Every Nuclear, Biological and Chemical (NBC Shelter) refuge should have the capability of complete isolation from the external environment.
In the immediate aftermath of a seismic nuclear incident such as an explosion or reactor failure, radioactive particles (alpha, beta, and gamma), in addition to high energy x-rays, will propagate out from the impact site. Radioactive fallout poses the greatest threat to people in the days following a blast.
NBC Shelter Ventilation Systems
Commonly available ventilation systems require potentially contaminated air being drawn in from the external environment to function. Although they use HEPA or charcoal filtration, they can only provide minimal protection from chemical and biological agents. Nor are they tested against any form of nuclear radiation.
The National Institute for Occupational Health & Safety (NIOSH) states in their guidance document, that “…filtration and air cleaning devices would be ineffective at stopping the blast and radiation itself.”
Shutting off the internal ventilation from the contaminated air outside is the only way to ensure the filtration system does not become contaminated with nuclear particles.
With the NBC Shelter isolated from the external environment, it is critical to have a system available to remove carbon dioxide exhaled by the people inside the shelter and provide a source of oxygen. Without a means to remove the carbon dioxide and add oxygen to the air within a sealed environment, the occupants will quickly suffer carbon dioxide poisoning and then suffocate from a lack of oxygen. The time in which this will occur is the volume of the shelter and the number of occupants.
Standalone Scrubber Solution
One solution is an AirGEN Standalone Scrubbing System, combined with an independent oxygen supply.
A single AirGEN provides the capacity to survive in isolation from the outside atmosphere for up to a week without electrical power or indefinitely using any 6-34V DC power supply. With radioactive fallout decaying rapidly, with time, using the AirGEN to isolate the outside atmosphere ensures a better chance of safeguarding shelter occupants until the outside air clears or rescue occurs.