Which type of fire risk is associated with greater sensitivity to fast-flaming fires, typically detected quickly by a certain detector type?

• A. Dual Sensor
• B. Ionization
• C. Photoelectric
• D. Optical

Answer: (B)

The main idea is how detectors respond to different ways a fire develops. Ionization detectors are wired to react quickly to flaming fires. They use a tiny amount of radioactive material to create a constant ion current in the air; when fast flames produce certain combustion byproducts and quick changes in ionization, the alarm triggers almost immediately. This makes them particularly sensitive to fast-flaming fires, which tend to generate those rapid changes before a lot of smoke has built up.

In contrast, smoke-based detectors like photoelectric (optical) detectors sense light scattered by smoke particles and tend to respond sooner to smoldering, smoky fires rather than burst flames. Dual-sensor units mix both technologies to cover both fire styles, but the specific sensitivity to fast-flaming fires points to ionization detectors.