FIXED CO₂ EXTINGUISHING SYSTEM

• For cargo space, a minimum of 30% of the volume of the largest cargo space.
• For Ro-Ro space, a minimum of 45% of the volume of the largest cargo space.
• For machinery space, a minimum of 40% of the volume of the largest machinery space without casing.
• For machinery space, a minimum of 35% of the volume of the largest machinery space, including casing.
• For machinery space, the above figure can be reduced to 35% and 30%, respectively, for ships of less than 2000 GRT.

• Should have two separate release controls.
• For machinery space, 50% should be discharged within 1 min & 85% within 2 min.
• For container & general cargo space, 2/3rd should be discharged within 10 min.
• For solid bulk cargo spaces, 2/3rd should be discharged within 20 minutes.

• Permanent piping should be there.
• Distribution piping more than 19 mm in diameter
• Should have an alarm when it operates.
• Safeguard against unauthorized usage.

• The system consists of main CO₂ bottles, release cabinet, master valve, common manifold, and distribution pipelines.
• Break the glass & take out the key.
• Open the release cabinet. Audio-visual alarms will sound, and ventilation blower trips will activate.
• Open one of the pilot bottle valves. Another pilot bottle is for standby (The pressure inside the pilot bottle is the same as that of the main bottle; only the quantity is different)
• Open valve 1, where CO₂ from the pilot bottles opens the master valve.
• Open value 2, where CO₂ from pilot bottles reaches the time delay unit, which creates the delay of 20-30 s.
• After a delay, CO₂ reaches the bottlehead assembly and opens all the pressure-operated cylinder valves.
• All the CO₂ releases to the common manifold.
• Since the master valve is already open, CO₂ is released to the protected space.

• Ensure all personnel vacated the engine room.
• Muster and take a head count.
• The chief engineer will decide in consultation with the master.
• The nearest port authorities are to be informed.
• All access doors, vent flaps, blower flaps, skylights, and quick-closing valves are to be closed.
• All machinery in the engine room is to be stopped.
• Make sure the emergency generator is running and on-load.
• CO₂ is then released by the Chief Engineer.

• Should be located behind the forward collision bulkhead.
• Should be used for no other purpose.
• Should have access from the open deck.
• Access doors shall open outwards.
• Shall be provided with a mechanical ventilation system designed to take air from the bottom of the space & provide at least 6 air changes/hour.

• Alarm before the master valve activates at 4 bar.
• Touch all bottles physically.
• By weighing: Radioactive isotope gauge.

a) What type of ventilation system is used inside the CO₂ room?

     Mechanical ventilation system

b) Why is air taken from the bottom?

     Because CO₂ is 1.5 times heavier than air. Hence, CO₂ settles down & displaces air.

• CO₂ is 1.5 times heavier than air. Hence it settles down & displaces the air.
• It can be easily liquefied & bottled.
• No deterioration with age.
• No residue left after application.
• Non-corrosive.
• Non-conductor of electricity.