We have designed several anti-claustrophobia measures into the NORAD S-Series shelter design. Unlike cylindrical designs, the S-Series has straight walls as they are in a normal house. But while the average house ceiling is 7 ft 6 in. or 8 ft, the shelter ceiling starts at 8 ft. high and slopes up to 10 ft. in the middle. It is not required that you bend over to get from one area to another, as if often the case in cylindrical shelters.