is different from that on the model 104. The
GTGS FIRE STOP AND CO2
following actions occur if a fire is detected by the
SYSTEM
UV sensors:
Two UV detectors are used to sense a fire
1. The cooling fan(s) stop(s), if running.
condition in the engine enclosure. Only the engine
enclosure is protected by the installed CO2 system.
2. A 20-second delay is activated if the fire
The UV sensors and signal conditioners used on
the GTGS are similar to the type used on the
signal remains for 1.5 seconds or longer.
LM2500 GTE. The two sensors are mounted in
3. After 20 seconds the following actions
the enclosure near the compressor inlet. The signal
occur:
conditioners are mounted in the alarm terminal
box located on the generator end of the base. The
fire stop logic is controlled by the module cooling
a. A stop command is sent to the LOCOP.
b. Ship's service LP air is ported to the
fan controller.
5th- and 10th-stage bleed air valves to
keep them closed.
c. The fire dampers are closed.
Model 104 Fire Stop Logic
d. Primary CO2 is released.
e. Fire alarms are activated at the DCC,
When a fire is detected by the UV sensors in
EPCC, and the SWBD.
the module of the model 104 GTGS, a signal is
sent to the fire shutdown relays. The following
4. The LOCOP stop command closes the
actions then occur:
engine fuel valve. When the engine drops
to 12,780 rpm, the 14th-stage bleed air
1. A 5-second delay occurs. This prevents any
valve closes.
stray signals from causing a fire stop. The
fire condition must exist for these 5
seconds.
CO2 System
2. After the 5-second delay, the following
actions occur:
The primary CO2 system has two 50-pound
CO2 cylinders (one master and one slave), two
a.
Primary CO2 is released.
pressure switches, and two high-volume, low-
b.
A stop command is sent to the LOCOP.
velocity nozzles. The CO2 cylinders are mounted
The module fire damper is closed.
c.
in racks adjacent to the module. The pressure
The cooling fan is stopped.
d.
switches are located in the piping system. One is
Ship's service LP air is ported to the
e.
outside and the other is inside the enclosure. The
5th- and 10th-stage bleed air valves to
nozzles are mounted on the air intake assembly.
keep them closed.
Figure 3-5 shows the CO2 system components and
f. Fire alarms are activated at the damage
their location on the GTGS.
control console (DCC), EPCC, and the
Normally, the primary bank is activated by
summary alarm at the SWBD.
fire stop logic. You can also activate the primary
3. The stop command to the LOCOP closes
bank manually at the bank or remotely from the
the fuel valve. When the GTGS rpm drops
pull box. When the two pressure switches are
below 12,780 rpm, the 14th-stage bleed air
activated by CO2 pressure in the header, a CO2
valve closes.
release alarm is initiated locally and at the DCC.
The summary alarm at the SWBD is also
4. Door interlocks are provided to prevent
activated. Once started, CO2 discharge cannot be
CO2 discharge if the engine section module
stopped. The primary discharge occurs at the rate
doors are open.
of 200 lb/min until the primary cylinders are
exhausted.
The secondary system has three 50-pound CO2
Model 139 Fire Stop Logic
cylinders (one master and two slave) and two high-
volume, low-velocity nozzles. These are connected
The model 139 fire stop is also controlled by
by a common piping system. The secondary bank
the cooling fan controller. The fire stop sequence
3-10
