Could I suggest applying Occam's Razor to these proposals for UV-filtres.
Arent there two variables to fail? the plastic film and the UV-absorbing
material contained within? Can one trust the Rohm & Haas specs for the
expected life of its vinyl products. Can anyone present a fifty-year-old
piece of plexiglas/perspex that looks like new?

 What about a design-driven solution such as a louvered blind or a
baffle-system such as the magnificent Kimbell Museum/Kahn-designed natural
lighting system? It can never fail as there is nothing to fail.

A design solution, to me, is preferable to the UV-absorbing this-and-thats...

What about a thin wash of titanium dioxide-containing paint applied to the
interior of the windows?

What about a replacable UV-absorbing blind (Say in Saran) fitted to the inside?

 A curtain? Fixed venetians that reflect the light upward? What about a
bedsheet?

Within the Historic Houses Trust of NSW, we have used a UV-absorbing film
on selected windows on occasion. In one instance it altered the colour of
the light to an unacceptable degree. The colour perception of the
collection was adversely affected. In another instance, the film remained
on but scratched/scuffed in cleaning to such an extent that we removed it.
That removal, in itself, is another story...

In my experience, the weathering ability of the weather-resistant
vinyl-based films and solid plastics is wildly over-rated. And imagine
trying to follow through on the warrenty in ten years. Or twenty.

Does this help?

Michael Bogle
Historic Houses Trust of NSW
Sydney Australia

We are preparing specifications for new insulated glass windows to be
>installed in the Henry Ford Museum building.  We are looking at a couple
>of options for UV filtering and light reduction glazing and are
>interested to know what experience/analysis/thoughts others might be
>able to share with us.
>
>We are currently looking at two options:
>*       A laminated glass composed of a plastic UV-filtering film
>sandwiched between two sheets of tinted glass.  The performance
>characteristics of this laminated glass are similiar to UF-4 plexi.
>*       UV filtering film applied to tinted glass after the windows are
>installed.
>
>Has anyone done any studies or had any experience with the performance,
>long term effectiveness, useful life etc. of either of these systems?
>In the literature I've reviewed, there doesn't seem to be any concensus
>on the lifespan of the UV films; have I missed something?  I've never
>seen anything written on the laminated glass systems, though logic would
>suggest they would last longer than the applied films.
>
>The laminated glass has a single supplier and we are expecting to have
>to pay a premium for it.  We are wondering what kind of fallback the
>applied film represents if we have to start reducing costs.
>
>Any good ideas outside of these two options are also welcome.
>
>Thanks in advance.
>
>Jim McCabe
>Manager, Collections Care
>Henry Ford Museum & Greenfield Village
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>313-982-6078

Mike Bogle & Peta Landman & Ariel Bogle
429 Riley Street
Surry Hills, Sydney
Australia 2010
(61) (2) 9212 7069