5 April 2022 - Lara Velasco

Featured in: Market Insights, Intrusion detection

The protection of critical infrastructure is a significant challenge because of the potentially devastating impact it could have on society. Physical security is one of the main concerns to avoid a breach into the perimeter and the risk of critical assets being damaged.

The first layer of physical protection is normally a fence or wall which surrounds the perimeter and acts as a barrier to deter or delay intrusions. In the perimeter protection market, fibre optic technologies have become one of the preferred choices as they make the security system extremely reliable and are suitable for critical infrastructure sites of every kind.

How does fibre optic technology work and what can it detect?

Fibre optic cable sensors are typically mounted on a fence or wall fabric to detect any attacks on them. An Alarm Processing Unit (APU) will send a laser pulse over the fibre optic cable and analyse the change in the interference pattern along the cable, allowing it to detect if anyone is unsettling the fence or wall. With dedicated algorithms it gives the ability to determine what kind of disturbance is happening: an intruder cutting through the fence, climbing, crawling under or attacking the fabric of the wall. The configuration software enables it to be calibrated to tune out any noise that could cause nuisance alarms such weather, vibrations caused by the wind, nearby traffic or small animals, making the system extremely reliable.

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Protection for remote and large perimeters

One of the main challenges for large critical infrastructure sites such as airports, large industrial and manufacturing facilities, fixed military bases, data centres or power plants is the huge perimeter line that needs to be protected. Fibre optic sensors, from Fiber SenSys for example, are ideal to cover long length perimeters up to tens of kilometres and with the option to split into different zones – up to 25 on each APU - with different alarm outputs programmed to PTZ camera inputs that can be pre-set along the wired fence.

There are two primary types of optical fibre: single mode and multimode. Single mode allows only one mode of travel or one path for light to follow through the core, it is most often used as “insensitive” lead-in to transfer the data and supports remote control rooms and security stations, which can be installed as far as 20km away from the zone to be sensed. Multimode fibre allows more than one mode or pathway of traveling light and is typically used as a “sensitive” cable installed directly on the fence or wall.

Safety and reliability

Fibre optic technology provides immunity from lightning, EMI/RFI, radar interference plus it’s intrinsically safe for use in hazardous areas (such as oil and gas), or extreme temperature environments. Fibre optic technology will also not interfere with any systems that may already be installed on site.

The optic fibre cables are also lightweight and allow greater distances to be protected without the need for repeaters or additional field-based hardware. They are resistant to cable cutting and sabotage so even if a zone is cut, this will not interrupt the detection on the other zones.

Additionally, fibre optic sensors offer a relatively low cost of ownership as it is very resistant and has long-life span (it can last up to 20 years) and does not require more than a yearly maintenance visit.

In conclusion, fibre optic technology is a reliable, versatile and cost-effective solution for the protection of critical infrastructure perimeters.