CSLB C-39 Roofing ContractorSafety and RepairMedium

A roofing crew is performing hot work involving torch-applied modified bitumen on a commercial roof. Cal/OSHA requires a fire watch to be maintained during and after the hot work. For how long must the fire watch remain on site after the hot work has been completed?

  1. AAt least 1 hour
  2. BAt least 15 minutes
  3. CAt least 2 hours
  4. DAt least 30 minutes
Show answer & explanation

Correct answer: D. At least 30 minutes

Cal/OSHA regulations require that a fire watch be maintained for at least 30 minutes after the completion of hot work operations to ensure any smoldering embers or latent heat does not ignite a fire.

Why the other options are wrong

  • A. While longer is always safer, 1 hour is not the minimum specified by Cal/OSHA.
  • B. 15 minutes is insufficient time for a fire watch according to Cal/OSHA regulations.
  • C. 2 hours is a common recommendation for some jurisdictions or high-risk scenarios, but Cal/OSHA's minimum is 30 minutes.

Cal/OSHA Hot Work Fire Watch Duration

Cal/OSHA requires a fire watch to remain on site for a minimum of 30 minutes after hot work operations are completed.

  • Prevents delayed ignition.
  • Applies to all hot work (torch, welding, etc.).
  • Fire watch must be properly equipped.

Memory trick: Thirty minutes, watch the fire's last gleam, then you can leave, like a fading dream.

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