U.S. Office of Government Ethics is the resource to find the federal government rules for ethics including the personal use of public property.  Usually, the individual agency allow some latitude for personal use. I don't have their address before me, but a web search will give it to you. It looks to me like this is the type of information you want.
 
 
========================================================= Important Subscriber Information:

The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes).

If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).