With the engine at idle and all hatches and the gun breech closed,
the system must maintain a minimum of 0.06 psi positive pressure in
the tank to keep NBC contaminated air out.
As long as the tank's
engine runs, even if the tank loses electrical power, the main NBC
system provides cool decontaminated air.
Commander's Control Panel.
A particle filter filters the engine bleed
air, which the system uses for distribution air, prior to
entering the engine.
A separate particle filter filters
the cooling air, which the system uses for heat transfer in
NBC filtration takes place in the distribution
System status indicators.
The NBC main system has several
-- Sponson in. When this indicator lights, it indicates the
SPONSON IN temperature exceeds 325 +10,F.
-- Sponson out.
When this indicator lights, it indicates
the SPONSON OUT temperature exceeds 150 +7,F.
-- Filters clogged.
When this indicator lights, it
indicates the NBC filter's back pressure exceeds 1.18