What are Grades in sensors and why are they important?

27 February 2023

The grade of a security system that a business requires depends on the property’s risk level. Making the right choice of graded sensors is key not only to ensure security, but also to satisfy the requirements of the insurance policy. Read our guide on intruder alarm grades.

Choosing the right sensors is crucial in ensuring the security and safety of any premise and the Grade is one of the most important criteria. This article will examine the features, benefits, and applications of the different grades of security sensors, providing insights into when to use each type in different applications. Whether you are securing a residential property or a commercial premise, this article will help you make an informed decision.

Security grading systems explained

According to European and UK standards on intruder alarms (BS EN 50131) security systems are categorised into four grades based on their reliability and endurance against intruders. Out of the four grades, only Grades 2 and 3 can get police response to alarms.

Grade 1: For sites with a very low intrusion risk that can resist inexperienced attackers by protecting obvious entry points like doors or windoes. Commonly it doesn’t have an insurance requirement for an alarm system.
Grade 2: For sites with a higher risk of intrusion and resisting more experienced intruders that may try to overcome the system by using tools or checking for other entry points.
Grade 3: For sites with a substantial risk where there is a more obvious motive for intruders to attempt an attack, for example containing valuable assets. The security system should be able to resist experienced attackers that have specialised tools and in-depth knowledge, by protecting every possible entry point including walls and ceilings.
Grade 4: For sites with the highest risk of attack where intruders may plan a detailed attack well ahead of time and have all kinds of specialised equipment. These types of systems are often used in the military or sites prone to terrorist attack.

Optex grading intruders horizontal 2023 02 27 152309 zhxh

The entire security system is graded based on the lowest ranking product. For example, a system with 10 Grade 3 sensors and 1 Grade 2 sensor will be a Grade 2 system, so it is important to consider the types of sensors used throughout.

Testing and grading

To obtain a certification, manufacturers need to get their products tested by an independent test house, passing the following tests: general, functional, anti-tampering, environmental, power supply and responsivity to show that their sensors really can do the job. OPTEX sensors are tested at some of the most demanding and trusted testing houses.

Prior to the official tests at the independent certification body’s testing facilities, at OPTEX we like to be prepared and have our own dedicated testing facilities where we put our sensors through a rigorous testing process which includes over 150 tests.

To test the general capability and functionality of our sensors, we carry out human detection tests for both Grade 2 and 3 sensors, to make sure that even when intruders get creative with their movements, they won't make it past our detectors. We test for people running, creeping slowly, crawling, rolling (yes we do actually roll around in front of our sensors), people of different heights, hair styles, clothes and more.

Optex sensor testing images 2023 02 27 103351 ctbm

To further ensure durability, we really do push our products to the limit as we attempt to vandalise and physically harm them. Our relentless “shock tests” actually involve squashing sensors with weights or hitting them with steel bats (another fun activity for our testing team) to make sure that even in these conditions they will still work. So when we say certain products are resistant to vandalism… we really mean it. For our Grade 3 sensors, we go a step further and attempt to mask or cover them to be sure that even under these circumstances, their intelligent logic will be able to analyse this and trigger an alarm.

We also make sure our sensors work perfectly in all kinds of the environment including different temperatures and strong sunlight.

So how do you decide when to use Grade 2 or Grade 3 sensors?

When it comes to choosing the right sensor for your security system, it's important to consider the level of risk in your environment. Grade 2 PIR sensors are best suited for low-risk environments, for instance residential, offices or small retail spaces, where security needs are on a smaller scale.

On the other hand, Grade 3 security sensors are a more advanced and sophisticated option. They are designed to provide a higher level of security and are ideal for commercial and industrial properties with increased security requirements, for instance, been able to cope with fluctuation of temperatures and background noise. Grade 3 sensors come with more advanced features such as anti-masking that make them more reliable against experienced intruders and can detect fast-moving intruders who are attempting to bypass security systems.

If you are still unsure on which grade sensor will be best for your requirements, we have created a dedicated checklist to help you in making your decision: