Good Morning:
If you are looking at conducting long-term environmental monitoring of
T/RH/light/UV and dewpoint, I recommend investigating full data logging
systems such as the HOBOs, Hanwells and ACRs. The Elsec is better used as a
spot check device.
As a conservator, I use the Elsec 764 made by Littlemore Scientific when I
am conducting spot checks of environmental conditions as part of a general
conservation assessment. I also have found it useful in a variety of other
situations. For instance, when I am working with a client on-site and there
are questions about immediate conditions: I can check discharge T/RH at air
supply vents that may be located close to collections materials to make the
case for relocating the object(s); to test UV filters for efficacy; in
training sessions to show staff that reducing light levels does not always
reduce visibility; and to check calibration of other equipment. I often work
with an engineer who is interested in looking at dewpoint in historic
structures as we are beginning to analyse the comportment of the building
with respect to climate management for collections; the Elsec can give us a
snapshot of this as well (note: we then use other types of instruments for
the full evaluation).
I purchased my Elsec 764 for about $1300 about 5 years ago with the data
logging function from Scientific Sales in New Jersey. I believe that Art
Conservation Services in NYC also sells them. There are probably other
vendors out there as well.
I believe that they are good instruments for spot checking environmental
conditions. However, they do require regular calibration - especially the
RH sensor. I regularly check the temperature readings against a mercury
thermometer and have purchased the Elsec calibration kit for the RH sensor.
When I get the chance I compare my UV and light readings against other
equipment, knowing full well that there is a margin of error with all of
this equipment and if we are within the margin of error for both pieces we
should be OK. (Another note: some may fault the lack of absolute precision,
but for the type of evaluation that I do, mostly working with collections
housed in historic or retrofitted structures, I believe that this is
acceptable.)
I will only use the Elsec to check the calibration of hygrothermographs and
hygrometers when I have recently calibrated the Elsec. The Elsec
calibration kit uses 2 soluble salts that will create known RH in the closed
chamber. This will calibrate to 2 points (high and low RH). I have
colleagues who recommend 3-point calibration for greater accuracy.
I have rarely used the data logging function of the Elsec because I have
found other types of equipment (HOBO Pro-8 loggers for T&RH, from Onset
Computer, for instance) easier to use. But in a pinch it has come in handy
when I haven't tossed in an extra logger before I go on-site.
There are other good hand-held instruments out there. I am not sure, but I
believe that the Elsec is the only one that can be used to spot check
T/RH/UV and light. Please weigh in, other conservators out there, if you
have additional information on other equipment.
Hope this provides the information you need. Please feel free to contact me
if you have any additional questions.
Wendy
Conservator
Wendy Jessup and Associates, Inc.
Care of Cultural Property
933 North Kenmore Street, Suite 323
Arlington, VA 22201
(703) 522-2801
Fax: (703) 522-2802
www.collectioncare.com
-----Original Message-----
From: Museum discussion list [mailto:[log in to unmask]] On Behalf
Of John Martinson
Sent: Thursday, May 18, 2006 4:38 PM
Subject: Environmental monitor and data logger, Type 764
Do any of you use the Littlemore Scientific Engineering ELSCEC monitor &
data logger?
They are made in the UK but are there a distributors or counter-parts
here in the States?
Do you have a general idea what they run/price? Are they a good
product for tracking
UV, visible light, % relative humidity, dew point and temperature?
Thanks in advance.
John
Boise, ID
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