Window glazing specifications

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

Dear Jim:

Since I manage The International Cultural Property Protection Exposition held in conjunction with The National Conference On Cultural Property Protection each year, I have always been trying to obtain exhibitors who manufacture the Glass Film because it can serve a dual purpose - security and UV light protection. This year I had a exhibitor who does make a window film which does both - if you will contact me off the list, I will provide you with that source and perhaps a couple of others.

Kind Regards

Roger Wulff

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Jim,

Are you working with an architect knowledgable about glass and window specifications and your building? He/she should be able to help you with this problem. Tinted glass can be very unfriendly looking, and if your building is historic, it may also look odd, especially if new window frames and mullions are also very different in proportion to the originals. An alternative I often specify when we want the benefits without the discoloration is clear glass (or very lightly tinted) insulating units with a low-E (emissivity) coating on the inside. Viracon makes this product and it is relatively expensive glass. The shelf life of the applied films may depend on the exposure of the window, your interior conditions such as the extent of condensation on the glass, and on whether people can reach it and help peel it off when it inevitably starts to come loose.

We once specified some extra thick and expensive plexiglas for an ornamental item at a museum and the manufacturer turned out to be a museum supporter and I believe donated it. You might investigate that route...

Ann Trowbridge, AIA