Ventilation openings in a bunker must be protected by blast valves. A blast valve is closed by a shock wave, but otherwise remains open. If the bunker is in a built-up area, it may include water-cooling or an immersion tube and breathing tubes to protect inhabitants from fire storms. In these cases, the secondary exit is also most useful. #reganvest #blastvalves #blastvalve #nuclearbunker #bunker #Atombunker
