Agent of Deterioration #2: Incorrect Temperature

As a summer conservation series, we will be talking about the Agents of Deterioration as defined by the Canadian Conservation Institute (CCI) in Ottawa.  If you want to learn more about CCI see their website or our April 29th blog post.

This week we are talking about our second agent of deterioration, Incorrect Temperature. We all talk about temperature everyday; what the predictions are for the day and what we wish it were going to be.  Through discussions like this we express our happiness or disdain for what is going on; talking about what makes temperature incorrect (or correct) for us individually. If your museum objects were asked this question, what would they say? What temperatures allow them to be preserved the longest?

Just like in our discussion of Incorrect Relative Humidity, CCI has outlined 3 situations of Incorrect Temperature:

1.     Temperature too high

2.     Temperature too low

3.     Temperature fluctuations

Lets break down these categories a bit more to understand them.

1.  Temperature too high

This one is simple. When the temperature in your collection areas is too high, it can melt or disfigure artifacts. Not only may that happen but also high temperatures increase the rate at which your artifacts deteriorate chemically. Make sure to pay special attention to cellulose nitrate film and sheets as they become flammable above 38°C!

2.  Temperature too low

Having your collections in too low temperatures can also cause physical damage.  Artifacts most at risk are pieces of art. Though CCI does state that Conservators use freezing (up to -40°C!) as a non-toxic way of eliminating pests on objects.  The pests are a greater risk than the freezing itself.

3.  Temperature fluctuations

In this category, it is referring to the process from going high to low or low to high temperatures.  It is thought that these changes cause rapid expansion and contractions, creating damage.  This can be especially true when the attached materials expand and contract at different rates.  There appears to be a debate on how much daily fluctuations an object can take.  One practical thing to take out of it is that if an object has already experienced one of these extreme changes, don’t worry about it too much.  The object has already been “proofed”; meaning that it has shown what will happen to it within certain environmental boundaries and situations.  Just note what these boundaries are and avoid going past them.  

What affects Temperature?

There are several sources that might change the temperature in your museum.

·      Sunlight

·      Outdoor Climate

·      Electric Lighting

·      Climate Control (like heating systems)

If you are experiencing incorrect temperature issues, see if any of these sources are uncontrolled or mismanaged in your space.  Perhaps it is time to make some changes.  

What is the ideal temperature? The ideal temperature is more of an ideal temperature range: 18-21°C. However, lower (but above freezing) and stable is also acceptable.

How do we fix an Incorrect Temperature?

Knowing what is going on in the environment is the first step.  Using the Environmental Monitoring Equipment Loan program here at MAS is a great way to help you identify temperature (as well as relative humidity) issues. We will send out equipment to your site for you to use.  When you are done you would send us the equipment back for us to download the information as well as identify what is going on at your site; below is a sample of what a dataset from your museum might look like. We will take a look at it and provide some suggestions as to what is going on and what you can do about it.

A small example of what measurements could yield

To correct for the Incorrect Temperature, perhaps you need to make sure that you are blocking out sources of extreme heat (such as sunlight or improper artifical lighting) or controlling the artifical environment properly (like the heater in winter).  

Incorrect Temperature has many aspects that isn’t covered here. If you have any specific questions or situations that you want to discuss, please contact me at the MAS office: 306-780-9266.

Resources:

This blog post was a summary of the CCI page concerning the Agent of Deterioration Incorrect Temperature.  The original page can be seen here.