The background to the environmental levels that are the subject of the committees deliberations goes back to a defining moment shortly after the Second World War. The value of a stable environment for the long-term preservation of artworks and objects was increasingly being acknowledged at the time, it was the experience of London's National Gallery that directly showed the importance of appropriate temperature and relative humidity levels.
The Gallery's collection had been stored in a mine in North Wales out of the way of the Blitz, and after seven years upon its return to London was found to be in the same condition as when placed there.
The mine conditions were assessed and from there the so-called 20/50 norm (20 degrees celsius and 50% relative humidity) was enshrined as the ideal display and storage environment. Over the years since, as building climate control systems have become more sophisticated, so has the demand for variations from this norm to be minimised. The tighter the parameters for the museum environment to fluctuate in, the more energy is consumed, and in days of plentiful cheap energy this was acceptable.
However as energy costs have dramatically increased, the need for tight parameters is being increasingly questioned, as indeed is whether the norm does actually provide the best preservation environment for all types of objects.
Scope of project
The Environmental Standards Committee (previously known as the Environmental Controls Taskforce) was established at the 2009 National Conference to look at international movements in changing environmental guidelines for cultural collections, and what this might mean for collections in Australia.
An interim position
In the March, 2014 AICCM announced that an interim position on environmental conditions for collections had been reached. A summary of the findings are as follows:
The AICCM recommended Interim Temperature and Relative Humidity Guidelines for acceptable storage and display conditions of general collection material are:
• Temperature: between 15–25°C with allowable fluctuations of +/-4°C per 24 hr.
• Relative Humidity: between 45-55% with an allowable fluctuation of +/- 5% per 24 hr.
Where storage and display environments experience seasonal drift, RH change to be managed gradually across a wider range limited to 40% – 60%.
Temperature and Relative Humidity parameters for preservation of cultural materials will differ according to their material, construction and condition, but stable conditions maintained within the parameters above are generally acceptable for most objects.
The full article can be read here, or alternatively you can find it in the March edition of the National Newsletter.
At the IIC congress in Hong Kong and the ICOM-CC conference in Melbourne in September 2014, delegates discussed and agreed on a new position for Environmental Guidelines. You can find details on the IIC website.