Procedures & Alarms

Milestones:

• Learning and Training Phase – Pre-Requisites for the start of operation:

1. Start the Portable Multi Gas Detector and Dew Point Meter
2. Install the Spool Piece to Connect the Inert Gas Line to the Liquid Line
3. Set Cargo Tank Vapour Valves
4. Set Cargo Tank Liquid Valves
5. Set the Vapour Line to No. 1 Vent Mast Regulating Valve
6. Set the Inert Gas Line Valve
7. Prepare and Start Ballast Pump 2
8. Prepare Inert Gas Generator in Inert Gas Mode

• Assessment Phase – Operational flow and Assessment:

9. Start Inert Gas Generator in Inert Gas Mode
10. Cargo Tank Dew Point < -40°C
11. Cargo Tank Oxygen Content < 2% in Volume
12. Maintain Cargo Tanks Pressure Between 5kPa and 7kPa
13. Check the Sampling Point on Vapour Line in All Cargo Tanks
14. When All of the Cargo Tanks and Piping Are Inerted, Stop the Supply of Inert Gas

 

Exercise Actions and Warnings:

• Deviation from Exercise: Ensure no unnecessary valves are opened or required ones closed once gassing up begins. A caution message will be shown if an incorrect action is taken, and failure to correct it may result in exercise termination.
• Flow Maintenance: Keep the IGG outlet flow and the flow to atmosphere between 15,500 kg/h and 16,500 kg/h during the inerting process. Failure to do so within 1 minute of a high-priority alarm will result in exercise failure.
• Pressure Maintenance: Ensure that the cargo tank pressure stays between 5 kPa and 7 kPa to maintain the proper piston effect.

 

Alarms & Remarks:

Alarm Condition	Alarm Time	Alarm Level	Alarm Title	Alarm Description	Action
	Supply Started	remark	Inerting Of Cargo Tanks Started	Inerting of the cargo tanks has started.
	On Inerting completed	remark	Inerting of tanks completed	Inerting of cargo tanks is completed, stop the delivery of inert gas.
	On Inerting completed	remark	Check the sampling point on vapour line	Check the sampling point on vapour line for dry air properties, in all cargo tanks.
	Stopped delivery of inert gas	remark	Close Valve CG702	Inerting of tanks is stopped, close the valve CG702.
	started delivery of Inert gas	remark	Open Valve CG702	Open the valve CG702, to vent out the dry air.
	During inerting process	caution	Maintain IGG Outlet Flow And Outlet Flow To Atmosphere	Maintain IGG outlet flow and outlet flow to atmosphere between 15500 kg/h to 16500 kg/h.
	During exercise	caution	Deviation Detected	Deviation from the exercise is detected, undo your last action.

Step By Step Procedure:

• Learning and Training Phase – Pre-Requisites for the start of operation:

1. 1. Start Portable Multi Gas Detector and Dew Point Meter:

• • Navigate to the Miscellaneous Equipment section.
  • Press and hold the power button for 5 seconds to start both devices.

1. 2. Install the Spool Piece to Connect the Inert Gas Line to the Liquid Line:

• • Connect the spool piece above valve CL701 linking the inert gas and liquid lines.

1. 3. Set Cargo Tank Vapour Valves:

• • Open the following valves: CG100, CG101, CG200, CG201, CG300, CG301, CG400, CG401.

1. 4. Set Cargo Tank Liquid Valves:

• • Open the following valves: CL100, CL107, CL200, CL207, CL300, CL307, CL400, CL407.

1. 5. Set the Vapour Line to No. 1 Vent Mast Regulating Valve:

• • Open valve CG701.

1. 6. Set the Inert Gas Line Valve:

• • Open valve CL701.

1. 7. Prepare and Start Ballast Pump 2:

• • Navigate to the Ballast System page.
  • Open the discharge, suction, and outlet valves.
  • Start a generator to ensure at least two are operational.

1. 8. Prepare Inert Gas Generator in Inert Gas Mode:

• • Set the Generator Mode to “Inert Gas.”
  • Set Operating Percentage to 100%, turn on Fuel Pump and IG Chiller Unit.

• Assessment Phase – Operational flow and Assessment:

1. 9. Start Inert Gas Generator in Inert Gas Mode:

• • Wait for chiller temperature to drop below 3°C and oxygen analyzer to read ≤ 0.9%.
  • Start the inert gas generator.

1. 10. Ensure Cargo Tank Dew Point < -40°C:

• • Confirm the dew point is lower than -40°C using the dew point meter.

1. 11. Ensure Cargo Tank Oxygen Content < 2% in Volume:

• • Monitor oxygen content in the vapour line using the portable gas detector.

1. 12. Maintain Cargo Tanks Pressure Between 5kPa and 7kPa:

• • Adjust pressure by regulating the vent mast valves.

1. 13. Check Sampling Point on Vapour Line in All Cargo Tanks:

• • Verify gas properties (CH₄, O₂, CO, CO₂, and dew point) at sampling points.

1. 14. Stop the Supply of Inert Gas When All Cargo Tanks and Piping are Fully Inerted:

• • Stop inert gas delivery in the IGG System page and close valve CG702.

 Proper Line Up For Inerting: