Welcome to the website where you can pass online the CES CBT CD-7048 test on the subject «TOTS 1C-The Flammability Diagram». Practice like this will help you as a marine specialist improve your knowledge with the help of online studying and appraisal practice. CES based on practical information and marine specialists experience.
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Current test contains Seagull CES questions on the subject «TOTS 1C-The Flammability Diagram». Those questions can be used for competence verification specialist capable of preventing accidental situations related with transporting safety, or also for self-examination.
«TOTS 1C-The Flammability Diagram» subject includes theoretical and practical information about advanced training for work on any type of vessel. The test provides in-depth knowledge essential for maritime professionals working on various types of vessels. This course focuses on understanding flammability diagrams, which are crucial for assessing the safety of gas mixtures in different environments. Participants will learn to interpret and apply these diagrams to prevent fire and explosion hazards. The training includes hands-on exercises to identify flammable limits and control measures for different substances. Emphasis is placed on safety protocols and compliance with international maritime regulations. Advanced topics cover the latest technologies and methods for monitoring and managing flammable atmospheres. This comprehensive training is critical for ensuring the safety and efficiency of vessel operations.
On this site Crew Evaluation System Test on the subject «TOTS 1C-The Flammability Diagram» contains 47 questions you need to answer with no possibility to go back to previous question. Therefore, we recommend carefully reading each question and making decision with no hurry. In case you have some difficulty answering, you have also possibility to request a hint.
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* Some questions may have more than 1 correct answer.
A gas turbine with afterburner will produce similar inert gas to an independent inert gas generator. What level of oxygen might typically be delivered?
1,5-2,5 % by volume.
5 % by volume.
8-10 % by volume.
Approximately 12 % by volume.
After inerting a cargo tank, the oxygen content was found to be 7,5 %, and the hydrocarbon gas content 2 %. Using the Flammability Diagram, would you consider the tank to be safely inerted before gas freeing?
No, inerting must be continued.
No, the tank atmosphere is in the Flammable Range.
Yes, the atmosphere is below the critical dilution line.
Yes, the tank atmosphere would remain too rich to support combustion.
At high concentrations, hydrocarbon gas has a high relative density. How will this affect the sampling procedure?
Air may be drawn into the sample line, giving a false reading.
Gas content readings may be inaccurate due to the higher density.
The atmosphere must be sampled at different depths, because the gas tends to layer and form pockets.
It may be impossible to obtain samples from the bottom of the tank because the gas is too heavy.
Define the «Lower Flammable Limit» of a hydrocarbon gas?
It is the gas concentration above which there is not sufficient air to support and propagate combustion.
It is the gas concentration above which there is too much gas to support and propagate combustion.
It is the gas concentration below which there is not sufficient gas to support and propagate combustion.
It is the gas concentration below which there is not sufficient oxygen to support and propagate combustion.
Define the «Upper Flammable Limit» of a hydrocarbon gas?
It is the gas concentration above which there is not sufficient air to support and propagate combustion.
It is the gas concentration above which there is too much oxygen to support and propagate combustion.
It is the gas concentration below which there is not sufficient gas to support and propagate combustion.
It is the gas concentration below which there is not sufficient oxygen to support and propagate combustion.
Explain how very cold weather conditions can cause over-pressurisation of cargo tanks?
Ice could form on the vents, or the P/V or high velocity vent valves could freeze.
Cold weather may cause malfunctioning of cargo monitoring equipment, including pressure monitors.
Low temperatures will increase the viscosity of the cargo, and may make it unpumpable.
The increased density of the cargo could lead to overloading.
Explain why the atmosphere in a cargo tank must be sampled at different depths?
To ensure that enough gas is drawn through the equipment to avoid it remaining in the sampling line.
To make sure that the detection equipment is working correctly.
To obtain an average reading throughout the tank.
Due to the high relative density of hydrocarbon gas, it tends to layer, and collect in pockets.
Gas detection equipment showed the oxygen content of a cargo tank to be 2 %, and the hydrocarbon gas content to be 2 %. Using the Flammability Diagram, is it safe to gas free the tank with fresh air?
No the tank must first be purged with inert gas.
No, the tank atmosphere is in the Flammable Range.
Yes, the tank atmosphere would remain too rich to support combustion.
Yes, the atmosphere would remain outside the Flammable Range.
Gas detection equipment showed the oxygen content of a cargo tank to be 3 %, and the hydrocarbon gas content 8 %. Using the Flammability Diagram estimate whether it is safe to gas free the tank with fresh air?
No the tank must first be purged with inert gas.
No, the tank atmosphere is in the Flammable Range.
Yes, the atmosphere would remain outside the Flammable Range.
Yes, the tank atmosphere would remain too rich to support combustion.
If cargo tank openings are opened frequently for operations such as sampling and dipping, inert gas quality may be affected. How so?
Inert gas would escape, lowering the tank pressure.
Moisture from the atmosphere could enter the tank.
The hydrocarbon content of the tank atmosphere would be increased.
Air could enter the tanks through the openings.
In addition to the manufacturer’s tests of the inert gas plant, what other checks must be performed before inerting operations?
Checks of the fixed and portable oxygen meters and gas detectors.
A pressure test of the cargo and inert gas pipework.
A test of the crude oil washing system, if fitted.
An inspection of the cargo tanks.
In practical terms, what figures can be used for the Lower and Upper Flammability Limits of oil tanker cargoes?
1 % and 10 % of gas.
5 % and 21 % of oxygen.
5 % and 50 % of gas.
19 % and 21 % of oxygen.
Inert gas quality in slop tanks may be degraded when tank washings from non-inerted tanks are added: Why?
Air would be trapped in the washings, particularly if an eductor was in use.
Adding washings would increase the pressure in the tank, forcing inert gas out via the vent line.
The higher temperature of the slops caused by adding washings would result in increased evolution of hydrocarbon vapours.
The turbulence in the slops caused by adding washings would result in increased evolution of hydrocarbon vapours.
Pressure in the cargo tanks may be reduced due to low night time temperatures. How could this affect inert gas quality?
Components of the inert gas may break down at low pressure.
The inert gas may condense into the cargo at low temperatures.
Air could be drawn into the system.
The rate of evolution of cargo vapours could be increased.
The characteristics of the vapours given off by clean products such as motor or aviation gasoline can be represented by those of butane. What is the relative density of butane?
1,00.
2,00.
2,55.
5,50.
The characteristics of the vapours given off by crude oil can be represented by those of propane. What is the relative density of propane?
0,55.
1,00.
1,55.
5,50.
The characteristics of the vapours given off by natural gasolines can be represented by those of pentane. What is the relative density of pentane?
0,55.
1,00.
2,50.
5,50.
What action must be taken if the inert gas plant fails during cargo discharge operations?
You should prevent air from entering the tanks, and stop discharge from inerted tanks.
You should carefully allow fresh air into the tanks to prevent under-pressurisation.
You should continue discharge, monitoring oxygen and gas concentration in the cargo tanks.
You should reduce the discharge rate until the plant is repaired.
What action should be taken if the pressure in inerted cargo tanks falls to the low pressure alarm level during a ballast passage?
If the tanks are not loaded, they can be opened to atmosphere to prevent under-pressurisation.
The P/V valve will take care of fluctuations in the tank pressure.
The tanks should be gas freed.
The inert gas plant should be used to top up the tanks, and the oxygen content should be less than 5 %.
What adverse results may occur if cargo tanks are allowed to become over-pressurised?
Major deformation or failure of the tank structure could occur, leading to explosion, fire or pollution.
There could be a loss of cargo due to excessive venting.
There could be difficulty continuing the loading operation due to high pressure.
There could be leakage of cargo and vent pipelines.
What are the main components of inert gas delivered from a flue gas plant?
What are the main factors which could cause over-pressurisation of a cargo tank?
Excessively high delivery pressure from the inert gas plant or shore delivery supply.
Inadequate venting arrangements or overfilling the tank.
Pump failure during discharge.
All three answers.
What inert gas monitoring instrumentation must be fitted in the cargo control room of a tanker?
Instruments to continuously indicate and permanently record the oxygen content and deck main pressure.
A device to permanently record the times of stopping and starting the inert gas plant.
Instrumentation showing all operating parameters of the inert gas plant.
Instrumentation showing the cargo tank temperature and pressure.
What is meant by the «Dilution» method of inerting a cargo tank?
The incoming inert gas is mixed with the tank atmosphere to form a homogenous mixture throughout the tank.
The inert gas is introduced slowly at the bottom of the tank so that a stable horizontal interface is formed.
The inert gas is introduced slowly at the top of the tank so that a stable horizontal interface is formed.
The inert gas is mixed with fresh air, and introduced rapidly into the tank.
What is meant by the «Displacement» method of inerting cargo tanks?
The inert gas is introduced slowly at the top of the tank so that a stable horizontal interface is formed.
The incoming inert gas is mixed with the tank atmosphere to form a homogenous mixture throughout the tank.
The inert gas is introduced slowly at the bottom of the tank so that a stable horizontal interface is formed.
The inert gas is mixed with fresh air, and introduced rapidly into the tank.
What is the maximum oxygen content allowed by SOLAS in the output from an inert gas plant?
Not more than 1 %.
Not more than 5 %.
Not more than 8 %.
Not more than 21 %.
What is the maximum oxygen content which should be maintained in a cargo tank during operations?
Not more than 1 %, except when gas freeing.
Not more than 8 %, except when gas freeing.
Not more than 18 %, except when loading.
Not more than 21 %, except when loading.
What is the minimum recommended pressure for cargo tanks connected with an inert gas main?
0,25 bar.
100 mm water gauge.
500 mm water gauge.
One bar.
What is the operating principle of a dry type deck seal in an inert gas system?
A large diameter non-return valve is fitted, which will close when the inert gas supply stops.
The chamber contains a number of baffles which prevent solid materials from entering the cargo tanks, and help regulate the pressure of the inert gas main line.
The chamber is drained when the inert gas plant is prepared for operation, but can be filled with water when the plant is not in use, forming a seal.
A dump valve is fitted, which opens, filling the lower chamber with water to form a seal when the inert gas supply stops.
What is the purpose of the deck water seal in an inert gas system?
To prevent cargo liquid or vapour from entering the engine room.
To clean the inert gas before delivery to the tanks.
To cool the inert gas before delivery to the tanks.
To regulate the pressure of the inert gas main line, and help prevent over-pressurisation of the tanks.
What is the relative density of hydrocarbon gas at concentrations near the Lower Flammable Limit?
Approximately 0,7, lighter than air.
Approximately 1,0, the same as air.
Approximately 1,5, heavier than air.
Approximately 2,0, much heavier than air.
What oxygen content would normally be expected from an independent inert gas generator?
1,5-2,5 % by volume.
5 % by volume.
8-10 % by volume.
Approximately 12 % by volume.
When using the «Dilution» method of inerting a cargo tank, inert gas is introduced rapidly into the tank. Why?
Because inert gas is slightly less dense than hydrocarbon vapour, and a stable horizontal interface can be formed.
Because the incoming inert gas must have enough velocity to reach the bottom of the tank and mix thoroughly with the tank atmosphere.
Because the incoming inert gas must have enough velocity to reach the bottom of the tank and form a stable interface.
Because the inert gas is hotter than the tank atmosphere, and it is necessary to mix thoroughly with the tank atmosphere.
When using the «Dilution» method of inerting, it is essential that only a small number of cargo tanks are open. Why?
Because the inert gas must be introduced at a high enough rate to mix thoroughly with the tank atmosphere.
Because it is difficult to monitor the hydrocarbon levels properly if a large number of tanks are open.
Because the incoming inert gas must form a stable interface with the tank atmosphere.
Because the inert gas plant works more efficiently when the back pressure is higher.
When using the «Displacement» method of inerting cargo tanks, inert gas is introduced slowly at the top of the tank. Why?
Because inert gas is slightly less dense than hydrocarbon vapour, and a stable horizontal interface can be formed.
Because inert gas is denser than hydrocarbon vapour, and a stable horizontal interface can be formed.
Because the incoming inert gas will mix with the tank atmosphere throughout the tank.
Because the inert gas is hotter than the tank atmosphere and it is necessary to avoid violent mixing.
When using the «Displacement» method of inerting, it is common practice to inert several tanks at the same time. Why?
Because it is easier to compare the hydrocarbon levels in the tanks if a large number are open.
Because the inert gas must be introduced at a high enough rate to mix thoroughly with the tank atmosphere.
Because the inert gas plant works more efficiently when the back pressure is lower.
Because the inert gas must be introduced at a slow enough rate to enable the formation of a stable horizontal interface.
Why is an oxygen content of not more than 8 % considered to be the safe limit in a cargo tank atmosphere?
Because the atmosphere is safely outside the Flammable Range.
Because 8 % hydrocarbon gas is above the Upper Flammable Limit.
Because 8 % hydrocarbon gas is below the Lower Flammable Limit.
Because the tank atmosphere was outside the Flammable Range at the time the readings were taken.
With reference to the Flammability Diagram, if a cargo tank atmosphere was at point F, what would be the effect of diluting with fresh air?
The hydrocarbon concentration would be increased, taking the atmosphere into the Flammable Range.
The hydrocarbon concentration would be reduced, and the oxygen level increased, resulting in a safe tank atmosphere.
The hydrocarbon concentration would be reduced, and the oxygen level increased, taking the atmosphere into the Flammable Range.
The oxygen level would be increased, resulting in a safe tank atmosphere.
With reference to the Flammability Diagram, if a cargo tank atmosphere was at point F, why would it be necessary to dilute the atmosphere to point H with inert gas before gas freeing with fresh air?
To reduce the hydrocarbon level below the critical dilution line.
To help prevent corrosion in the tank.
To increase the hydrocarbon level above the Upper Flammable Limit.
To reduce the oxygen level to below the critical dilution line.
With reference to the Flammability Diagram, if a cargo tank atmosphere was at point F, would you consider it to be safe to gas free the tank with fresh air?
No, the tank atmosphere is in the Flammable Range.
No, the tank must first be purged with inert gas.
Yes, the atmosphere would remain outside the Flammable Range.
Yes, the tank atmosphere would remain too rich to support combustion.
With reference to the Flammability Diagram, if a cargo tank atmosphere was at point H, would you consider it to be safe to gas free using fresh air?
No, the tank atmosphere is in the Flammable Range.
No, the tank must first be purged with inert gas.
Yes, the atmosphere would remain outside the Flammable Range.
Yes, the tank atmosphere would remain too rich to support combustion.
With reference to the Flammability Diagram, what conditions are shown at point A?
The hydrocarbon gas concentration is at its Lower Flammable Limit.
The tank atmosphere contains no oxygen, and cannot support combustion.
The tank atmosphere is too rich to support combustion.
The tank contains fresh air, with no hydrocarbon gas, and cannot support combustion.
With reference to the Flammability Diagram, what conditions are shown at point B?
The tank atmosphere is too rich to support combustion.
The hydrocarbon gas concentration is at its Lower Flammable Limit.
The hydrocarbon gas concentration is at its Upper Flammable Limit.
The tank atmosphere is too lean to support combustion.
With reference to the Flammability Diagram, what conditions are shown at point C?
The hydrocarbon gas concentration is at its Upper Flammable Limit.
The tank atmosphere contains no oxygen, and cannot support combustion.
The tank atmosphere is too rich to support combustion.
The hydrocarbon gas concentration is at its Lower Flammable Limit.
With reference to the Flammability Diagram, what conditions are shown at point D?
The hydrocarbon gas concentration is at its Upper Flammable Limit.
The hydrocarbon gas concentration is at its Lower Flammable Limit.
The tank atmosphere contains no oxygen, and cannot support combustion.
The tank atmosphere is too lean to support combustion.
With reference to the Flammability Diagram, what point on the diagram shows a hydrocarbon concentration at its Lower Flammable Limit, with no inert gas?
Point A.
Point C.
Point D.
Point G.
With reference to the Flammability Diagram, what point on the diagram shows a hydrocarbon concentration at its Upper Flammable Limit, with no inert gas?
Point A.
Point C.
Point D.
Point G.
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