Diana,
The concept of around 70 degrees F as ideal for collections preservation is
what most of us were taught. What we weren't taught was that this is
actually a compromise between human comfort and the needs of collections.
If human comfort is removed from the equation, preservation of most
materials/objects is better the colder the temperature. This is due to a
law of chemistry - that chemical reactions double in speed for roughly every
10 degree C (18 degree F) increase in temperature. Natural deterioration
processes (as opposed to human-inflicted) are chemical reactions. Thus,
deterioration decreases in half for roughly every 18 degrees F temperature
drop. Collections at 52 degrees will have 1/2 the deterioration of
collections at 70 degrees. At 34 degrees, they will have 1/4 the
deterioration of 70 degrees. (Stated the other way around, collections at
70 degrees will have 2 times the deterioration of collections at 52 degrees,
and 4 times the deterioration of collections at 34 degrees.) Of course,
lots of other factors also impact preservation, but isolated out, in
general, lower temperatures mean better preservation.
My concern with your stated situation is that you make no reference to RH
levels. If specific controls/systems for RH control are not implemented and
maintained, generally when the temperature is dropped using HVAC systems,
the RH rises (colder air holds less moisture, thus relative humidity is
higher unless a significant amount of moisture is removed - often, A/C alone
is not adequate). If your systems are keeping the temperature low and are
also keeping the RH below 60%, you should have better preservation at the
colder temperatures. If lowering the temperature is raising the RH above
60%, you may be facilitating mildew growth. If you can provide further
information on your RH levels, I may be able to refine my answer.
Marc
American Conservation Consortium, Ltd.
4 Rockville Road
Broad Brook, CT 06016
www.conservator.com
860-386-6058
*Collections Preservation Consultation
*Conservation Assessments & Surveys
*Low-Tech Environmental Control
*Moisture Management Solutions
*Collections in Historic Structures
*Conservation Treatment of:
Furniture
Painted Wood
Horse-Drawn Vehicles
Architectural Interiors
Marc A. Williams, President
MS in Art Conservation, Winterthur Museum Program
Former Chief Wooden Object Conservator, Smithsonian Institution
Fellow, American Institute for Conservation (AIC)
----- Original Message -----
From: "Diana Zlatanovski" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, November 16, 2006 11:04 AM
Subject: [MUSEUM-L] Textile storage conditions
Hello all
I manage a collection of textiles. The HVAC system in our storage areas is
programmed to
keep the temperature between 60 and 65 degrees. Often, it is on the low end
of that. I've
always been taught that between 68 and 72 degrees is, in general, the ideal
temperature for
collections storage. Can anyone tell me if the lower range is for any
reason more
appropriate for textiles? Or if it is detrimental to them?
Thanks,
Diana
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