Fiber Optic Sensing For Protection Of Tunnels, Parking garages And Metros

 How is a fiber optic cable used for temperature monitoring?

Distributed Temperature Sensing uses a single fiber optic cable as a linear temperature sensor in conjunction with a physical effect called “Raman backscattering”.
By analyzing reflected laser light that is emitted into the fiber by a Linear Heat Detection (LHD) interrogator unit, this technology provides thousands of temperature measurements.
Temperature events can be precisely localized down to even less than 1 meter.

What makes fiber optic sensing an advantageous method of fire detection?

The fiber optic cable is a completely passive linear sensor which can easily be installed in a tunnel or other important infrastructure such as parking garages or metro stations.
Fiber optic LHD is the perfect solution when it comes to large infrastructures where spot sensors are neither technically nor commercially suitable.
The fiber optic cable is also immune to dust, dirt, vibrations, or lectrical/magnetic fields.
The fiber optic-based LHD has multiple advantages in comparison to conventional fire detection systems or non-fiber optic LHD.
One single passive fiber covers a long range up to 10 km, whereas traditional solutions would need many sensors as well as individual systems.
The high sampling interval is less than one meter, which permits quick activation of countermeasures in an emergency situation.
Because of its low laser power, AP Sensing’s LHD is well-suited for hazardous environments such as those found in chemical plants, coal storage facilities, mining conveyor belts, or other facilities requiring ATEX/IECEx certification.
It is easy to integrate into existing fire alarm systems and can be utilized either as an alternative or an enhancement to existing fire detection systems.
LHD enables early identification of rate of heat rise, and therefore detects heat abnormalities earlier than other technologies, with discrete trigger points at a higher temperature.
Based on temperature delta, our LHD system differentiates between fire and temperature increases due to seasonal changes.
Thanks to the distributed fiber optic technology, linear heat monitoring enables gapless monitoring and complete asset coverage. 

What are some advances in the field of fiber optic sensing for road, parking garage and rail?

Fiber optic sensing provides great benefit when monitoring long assets and infrastructures, as it is cost effective and requires a low installation effort.
The system can operate without power supply or communication installation points along the entire route, and the entire asset can be monitored by a single device that is installed in a centralized location.

What is unique about AP Sensing’s solution? 

Unsurpassed quality and reliability bring you peace of mind and lower cost of ownership.


What challenges in tunnel safety are addressed with fiber optic Linear Heat Detection (LHD)?

Fiber optic LHD is the perfect solution when it comes to large infrastructures where spot sensors are neither technically nor commercially suitable.
Some examples of where our LHD system is in use include traffic tunnels, parking garages, bus ducts and metro stations.
The sensors are immune to vibrations, electrical/magnetic fields, and dust or  dirt.
 A blazing fire can have devastating consequences: risk to human life, damage to valuable infrastructure and assets, and long downtimes. A proper fire protection installation is made more complex when the area is affected by harsh environmental conditions. Industrial facilities frequently produce dirt, dust, humidity and corrosive atmospheres in the production, storage or transport of goods. Conventional sensor technology often fails and tends to produce false alarms. Some of the costs of false alarming include, for example, activating the deluge or high-expansion foam fire suppression systems in aircraft hangars. These technologies also require periodic, time-consuming maintenance efforts.

AP Sensing’s unique Linear Heat Detection (LHD) solution reduces operational costs and offers maximum reliability even under severe conditions like:

  • Dirt, dust and corrosive atmospheres

  • High humidity and extreme temperature changes

  • Solvent vapors and radioactivity

  • Electromagnetic interference (EMI)

  • Explosive environments due to gas or dust (ATEX / IECEx)

Why is fiber optic sensing an important investment into your infrastructure?

Fiber optic sensing provides a highly reliable and maintenance-free investment.
It provides precise temperature and location information 24/7, with the industry’s fastest fire detection and lowest false alarm rate. In the case of a fire, our technology accurately tracks the size and direction of a spreading fire regardless of air currents, leading to quick activation of firefighting countermeasures.

AP Sensing's SmartVision software provides a visual overview of alarm zones, operational status, and real time temperatures at a glance, controlled by an easy-to-use graphical interface (GUI).

Monitored assets and facilities are mapped and color-coded to show the measured temperatures, alarm zones and fire locations, as well as fire size and spreading.

Alarm zones can be individually defined for flexible alarm levels and types. SmartVision seamlessly integrates many sensors, such as Distributed Acoustic Sensing (DAS), DTS, CCTV and others, into a single platform.

With a proven track record and continued innovation, AP Sensing offers a completely integrated, end-to-end solution made in Germany. Our team works together with you to select the right combination of technologies to fit your requirements.

Fire Detection   Infographic