Confined Space: Atmospheric and other hazards

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. A street manhole is next to busy traffic. Which contaminant may enter it from outside?

   1. Extra oxygen pushed in by passing trucks
   2. Chlorine from nearby swimming pools
   3. Ozone created by the traffic lights
   4. Carbon monoxide from vehicle exhaust

2. What does "escape unaided" mean in Ontario's confined space rules?

   1. Getting out within 30 seconds of hearing any alarm sound inside
   2. Getting out without a respirator, equipment or another person's help
   3. Getting out after the attendant has opened the hatch for you
   4. Getting out through any opening other than the main entry

3. Above what oxygen level is a confined space atmosphere considered oxygen-enriched in Ontario?

   1. 21 per cent
   2. 23 per cent
   3. 30 per cent
   4. 19.5 per cent

4. Organic material is decomposing at the bottom of a pit. Which gases can it produce?

   1. Only harmless water vapour
   2. Argon and neon gas only, nothing else
   3. Pure oxygen and helium gas
   4. Methane and hydrogen sulphide

5. A steel tank has been sealed for months and its walls are rusting. What hazard may have developed?

   1. Explosive dust, because rust floats in the air
   2. No hazard, because rust is a harmless solid
   3. Oxygen enrichment, because rusting releases oxygen
   4. Oxygen deficiency, because rusting uses up oxygen

6. Toxic contaminants count as an atmospheric hazard in Ontario when they could do what?

   1. Threaten life or stop a person escaping unaided
   2. Make the space slightly warmer than outside
   3. Leave dust on the worker's clothing after work
   4. Cause a mild smell that bothers some of the workers

7. At around 16 per cent oxygen, what does the Ontario guideline say happens?

   1. Judgement and breathing become impaired
   2. Fire risk becomes extreme in the space
   3. Nothing happens; 16 % is normal for indoor air
   4. Death occurs within seconds every time

8. In Ontario, an oxygen level below what percentage is an atmospheric hazard?

   1. 16 per cent
   2. 21.5 per cent
   3. 19.5 per cent
   4. 23 per cent

9. A worker cleans the inside of a tank with a solvent. How can this change the space's atmosphere?

   1. It cannot change the air, since the tank was tested before entry
   2. It adds oxygen to the space, since solvents release oxygen
   3. The work itself can create solvent vapours inside the space
   4. It removes every hazard, since cleaning makes the tank safer

10. Which of these is a biological hazard that may be found in sewers and digesters?

    1. Noise from the pumps running nearby
    2. Low lighting inside the space
    3. Bacteria from fecal matter and sludge
    4. Heat from a boiler that is still cooling down

11. What do simple asphyxiants such as nitrogen, argon and carbon dioxide do?

    1. Add oxygen to the air and make breathing easier
    2. Burn the skin on contact like a strong acid would
    3. Displace oxygen, so a person can collapse within minutes
    4. Make a strong smell that warns everyone nearby

12. About how much oxygen does normal outdoor air contain?

    1. About 78 per cent
    2. About 21 per cent
    3. About 16 per cent
    4. About 50 per cent

13. Which hazard involves being buried or trapped by grain, sand or other bulk material?

    1. Oxygen enrichment
    2. Asphyxiation by gas
    3. Thermal stress
    4. Engulfment

14. Which is a common cause of oxygen enrichment in a confined space?

    1. Nitrogen used to purge the space earlier
    2. Rust forming on the inside walls of a tank
    3. Decaying leaves at the bottom of a pit
    4. A leaking oxygen line or welding equipment