[NHCOLL-L:3666] Re: Deep Freezing a Museum's Exhibit Hall

[Victoria Book]

Hello,

I like the thought--take a bad circumstance (no heat or constant temp) 
and make it work for you (pest control).  Unfortunately, I'm not 
optimistic about it.

Firstly, the temperature will need to be around 0 degrees F ( -15 to 
-20 C) for several consecutive days to kill the pests.  Around 
freezing, they will basically hibernate.  It may or may not kill adults 
and larvae, but eggs will certainly survive and become active when it 
heats up again.  Also, I learned a few things during this recent 
Oklahoma ice storm and the subsequent power outages (many homes are 
still without power).  The concrete pallet and other building materials 
act as heat sinks and retain heat for several days.  Even in small 
homes with no heat for three days in 28-35 degree F weather, the 
ambient temperature in the houses was in the 50s F.  Two weeks in a 
Vermont historic house will certainly be much more brutal, but I don't 
know if you will actually get much low-enough freezing temperatures 
inside for several consecutive days.

Secondly, the freeze-thaw cycle will not be good.  The additional 
"envelopes" to buffer the collections is a good idea.  You can use bags 
(double and triple bagging is even better), packing blankets around 
closed cases, foam or plastic wrapping layered loosely but completely 
around the larger mounts, and putting smaller specimens in cases or 
storage boxes will buffer them a little from the temperature.  The 
objects will still experience the temperature and RH change, but in a 
gentler way.  It may also prevent condensation directly on the objects. 
  (Which reminds me...what about your relative humidity?  Can you adjust 
that at all?  You will want to keep the RH as stable as possible if you 
can, but you may be very dry in winter as it is.)

Good luck!  This is something that no museum wants to experience, and 
my fingers are crossed for you.  Please let us know what you end up 
doing and how you fair.
Victoria

P.S. I also would be interested to hear what others think, especially 
if anyone has experienced similar challenges.  Please write in!

Victoria Book
Conservator
Sam Noble Oklahoma Museum of Natural History
University of Oklahoma
2401 Chautauqua Avenue
Norman, Oklahoma   73072-7029
phone 405.325.5163
fax 405.325.7699
www.snomnh.ou.edu

On Dec 12, 2007, at 2:17 PM, Mary Beth Prondzinski wrote:

> Greetings:
>  
> My Vermont Victorian museum will need to replace its furnace in 
> January, a procedure requiring the heat be shut off for two weeks.  
> Where there is no guarantee the ambient temperature will be/remain 
> below freezing the entire two weeks, we thought that the extended cold 
> might help kill off any pest activity that has been previously 
> encountered.  Most of the specimens are in glass and wood cases, but 
> some of the larger taxidermy mounts are open to the elements.  The 
> main exhibit hall has a barrel-vaulted ceiling with the 
> historical/anthropological/ethnographic artifacts exhibited on the 
> upper level balcony, again encased in glass and wood. 
>  
> Would such an uncontrolled freeze be damaging to the 
> artifacts/specimens as long as they remained closed in their cases?  
> Would it be advisable to "bag" the taxidermy mounts to contain them 
> during the two-week freeze and subsequent thaw?  Or would it be 
> advisable to keep the ambient temperature as consistent as possible 
> (i.e. above freezing) during the two weeks without central heat and 
> use space heaters throughout the museum?  For the record:  the current 
> ambient temperature of the museum is cold, regardless of the furnace, 
> because the building is very old and constructed of stone.
>  
> Has anyone ever experienced this in a museum setting???   Any ideas or 
> suggestions would be greatly appreciated...
>  
> Thanks!
>  
> Mary Beth Prondzinski
> Director of Collections
> Fairbanks Museum & Planetarium
> 1302 Main Street
> St. Johnsbury, VT 05819
> (802) 748-2372 x110
> mprondzinski at fairbanksmuseum.org
>  
> http://fairbanksmuseum.org/
> http://vermonttv.net/
>  
>  

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