3-4: DC Systems Installed Fire Protection

Question 1

How to activate Halon

Answer 1

1) Break the glass, or open the enclosure at a remote actuating station. Remove the safety pin secured by an anti-tamper seal.
2) Fully operate the discharge lever, and secure it in the OPERATE position. The released CO2 will immediately actuate two pressure switches. One pressure switch operates lights and horns (or bells) and the other pressure switch initiates the shutdown of ventilation fans and operates any installed vent closures.
3) If the alarms do not operate, or the ventilation does not shut off, pull out the reset/actuation knob on the associated pressure switch. If operation still does not occur, manually shut off the ventilation systems, and evacuate all personnel from the space.
4) After the time delay operates, the CO2 pressure activates the Halon cylinder valve to discharge Halon to its associated nozzles. A third pressure switch, downstream of the TDD, then actuates a red light indicating Halon discharge. WARNING
The time delay bypass valve should not be operated until after the full delay time of 30 or 60 seconds has passed.
5) If the TDD timing exceeds 70 seconds (for a 60-second device), or 35 seconds

Question 2

What is the effect of pulling the CO2 system control head cable handle out 3-5in?

Answer 2

The handle pulls the control cable which causes the wheel assembly to roll along the pinned lever and the movement of the wheel depresses the plunger

Question 3

Time limit for continuous operation for the water mist system supply tank

Answer 3

15min

Question 4

Main components of the AFFF fixed eductor system

Answer 4

eductor, hytrol valve, powertrol sprinkler control valve, concentrate tank, FM psi gauge, SOPV, hose reels

Question 5

Difference between open head and closed head sprinkler

Answer 5

open head: all heads spray when the COV is opened
closed head: only heads that are opened by heart from the fire will spray water

Question 6

3 types of nozzles in the APC system

Answer 6

1) Appliance nozzle: discharges on protected appliance (mounted on hood over the fire)
2) Plenum range hood nozzle: discharges port along access to plenum (centrally located in plenum)
3) Duct nozzle: discharge port along axis of duct (inside exhaust duct)

Question 7

How are Halon cylinders identified?

Answer 7

white stripe over gray stripe

Question 8

How are the HFP cylinders identified?

Answer 8

grey stripe over black stripe

Question 9

What ship designs are equipped with miscellaneous wet-type sprinkling systems?

Answer 9

DDG 51, LPD 17