To prevent the formation of flammable mixtures in the event of any LNG leakage. To permit easy detection of any LNG leakage through the barrier(s). To prevent corrosion in the insulation space.
LNG1032-232 :
A :
What are the reasons for supplying nitrogen as a dry inert gas to the insulation spaces on LNG carriers? Wrong or Missed Data? Click
0.2kPa to 0.4kPa
LNG1032-233 :
A :
What is the normal controlled pressure in the primary barrier space of a membrane vessel? Wrong or Missed Data? Click
GTT NO96 system
LNG1032-234 :
A :
Which containment system has a pressure control system for the insulation spaces that is common to all tanks? Wrong or Missed Data? Click
The Hold Space.
LNG1032-235 :
A :
Where does the nitrogen supplied to the annular space exhaust to on a Moss vessel under normal stable conditions? Wrong or Missed Data? Click
No. An LNG leak through the barrier needs to be detected.
LNG1032-236 :
A :
Is it allowed to have the primary space above tank pressure? Wrong or Missed Data? Click
5°C
LNG1032-237 :
A :
At what temperature should the cofferdam heating maintain the cofferdams during the loaded passage? Wrong or Missed Data? Click
The void space around the liquid domes.
LNG1032-238 :
A :
Apart from the cofferdam, what other space is usually heated by the cofferdam heating? Wrong or Missed Data? Click
Cargo pump discharge lines. HD and LD compressor discharge lines. Inert gas supply line.
LNG1032-239 :
A :
Can you give 3 examples of non-return valves fitted on the vessel lines? Wrong or Missed Data? Click
So that trapped vapour in the spindle insulates the operating mechanism and stops it from freezing.
LNG1032-240 :
A :
Why are most cryogenic valves fitted with extended spindles? Wrong or Missed Data? Click
Videotel CBT LNG Vers 1.0.32 (QUESTIONS & CORRECT ANSWERS)
3.Support Systems (Module 3) - test for Chief Officer
Expansion/contraction must be allowed for in the form of either bellows or loops in the pipe line. Only a couple of supports on the line are fixed, the rest allow the pipeline to move horizontally. Where bellows are fitted in pipelines they are not lagged but must be kept covered with an air tight shroud to prevent freezing and ice build up on them.
LNG1032-241 :
A :
What is specific about the construction of LNG pipelines? Wrong or Missed Data? Click
Secondary barrier. Cofferdam. On inner hull in duct keel. On inner hull in trunk deck.
LNG1032-242 :
A :
Where are temperature indicating devices installed on a membrane vessel? Wrong or Missed Data? Click
It is better to suspend operations in a controlled manner and rectify the problem rather than allow trips or shut-downs to occur. A record of alarms and subsequent actions should be maintained.
LNG1032-243 :
A :
In the event of an alarm, if the situation cannot be rectified, is it OK to continue operations until the associated trip operates? Wrong or Missed Data? Click
The lowest concentration of the gas in air that will support a self-propagating flame when ignited.
LNG1032-244 :
A :
What is the lower flammable limit (LFL) of a combustible gas? Wrong or Missed Data? Click
Electric motor rooms. Ventilation hoods and gas ducts (swept trunking for gas to boilers). Air locks, such as to accommodation and CCR entrances. [3 examples only] There is no gas detection head in the cargo tank insulation spaces.
LNG1032-245 :
A :
Can you give 3 places that would be fitted with a constant sampling catalytic gas detection head? Can you find such a gas detection head in the cargo tank insulation spaces?
Wrong or Missed Data? Click
Catalytic gas detectors require the gas sample to be mixed with air or oxygen in order to operate. Infra-red gas analysers do not require the gas sample to be mixed with air or oxygen in order to operate.
LNG1032-246 :
A :
What is the difference between catalytic gas detectors and infra-red gas analysers in relation to the gas sample? Wrong or Missed Data? Click
30% LFL
LNG1032-247 :
A :
At what gas concentration should the alarm point be set for the gas detection units on board an LNG vessel? Wrong or Missed Data? Click
Detectors should be subject to regular calibration every 3 months to ensure that the zero and span of the instrument is correct.
LNG1032-248 :
A :
What are the requirements for testing of the gas detectors? Wrong or Missed Data? Click
Detectors should be subject to regular calibration every 3 months to ensure that the zero and span of the instrument is correct. On cyclic sampling systems, suction line integrity and filters should also be checked at regular intervals.
LNG1032-249 :
A :
What are the requirements for testing of cyclic sampling gas detection systems? Wrong or Missed Data? Click
3.Support Systems (Module 3) - test for Chief Officer
At least 2 sets
LNG1032-250 :
A :
How many sets of portable gas detection equipment, suitable for detecting vapour up to the LFL of gas on board, must an LNG vessel carry?
Wrong or Missed Data? Click
Top, mid height and bottom of the tank.
LNG1032-251 :
A :
When testing a confined space for gas prior to entry, where should the sample be taken from? Wrong or Missed Data? Click
Infra-red type instrument
LNG1032-252 :
A :
What type of meter is used to measure hydrocarbon concentration in an inert atmosphere? Wrong or Missed Data? Click
Sample A.
LNG1032-253 :
A :
Which sample of air, having the dew point readings given, would contain the most moisture? Sample A with a dew point of -20°C or Sample B with a dew point of -45°C?
Wrong or Missed Data? Click
Meters with infra-red sensors
LNG1032-254 :
A :
Which of the meter types can not be used to measure oxygen levels? Wrong or Missed Data? Click
Catalytic meters are using a sensor filament that varies in resistance when the gas combined with the oxygen burns inside the filament chamber. Catalytic meters are fitted with flashback arrestors in the inlet and outlet of the detector filament chamber to prevent the possibility of flame propagation from the chamber to a hazardous area.
LNG1032-255 :
A :
Why do catalytic meters require the presence of oxygen in the sample in order to measure the gas concentration? What needs to be fitted to the meter inlet and outlet as a consequence of this principle of operation?
Wrong or Missed Data? Click
The material of the sample hose used must be of the correct type as some rubber hoses can absorb gas and give false readings.
LNG1032-256 :
A :
Is the material of the sample hose of a gas meter important? And why? Wrong or Missed Data? Click
Yes.
LNG1032-257 :
A :
Can a meter using infra-red sensors be made specific to a particular gas? Wrong or Missed Data? Click
During the final stages of gassing up the cargo tanks.
LNG1032-258 :
A :
During which operation would CO2 readings be taken to check the amount of CO2 present? Wrong or Missed Data? Click
Videotel CBT LNG Vers 1.0.32 (QUESTIONS & CORRECT ANSWERS)
3.Support Systems (Module 3) - test for Chief Officer
Evacuate the space immediately.
LNG1032-259 :
A :
If, while work is in progress in a confined space, either the O2 reading is seen to decrease or the gas content increase during a periodic check, what should be the first course of action?
Wrong or Missed Data? Click
Main cargo and stripping pumps. HD compressor. Manifold valves. Cargo loading and discharge valves.
LNG1032-260 :
A :
In the event of an Emergency Shut Down (ESD) on an LNG vessel carrying out cargo operations in port, can you state 4 items that will be shut down?
Wrong or Missed Data? Click
An ESD 1 can be activated by either ship or shore. An ESD 2 is actived by the shore. An ESD 2 activates everything an ESD 1 does plus it closes valves in the loading arms and disconnects them from the vessel.
LNG1032-261 :
A :
Who activates an ESD 1? And an ESD 2? What does an ESD 2 in addition to ESD 1? Wrong or Missed Data? Click
No longer than 30 seconds.
LNG1032-262 :
A :
What is the time required by the International Gas Code for closing the manifold valves? Wrong or Missed Data? Click
Very High cargo tank level 99%. Cargo tank pressure falls to within 0.5kPa of primary space pressure. Vapour line pressure falls within 0.3kPa of atmospheric pressure. Loss of control air pressure. Loss of cargo valve hydraulic oil pressure.
LNG1032-263 :
A :
Can you give 5 causes of ESD? Wrong or Missed Data? Click
Trip ship's cargo and spray pumps (if discharge port). Trip HD compressors (if loading port). Close ship's Manifold/ESD valves.
LNG1032-264 :
A :
In the event of a shore side ESD being activated, what will occur on board the vessel? Wrong or Missed Data? Click
Prior to arrival at each loading/discharge port.
LNG1032-265 :
A :
How often should the ESD system trips and alarm be tested? Wrong or Missed Data? Click
Yes
LNG1032-266 :
A :
May the terminal have specific requirements for testing the ESD? Wrong or Missed Data? Click
The quick release hooks can be activated and the vessel moved from the berth by tugs using the fire wires without the assistance of crew.
LNG1032-267 :
A :
What is the purpose of the quick release hooks? Wrong or Missed Data? Click
3.Support Systems (Module 3) - test for Chief Officer
Fire wires are rigged forward and aft to hang over the outboard side (opposite side to the berth) of the vessel on arrival at each port.
LNG1032-268 :
A :
Where are rigged the fire wires? Wrong or Missed Data? Click
During all cargo transfer operations
LNG1032-269 :
A :
When should water curtains which spray water down the ship's side under the manifolds be operated? Wrong or Missed Data? Click
The drench system must protect the accommodation, CCR, compressor room, valves and equipment etc. from heat and spread of fire in the event of a fire/explosion in the cargo area.
LNG1032-270 :
A :
What is the role of the water drenching system (spray system)? Wrong or Missed Data? Click
The pump(s) must be able to be started remotely from outside the cargo area.
LNG1032-271 :
A :
Where can you operate the pump(s) of the water drenching system (spray system)? Wrong or Missed Data? Click
At least two hand held hoses or combination hoses/monitors are required to cover any part of the cargo deck including all above deck piping.
LNG1032-272 :
A :
What is the required capability of a fixed dry powder type extinguishing system on board an LNG vessel? Wrong or Missed Data? Click
Compressed nitrogen.
LNG1032-273 :
A :
What medium is used as the propellant in fixed dry powder extinguishing systems to discharge the powder? Wrong or Missed Data? Click
Monitors should be fitted to protect the manifold areas and be capable of actuation both locally or remotely.
LNG1032-274 :
A :
Where are monitors fitted? Where could they be activated? Wrong or Missed Data? Click
10kg/sec
LNG1032-275 :
A :
What should be the minimum discharge capacity of a fixed dry powder monitor? Wrong or Missed Data? Click
3.5kg/sec
LNG1032-276 :
A :
What should be the minimum discharge capacity of a fixed dry powder hand held hose nozzle? Wrong or Missed Data? Click
Videotel CBT LNG Vers 1.0.32 (QUESTIONS & CORRECT ANSWERS)
3.Support Systems (Module 3) - test for Chief Officer
35 metres
LNG1032-277 :
A :
What should be the maximum length of a fixed dry powder hand held hose line? Wrong or Missed Data? Click
45 seconds
LNG1032-278 :
A :
A sufficient quantity of dry chemical powder should be stored in each unit to ensure that all monitors and hand held hoses will discharge for which minimum time?
Wrong or Missed Data? Click
Float type. Radar type. Capacitance type.
LNG1032-279 :
A :
Can you give 3 cargo tank gauging devices that can be used on board an LNG vessel? Wrong or Missed Data? Click
There must be an independent alarm and ESD trip for very high level completely independent from the gauging system.
LNG1032-280 :
A :
Can the tank gauging system be combined with the high alarm that will close that particular tank's filling valve? Can the tank gauging system be combined with the high high alarm that will cause an ESD?
Wrong or Missed Data? Click
To ensure that the float maintains the same level of immersion irrespective of the amount and weight of the tape paid out.
LNG1032-281 :
A :
In a float level gauge why is a constant torque spring incorporated into the tape winding pulley? Wrong or Missed Data? Click
Never. Floats should always be left in the stowed position after taking a reading and never left in the "down" position, even when loading or discharging as well as when at sea.
LNG1032-282 :
A :
When can the float level gauges be left in the "down" position? Wrong or Missed Data? Click
The capacitance segments and cables are all inside the tank.
LNG1032-283 :
A :
What is the biggest disadvantage of a capacitance type level gauging system? Wrong or Missed Data? Click
There are no moving parts or electrical connections inside the tank.
LNG1032-284 :
A :
What is the biggest advantage of a radar type level gauging system? Wrong or Missed Data? Click
It is the accurate measurement of the volume, temperature and pressure of the cargo loaded or discharged.
LNG1032-285 :
A :
What is meant by Custody Transfer System (CTS)? Wrong or Missed Data? Click
3.Support Systems (Module 3) - test for Chief Officer
Volume Temperature Pressure The density is determined ashore.
LNG1032-286 :
A :
What is supplied by the vessel for calculating the calorific content of the LNG discharged? Wrong or Missed Data? Click
The radar transmitter located on the top of the tank emits microwaves, directed by an antenna, towards the surface of the tank contents. The antenna picks up the echo from the surface. The difference in frequency between the transmitted and reflected signal is directly proportional to the measured distance which is the ullage.
LNG1032-287 :
A :
What is the basic principle of a radar type level gauging system? Wrong or Missed Data? Click
Before loading After loading Before discharging After discharging
LNG1032-288 :
A :
At what stage(s) in cargo operations are CTS reports (LNG Certificates) printed out manually and also filed electronically? Wrong or Missed Data? Click
The Float System.
LNG1032-289 :
A :
Which gauging system is independent of all other systems and external sources (e.g. electrical)? Wrong or Missed Data? Click
The Radar System.
LNG1032-290 :
A :
Which gauging system has no electrical cabling or moving parts inside the tank? Wrong or Missed Data? Click
The Capacitance System.
LNG1032-291 :
A :
Which gauging system cannot be removed and overhauled with the tank still in service? Wrong or Missed Data? Click
No.
LNG1032-292 :
A :
Is an area 3 metres aft of the cargo area and 3 metres above the weather deck classed as being in the gas dangerous zone on an LNG carrier as defined by the IGC?
Wrong or Missed Data? Click
The control panel, monitor screen and alphanumeric keyboard.
LNG1032-309 :
A :
What is the IAS system (Integrated Automation System) operator interface? Wrong or Missed Data? Click
Power management. Propulsion plant. Cargo and ballast control. Watch call system.
LNG1032-310 :
A :
What is the role of the AIS (Integrated Automation System)? Wrong or Missed Data? Click
Videotel CBT LNG Vers 1.0.32 (QUESTIONS & CORRECT ANSWERS)
3.Support Systems (Module 3) - test for Chief Officer
Process and system monitoring Event logging and monitoring Control functions (motor control, valve control, PIDs)
LNG1032-311 :
A :
What are the basic functions carried out by the IAS (Integrated Automation System)? Wrong or Missed Data? Click
The IAS is a distributed processing system because the control functions are defined locally in the process stations and not in the operator stations. In the event of failure of control of any equipment then it is possible to change from IAS control to manual local control.
LNG1032-312 :
A :
Why is AIS (Integrated Automation System) defined as a distributed processing system? Wrong or Missed Data? Click
An impulse turbine has fixed nozzles that change the steam flow into high speed steam jets. These jets contain significant kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction. A pressure drop occurs across only the stationary blades with a net increase in steam velocity across the stage.
LNG1032-315 :
A :
How does operate an impulse turbine? Wrong or Missed Data? Click
700-900°C
LNG1032-316 :
A :
What temperature does the air reach on the compression stroke in the cylinder of a diesel engine? Wrong or Missed Data? Click
Turbo chargers are used to compress the air into the cylinders of a diesel engine so that more fuel can be burnt and so more power can be developed.
LNG1032-317 :
A :
What is the use of turbo chargers on Diesel engines? Wrong or Missed Data? Click
In a diesel electric power plant the diesel generators are run at their optimum load for fuel efficiency and are stopped or started depending on the speed required.
LNG1032-318 :
A :
What is the main advantage of a diesel electric power plant? Wrong or Missed Data? Click
Gas turbines have a high power-to-weight ratio.
LNG1032-319 :
A :
What is an important advantage of gas turbines? Wrong or Missed Data? Click