Space suits are pretty easy. They only have to hold 15 PSI of air and in fact hold less because we don't fill them with 20% Oxygen. Compare that with under water: 30 feet down = another 15 PSI. 60 feet down from sea level = another 30 PSI, ETC.
Same thing with the space station walls. They only have to take a 15 PSI difference at most. When you build a submarine or underwater habitat, it has to take a 15 PSI difference for every 30 feet deep it is.