CHL mandates 80 minutes (1 hr 20 mins) for a game, NO EXCEPTIONS.  There is to be a 3 minute warm-up (3 MINUTES) and the game begins.  It doesn't matter if it's a close game going into the 3rd period or not, you take the time remaining, divide by 2 and post that amount of time on the clock.  Simple math.  If the clock has not expired at the end of 80 minutes, THE GAME IS OVER!!  Notify the referees and get the players off the ice.