I don't know what an average lifespan might be; I would think it depends upon the wattage of the tube it is filtering. My understanding as to why the filters expire is that they become saturated, i.e., the filters absorb the UV rays and they can only hold so much. Catherine Bruck University Archivist Illinois Institute of Technology Paul V. Galvin Library 35 W. 33rd St. Chicago, IL 60616 312/567-6840 FAX 312/567-5318 [log in to unmask] -----Original Message----- From: Archives & Archivists [mailto:[log in to unmask]]On Behalf Of Heidi Dressler Sent: Wednesday, December 12, 2001 4:57 PM To: [log in to unmask] Subject: UV light filters Hello, Can anyone tell me what the average lifespan of a UV filter sleeve for a fluorescent light bulb is? (And for bonus points, why they expire, if they do.) Thank you, Heidi Dressler Local History Librarian Wichita Public Library A posting from the Archives & Archivists LISTSERV List! To subscribe or unsubscribe, send e-mail to [log in to unmask] In body of message: SUB ARCHIVES firstname lastname *or*: UNSUB ARCHIVES To post a message, send e-mail to [log in to unmask] Or to do *anything* (and enjoy doing it!), use the web interface at http://listserv.muohio.edu/archives/archives.html Problems? Send e-mail to Robert F Schmidt <[log in to unmask]> A posting from the Archives & Archivists LISTSERV List! To subscribe or unsubscribe, send e-mail to [log in to unmask] In body of message: SUB ARCHIVES firstname lastname *or*: UNSUB ARCHIVES To post a message, send e-mail to [log in to unmask] Or to do *anything* (and enjoy doing it!), use the web interface at http://listserv.muohio.edu/archives/archives.html Problems? Send e-mail to Robert F Schmidt <[log in to unmask]>