Oxygen Free Display in Museum Showcases
Anoxic conditions are occasionally used in museum display. In theory – the advantages are extremely attractive: one can create an environment where pollution, humidity, and oxygen levels are all controlled, and the artefacts enclosed will be free from the dangers of corrosion, biological attack and most other forms of degradation. In fact – a truly oxygen-free environment is devilishly difficult to achieve and maintain.
What is meant by “oxygen-free”?
The first challenge for creating anoxic conditions is determining your limits. Some artefacts may benefit from slightly lower oxygen levels, say down to less than 1% (one part per hundred) oxygen. However, practically, the acceptable limit for museum storage and display is 0.3% (three parts per thousand), as this is the limit above which there is enough oxygen still available to maintain many common organic chemical reactions. This level is higher than the amount of oxygen needed for corrosion on metals, while slightly lower than the levels usually created to destroy insect pests (0.5%). It is important to note that as the oxygen concentration in a container is reduced, the tendency for oxygen outside the container to enter (sometimes referred to as “vapor pressure”) is substantially increased. This means, the lower your oxygen content, the greater your expected leakage rate.
What are the components of an oxygen-free showcase?
An anoxic display always consists of an extraordinarily well-sealed enclosure, and a means of creating and maintaining an atmosphere which is oxygen-free, pollution-free, and humidity controlled. Both active and passive systems have been used and proven effective, and each has its advantages and challenges.
Click here for more information on Passive Anoxic Display
Click here for more information on Active Anoxic Display
Keepsafe Microclimate Systems can provide all necessary equipment for creating oxygen-free display or storage, including nitrogen generators and humidity controllers.