Fire alarm systems are designed to notify property owners of emergencies so they can take proper action. To do this effectively, fire alarm systems are comprised of four components, which include: o   Heat detectors Heat detectors work on either a fixed temperature or a rate of change in the temperature. If the temperature exceeds the pre-set value, it will trigger an alarm. o   Smoke detectors Smoke detectors detect smoke in the air in three ways: ionization, light scattering, light obstruction. o   Carbon monoxide detectors Carbon monoxide detectors are used to indicate the outbreak of a fire by sensing the CO levels in the air. These detectors have an electrochemical cell. This works to sense CO, but not smoke or any other types of combustion. o   Multi-Sensor Detectors Multi-sensor detectors combine the inputs of both heat and optical sensors with an algorithm built into the detector circuitry. The control panel and detector return a value based on the combined responses from the heat/optical sensors – and are designed to be extremely sensitive.