NFPA 72 Fire Alarm and Signaling Exam Prep 2025 – Complete Practice Test

The photoelectric sensor is well-suited for detecting thick visible smoke particles because it utilizes a light beam to identify smoke. When smoke particles enter the sensing chamber, they scatter the light beam, which triggers the alarm. This type of sensor is particularly effective for smoke that is dense and contains larger particles, such as that produced by materials like paper or wood, which typically generate visible smoke.

Other types of sensors also exist, such as ionization sensors, which are more reactive to fast-flaming fires that produce less visible smoke. Thermal sensors detect changes in temperature rather than smoke particles, making them unsuitable for situations where smoke detection is required. Multispectrum sensors incorporate various technologies to detect different types of fires but may not be specifically tailored for thick, visible smoke like photoelectric sensors are. Thus, the photoelectric sensor's reliance on light scattering makes it the best choice for effectively detecting thick smoke.