Hello Tim, When I worked at UCSF, we had five -80C sub zero freezers stored in a cool room AND on those occasions, when a freezer did malfunction, our "safe" temperature was -50C - mostly because ALL our frozen specimens were brain.
We had a protocol in place for checking each freezer (weekly) for ice blockage/build-up on the door & around the front inside, so as not to create problems w/the freezers...later. However, when a freezer malfunction did occur it was mostly because of the compressor unit (some freezers have 2 compressors.) When a compressor (or any other part) on a particular freezer was replaced, this information was always recorded. In any case, we never opened the door, except to quickly place 1 (5-lb) block of dry ice per shelf, to keep the low temperature in the freezer constant (overnight) until an outside repair technician could come & make repairs the next day. **We always kept a large supply of dry ice. During my 7 years at UCSF, there was only 1 time, we had to transfer all tissue racks into another -80C freezer. We were very lucky, because we had just purchased a new freezer & the freezer was turned ON the night before. Tim, I hope this helps. Let me know if you require any further help. Maria Mejia Affymetrix, Inc. On Mar 29, 2013, at 8:16 AM, Morken, Timothy wrote: > Hi all, For a minus 80 freezer what would you consider a "safe" time period > that it can go without power before the temperature gets too high and > contents need to be transferred (assuming door stays closed)? I'm thinking > -40 would be a cutoff temp to move samples. Anyone else think differently > about that? > > Thanks for any info! > > > Tim Morken > Supervisor, Electron Microscopy/Neuromuscular Special Studies > Department of Pathology > UC San Francisco Medical Center > 505 Parnassus Ave, Box 1656 > Room S570 > San Francisco, CA 94143 > > (415) 353-1266 (ph) > (415) 514-3403 (fax) > tim.mor...@ucsfmedctr.org<mailto:tim.mor...@ucsfmedctr.org> > > _______________________________________________ > Histonet mailing list > Histonet@lists.utsouthwestern.edu > http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet
