Recognising that conservation practices should not harm the environment, harm people, or contribute to
global warming, the conservation-restoration profession has more recently focused on practices that reduce waste, reduce energy costs, and minimise the use of
toxic or harmful solvents. A number of research projects, working groups, and other initiatives have explored how conservation can become a more environmentally sustainable profession. Sustainable conservation practices apply both to work within cultural institutions
Choice of materials Conservators and restorers use a wide variety of materials - in conservation treatments, and those used to safely transport, display and store cultural heritage items. These materials can include solvents, papers and boards, fabrics, adhesives and consolidants, plastics and foams, wood products, and many others. Stability and longevity are two important factors conservators consider when selecting materials; sustainability is becoming an increasingly important third. Examples of sustainable material choices and practices include: • Using
biodegradable products or those with less environmental impact where possible; • Using '
green solvents' instead of more toxic alternatives, or treatment strategies that use much smaller amounts of solvents - for example, semi-rigid aqueous gels, emulsions or nano materials; • Preparing smaller amounts of material (e.g. adhesives) to avoid waste; • Observing recommended disposal protocols for chemicals, recyclable materials and compostable materials, particularly to avoid contamination of waterways; • Choosing protective work wear that can be washed or cleaned and reused, rather than disposable options; • Tracking stock quantities to avoid over-buying, especially for materials with expiration dates; • Using durable materials for packing that may be washed and re-used, such as
Tyvek or
Mylar; • Repurposing consumables such as blotting paper, non-woven fabrics, and
polyester film when they are no longer fit for their original purpose; • Using locally produced products whenever possible, to reduce carbon footprints; • Reusing packaging materials such as cardboard boxes, plastic wrap and wooden crates; • Using standard sizes of packaging and package designs that reduce waste; These decisions are not always straightforward - for example, installing
deionised or
distilled water filters in laboratories reduces waste associated with purchasing bottled products, but increases energy consumption. Similarly, locally made papers and boards may reduce inherent
carbon miles but they may be made with pulp sourced from
old growth forests. Another dilemma is that many conservation-grade materials are chosen because they do not biodegrade. For example, when selecting a plastic with which to make storage enclosures, conservators prefer to use relatively long-lived plastics because they have better ageing properties - they are less likely to become yellow, leach plasticisers, or lose structural integrity and crumble (examples include
polyethylene,
polypropylene, and
polyester). These plastics will also take longer to degrade in landfill.
Energy use Many conservators and cultural organisations have sought to reduce the energy costs associated with controlling indoor storage and display environments (
temperature,
relative humidity,
air filtration, and lighting levels) as well as those associated with the transport of cultural heritage items for exhibitions and loans. In general, lowering the temperature reduces the rate at which damaging
chemical reactions occur within materials. For example, storing
cellulose acetate film at 10 °C instead of 21 °C is estimated to increase its usable life by over 100 years. Controlling the relative humidity of air helps to reduce
hydrolysis reactions and minimises cracking, distortion and other physical changes in
hygroscopic materials. Changes in temperature will also bring about changes in relative humidity. Therefore, the conservation profession has placed great importance on controlling
indoor environments. Temperature and humidity can be controlled through passive means (e.g.
insulation, building design) or active means (
air conditioning). Active controls typically require much higher energy use. Energy use increases with specificity - e.g. in will require more energy to maintain a quantity of air to a narrow temperature range (20-22 °C) than to a broad range (18-25 °C). In the past, conservation recommendations have often called for very tight, inflexible temperature and relative humidity set points. In other cases, conservators have recommended strict environmental conditions for buildings that could not reasonably be expected to achieve them, due to the quality of build, local environmental conditions (e.g. recommending temperate conditions for a building located in the tropics) or the financial circumstances of the organisation. This has been an area of particular debate for cultural heritage organisations who lend and borrow cultural items to each other - often, the lender will specify strict environmental conditions as part of the loan agreement, which may be very expensive for the borrowing organisation to achieve, or impossible. The energy costs associated with cold storage and
digital storage are also gaining more attention. Cold storage is a very effective strategy to preserve at-risk collections such as
cellulose nitrate and
cellulose acetate film, which can deteriorate beyond use within decades at ambient conditions. Digital storage costs are rising for both born-digital cultural heritage (photographs, audiovisual, time-based media) and to store digital preservation and access copies of cultural heritage. Digital storage capacity is a major factor in the complexity of preserving digital heritage such as
video games,
social media, messaging services, and
email. Other areas where energy use can be reduced within conservation and restoration include: • Exhibition lighting - e.g. using lower-energy LED lighting systems and light sensors that switch lights on only when visitors are present; • Installation of green energy capture systems in cultural organisations, such as
solar photovoltaic plates,
wind energy systems, and
heat pumps; • Improving the energy performance of cultural buildings by installing insulation, sealing gaps, reducing the number of windows and installing double-glazing: • Using
microclimates to house small groups of climate-sensitive objects instead of seeking to control the environmental conditions of the whole building.
Sustainability in the practices of conservation laboratories Source: In the routine work of conservation laboratories, a series of practices can be implemented with a view to management that favors ethical sustainability criteria, as well as actions such as pragmatic responses to climate emergencies. It is fundamentally that we strive to make practices such as the following commonplace: • Prepare small quantities of products to avoid producing waste. • Prepare small quantities of products to avoid producing waste. • Establish a routine disposal of chemicals according to biosecurity standards • Disseminate and instruct users of the laboratories on sustainable practices • Stimulate the use of green solvents; use of less toxic and lower environmental impact solvents (reduction of the use of aromatic solvents and substitution for less toxic, ecological, biodegradable products); • If possible, give preference to the use of gel solvents (minimizes direct contact with liquid solvents, decreases the amount of volatile material dispersed in the environment, and improves application control and reduces losses and contamination) • If possible, give preference to using biodegradable products for surface cleaning procedures, such as agar-agar. • Use preferable LED lighting in laboratories and storage rooms, high energy-efficiency equipment, and climate control monitoring to avoid waste • Reuse packaging materials and choose sustainable materials whenever possible. • Give preference to digital documentation and avoid excessive use of paper. ==Country by country look==