment to the sensitivity of the materials.