Did you consider closing on Saturday instead of Friday, if needed?
UPDATE - The library will NOT be closed on Fridays during 2010.
We chose which day to close based on several factors, including how many people use the library each day, how many books check out, when programs are usually scheduled, and how other people and groups use the building. Friday is neither the busiest nor the slowest day for users and checkouts - in fact, it's about average. But it's not a school night, so parents and school kids needing our resources for the next day's homework aren't affected. We don't usually offer programs (such as story times, Reading Buddies, and the Homework Center) on Fridays, so closing on Fridays doesn't disrupt our program schedule. And because we are closed on Friday evenings anyway, groups wanting to use the meeting rooms aren't affected either. On the other hand, many library users can't get to the library Monday through Friday and rely on our being open on the weekend. Saturday is often one of our busiest days of the week. So, it made more sense to us to choose Friday as the day we will be closed, if we must do so.