sounds an alarm at the propulsion control
console (PCC) to notify the engineering officer
of the watch (EOOW). Fire may also be sensed
by the flame detectors (fig. 2-10) or either of the
two temperature switches may detect enclosure
temperature above preset limits.
The Halon discharge nozzle is located inside
the enclosure. It is mounted on the underside of
the crossbeam under the compressor front frame.
This one nozzle provides both initial (primary) and
standby (reserve) Halon discharge. The fire
extinguish inhibit switch is mounted above the fire
alarm push button on the outside of the module.
When in the ACTIVE position, this switch will
allow automatic or manual discharge of the
Figure 2-10.--FFG fire system block diagram.
Halon. When in the INACTIVE position, this
switch provides a signal to the ship's system that
5. The module cooling air fan is shut down.
is used to prevent discharge of the Halon,
6. The module vent damper is closed.
However, this switch does not override manual
7. The bleed air valve is closed.
activation locally.
8. The enclosure lights flash (only if lights
were previously on).
You can extinguish a fire in either enclosure
9. After a delay of 20 seconds, the initial CO2
by filling the enclosure with Halon. The PCC has
discharge occurs.
a FLAME DET ALARM/HALON FLOOD push
button for each enclosure. To prevent an
To prevent CO2 discharge, position the release
enclosure from being flooded with Halon while
inhibit switch to the INACTIVE position during
personnel are inside, place the fire extinguish
the 20-second time delay. The initial discharge
inhibit switch in the INACTIVE position.
delivers 150 pounds of CO2 at a rate of 50 lb/min.
If required, the extended CO2 discharge is
Activation of the FLAME DET ALARM/
manually activated. The extended discharge
HALON FLOOD switch on the PCC will provide
delivers 200 pounds of CO2 at the rate of
the initial Halon discharge of 60 pounds at a rate
10 lb/min.
of 1.45 lb/sec. An additional 60 pounds, with the
same rate of discharge, is available on standby
(manually activated).
FFG-Class Ship
Like the other ship classes already discussed,
the fire detection system of the FFG-class ship has
AIR INTAKE SYSTEM
three flame detectors, a flame detector signal
conditioner, and two temperature switches. The
The air intake system for the LM2500 GTE
provides the large quantity of air with a minimum
manual alarm system has a fire alarm push
button. The extinguishing system has a single
pressure drop that is needed for proper engine
Halon discharge nozzle, connecting tubing, and
operation. The design of the ducting varies with
the ship class. However, the function of the
an extinguish release inhibit switch.
systems are the same. The intake system reduces
The UV flame detectors of the FFG-class ship
are identical to the type on the other class of
the flow distortion, pressure drop, and salt
GTE-powered ships, but provide only an
ingestion. The intake system also provides duct
silencing, a supply of cooling air, anti-icing
alarm. The RTE fire sensor will also sound that
protection, and mounting for moisture separation
same alarm, indicating a fire is present.
The manual fire alarm push button is mounted
pads, and allows for engine removal by a system
of rails on the duct walls. Blow-in doors located
on the outside of the enclosure, next to the side
on the ship's upper level protect the GTE from
access door. When activated, a contact closure
air starvation if inlet blockage occurs.
signal is provided to the ship's system which
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