CSLB C-39 Roofing ContractorSafety and RepairMedium

A roofing crew is performing hot mop roofing on a commercial building. Which of the following is an essential fire prevention measure specifically required by Cal/OSHA for hot-applied roofing operations?

  1. AMaintaining a minimum of 20 feet clearance between kettles and combustible materials.
  2. BEnsuring all workers wear fire-retardant clothing and gloves.
  3. CHaving a designated fire watch present for at least 30 minutes after operations cease.
  4. DUsing only propane-fired kettles with automatic shut-off valves.
Show answer & explanation

Correct answer: C. Having a designated fire watch present for at least 30 minutes after operations cease.

Cal/OSHA regulations for hot-applied roofing require a fire watch to remain on duty for a specified period after hot work has concluded, typically 30 minutes, to monitor for smoldering or delayed ignition.

Why the other options are wrong

  • A. While clearance is important, the specific Cal/OSHA requirement for fire watch duration is more directly applicable here than a general clearance distance.
  • B. While personal protective equipment (PPE) is crucial, fire-retardant clothing for all hot-mop workers is not a universal Cal/OSHA mandate as a primary fire prevention measure; the fire watch is specifically for preventing fires after the work.
  • D. Cal/OSHA specifies requirements for kettles, but does not mandate only propane or automatic shut-off as the sole method; other types are permitted with safety measures.

Cal/OSHA Hot Work Fire Watch

For hot-applied roofing, a fire watch must be maintained for at least 30 minutes after operations cease to prevent delayed ignition.

  • Required for hot-applied roofing and other hot work.
  • Monitors for smoldering materials or hidden fires.
  • Minimum duration is typically 30 minutes after work stops.

Memory trick: Hot mop needs a keen eye, even after the work is done, to prevent a fiery surprise.

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