We recently purchased a commercial grade freezer to utilize as cold storage for nitrate negatives within our collections. Prior to placing any archival materials in the freezer I ran an environmental test using data loggers. The results of this test show that the freezer runs a defrost cycle every 6 hours. As you would expect, during a defrost cycle both the temperature and relative humidity increase significantly. The max temperature was recorded as 19.73 degrees Fahrenheit, and the max RH was recorded as 92.33%. Average running temperature of the freezer was recorded as 1.44 degrees Fahrenheit and average RH was 75.54%.
My two major concerns are the high RH readings, and the amount flux (in both Temp and RH) in such a short period of time. I'm seeing over a 20 degree flux in temperature within less than 24 hours. Information quoted below is from the CoOL website and seems to indicate that as long as such low temperatures are maintained, RH is less of a concern. Thoughts? "Relatively inexpensive cold storage is available through the acquisition of a large commercial freezer. The freezer should defrost automatically (a cycle of three times a day is acceptable). Recent research indicates that precise control of relative humidity is, on balance, not of primary concern at such low temperatures (McCormick-Goodhart, 1993). Therefore, humidity controls within the freezer, if considered cost-prohibitive, can be omitted." Has anyone out there used a commercial grade freezer for nitrate negative storage before and if so how did you address these concerns? Thank you in advance for any and all input! Amy Minger, Archival Assistant for Conservation Arkansas State Archives an agency of the Department of Arkansas Heritage email: amy.min...@arkansas.gov<mailto:amy.min...@arkansas.gov> office: 501.682.6905 ****** Unsubscribe by sending a message to consdistlist-le...@cool.conservation-us.org Archives through August 2016 at http://cool.conservation-us.org/byform/mailing-lists/cdl/ Archives from September 2016 onward at https://www.mail-archive.com/consdistlist@cool.conservation-us.org/
