CSLB C-36 Plumbing ContractorSafetyHard

A plumbing contractor is using a portable propane torch for soldering copper pipes in a confined area with limited ventilation. What is the MOST significant atmospheric hazard that could develop if proper precautions are not taken?

  1. ADepletion of oxygen.
  2. BAccumulation of methane gas.
  3. CIncrease in carbon dioxide from combustion.
  4. DRelease of hydrogen sulfide.
Show answer & explanation

Correct answer: A. Depletion of oxygen.

Combustion processes, such as those from a propane torch, consume oxygen. In a confined area with limited ventilation, this oxygen consumption can rapidly lead to oxygen depletion, posing an immediate and severe risk of asphyxiation to workers.

Why the other options are wrong

  • B. Methane gas is typically associated with natural gas leaks, not directly from propane torch combustion.
  • C. While carbon dioxide is produced by combustion, oxygen depletion is the more immediate and life-threatening hazard in a confined space with limited ventilation.
  • D. Hydrogen sulfide is a toxic gas associated with sewage or decomposition, not directly generated by a propane torch.

Oxygen Depletion (Confined Space)

A hazardous condition in a confined space where the oxygen concentration falls below a safe level (typically 19.5%), often due to combustion, displacement by other gases, or biological processes.

  • Can cause rapid asphyxiation.
  • Common in confined spaces with combustion sources.
  • Requires atmospheric testing and ventilation.

Memory trick: In a box, with a flame, oxygen goes down, that's the dangerous game.

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