[Nhcoll-l] 3M window film turning hazy

[Kristian Murphy Gregersen]

Dear colleagues

We've encountered a small problem at a local museum concerning their UV window film.
Between 2011-2014 the museum had installed UV film (3M(tm) Sun Control Window film Prestige 70 Exterior) on 33 of it's windows as a means to limit the amount of UV and heat in its exhibition rooms. The windows are all secondary glazed, and the film was mounted on the outer surface of the secondary glazing.
To start with the films were clear and performed as promised by the company. As the years went by, the film started to turn opaque, hazy, and a bluish grey powder appeared on its surface.
This has happened to all of the windows mounted with the UV film, no matter if they're facing North, South, East or West. Even the windows facing other buildings have this problem, so sunlight might not be the issue. That said, areas of the windows that never get any direct or indirect light from the outside do not appear to have been affected.

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We are wondering if anyone else has had the same experience with UV window film, and/or if anyone has any ideas as to why this is happening?

All the best,

Kristian

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Kristian Murphy Gregersen
Teaching associate professor
Head of Natural History Programme
Institute of Conservation

M:  +45 41701764
E:  kgre at kglakademi.dk<mailto:kgre at kglakademi.dk>
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Royal Danish Academy -
Architecture, Design, Conservation
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