| Blast
valves are mounted on the air intake and air outflow pipes
inside a bomb shelter. As a high pressure wave from a nearby
detonation passes over the shelter, the pressure travels
down the pipes and into the shelter. If this high pressure
is not stopped, it will destroy the air filtration equipment
and injure or kill the occupants. Directly behind this high
pressure wave is a vacuum wave - all of the atmosphere is
blown outward from the epicenter of the detonation. This
vacuum wave can be as deadly as the pressure wave. That
is why these valves are double acting - pressure and vacuum.
The
ARS-101-BV automatic double- acting blast valve automatically
and near instantly closes when the initial
positive pressure wave from an explosion hits and automatically
closes a second time (in the other direction) when the outside
air pressure goes negative (a vacuum) in relationship to
the internal shelter pressure. When the outside air pressure
returns to normal, the blast valve automatically returns
to its normally open state. In other words, it lets air
flow into your Safe Cell and out of your exhaust port for
normal operation, but will not allow a
blast of high-pressure air to enter your shelter - and bring
contaminants with it.
This
blast valve is designed and tested to protect
an underground shelter from a 100 pound per square inch
detonation.
In
order to withstand this pressure, these blast valves are
fabricated from ASTM grade A steel. This is a heavy, robust
item designed to keep the massive pressures of a nearby
conventional or nuclear blast from injuring or killing the
occupants of your bomb shelter.
These
valves are only necessary in hardened bomb shelters and
should be used in pairs - one on the air intake pipe and
one on the air outflow pipe.
For
more information, please see the installation
and operation manual (PDF).
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