A shock (vibration sensor) can detect the mechanical vibration (shock) associated with door or window intrusion. They can also be used on perimeter fencing to detect an intruder climbing a fence. When a large shock wave is detected, the shock sensor activates, and a signal is sent to the alarm system to inform it of the security breach.

Shock sensors must comply with applicable standards, such as ANSI/UL 639, Standard for Safety for Intrusion-Detection Units.

According to UL 639, Section 1.1, “These requirements cover intrusion-detection units intended to be used in burglary-protection signaling systems. These units are intended to be used in indoor or outdoor locations to automatically indicate the presence of an intruder by actuating electrical control circuits.

1.2 An intrusion detector, as covered by these requirements, consists of one or more unit assemblies of electrical components that are designed to detect the presence, movement, sound or other activity of an intruder. Provision is made for connection to the assembly of power supply, remote control, and signal circuits by a prescribed method of wiring.

1.3 Intrusion-detection units covered by these requirements are intended to be installed in accordance with the Standard for Installation and Classification of Burglar and Holdup Alarm Systems, UL 681”.

Below is a sample of NFPA 731. For the complete section, see the actual NFPA 731 text at NFPA.ORG. Once there, click on the free access link to the latest edition of NFPA 731.

5.3.3.1.5 Shock (Vibration) Sensors. Shock sensors shall be in compliance with applicable standards, such as ANSI/UL 639, Standard for Safety for Intrusion-Detection Units.