It is a device that is widely used in fire detection systems due to its capability of detecting most types of fires in their early stages. These devices are classified into three categories:

1. Ionization Smoke Detector: Detects both visible and invisible smoke as well as small particles that rise due to heat. It is used in fires such as paper fires because of the fast combustion.

2. Photoelectric Smoke Detector: Detects visible smoke and larger particles that rise due to heat. It is used in areas where cables or PVC materials are present, but it is sensitive to cigarette smoke or similar sources.

3. Duct Smoke Detector: Installed within air conditioning ducts (return air ducts).

Factors affecting the performance of a smoke detector:

• Vapors, dust, or humidity.

• Airflow greater than 1.5 m/s.

• Paint fumes, cleaning agents, chemicals, air fresheners, or strong odors.

• Excessive smoking or similar sources.

• Vibrations or shocks.

• Insects.

• Magnetic fields or radiation.

• Ceiling height.