Pat et al.,
 
I got some additional information on UV Plexi from our house curator.
 
The plexiglas is 1/8" UF3 or OP2 plexi.  The manufacturer doesn't matter as
much as the rating.  We also use flexible plexiglas coverings for the one
flourescent fixture in the house.  The curator chose the flexible plexi because
it can be easily cut to size and slipped over bulbs without taking them out,
and can be easily switched when the bulbs are changed.  They were also
installed in the fixtures in our registrar's office, where they were apparently
double layed because of the excessive number of lights.  The UV meter is a
Crawford meter, and costs $1,200.  We bought ours from Art Preservation
Services in New York City (539 E. 81st St, NYC, NY 10028, fax 212-794-3045).
 
Leslie Johnston
Historic New Orleans Collection
[log in to unmask]