Mar 22, 2019

Improving road safety with state-of-the-art solutions

Road tunnels are among the most demanding environments for fire safety technology and require careful planning and rigorous testing before entering into service. Naturally, modern traffic with fast-moving cars of varying temperatures and speeds need to be taken into account as potential fire hazards. Furthermore, tunnels serve as an integral part of modern infrastructure, which should remain operational around the clock, increasing the expectations of fire safety equipment, software and knowhow to an even higher level. While the safe evacuation of all car passengers and the preservation of life and health of the people inside the tunnel is a primary target that is shared by all fire safety equipment, each tunnel has unique properties and requirements that need to be considered, from its length to variable air moisture depending on the location and different conditions in different segments of the tunnel.

tunnel opening

Applying knowhow on both shores of River Vltava

The tunnels on the belt highway around Czech Republic’s capital, Prague, showcase how Honeywell meets the requirements and challenges of each new project. Connected by a bridge over the Vltava River, both tunnels are approximately 2,000 meters long. Meeting all standards and regulations, we installed an advanced fire alarm system with distributed thermal sensing (DTS) technology. Initially, the project plans included a single loop linear heat detector from a different manufacturer. After a detailed analysis, the Czech team was able to convince the client with a new redundant loop configuration, incorporating reliable ESSER by Honeywell technology in the fire alarm system.

Did you know?

DTS incorporates optical fiber cables that have unique properties ideally suited to the tough demands of tunnel environments:

  • Diameter: 5 mm
  • Bending radius: 4-8 cm
  • No active elements
  • Max. length 10 km, detection over entire length
  • Ability to with stand temperatures of up to 1,000° Celsius

By utilizing the Raman effect, the optical signal within the cable is analyzed using an advanced process that can localize fires with a resolution of 0.5 meters and an accuracy of 1° Celsius at a refresh rate of 10 seconds.

Trial run under real-world conditionsspeed tunnel impression

Before entering into service, each system needs to be tested and certified, meeting constantly evolving rules and regulations that can vary from country to country. After installing a DTS fire detection system in a road tunnel near Hinterglemm, a popular Austrian ski resort, all Honeywell products were thoroughly carefully examined by the authorities for certification, as officially required by the Austrian tunnel regulations. Both the line-type heat detector for the driving area in the tunnel and the sensor control units were subjected to real-world conditions by creating a test fire in the tunnel. In 2015, the road tunnel under Martwa Wisla river, which connects the city of Gdansk with its port island, was equipped with ESSER by Honeywell fire detection technology by the Polish team. Over the tunnel length of 1370 meters, the system incorporates DTS fiberoptic linear heat detection, combined with a sophisticated PA/VA system with special tunnel loudspeakers. Prior to installation, a precise audio simulation was carried out to find the appropriate speaker configuration.

As Honeywell is offering a full range of fire safety products, each fire alarm system can be complemented with additional product lines respectively tailored to customer needs to meet the legal, technical or financial requirements of each individual project. From seemingly simple manual call points to advanced optical and acoustical signalization solutions and sophisticated smoke and fire detection by video analysis, Honeywell continues to provide high quality products and extensive knowhow on tunnel environments.

Read more about the tunnel safety issues Honeywell addressed and the feasible solutions adopted in our Best Practice Study for Tunnel Solutions.