You would have to ask Fencer the exact times, but like Czuch said - I'm sure there is a script that runs every so often which "time out" games which are past their limits.
I don't think it is every hour - maybe every 5-10 minutes? Again, that is just a guess.
I was watching the "live" games and did notice that a couple of you were at 0 minutes left - but even still without them timing out, it looked like the tournaments worked very well - and pretty quick.