Welcome to the website where you can pass online the CES CBT CD-0426 test on the subject «Gas Measurement, Measuring Instruments». 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.
CES tests developed for evaluating seaman basic knowledge by Seagull Company (rebranded as «OTG»), is an evaluating online-tool, used for revealing any professional preparation needed in specific fields of knowledge, defined by STCW.
CES tests have proven themselves as good tools for the selection and recruitment process, as well as advancing the level of knowledge of the current officers and crew. Ocean Technologies Group use various subjects for question creation, which includes:
Crowd and Crisis Management;
Integrated Navigation System (INS);
Ballast water management;
Handling and Stowage;
Vessel operation management and safety;
Marine engineering;
Maintenance and repair, etc.
Current test contains Seagull CES questions on the subject «Gas Measurement, Measuring Instruments». Those questions can be used for competence verification specialist capable of preventing accidental situations related with transporting safety, or also for self-examination.
«Gas Measurement, Measuring Instruments» subject includes theoretical and practical information about advanced training for work on any type of vessel. The test provides training on the safe and accurate measurement of gases onboard vessels. Participants learn about the principles of gas detection, measurement techniques and the operation of various gas measuring instruments. The course covers the use of tools such as gas analyzers, detectors and calibration equipment for monitoring different gas types, including toxic, flammable and inert gases. Emphasis is placed on understanding gas properties, safety precautions and compliance with international maritime regulations. Practical training includes hands-on experience with detecting gas leaks, calibrating instruments and interpreting gas measurement data. The program also teaches emergency response procedures for handling hazardous gas situations in confined spaces or other critical areas. By completing this course, participants gain the skills needed to ensure safe and efficient gas monitoring operations on any type of vessel.
On this site Crew Evaluation System Test on the subject «Gas Measurement, Measuring Instruments» contains 28 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 sampling pump for an oxygen analyser has a capacity of 100 ml per stroke. It is connected to a 10 metre sampling line with a capacity of 25 ml per metre. What is the minimum number of strokes of the pump needed to obtain a representative sample? Select the ONE correct answer.
2.
4.
10.
25.
For common hazardous gases like hydrogen sulphide, what is the main advantage of using a personal gas monitor rather than a long term gas detector tube when working in a potentially hazardous space? Select the ONE correct answer.
The personal monitor can be used to check total exposure throughout the working period.
The personal monitor will give an alarm if the exposure limits are exceeded.
The personal monitor can be used to obtain a time weighted average.
The personal monitor can check for any hazardous gas.
How is a Time Weighted Average reading obtained from a diffusion type detector tube that has been used over a working period of eight hours? Select the ONE correct answer.
Divide the total reading on the tube by 8.
Half the reading on the tube to get a mid point reading.
Multiply the total reading on the tube by 8.
Take a direct total reading from the tube.
How is the correct volume of the sample controlled when using short term gas detector tubes with a manually operated hand pump? Select the ONE best answer.
By always operating the pump for the same period of time for each tube.
By always using a fixed number of complete strokes of the pump for each tube.
By checking how many complete pump strokes are required for that particular tube.
By always using a single complete stroke of the pump for each tube.
It is generally recommended that non metallic sampling lines and sensors are used when obtaining gas samples from cargo tanks. What additional precautions are required when taking samples during inerting of a cargo tank? Select the ONE best answer.
The inerting operation should be stopped for at least 30 minutes before introducing sampling equipment into the tank.
It is safe to take samples during inerting.
Samples should never be taken from a partly inerted tank.
The inerting operation should be stopped while samples are obtained.
Many of the oxygen analysers used onboard ship use paramagnetic type sensors. What is meant by the term «Paramagnetic»? Select the ONE correct answer.
That a material is non magnetic under any circumstances.
That a material is permanently magnetized when exposed to a magnetic field.
That a material is repelled by a magnetic field.
That a material is temporarily magnetized when exposed to a magnetic field.
Metal oxide semiconductor type sensors are increasingly being used in personal gas monitors. What is the operating principle of this type of sensor? Select the ONE correct answer.
Change of electrical resistance as oxide adsorbs the target gas.
Absorption of specific wavelengths of light.
Combustion of target gas on heated filament.
Conduction of heat from oxide surface by target gas.
What TWO types of sensor are normally used in portable oxygen analysers onboard ship? Select the TWO correct answers.
Paramagnetic.
Catalytic filaments.
Infra red absorption.
Galvanic cell.
What are the TWO main reasons for measuring the oxygen content of an enclosed space onboard a ship? Select the TWO correct answers.
To check if the oxygen content is low enough to avoid flammable mixtures.
To ensure the oxygen content is sufficient to allow safe entry.
To check the amount of hydrocarbon gas present.
To check the amount of toxic gases present.
What are the minimum checks that should be carried out before a gas detecting instrument is used to check the contents of an enclosed space? Select all correct options.
Check battery condition.
Check calibration.
Check condition of sample pump and lines and any filters.
Check for general condition.
What facility is normally provided for making a zero adjustment to a paramagnetic oxygen analyser? Select the ONE correct answer.
Adjust the electrical circuit.
Alter the relative position of the optical system.
Change the rating of the light source lamp.
Reposition the meter needle to zero.
What is meant by the term “bump test” in relation to gas detecting instruments? Select the ONE correct answer.
Checking the reading of the instrument against a known concentration of test gas.
Adjusting the span of the instrument.
Adjusting the zero setting in fresh air.
Knocking the instrument to see if the meter needle is sticking.
What is normally used to remove dirt and moisture from a gas sample prior to entry into a combustible gas indicator? Select the ONE correct answer.
A paper filter.
A cotton filter.
Cardboard.
Soda lime.
What might indicate that a galvanic cell type oxygen measuring instrument requires a replacement sensor cell? Select the ONE correct answer.
Unstable readings during calibration.
Meter indicates maximum reading during test.
Reading less than 8 % oxygen when testing an inerted cargo tank atmosphere.
Reading of 20,9 % when testing fresh air.
What precaution should be taken before using an oxygen analyser that has automatic calibration? Select the ONE correct answer.
No precautions are necessary.
The analyser should be switched on 30 minutes before use.
The analyser should be switched on in fresh air.
The analyser should be switched on with the sensor placed in the space to be tested.
What reading will be obtained if an explosimeter, with a range of 0–100 % LEL, is used to check the hydrocarbon gas content in an atmosphere containing a concentration of hydrocarbon gas which is three times the LEL. Select the ONE best answer.
The meter needle will move to full scale deflection and then fall close to zero.
The meter needle will move to full scale deflection and remain there.
The meter reading will oscillate between full scale deflection and zero.
The meter reading will stay at zero.
What should be used as the reference gas when carrying out the zero setting of a combustible or hydrocarbon gas detecting instrument? Select the ONE correct answer.
2 % butane in nitrogen.
Inert gas.
Pure oxygen.
Fresh air.
What simple test can be carried out to check for leaks in a bulb type aspirator pump for a gas detecting instrument? Select the ONE correct answer.
Nip the inlet line after squeezing the bulb to see if it stays deflated.
Nip the outlet line after squeezing the bulb to see if it stays deflated.
Pressure test the pump with gas from a span test canister.
Submerge the pump in liquid and check for bubbles as it is operated.
What test gas should be used to check the span during calibration of a combustible gas or hydrocarbon gas detector? Select the ONE best answer.
A known concentration of butane in nitrogen.
A known concentration of butane in air.
A known concentration of butane in inert gas.
Fresh air.
What would be the effect, if any, on the meter reading of a catalytic filament type combustible gas indicator if the oxygen content of the sample was less than 11 %? Select the one best answer.
The reading would be zero.
The reading would be unreliable.
The reading would show full scale deflection.
There would be no effect and an accurate reading would be obtained.
When carrying out a span check of a combustible or hydrocarbon gas detector the sample gas should normally be taken from a gas bag rather than direct from the gas canister? Why should this procedure be followed? Select the ONE correct answer.
To avoid excess pressure or flow in the instrument.
Connection of the gas bag to the instrument is easier.
To control the quantity of test gas used.
To reduce the temperature of the test gas by expanding it into the bag.
When carrying out checks of the atmosphere in a cargo tank following gas freeing, at how many levels in the tank should samples be taken to ensure there are no variations in the tank atmosphere? Select the ONE correct answer.
At least two levels.
One level is sufficient.
At least three levels.
Samples should be taken every metre depth in the tank.
Which TWO of the following gases are likely to result in poisoning of the sensor element in a catalytic filament type combustible gas detector? Select the TWO correct answers.
Carbon monoxide.
Hydrogen sulphide.
Carbon dioxide.
Oxygen.
Which TWO types of combustible/hydrocarbon gas detectors rely on resistance change with temperature for their operation? Select the TWO correct answers.
Non-catalytic heated filament type.
Infra red absorption type.
Catalytic filament type.
Refractive index type.
Which gas would be most likely to affect the reading from a refractive index type hydrocarbon gas measuring instrument? Select the ONE correct answer.
Carbon dioxide.
Hydrogen sulphide.
Nitrogen.
Oxygen.
Which material is recommended for the removal of carbon dioxide from a gas sample when measuring the hydrocarbon gas content of an inerted cargo tank atmosphere with a refractive index or infrared absorption type detector? Select the ONE correct answer.
Cotton wool.
Gauze.
Silica gel.
Sodalime.
Which type of hydrocarbon gas detecting instrument uses thermal conductivity of the gas as the means of measuring gas content in a sample? Select the ONE correct answer.
Non-catalytic heated filament type.
Catalytic filament type.
Infra red absorption type.
Refractive index type.
You are going to use a galvanic cell type oxygen analyser for checking LOW concentrations of oxygen. Which ONE of the following should be used for the span test?
Fresh air.
A test gas with 2 % oxygen and 98 % nitrogen.
A test gas with 2 % butane and 98 % nitrogen.
Inert gas with 8 % or less oxygen content.
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