function and operation of fixed firefighting

Question 1

State the function of AFT AFFF system

Answer 1

1. To provide an AFFF fixed firefighting facility to MMS, aft dome and AMS 2/2 main hydraulic plant room via fixed spray heads.
2. To supply AFFF to 3x CLHR aft of 116 bkhd and 1x disconnected CLHR is the RSC
3. To supply freshwater to the aft pyro flood locker

Question 2

State the operation of AFT AFFF

Answer 2

1. Initiate with an IPB in the environmental panel.
2. The LPA blower now interacts with RFT 3 or 4
3. The pressurised water can be used for the pyro flood lockers.
4. The pressurised water can supply the AFFF concentrate tank in AMS 3/1
5. The 3 way diverter directs the AFFF to the mixer which then combines with the pressurised water.
6. The AFFF mix is supplied to the CLHR
7. AMS 2/2 is supplied via initiation valve if required
8. The diverter valve sends the AFFF mixture to the aft dome or the mms.
9. The diverter valve will redirect the AFFF mixture back to the CLHR.

Question 3

State the function of the halon system.

Answer 3

To provide a fixed firefighting system to either port or stbd DG compartments via 2 shots of inert halon gas

Question 4

State the operation of the halon system

Answer 4

1. Select the relevant DG watchkeepers booth
2. This will set off the alarm
3. Open the relevant compartment isolation valve which is located inside the control box
4. Insert the CO2 extinguisher into the relevant injection port
5. inject the contents of the CO2 extinguisher into the injection port this will open the halon isolation valves on top of the halon bottles
6. This will drench the selected compartment with halon
7. An IPD on the SCC will illuminate to show drenching is taking place
8. A second shot of halon is available if required

Question 5

State the function of the nitrogen drench system

Answer 5

Primary function - to provide an N2 drench facility to the MC

Secondary function - to provide an N2 drench facility to the follwing areas:
fwd 27 bkhd 
fwd 67 WTB 
RC 
aft 116 WTB

Question 6

State the operation of the nitrogen drench system

Answer 6

1. N101 is opened from the scc
2. N101 can be operated locally from a hydel when 24v dc is lost and manually on loss of hydraulics
3. No nitrogen enters the compartment at this point
4. The MC is evacuated of all non essential personnel and fully shut down
5. APL reports to DCHQ and N102 is ordered open by the DCO
6. N102 is opened by operation of the local hydel located outside the MCC above the round window
7. The N2 pours into the compartment until compartment pressure indicates 0.8 bar or for 188 seconds