Understanding Sensor Grades and Their Importance in Security Systems

However, not all intrusion detection sensors offer the same level of reliability and performance. One effective way to evaluate sensor reliability is by checking whether they comply with internationally recognized standards. One of the most widely adopted is the European EN 50131 standard, which categorizes security sensors into 4 grades, based on their resistance to tampering and ability to withstand attempted break-ins.
This article explores the concept of sensor grades, their role in intrusion detection systems, and how they guide the selection of suitable security solutions based on risk levels.

Sensor grade refers to the classification of security sensors based on their ability to detect intrusions and resist tampering or bypass attempts. These grades are defined by international standards such as the European EN 50131, which categorizes alarm systems into four levels—Grade 1 to Grade 4—according to the level of protection they offer.

Each grade corresponds to a specific risk environment, ranging from low-risk residential areas to high-security facilities such as military sites. Understanding sensor grades helps security professionals and property owners select the appropriate level of protection for their needs, ensuring that the system’s capabilities align with the potential threats of the environment.

The four EN 50131 grades range from Grade 1 (low risk) to Grade 4 (very high risk). The table below outlines each grade and suitable application examples.

The choice of sensor grade should reflect the level of risk your property faces.

For medium-risk environments, such as homes or small businesses, Grade 2 sensors are generally sufficient. They provide essential protection while remaining cost-effective.
For higher-risk environments, such as commercial or industrial properties, Grade 3 sensors are recommended. These more sophisticated devices can withstand fluctuating temperatures and background noise, and often include advanced features like anti-masking, making them ideal for detecting experienced intruders.

OPTEX offers both Grade 2 and Grade 3 certified products that comply with EN 50131 standards. Each sensor undergoes more than 150 product evaluation tests to ensure reliability under real-world conditions, including environmental changes, vandalise and attempts at tampering.

Understanding sensor grades is essential for designing effective intrusion detection systems that match the level of risk in each environment. The EN 50131 standard provides a clear framework for evaluating sensor performance, from basic protection in low-risk areas to advanced security in high-risk facilities.

OPTEX offers certified Grade 2 and Grade 3 sensors that meet international standards and undergo rigorous testing to ensure reliability under real-world conditions. By selecting the appropriate sensor grade, security professionals and property owners can enhance protection, reduce false alarms, and respond proactively to potential threats.