AIC RATS – Microclimates
June 1, 2011
Museum environmental guidelines and the implementations of change
Charlie Costain – Conservation and Scientific Services,
Canadian Conservation Institute (CCI)
Follow up to “plus/minus” dilemma we’ve been having otherwise known as: “Should we loosen up the environmental restrictions on museum loans to other institutions?”
At CCI – 2,500 museums support across Canada and 500 archives. They were looking for an approach that can be adapted for a variety of organizations.
Recap of “Plus/Minus Dilemma” at AIC 2010: http://www.iiconservation.org/dialogues/
Highlights:
• Jerry Podany: IIC – heritage conservation in the broader context of the modern world;
• Max Anderson: candor and honesty of what you’re doing and flexibility between parties and technical capacity of the buildings and energy concerns;
• Nancy Bell: in the UK AVISO group ask staff at Tate to reexamine conditions for loans and exhibitions – carbon emission reductions and new funding for research IGOR;
• Karen Stothart: talked about the balance of need of exhibitions and loans and the protection of those 50% RH does shift during winter;
• Cecily Crzywacz: there is no magic bullet for conditions for all institutions;
• Stefan Michalski: he felt that consensus that 10% +/- OK for most collections;
• Terry Weisser: conservators are concerned about energy savings, but need to take care of collections also. Welcomes more research in this area for wider and looser parameters.
ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers)
This is the organization that conservators look to when determining setpoint and HVAC standards for museums. There is an ASHRAE handbook that is put out every three years that includes information about designing museums . However, the temperature and RH setpoints/ standards have not changed since 1999! This handbook is written in engineer language; design parameters; system selection for engineers. ASHRAE proposes classes of control: AA, A1, A2, B, C, and D. Cool, cold, and dry are the best conditions (duh) and each class has its collection risks and benefits. See list below:
Class of control / Relative Humidity / Temperature
AA: 50% RH +/- 5% 75°F (high) 55°F (low) +/-4°F
A1: 50% RH +/- 10% 75°F (high) 50°F (low) +/-4°F
A2: 60% RH in summer and 40% RH in winter +/- 5% 75°F (high) 50°F (low) +/-4°F
B: 60% RH in summer and 40% RH in winter +/- 10% 75 +/- 5 and cold +/-5
C: 50% RH +/- 25% Below 85°F
D: Below 75% RH Below 85°F
ASHRAE also has building types; higher Roman numerals have more climate control
Climate control: (VI) collection vaults, (V) museums
Partial control: (IV) and (III)
Uncontrolled: (II) and (I)
Why ASHRAE?
• Consistent with risk approach to making decisions on collections
• Flexibility for difference types of collections and locations and building types
• Facilities communication between engineers and collections folks
Example: Risk assessment on historic house in Ontario
First questions during the assessment: collections and relative value of collections; created collections “pie” chart; building vs. collection; and collections overall by percentages.
They decided the building was the most important asset, but spalling was occurring because they were trying to maintain 45% RH inside; reduce RH will reduce strain on building envelope.
There is some confusion about RH and temperature. There is a perception that RH is an issue of paramount importance which can lead to inappropriate RH as in the above example.
• Lack of awareness of options
• Lack of transparency in operations, loans and grant requirements
• As a result, discussions have begun on the federal level in Canada
“Saving Money, Preserving Collections” dialogue
• Overview of evolution of guidelines for museum environment
• Operation of facilities – facilities managers
• Current operations – shared opportunity for savings
• Conditions for loans/ funding
What temperature and relative humidity can we have to satisfy loan and grants?
Operating Conditions in National Museums
o Differs depending on type of building and collections
o Purpose building facilities run at 50% RH +/-5% in the summer and 43% RH +/- 5% in the winter, with a temperature at 21°C
Agreement on the following from museums across Canada:
• When sending materials to another Canadian museum, the loaning museums will not demand better conditions than their own
• Museums will lend objects containing hygroscopic materials to institutions that can achieve Class A conditions
• Federal grant class A will be requirement where applicable
• This is not a strait jacket – meant to be a starting point – obligation as to why this object is not suitable – more candor and information exchange
• Having the discussion and getting agreement from some of these major players is a starting point
o Moving from a rules based approach to a risk based approach – there is work to be done in terms of communication and research
Any suggestions? CCI would appreciate your input – drop him a line! Charlie.costain@pch.gc.ca 613-998-3721
The Off-Grid Museum
National Museum in Denmark
Dr. Poul Larsen and Tim Padfield
Energy savings – Denmark has been doing it WAY before it was cool and hip. Tim has worked with saving energy in conservation for many years. The presentation was given by Dr. Larsen from the National Museum in Denmark.
He showed us buildings that are relevant to the subject: energy savings
As you know, buildings depend on external energy sources to function – light, temp, RH, etc. Museums are big time energy consumers and Denmark is trying to create a building that doesn’t rely on external energy sources and uses only renewable energy sources, taking into account climatic exceptions.
One example that he gave was this Nydam Iron Age warship that was exhibited in a temporary shelter designed as a balloon. As you can imagine, energy use quite large because sealing a balloon is no small feat. Needless to say, the “balloon” leaked, causing an unstable climate – maybe C or D class in ASHRAE terms. Air conditioning depends heavily on the building envelope and the envelope was failing in this example. TO add some more fun to the mix, there was a 6 hour power outage and the balloon collapsed – only held up by wires. Constant energy supply may become a luxury and not a constant.
He showed us another warship that was transformed into an exhibition building – a submarine-turned-museum. The interior of the submarine had a kitchen, bath, and “artwork” aka pinup girlie pictures. Hilarious!! This space has a very unstable climate – doesn’t even class in ASHRAE system.
Example: A museum building with thick concrete walls located in the open landscape from the 1930s. Truly off grid – not even a telephone line and all one level. Museum has only natural lighting – insulation – high ceiling for human health requirement. Natural ventilation sufficient for air quality, no temperature and RH control. In winter we need heat for humans – ground heat pump is the most energy efficient way to heat.
Example: Gallery for minerals display that has a ground heat pump for winter heating and underfloor heating. It uses 4-5 kilowatt hour for heat. Wind energy index can be used as an energy source – a lot of wind in winter and coexists well with heat pump that could be powered by wind energy if necessary. The gallery has a heavy structure to give thermal stability and thermal insulation to reduce heat loss. Small windows reduce solar heating but allow for natural lighting. No humidity control but passive humidification from the walls but not intended – buttresses are taking in the rain water. Efflorescence is occurring on the walls, but it is not as dry in winter so it actually helps.
Example: 17th century house in Liselund Park. This house is only open to public in the summer and not heated with interior impermeable surfaces and finishes. Dehumidified air is injected to each room through small ducts in the floor to keep RH down. It works quite well according to environmental data. However, the temperature is not steady. Dehumidifier keeps the RH to about 60% – but the dehumidifier is totally keeping it in check – if it fails you’re in trouble. Humidity-sensitive objects should be in microclimates because mechanical systems cannot be relied upon. Energy consumption for dehumidification is constant over the year – could use water turbine to power the dehumidification in summer, which would be a good off-grid solution. Mechanicals are unpredictable, but water freezes so what about winter?
Example: Runic stones in Jelling from 950-970 BC outside – no energy use at all (ha ha ha). Polychrome paintings that were on the stones are lost however – copies are displayed in museum nearby – photovoltaic panels integrated into skylights to give natural and artificial light – solar energy better in summer than winter, but condition stability problem during the seasons. Combine solar and wind energy then it will meet required energy needs for museum.
Read more at www.conservationphysics.org
Some of the questions/ comments:
Isn’t there a substantial cost to building thick walls? They anticipate that the buildings will last many years so that the cost of building will be gained back due to that.
One should note the practical limitations in USA with this type of off-grid environmental controls. Denmark is in Zone 5 maritime – mild climate; the USA varies from Zone 1 Humid to Zone 7 Dry maritime and humid – Zone 5 is very small geographically. One should design a museum to the specific location and its limitations in terms of environment.
New Technologies for Energy Storage Applied to Cultural
Heritage Buildings: The Microclimatic Monitoring of Santa Croce
Museum in Florence
Consiglio Nazionale delle Ricerche,
Istituto di Scienze dell’Atmosfera e del Clima CNR-ISAC
Francesca Becherini
I will admit that I had a difficult time following this talk, so I apologize in advance for the lack of information here. The main idea of this talk was to demonstrate a method of conserving heat (as energy) in Santa Croce, Florence by using a special kind of material in drywall. Storing and then release energy is the concept. I’m thankful I understood that!
Well… here goes nothing…
The folks at the Consiglio Nazionale want to develop, evaluate, and demonstrate an affordable multisource energy thermal and electronic storage system integrated in building based on new materials, technologies, and control system: http://www.messib.eu/
So they installed this system in two civil buildings: S Croce Museum was one of them. S Croce has heating system radiators, but no air conditioning. Illumination is halogen and metal halide lamps.
As I understood it, the materials that will hold the energy or heat are phase change materials (PCM) which has the capacity to stores much more heat per unit volume. It also has a desirable melting temperature in the desired temperature operation range, a high specific heat, small volume change with high thermal conductivity. This material (which I never actually got the name of – maybe they never said it because it’s proprietary?) is available as a paraffin or hydrated salts and used in heating panels and solar (as in sun) systems. There is not much information on the long-term durability of this material nor is it inexpensive. PCM embedded in gypsum plasterboards PCM distributed in 20 with respect to gypsum.
So measurements of this material were made with automatic and manual air, temperature, relative humidity, and surface temperature contact on the surface of the art (I think) as it hung on the wall where the PCM material was infused in the gypsum wall. They chose rooms based on how much art was displayed in the room. Main results are below (as best as I caught them):
Installed panels with monitors for air temperature, RH, temperature of panel, and contact panel of wood board to simulate canvas painting. They also monitored VOCs in museum and lab. Found aromatic chlorinated alcohol terpene compounds, aldehydes, and organic acids. PCM emits low VOCs, but it is strongly reduced when in gypsum panel. Can’t tell about aldehydes and organic acids – formic acid is from gypsum panel perhaps? Not PCM? There were lots of graphs about the PCM effects in the lab. Honestly the explanations aren’t totally clear – something about the melting point of PCM? Maybe?
Anyway, according to all of the testing and graphing, they need more information on the material’s thermal behavior, VOCs emissions, and interactions of VOCs and artifacts.