David Harvey <[log in to unmask]> writes:
>I am interested, however, in how insititutions utilize their hygrothermograph
>charts.

We rely heavily on hyugrothermograph charts for recording temperature and
relative humidity, especially in our storage areas.  We have two storage
areas, each run by a separate (and different) HVAC unit.  By showing the
charts over several months, we were able to convince our engineers that one
of the units wasn't functioning properly.  We've been able to work with the
HVAC engineers to pinpoint what is malfunctioning, based on their readings
of the charts.  I check the charts every day to see if there are problems.
Some are simple enough that our own engineers can fix.  The chart paper is
changed every week.

We also have a few recording hygros in exhibit cases.  These are awkward
and time-consuming to change every week, but having that data is crucial
when we're working on updating or changing our exhibits.  We also use
smaller T/RH monitoring devices in most of our exhibit cases.  These don't
record, so someone has to go around, look at each case, and manually record
the T & RH.  Another time-consuming task.  We have individually controlled
exhibit cases, so it's crucial for us to know the conditions in each one.

I'd love to hear from others who are using dataloggers.  Dataloggers sound
simpler, but, I have to admit that I've been unable to decipher the
technical jargon to make an educated investment in them yet.  I had
conservators warn against using them, at least as an initial recording
device, because of the tendency to "forget" to download the data.  That,
and the fact that they only tell you what the conditions HAVE been, not
what they are, so that if you see a problem on the chart, it's too late,
it's already happened.

It really is key to use the data you get from hygros.  Even just having a
record of the conditions is incredibly helpful when planning exhibits and
working with conservators on the condition and treatment of artifacts.
Yes, the work involved is time-consuming and boring, but worth it.

Kate Desulis                            (312) 322-0821 phone
Adler Planetarium & Astronomy Museum    (312) 322-2257 fax
1300 S. Lake Shore Drive                [log in to unmask]
Chicago, IL 60605                       URL http://astro.uchicago.edu/adler/