What device senses both visible and invisible particles of combustion?

A smoke detector is specifically designed to sense both visible particles, such as those from smoldering fires, and invisible particles that may result from fast-burning fires. It typically operates using two main types of sensing technologies: ionization and photoelectric.

The ionization type responds quickly to fast flaming fires by detecting the ions and particles in the air created during combustion, while the photoelectric type is more responsive to smoldering fires and detects the light reflected by larger particles of smoke. This ability to sense both types of combustion particles makes smoke detectors particularly effective in providing early warning and enhancing safety, which is critical in various settings, including commercial buildings.

In contrast, a smoke alarm generally refers to a simpler device that may detect smoke but does not necessarily include both sensing technologies. A thermal detector focuses on changes in temperature rather than particle detection. A gas detector is intended to sense the presence of combustible gases and doesn’t detect the combustion particles produced by a fire. Thus, the smoke detector stands out as the appropriate answer for sensing both visible and invisible forms of combustion particles.