Sustainability in Conservation: how light is your collection environment?

Wilma Bouwmeester ACR, Heritage Preservation Consultant

I’ve worked in the conservation of collections for nearly 30 years and have applied concepts of sustainability to my work for some time.  I recently became Certified Carbon Literate, and then came across Christopher Garthe’s book The Sustainable Museum*, in which he brings together several concepts on sustainability I have been a firm believer of for some time.  In this article I’ve tried to summarise some of these concepts in the context of Environmental Control in art and heritage organisations.

The current global crises need to be our starting point – we are close to a tipping point from which there is no return, but it is not too late yet and there is much we can do. I firmly believe we can only turn the tide if we stop competing and start cooperating, as competition polarises and creates conflict, whereas cooperation brings people together and encourages connection, which is essential in our lives and our work. Everything is connected, including the seemingly separate issues of climate change, financial market crises, global division, and migration. The cause lies in the fossil fuel-based economy, which results from a ‘growth-first’ mentality that is governed by principles of competition.

Sustainability is a holistic concept with three interconnected elements: social, financial, and environmental. In the not-so-distant past, finance was often the determining factor in decision-making processes; in recent years, discrimination and social inequality have become prominent. Now, the environment is at the forefront of our urgency. But all three need to be in balance. Here too everything is connected, and nothing happens isolation. A problem doesn’t appear by itself, it has a context, and therefore its solution also requires a cooperative approach, to include respect, care, tolerance, and altruistic thinking/behaving. This approach is the opposite to the rat-race society, the competitive struggle to get ahead of others.

For me it is like practicing Anne Herbert’s ‘random kindness and senseless acts of beauty’, a concept I try to apply in my personal life.

Of central importance is also social justice, ‘everyone-everywhere’, an equal right to a good life, now and in the future. This means giving more thought to degrowth and sufficiency (the ‘scarcity myth’ and the ‘sufficiency principle’, two more concepts I try to live by).

Sustainability is at the core of what we do, it is essential in all aspects of our professional and private life. When we build something new (a building, system, process, or method) sustainability needs to be included from the start: ‘we don’t do this unless we can do it sustainably’.

I compare the approach with the concepts of ultralight camping, where you don’t replace all your camping items with their lightest version, assuming that you still need all of them. Instead, you start from a base line of not taking anything, and ask yourself what is absolutely essential, then you find its lightest version.

I now advocate ‘good’ rather than ‘best’ practice, as getting from ‘good’ to ‘best’ often requires disproportionate amounts of resources for a small increase in return, whereas surely ‘good’ is good enough? No more ‘ideal’ and ‘acceptable’ levels of environmental control: if it is acceptable there doesn’t need to be an ideal.

Question all aspects of our situation

If we want to be like the ultra-light camper, we need to start asking some basic questions about:

·         collection de-growth and de-accessioning

·         physical storage organisation (by curatorial specialism or by material/environmental

needs?)

·         expectations and assumptions: does the public expect conservation and

environmental control to be invisible, and if so - why, have we made them expect

this?  Preservation is a core activity that needs to be shown and communicated as

part of all activities of the organisation.

How do we define a sustainable approach?

A sustainable approach includes:

·         Risk-assessment, working with your specific situation and what applies there

·         Identification of majority need, then minority specifics

·         Implementation of passive measures before considering active measures

·         Equal approach between needs of people and those of collections.

The simplest approach to environmental control would be to provide the same environment throughout the building to the needs of the most sensitive objects, giving full flexibility. This is of course entirely possible, but it comes at a price, and not only financially. The required plant will be large and running it costly, and in cost-saving exercises these systems often get switched off, leaving the collections vulnerable to poorly controlled environments in often poorly insulating buildings.

A different approach is needed, with environmental control strategies based on the real-life context of your particular museum. The redefining of environmental parameters is a current topic in the context of energy-efficiency, whether driven by a desire to save money, the planet, or both. It often leads to the adoption of wide control bands for RH and Temp, rather than setpoints with tights allowances either side.

Control of RH is the more important of the two, as museum artefacts tend to be more sensitive to changes in RH than changes in Temp. In high RH environments artefacts may absorb moisture and can swell and deform, or corrode, or become mouldy, whereas in low RH environments they give off moisture and dry out, shrink, or become brittle.

Frequent changes between the two can create movement from the swelling and shrinking which may cause tension and damage.

How do we question everything we currently do?

These are some of the questions we need to ask ourselves:

Do we need to control the environment for all spaces – what will they contain?

Collections only                                                                  People only

Focus on RH control                                                         Main control is Temp

T frost protect only                                                      RH control not always needed

                                        Collections and People

                                        Main control is RH and Temp

                                      of equal relevance/importance

In a building in good condition, RH and Temp are related: if Temp goes up RH comes down and vice versa. It may be possible to allow Temp to fluctuate (within limits) in favour of a stable RH. This approach is particularly suitable for spaces with collections only  but can also work in spaces where collections and people meet. It is called conservation heating: we manipulate Temp in order to maintain the desired RH.

In order to specify the environment for the three different scenarios, we can apply the basic concept of ‘zoning by environmental need’ (not by floor or wing of the building):

all stores might be one type of zone; all galleries another type of zone; restaurant, education suite, shop, toilets, a third type of zone.

Control system must be able to control different zones separately.

What is the widest environmental band most of our collections can safely tolerate?

The approach to unquestioningly apply text-book recommendations is now quite outdated.

A better approach is basing parameters on a combination of factors specific to collection and context:

How naturally sensitive is the collection – material, construction (absorbent, tensions);

How acclimatised has the collection become – history of the environment it has

been in and for how long;

How fragile is the collection now  – has its aging over time made it more fragile;

How big is the risk of damage - how susceptible is it, how likely is it to happen,   and how big the impact if damaged (curatorial, educational context).

We learn the above through condition assessments and risk assessments. The outcome will lead to some findings about the degree to which specific environmental control is needed:

·         basic conditions for collections that are not RH sensitive (basic being a watertight,

clean, dust free, organised space);

·         wide control bands with slow changes for normally sensitive items in good

condition;

·         specific tighter conditions for particularly fragile or significant collections.

This approach shows there is no need to provide the tightest conditions throughout the entire building.

How much of the required environment is the building already able to provide?

Contrary to what engineers may make you think, you already have an environment in your building, and you do not need equipment that supplies controlled air 24/7 all year round. Even if we take Health & Safety requirements for fresh air into account, there is probably no need for it. A CO2 sensor will indicate the quality of the air, and whether ventilation with fresh air is needed, rather than a standard number of litres per person per minute as determined by the Government’s building safety body.

Environmental monitoring  will show us what the baseline of our museum environment is, and how close it is to what we need in the various spaces. This in turn will indicate what spaces to use (or avoid) for stores, and how displays can best be designed to work with the building where possible (and this may be limited by the flow of an exhibition narrative, so here is another opportunity to work together with our curator colleagues).

This will also help identify how much additional work might be needed to create the required conditions. These should focus on passive measures first of all, those not needing ongoing energy. Are there improvements to be made around, or outside the building? Areas to consider are the existence/absence of shelterbelts, reduction/provision of shading, soil build-up against a wall, anything that might affect the ability of the building to provide a sound protective envelope around the people and collections inside it.

Good insulating properties of windows, roof, and walls, with cavity wall insulation, and double/secondary glazing are important to keep the inhospitable climate out and the good conditions in. Global warming and higher summer temperatures in the UK mean buildings may now require cooling. Here too there are passive measures to prevent heat from building up in the first place: light reducing glass, fixed or retractable awnings, deep overhang of roof, or setting back of glass facade to create shading.

The fabric of the building may be in good condition, but if finishes near doors, windows, or conduits are poor there may be air leakage. Such areas need to be finished properly, as they can also become entry points for pests.

It may seem more expensive to provide all this up front, but it will be balanced with reduced energy use over time. It is not only about project costs, the running costs over the next 5-10-20 years are equally - if not more - important.

All these integrated passive measures are likely to bring us closer yet to the conditions we need, or maintain them more often, or for longer periods of time.

Can we provide additional control passively, and in what form?

Further control may be possible by using the principle of rooms within rooms, or by surrounding collection spaces with non-collection spaces, to act as a buffer. The more layers are provided around objects, the more stable the environment near them, and this applies both in storage and on display.

Good quality display cases can be sufficient to further stabilise the environment and reduce fluctuations, or the environment can be modified with passive measures such as RH buffering silica gel and Artsorb.

If active control is necessary, how little is enough?

If the building is in good condition and able to provide a decent degree of control, and we can maintain a fairly wide band for the majority of collections the majority of the time, then it is likely that any active plant for further control can be modest in size, and its default setting is ‘off’. It will need to be on only to nudge conditions back into the acceptable band.

Does it need to be on 24/7? Some buildings are able to maintain conditions for several hours after equipment has been switched off (delay effect because of thermal mass), so plant may be switched off for short periods without creating an unduly fluctuating environment - this is being experimented with at the moment, e.g. switch off for an hour at night for a week or so and observe the effect in your monitoring data. If there are no significant changes, trial switching off for 2 hours a night. (Only experiment like this in spaces where conditions are being monitored so the effect can be checked.)

When plant needs to be on, does it need to be on at full setting straight away or can an excursion outside the parameters be caught early and nudged back by using a 50% setting? Get the plant programmed to try this first, before switching it on at full capacity. How exactly this needs to be specified depends on the type of equipment and the control software. This is where we want to work closely with the M&E engineers who design and programme our systems.

Conclusion

By following a structured, tailored, and sensible approach to the provision of environmental conditions, we can design and implement good environmental control for collection preservation that is compatible with the requirements for people comfort, energy (and cost) efficiency, and broader environmental concerns for the planet.

How light can you make your environmental management?

* Garthe, Christopher J, The Sustainable Museum. How Museums Contribute to the Great Transformation. Routledge, London & New York, 2023.