UV filtering materials

Barry Knight <barry.knight [at] bl__uk> writes

>Joachim Huber <joachim.huber [at] prevart__ch> writes
>
>>... Many museums use their UV protection films on windows
>>for more than 10 or even 20 years believing that there is still full
>>optimum uv protection. Has somebody actually measured UV levels of
>>"old" UV protection films after 10 or more years of use? ...
>...
>In my experience, UV window films will normally last 7 to 10 years
>before they need to be replaced. ...

At Staatsburgh (Mills Mansion) State Historic Site, we checked the
effectiveness of applied UV films about 12 years after installation.
Most of the films were still fine, but the films on the very exposed
west facade (the site is on a hill, with a large open lawn to the
west), the films had degraded and were no longer providing
sufficient uv protection.  To me that made sense, that the film
degraded not based on time, but on extent of exposure.  So I second
Barry Knight's recommendation to check the film with a meter. Based
on discussions on this list, we did not replace with film, but with
UV-filtering and light reducing shades.

Deborah Lee Trupin
Textile Conservator
New York State Office of Parks, Recreation and Historic  Preservation
Bureau of Historic Sites
Peebles Island
PO Box 219
Waterford NY 12188 USA
518-237-8643 ext. 3241

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                  Conservation DistList Instance 19:10
                Distributed: Wednesday, August 17, 2005
                       Message Id: cdl-19-10-004
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