Rollover describes a condition where the unburned fire gases accumulated at the top of a compartment ignite and flames propagate through the hot-gas layer.

Rollover describes a condition where the unburned fire gases accumulated at the top of a compartment ignite and flames propagate through the hot-gas layer.

• A. The mixing of air and fuel at floor level
• B. The ignition of fuels at ground level
• C. The complete cessation of flame
• D. The unburned fire gases at the top ignite and flames propagate through hot gas layer

Answer: (D)

Rollover is a ceiling-level phenomenon where unburned fire gases accumulate near the top of a compartment. If those gases ignite, flames propagate through the hot gas layer, spreading along the ceiling rather than primarily from the floor. This differs from any ignition at ground level or a cessation of flame. So the description that matches rollover is the ignition of the unburned gases at the top with flames traveling through the hot-gas layer.

Rollover is a ceiling-level phenomenon where unburned fire gases accumulate near the top of a compartment. If those gases ignite, flames propagate through the hot gas layer, spreading along the ceiling rather than primarily from the floor. This differs from any ignition at ground level or a cessation of flame. So the description that matches rollover is the ignition of the unburned gases at the top with flames traveling through the hot-gas layer.