Environmental sustainability - reducing museums' carbon footprint
NMDC recognises that museums need to approach long-term collections care in a way that does not require excessive use of energy, whilst recognising their duty of care to collections.
There is general agreement within the international museums community that it is time to shift policies for environmental control, loan conditions and the guidance given to architects and engineers from the prescription of close control of ambient conditions throughout buildings and exhibition galleries to a more mutual understanding of the real conservation needs of different categories of object, which have widely different requirements and may have been exposed to very different environmental conditions in the past.
The Bizot Group - the group of the world's leading museums - agreed the Bizot Green Protocol in 2015. NMDC adopted these standards and hope they act as guidance for the rest of the museum sector.
Bizot Green Protocol
1. Guiding Principles
Museums should review policy and practice, particularly regarding loan requirements, storage and display conditions, and building design and air conditioning systems, with a view to reducing carbon footprints. Museums need to find ways to reconcile the desirability of long-term preservation of collections with the need to reduce energy use.
Museums should apply whatever methodology or strategies best suit their collections, building and needs, and innovative approaches should be encouraged.
The care of objects is paramount. Subject to this,
- environmental standards should become more intelligent and better tailored to specific needs. Blanket conditions should no longer apply. Instead conditions should be determined by the requirements of individual objects or groups of objects and the climate in the part of the world in which the museum is located;
- where appropriate, care of collections should be achieved in a way that does not assume air conditioning or other high energy cost solutions. Passive methods, simple technology that is easy to maintain, and lower energy solutions should be considered;
- natural and sustainable environmental controls should be explored and exploited fully;
- when designing and constructing new buildings or renovating old ones, architects and engineers should be guided significantly to reduce the building’s carbon footprint as a key objective;
- the design and build of exhibitions should be managed to mimimise waste and recycle where possible.
For many classes of object containing hygroscopic material (such as canvas paintings, textiles, ethnographic objects or animal glue) a stable relative humidity (RH) is required in the range of 40 - 60% and a stable temperature in the range 16-25°C with fluctuations of no more than ±10% RH per 24 hours within this range. More sensitive objects will require specific and tighter RH control, depending on the materials, condition, and history of the work of art. A conservators evaluation is essential in establishing the appropriate environmental conditions for works of art requested for loan.
Following publication of NMDC guidelines and an investigation by the AHRC/EPSRC Research Cluster, the British Standard Institute consulted on and published Publicly Available Specification 198: Specification for managing environmental conditions for cultural collections. This standard reflects research conducted since the publication of environmental guidance for museums, libraries and archives in British Standard 5454 (2000). The PAS 198 suggests users:
- Evaluate the sensitivity of their collection in response to temperature, relative humidity, light and pollution, recognising that different materials react in different ways to agents of deterioration;
- Think holistically and put in place an environmental strategy appropriate for the collection (and which takes into account the expected lifetime of the collection);
- Make decisions about suitable environments on the basis of the significance, condition, use or display of those specific objects.
NMDC guiding principles
NMDC developed a set of guiding principles for rethinking policy and practice with the aim of minimising energy use in 2009. The guidelines were developed in consultation with UK conservators, ICON and the National Trust among others. NMDC members agreed to commit to these guidelines, signalling a move towards a less energy intensive approach to collections care. The guidelines were accepted by the European Bizot Group of major museums at their May 2009 meeting.