Some years ago in our San Francisco museum, the flourescent lights were
installed with some sleeves said to reduce UV. I don't know what brand
they were, but they quickly cracked and crumbled right off of the lamps.
No good. Instead of replacing them, we laid sheets of UV filtering Mylar
over the "eggcrate" louvers that were beneath the light fixtures. The
material is 5 mil Mylar laminated with the UV filtering material the
photo labs put on prints. We cut pieces of it to protect individual
documents on display (in addition to the UV filtering plexiglass case
covers.
The Heard Museum in Phoenix has their lights in boxes above the
exhibits. The light goes through transluscent UV filtering panels.
Essentially, sleeving tubes does not seem to be the answer. Design the
exhibit cases and display areas to have a separation between light
fixtures and the exhibits and visitors.