Which type of alarm sensor detects heat from a human body?

A passive infrared (PIR) sensor detects heat emitted by a human body in the form of infrared radiation. These sensors are widely used in intrusion detection systems because they identify changes in the heat profile within their field of view, triggered when a warm object, such as a person, moves across the detection zone.

How It Works:

PIR sensors rely on a pyroelectric element to measure infrared radiation changes.

The sensor is passive because it does not emit energy but detects infrared radiation from external sources.

When a human body enters the sensor's field of view, it disrupts the ambient infrared balance, triggering an alarm.

Applications:

PIR sensors are typically used in motion detectors for securing indoor spaces, as they effectively distinguish between human motion and static heat sources.

ASIS Certified Protection Professional (CPP®) References:

Intrusion Detection Technologies: The CPP manual explains the mechanisms of PIR sensors and their suitability for detecting human presence in Chapter 6.

Physical Security Design: The advantages of PIR sensors in mitigating false alarms are discussed in the section on perimeter security systems.