This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. ----------------------------------------------------------- Dana - Yes, extending the length of time helps a great deal. Thermal control (as per Tom Strang, Mary Lou Florian and others) has proved to be very successful. Most of my personal experience is with natural history collections - not with archives. These are not nearly as dense as archives. It will take time to get the internal temperature of the boxes down to critical temperatures. Even with the collections that I have dealt with we often use the rule of thumb of 2 weeks in the freezer - just in case (It is difficult to monitor the interior of many objects and specimens to verify the temperature). And we freeze once then monitor - less stress on our specimens than the double freeze method. We always double bag the specimens. This significantly reduces moisture loss. The initial shock to the artifact is the freezing process. The faster the freeze the better. But once the object is frozen it can stay there for what ever length of time you want. The next shock is when you remove it from the freezer.
At my former museum we processed our entire study skin and osteological collection in this manner to mitigate a known dermestid and moth infestation prior moving it to a new storage facility. That was 12 years ago. The storage area is still pest free - nothing survived with no damage to the specimens. It took time because we were using a walk in freezer and could only do so much at a time. You can also reduce the temperature more - we generally aim for -20 deg. C., but colder is ok. (my entomologist uses much colder for a shorter period of time due to the situation in the lab. He has tested this extensively and it works. Remember pinned bugs are not at all densely packed - they freeze immediately with in minutes). As Tom mentions, different species have different tolerances to cold - but the method works! I refer you to Tom Strangs work at CCI. He has also published critical temperatures for specific pest species. Good Luck! gretchen ________________________________________ From: ad...@museumpests.net [ad...@museumpests.net] on behalf of dana senge [dkse...@gmail.com] Sent: Sunday, March 11, 2012 12:26 AM To: pestlist@museumpests.net Subject: Re: [pestlist] Freezer Trucks This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. ----------------------------------------------------------- Thanks Gretchen- I am glad to read that you feel the method works- have you found extending the freezing period is what makes this successful? Dana On Sat, Mar 10, 2012 at 8:20 PM, Anderson, Gretchen <anders...@carnegiemnh.org> wrote: > This is a message from the Museumpests List. > To post to this list send it as an email to pestlist@museumpests.net > To unsubscribe please look at the footer of this email. > ----------------------------------------------------------- > Dana - > > In addition you need to realize that boxes of archives are very dense - and > that paper is very good insulator. In fact, shredded paper is used to > insulate houses in northern climates. Given that, it is not surprising that > it took time to reach the the desired temperature. Be patient - the method > works. > > Gretchen Anderson > Conservator > Carnegie Museum of Natural History > ________________________________ > From: ad...@museumpests.net [ad...@museumpests.net] on behalf of > bugma...@aol.com [bugma...@aol.com] > Sent: Saturday, March 10, 2012 8:58 PM > To: pestlist@museumpests.net > Subject: Re: [pestlist] Freezer Trucks > > This is a message from the Museumpests List. > To post to this list send it as an email to pestlist@museumpests.net > To unsubscribe please look at the footer of this email. > ----------------------------------------------------------- > Dana - > > First of all, the temperature does not have to reach -20F in 4 hours. It > should reach 32F in 4 hours. That's sufficient. The reason you use a truck > capable of maintaining -20F, is it will reach the desired 32F in 4 hours. > Once the liquid in adults, larvae, and eggs reaches a freezing temperature, > ice particles form and destroy the cellular structure of the living > organisms. Unless you're dealing with "book worms", which I doubt you are > with archival records, any insects found in these materials will certainly > be killed. When freezing anything, you're trying to beat insects from > forming natural defenses to freezing. I think your process worked fine. > Have you found any live insects? > > I have had plenty of sucessful freezing episodes with freezer trucks, > containers, and warehouses. > > Tom Parker > > > -----Original Message----- > From: dana senge <dkse...@gmail.com> > To: pestlist <pestlist@museumpests.net> > Sent: Sat, Mar 10, 2012 8:41 pm > Subject: [pestlist] Freezer Trucks > > This is a message from the Museumpests List. > To post to this list send it as an email to pestlist@museumpests.net > To unsubscribe please look at the footer of this email. > ----------------------------------------------------------- > We recently tried using a freezer truck to process a large number of > boxes of archives. Record boxes were stacked in rows with 12" gaps > between the rows to allow for air circulation. We placed a datalogger > in the center of one of the boxes of archive materials (in the center > of the truck) and another outside the boxes to measure the temperature > of the air in the truck box. The results were surprising. > > We had been informed that the truck would go down to -20 degrees F in > 4 hours. Our data loggers showed that it took 10 hours for the air in > the truck to go from 44 degrees F to -15 degrees F, and the > temperature inside one of the record boxes took ~96 hours to drop from > 70 degrees to -15 degrees. (The boxes had been in a 72 degree > environment before being placed in the truck box). It appears that > the starting temperature of the boxes of paper was more difficult to > reduce than I expected. And the truck never achieved the desired > temperature. > > We are very disappointed in these initial results and are trying to > figure out if there is a different strategy for using a freezer > truck, or if this is just not feasible for freezing densely packed > materials, such as paper packed in a record box. We are discussing > packing boxes half full and packing the truck to allow for even more > air circulation. But it seems that getting to the goal of -20 degrees > F in 4 hours may not be feasible. > > Does anyone have any positive experiences working with a freezer truck > for processing a large quantity of materials? Especially dense > materials such as wood or boxes of paper? > > > Thanks, > > Dana Senge > Assistant Conservator > National Park Service > Intermountain Region Museum Services Program > Tucson, AZ 85745 > 520-791-6432 > dana_se...@nps.gov > > > ---------------------------------------------------------------------- > To send an email to the list, send your msg to pestlist@museumpests.Net > > To unsubscribe from this list send an email to pestlist@museumpests.net and > in > the subject put: > "unsubscribe" - no quotes please. > > You are receiving the Pestlist emails in standard mode. > To change to the DIGEST mode send an > email to imail...@museumpests.net with this command in the body: > > set mode digest pestlist > > Any problems email l...@collectionpests.com or l...@zaks.com > > > ---------------------------------------------------------------------- > To send an email to the list, send your msg to pestlist@museumpests.Net > > To unsubscribe from this list send an email to pestlist@museumpests.net and > in the subject put: > "unsubscribe" - no quotes please. > > You are receiving the Pestlist emails in standard mode. > To change to the DIGEST mode send an > email to imail...@museumpests.net with this command in the body: > > set mode digest pestlist > > Any problems email l...@collectionpests.com or l...@zaks.com > > The information contained in this message and/or attachments is intended > only for the person or entity to which it is addressed and may contain > confidential and/or privileged material. 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