Airlocks & Decontamination RoomsAir locks are interim rooms designed to gain safe access from the outside to the main shelter room. Airlocks should have two gas-tight doors, which are never to be opened at the same time. This assures protection of the shelter room from radiation, blast pressure and war gasses. People entering the air lock from the outside, must close the outside door and stay in a closed down condition until the air of the air lock has been purged and the air pressure has reached a positive state equal to that in the shelter room. The airlock should be small with a maximum area of 54 square feet, to assure the proper purging of the air. Airlocks are usually built of concrete. Entrances to steel shelters, however, can be placed into the concrete wall of the airlock.
The air lock, in small shelters, can also act as the decontamination room, which serves as a cleaning and dressing room for people contaminated by poison gas or radioactive dust. The decontamination room should be used to store protective clothing, which must be worn at all times by persons leaving the shelter. In larger shelters, the decontamination room should have a shower and toilet area built into the room. For shelters housing more than 100 persons, the decontamination room should be a separate room, having access to the airlock.
The airlock and decontamination rooms should be constructed of the same thickness of concrete, and same protection levels as are prescribed for the shelter room. Filtered air from the shelter room should be exhausted into the air lock (or from the shelter room into the decontamination room, and then to the air lock). Air from the airlock should be exhausted to the outside or into the basement. This allows for a continual movement of filtered air throughout the shelter and airlock. Each room has the same volume of air entering as it does exhausting.
People often use a concrete airlock to gain access to their steel shelters. The air lock is placed at the basement level. The steel shelter is placed 10 feet away from the house, and 8 to 10 feet below the air lock, depending on the diameter of the steel shelter. Access to the shelter can be gained in several ways. For instance, a steel hatch type door on the floor of the air lock can lead down to a 7 ft. stepladder, which then accesses a horizontal tunnel leading to the steel shelter at the lower level. The steel shelter should always have another exit to the outside.
Air locks are also used to gain access to underground generator rooms. Generator rooms should never have direct access to the shelter.