Standards Matter
July 13, 2023

Helping Protect Homes With Standards for Intrusion Detection Units: UL 639

Woman setting alarm at keypad.

Why It Matters

According to the FBI, burglary accounts for 16.1% of all property crimes in the U.S., totaling approximately 3 billion dollars per year in losses – an average of $2,661 USD per occurrence! 

In order to gain the upper hand and avoid worry while sleeping, taking vacations, and doing other activities they enjoy, property owners have come to trust either commercial or home burglary detection systems.

One of the most important components of a burglary detection system is the intrusion detection unit. This all-seeing and ever-watchful sensor is the piece of the system that detects and transmits data to the alarm portion of the system, alerting the authorities that someone or something has entered the property. Whether a person with harmful intent, or a curious racoon looking for an easy meal, this crucial piece of technology is the first point of contact.

What We’re Doing

Having a unit that can sense movement, sound, or other activity should not be a further cause of stress. To help ensure these units function properly, UL Standards & Engagement published UL 639, the Standard for Intrusion-Detection Units, which features requirements for construction, mounting, and function. The Standard’s requirements for glass breakage detectors help to evaluate enclosure strength, sealing of electrical components against unintentional contact, and mounting requirements. 

Glass breakage detectors attach to windows to generate alarm signals if breakage is detected. Although these detectors need to be sensitive, they also need to be selective enough to not generate an alarm signal from ambient noises – such as when a bird chirps. To ensure the sensors function as needed, UL 639 establishes testing requirements that fall within the limits of intrusion. During sensitivity and attack tests, for example, the detector is installed on a window according to manufacturer specifications and is struck by steel ball bearings of varying weights and sizes. In order to pass the tests, the detector will not generate an alarm signal unless the glass breaks on impact. 

There’s also the matter of fastening these detectors in a suitable manner to ensure optimum performance. To address this issue, UL 639 features requirements for adhesive performance under a variety of conditions. Not only must the adhesive perform well under an impact test at room temperature, but the Standard  also dictates performance parameters for extreme temperatures, water exposure, humidity, and load bearing (50 pounds for a minute). Thorough testing for long-term exposure to cleaning agents is also required by the Standard. All of this helps ensure solid placement, reliable sensor activation when appropriate, and reduced risk of a sensor failure via installation error.

How You Can Help 

Our standards are developed through a consensus-based process, which integrates scientific and testing expertise with input from our technical committee (TC) members and stakeholders. TC members represent a variety of interests, including industry, academia, government, retail, and manufacturing. If you are involved in the design, construction, sale, programming, or installation of intrusion-detection units, and you would like to help improve safety in your industry, please take a moment to learn how you can get involved.