Where I have placed a hygrothermograph is in a room where I have a large
fan and a dehumidifier...so I do suspect the measurement would be higher
(probably close to 100%). The HVAC system was installed 5 years ago -heat only.
Vents are only in our larger room...which is @ 30'x250'. The other room is
30'x60' and there is a large doorway between Perhaps I should turn it on just to
get some air circulation? Don't know if the budget can handle the use of
xtra propane, but if it's only for these wettest days...shouldn't be a
burden. Vents are only in our larger room...which is @ 30'x250'. The other
room is 30'x60' and there is a large doorway between these rooms.
Like Dave mentioned - it would be a good idea for me to cover the doorway
and this should help with the one room. Incidentally - none of the windows open
. I have a ventilation fan
at the end of the larger room - and I can open the door (which I keep closed to
try to stave off the humidity for as long as possible). I do open the door when
the weather is nice -but only to dry out. No screen door (I did request one last
Fall) so when I do this -barn swallows have flown in and all the flying insects.
How they find
. I have a ventilation fan
at the end of the larger room - and I can open the door (which I keep closed to
try to stave off the humidity for as long as possible). I do open the door when
the weather is nice -but only to dry out. No screen door (I did request one last
Fall) so when I do this -barn swallows have flown in and all the flying insects.
How they find Pretty much, I've found that during the summer indoor conditions are worse
than that present outdoors - for the most obvious reasons here. I do not use a
dehumidifier in the larger room because there are enough spaces open to the
outside and otherwise with no insulation I'd just be drawing moisture in.
The industrial fan that I just got for the smaller room - well what I
really needed was an exhaust fan installed but we weren't able to do this. I can
move air around but I really can't achieve good ventilation.
Just an example of the many challenges here - there are several
footlockers...all containing wool uniforms and cotton clothing. I've struggled
with deciding whether or not to place these in textile storage boxes.
With the humid conditions...the footlockers stay drier than boxes would. And I
would need to have all the items properly cleaned/conserved before doing this
anyway. I can't take objects from an unstable environment and place them in yet
another.
One solution I did find though is that I could hang these in the dry
storage closet. I did buy padding for hangers and archival plastic covers.
As always, whenever I post these issues I get useful information and often
these responses get the wheels turning in my head.
Oh one last question - just by chance there were no visitors to the museum
today. If it's much the same dampness tomorrow or on others days...should I
consider not having the museum open?
Thanks,
Pam
In a message dated 6/29/2006 9:18:20 P.M. Eastern Daylight Time,
[log in to unmask] writes:
Your humidity is higher than 70-75%, based on how you describe the feel
of things. Items in the room probably are getting cool at night, and
then, the even more humid night air (cooler air holds less water)
condenses as water on the cooler surfaces. This liquid water creates
even higher humidity as it evaporates back into the air, as water vapor,
as the dew point increases. Your air may have been as measured, 70-75%
RH, at some point midday, but if you feel wetness at that humidity, this
is telling you a different story.
You can live with 70-75% RH for a good long time.
Fabrics that feel damp in 70-75% air, are far wetter than fabric at
equilibrium with that moisture content should feel. They are probably
wetter, and are evaporating off that "gained" moisture as the "dew
point" of their local room air allows. Use a recording hygrothermograph
if you can find one, you can even use old charts if you can use a
different color of ink; the digital version would be ideal. These will
tell you the real story at night, in the morning and midday.
The most unstable materials are those that have already had contact with
mold in the past. [Big help, right?] Spores are dormant for a long
time waiting for the right pH, RH and lack-of-air-movement conditions.
Any of the materials you mentioned could be the first to go, based on
the degree of mold present in/on them. Closed books are slow to follow
moisture changes, even on the way back down again.
The solution is to put "devices" in "the room" that will condense water
from the air before it can condense on cool surfaces. When water
condenses on a surface, it is depositing moisture in the room more
permanently, rather than just being in the air, which can be transient.
These "devices" are dehumidifiers or window air conditioners. Install
as many as you an manage, with the windows closed. OK, if you're in the
area of the floods then you have problems. The next less effective
solution is to keep the air moving, with the windows open. If you are
getting condensation, then keep the air "moving" all night as well.
This means you will need active guards watching everything.
No good answers, sorry. You have a difficult situation, at a difficult
time. Its best to be vigilant, you'll smell mold before you can see it.
Tim Vitale
Paper, Photographs &
Electronic Media Conservator
Film Migration to Digital Format
Digital Imaging & Facsimiles
Preservation & Imaging Consulting
Preservation Associates
1500 Park Avenue
Suite 132
Emeryville, CA 94608
510-594-8277
510-594-8799 fax