NCIDQ IDFX Practice Exam

Which type of detector responds to ionized particles rather than smoke?

1. Photoelectric detector

2. Ionization detector

3. Flame detector

4. Temperature detector

The correct answer is: Ionization detector

The ionization detector is specifically designed to respond to ionized particles, which are produced from the combustion of materials. This type of detector contains a small amount of radioactive material that ionizes the air in the sensing chamber. When smoke enters the chamber, it disrupts the ionization process, which triggers the alarm. Ionization detectors are particularly effective at detecting fast-flaming fires that produce little visible smoke, making them a valuable tool in fire safety. In contrast, the photoelectric detector primarily responds to the presence of smoke particles by using a light source and a sensor. The flame detector is designed to detect flames through various means, such as infrared or ultraviolet light, and is more specialized for certain types of fires. The temperature detector monitors changes in temperature and is not sensitive to smoke or ionized particles at all. Thus, the ionization detector is the most appropriate answer as it directly relates to the detection of ionized particles resulting from combustion.