there have been a 5 min timeout since the implementation of TKTAuth, except it was broken (not declared at the right place) TKTAuth is pretty complicated as you have to declare variables in apache conf file, tkt conf file and the login page, and some only work at one place.
it will reset the counter everytime you reload the page, if the counter is at least half done. Which is the default behaviour but could be adjusted, to never reset or to reset whatever is its status.
Some will find 5 min is already too long to be secure. To my experience I would say that the 5 min could be a little too short for some people, if you feel the same, you can feel a NFR to be able to change the default timeout value.