| Monitoring Indoor Corrosion Activity: In
an article, with the apt title "Monitoring and beating the enemy within:
Indoor-generated pollutants", Grzywacz and Alten (see reference and link below) have
described monitoring strategies from a collection care and preservation perspective.
Compared with external atmospheric corrosion monitoring, the techniques required for
monitoring such indoor effects generally need to be particularly sensitive.
Probably the oldest reference to indoor air pollution was in Book XIX of Homer's
epic "The Odyssey", written around 8-12 centuries B.C., where surface damage to
armor is described (Source: http://www.iaq.dk/papers/homer.htm
). Considerable uncertainty exists on the time of Homer's works and his life in general.
The potential sources of corrosive indoor species
highlighted by Grzywacz and Alten [1] include:
- tobacco smoke
- photocopying activities
- wood products (it was stated that aged oak can release acetic acid for 800 years !)
- fabric treatments (dyeing, fire retarding, etc.)
- pesticides and other chemical treatments
- cleaning products
- air conditioning and refrigerant coolants
- adhesives, sealants, coatings, polishes etc.
- human activities such as cooking, eating, drinking, processing, manufacturing and
analysis of materials.
Warning signs (visual monitoring) described by the authors [1] include:
- blackening of silver
- "white powder" on lead
- "white, fluffy crystals" forming on sea shells, limestone and ceramic items
- staining on paper and textiles and discoloration in general
- formation of corrosion products, despite humidity control
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Indoor corrosion/degradation monitoring techniques
include:
- careful visual inspection, especially in areas vulnerable to (preferential) corrosion
damage such as edges, crevices, dissimilar metal interfaces, joints, seams, areas of
moisture accumulation/wicking etc.
- coupon corrosion sensors in the form of polished metal strips, with the option of
subsequent laboratory surface analysis techniques
- corrosion sensors based on the quartz crystal microbalance
- chemical sampling (for example acid indicator detection strips)
After a corrosion problem has been identified and the "baseline" problem
conditions characterized by monitoring, the ongoing monitoring of corrosion can be helpful
to confirm that corrective action has indeed solved the problem. Furthermore, early
warning of future problems can be provided from highly sensitive monitoring techniques.
Corrosion monitoring may be useful, as it is difficult to anticipate the influence of
numerous variables that could lead to corrosion problems, such as humidity, temperature,
light, historical exposure to corrosive environments (surface contamination), historical
surface/preservation treatments, materials of construction and their historical
processing, etc. |
References/Literature:
C. Grzywacz and H. Alten: "Monitoring and beating the enemy within:
Indoor-generated pollutants", 2002, published at the web site of Northern States
Conservation Center, www.collectioncare.org.
Links:
Monitoring and Restoring World's "Perfect Man"
Northern States Conservation Center, www.collectioncare.org (perform a search on the
term "corrosion" to access relevant articles)
IAQ (indoor air quality) in museums and archives, www.iaq.dk (hosted by the National Museum of Denmark, with
articles, photos and more ...)
Conservation Online, http://palimpsest.stanford.edu/
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