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TOTS 1B-The Flammability Diagram

CBT 19 questions

First 5 of 19 questions — with answers

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  1. Question 1

    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?
    • Yes, the atmosphere is below the critical dilution line.
    • No, inerting must be continued.
    • No, the tank atmosphere is in the Flammable Range.
    • Yes, the tank atmosphere would remain too rich to support combustion.

  2. Question 2

    Define the «Lower Flammable Limit» of a hydrocarbon gas?
    • It is the gas concentration below which there is not sufficient gas to support and propagate combustion.
    • 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 oxygen to support and propagate combustion.

  3. Question 3

    Define the «Upper Flammable Limit» of a hydrocarbon gas?
    • It is the gas concentration above which there is too much oxygen to support and propagate combustion.
    • It is the gas concentration above which there is not sufficient air 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.

  4. Question 4

    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.
    • Due to the high relative density of hydrocarbon gas, it tends to layer, and collect in pockets.
    • To obtain an average reading throughout the tank.

  5. Question 5

    In practical terms, what figures can be used for the Lower and Upper Flammability Limits of oil tanker cargoes?
    • 19 % and 21 % of oxygen.
    • 1 % and 10 % of gas.
    • 5 % and 21 % of oxygen.
    • 5 % and 50 % of gas.

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About this CBT test

TOTS 1B-The Flammability Diagram is a CBT test with 19 questions and verified answers. Common topics include: flammability diagram, flammable limit, cargo tank, relative density, atmosphere point, characteristics vapours, gas, reference.

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