Confined Space: Flammable atmospheres and hot work

All 14 questions in this test

Every question and its answer choices. The correct answers and explanations appear when you take the test above.

1. For hot work in Ontario, flammable gas or vapour must be below what level?

   1. 25 per cent of the LEL
   2. 10 per cent of the LEL
   3. 5 per cent of the LEL
   4. 50 per cent of the LEL

2. For inspection work only, with no ignition source, the flammable gas level must be below what?

   1. 100 per cent of the lower explosive limit
   2. 50 per cent of the lower explosive limit
   3. 25 per cent of the lower explosive limit
   4. 1 per cent of the upper explosive limit

3. What does CCOHS advise about bringing fuel containers into a confined space?

   1. Bring as many as the work might need
   2. Do not bring them in, if possible
   3. Bring them in, but keep them near the exit
   4. Bring them in only after the hot work starts

4. Which task is an example of cold work?

   1. Grinding a steel plate
   2. Cutting with a torch
   3. Welding a cracked pipe joint
   4. Adjusting a valve by hand

5. A space has been made inert. What must entrants use?

   1. Only a hard hat and safety glasses, since inert gas is harmless to people
   2. Nothing special, since an inert space cannot catch fire or explode
   3. Respiratory protection and equipment that allows rescue from outside
   4. Only a flashlight, so they can see where the inert gas is collecting

6. Before hot work in a confined space, what should be done with surfaces coated in combustible material?

   1. Leave them alone
   2. Paint over them first
   3. Clean or shield them
   4. Heat them first

7. Readings show 8 % of the LEL and 20.5 % oxygen. What work does Ontario's decision tree allow?

   1. No work at all; entry is refused
   2. Cold work or inspection, but not hot work
   3. Hot work, cold work and inspection
   4. Hot work only, if a fire watch is posted

8. When may a worker enter a space containing airborne combustible dust at a level that could explode?

   1. Any time, if the worker only uses hand tools and moves slowly
   2. Not at all, unless it is inerted and other conditions are met
   3. Any time, as long as the worker wears a dust mask and safety glasses
   4. Only during the day, when lighting inside is better for seeing

9. What does inerting a space with nitrogen do?

   1. Cleans the walls of the space so no residue remains
   2. Removes the fire hazard but leaves too little oxygen to breathe
   3. Adds oxygen so workers can breathe more easily inside the space
   4. Makes the space safe to enter with no breathing equipment

10. May hot work be done in a confined space that has no flammable gas, vapour or dust?

    1. No, hot work is banned in every confined space in Ontario
    2. Only if the worker signs a waiver releasing the employer
    3. Yes, and no permit or attendant is needed for that work
    4. Yes, if all the normal confined space measures are in place

11. Besides the 5 % LEL limit, which condition must be met for hot work in a space that may contain flammable gas?

    1. The space is tested once a week only
    2. The oxygen level is raised above 23 %
    3. The atmosphere is continuously monitored
    4. The welder works alone with no attendant

12. For cold work in Ontario, flammable gas must be kept below what level?

    1. 25 per cent of the LEL
    2. 10 per cent of the LEL
    3. 50 per cent of the LEL
    4. 5 per cent of the UEL

13. What is "hot work" in Ontario's confined space regulation?

    1. Work that can produce a source of ignition
    2. Work done during the night shift only
    3. Work done when the air is above 30 °C inside
    4. Work that makes the worker sweat a lot

14. Why must pure oxygen never be used to "freshen" the air in a confined space?

    1. It greatly increases the risk of fire and explosion
    2. It is heavier than air and sinks to the floor
    3. It makes gas monitors stop working properly inside
    4. It is too expensive to buy for regular work