Home and Apartment Safe Rooms
Collective protection for civil defense
A nuclear, biological, and chemical (NBC) safe room protects its occupants from inhaling harmful or deadly airborne toxins such as very fine particles of radioactive fallout, biological toxins, and chemical agents. In the past, the United States Government has poured extensive resources into providing the best information (at the time) for the protection of its citizens from NBC warfare agents. This is not the case today.
For protection of the U.S. population we have the government website: www.ready.gov. It suggests duct tape and plastic, then wait for further official instruction. Although the tape and plastic method would offer some immediate short term protection from low level toxins at low concentrations, it would be, at best, a short term solution. Most governments tend to only recommend emergency procedures that can be afforded by all their citizens.
As a contrast to most governments, both Switzerland and Israel require, and subsidize the cost of, NBC safe rooms in apartment buildings. They have strict standards in place governing both the construction of the room and the ventilation equipment protecting the room.
For protection of some of our military personal and government officials, the U.S. Department of the Army - Corps of Engineers has standards by which NBC airborne toxic free areas must comply. These standards dictate the differential pressure in the safe room (protected space) as well as the design of the NBC filter/ventilation system.
The main reasons why an un-pressurized room will not protect the occupants for very long is that the room "breaths" - in other words, it leaks air both in and out through the cracks as the external atmospheric pressure fluctuates - due wind or other atmospheric variables like temperature, and barometric pressure swings due to approaching weather fronts. Air constantly tries to normalize its pressure and temperature between different variants - as it does this, it brings with it whatever that air contains. Also, in a sealed room, there is no accommodation to replenish oxygen and expel the exhaled carbon dioxide of the occupants.
In order to create and maintain overpressure as well as give the required air exchanges to support the air supply needs of the sheltered occupants, a safe room must be equipped with true positive pressure NBC filter/ventilation unit and a means of a metering the exhaust air out of the protected space.
American Safe Room filter/ventilation equipment and related components are designed and manufactured specifically for this purpose.