30 September 2020 - Aude Desbrieres
Featured in: Product information and OPTEX tech tips, Product bulletin, Market Insights, Intrusion detection
Fibre optic Perimeter Intrusion Detection Systems (PIDS) are usually associated with high security fence protection and not always considered for smaller commercial or residential applications. While it is true that the fibre optic sensors are perfectly suited for large perimeters, usually located in harsh environments, it is important not to pigeonhole this technology only for those applications.
Our Fiber Sensys sensor range offers a range of products that would suit both a VIP residence and commercial application. It’s important to consider both the site and customer’s requirements.
What does fibre optic sensors detect?
Optical fibre conducts light using principles of reflection and refraction. An Alarm Processing Unit (APU) will send a laser pulse over the fibre optics cable and analyse the change in the interference pattern along the cable.
This principle allows to detect if anyone is unsettling the fence or wall where the cable is installed. Our algorithms give the ability to determine what kind of disturbance is happening: cutting through the fence would create one spectrum, while climbing or crawling under it would create a different spectrum. Drilling through a wall will in its turn create a different light pattern.
What disturbances can be tuned out?
The configuration software provided with the APU features a number of parameters enabling the ability to tune out any noise that could cause false alarms such as vibrations caused by wind, nearby traffic or small animals, hence making the system extremely reliable. Depending on the product series, the number of calibration parameters is six for our entry level solution and 30+ for the others.
What environments can it be implemented in?
The Fiber Sensys sensors provide immunity from lightning, EMI/RFI, and it is intrinsically safe for use in hazardous areas. They are designed to operate in extreme temperatures as well as in dusty or harsh environments
Fence applications
In most applications, fibre optic cable sensors are mounted on a fence. The cable sensor can be implemented in a conduit attached to chain-link, weld mesh, wrought-iron or other fence types using stainless steel wire ties. Implementation in conduit is the recommended approach if extra protection of the fibre optic cable is required from weather or to resist potential damage from wild animals. One of the key benefits of implementing our fibre optic sensors is that only the APU needs to be powered. Long perimeters can therefore be protected without the requirement to have access to the main power. In addition, a number of our APUs can be located remotely, up to 20km away from the fence, reducing even more the quantity of hardware on the field.
Although the alarm processors offer numerous user configurable parameters, fence quality plays a major role in the level of security. Before a fibre optic installation is initiated, a full physical site evaluation should be conducted, identifying and correcting any flaws in the fence. Some commonly overlooked flaws include trees standing near the fence line or large gaps along the length of the fence.
Wall Applications
OPTEX fibre optic intrusion sensors are also designed to be implemented on walls. This could be on perimeter walls or more commonly on the building itself. This would be used to detect intruders drilling holes to access inside buildings. Although it seems a ‘rough’ way to break it, it happens on a regular basis with cash machines being pull out of walls using diggers, or criminals drilling through warehouses and high-risk shops such as jewelry or armoury shops to access valuable goods or restricted merchandise.
The fibre optic cable will be implemented inside a galvanised conduit, which will be attached to the wall or embedded in the wall. The service life for the fibre cable is expected to be at least 20 years, which makes it long-lasting solution.
Alarm zones
Our APU series ranges from one to 25 zones, giving a lot of flexibility, depending on the total length of the perimeter and the number of alarm zones to be created. When working in conjunction with fixed cameras, it is common to create zones from 50 up to 100m with respectively one camera or two cameras at each end. This enables the security staff to visualize what is happening in the intrusion zone. Alarm zones can be set for much larger areas such as a couple of kilometers each if best suited to the site requirements.
Our Fiber Sensys fibre optic range (link to series) is a reliable, versatile and cost-effective intrusion detection solution. It can be implemented on fences and walls. Some of our series will be tailored for protecting critical infrastructure but other series are perfectly suited for residential and commercial applications. The fibre optic cable sensors can be integrated with Video Management Systems (VMS) for camera control of any alarms triggered by the sensor, or PSIM including alarm systems, access control and building management systems. The integration as part of the wider security system helps further improve the reliability and performance of the security system and ensures the deployment of multi-layered protection from the outer perimeter to the building itself.
