The fire ground clock starts when?

• A. On arrival
• B. When the first due apparatus sets the parking brake
• C. At the time of initial alarm
• D. When the incident is declared under control

Answer: (B)

The fire ground clock measures the duration of on-scene operations, so its start needs a clear, observable point when crews are actually ready to work on scene. The moment the first due apparatus parks and sets the parking brake provides that exact point: the vehicle is stationary, the crew has stabilized the scene, and they’re ready to begin tasks such as size-up, positioning, and initial actions. This gives a consistent starting reference for tracking how long actions take from arrival through containment and overhaul.

Starting at the initial alarm happens before any on-scene activity begins, and starting on arrival can occur while the unit is still stopping or preparing to operate. Declaring the incident under control marks the end of operations, not the beginning.