shelter ventilation

I have done a pretty fair search of old threads. I need to figure out what I will do for ventilation. I am planing on an underground area of about 8' x 8' x 20'. Proabably 4 adults and a kid or 2. I know bigger is better but this is a start. I was looking at using a 12v system with solar...

i want to make part of my basement into a fall out shelter/bomb shelter, i have the room with 3 walls concrete. the fourth is plasterboard with a door. what is the best way to make that as sturdy/gamma ray resistant, just buy a bunch of cinder block and pile them to the ceiling? and the...