I timed myself Sunday from E16 to C30 (one of the longest treks at IAH) just in case you asked this question, Boleslav. I walked very briskly and used all the moving walkways (still walking)...9 minutes. Getting to the north concourse of C (e.g., C-18) would have taken a couple more minutes, I'm guessing. Your walk, if taken at a more leisurely pace than mine, I would estimate at 11-13 minutes.