Fire safety in tunnels

Danfoss SEM-SAFE® system offers reliable fire protection for the millions of drivers and passengers in road, railway, or metro tunnels around the world.

The rapid growth in urbanisation throughout the world has led to an increased need for tunnel projects that provide safe travel for millions of people. Tunnels are at the core of physical infrastructure, making modern living possible. It is of paramount importance that tunnels are fully and properly equipped to handle a fire situation.

With the SEM-SAFE® high-pressure water mist system from Danfoss Fire Safety, the fight against fire is more effective, with particular attention to keeping people safe, and keeping the tunnels in operation.

Whether it is a road tunnel, railway, or metro tunnel, SEM-SAFE® is the perfect solution for fire protection

SEM-SAFE®  key benefits for tunnel fire protection:

  • Effective fire control, suppression and extinguishing
  • Excellent cooling
  • Facilitating the evacuation of people and safe fire fighter intervention
  • Reduced cost of ownership
  • Reduced ventilation and passive fire design requirements
  • Meeting the sustainable needs of modern tunnels
  • Long product life cycle due to the highest-quality material used
  • Economic benefits:
    • Fewer nozzles required due to large nozzle spacing
    • Faster installation
    • Smaller water reservoir due to low water consumption
  • The world’s lowest water density for the same test class
  • Safeguarding the tunnel’s structure
  • Easy system integration in retrofit projects

Best in class fire protection system

Our full-scale fire tests with fire loads up to 250 MW are in accordance with SOLIT2 and NFPA502, certified by accredited independent 3rd party laboratory and witnessed & verified by UL.

The unique engineered system and components, including superior nozzle performance, meet and supersede the expected passing criteria as highlighted in SOLIT2 and NFPA502. SEM-SAFE® is the system of choice to provide protection for structure and life safety and prevent/minimize tunnel operation interruption.

The SEM-SAFE® system is tested and certified for fires of both Class A (ordinary solid combustibles) and Class B (flammable liquids).

Click the links below and watch the full scale fire test videos for tunnel fire protection:

Class A fire test with Danfoss SEM-SAFE high-pressure water mist system150MW CLASS A
Tunnel fire test with SEM SAFE® high-pressure water mist system



50MW Class B

Tunnel fire test with SEM SAFE® high-pressure water mist system



“Fire safety in tunnels” article,  by Henrik Bygbjerg and Qusai Alasad

Access our article via the the link below and learn more details about :

  • the scenario and results of our fire tests
  • Computational Fluid Dynamics (CFD) simulation in one of the widest tunnel projects in India

Solid experience with tunnels

Istanbul Airport Metro tunnels in Turkey – the first metro tunnel project in the world protected by a fixed fire fighting system

Istanbul Metro is one of the key projects in the region that aim to ensure fast and convenient access to the Istanbul Airport. Its total length is approximately 70 km. This is a deep sub-sea metro tunnel, that reaches depths of 120 meters below sea level. The soil condition in certain areas of the tunnel made it impossible to build escape shafts. The SEM-SAFE® high-pressure water mist system proved to be the best choice for eliminating the need for escape shafts, while meeting all the safety design criteria.

The SEM-SAFE® high-pressure water mist system was chosen because of the following benefits:

  • safeguarding people and tunnel structures
  •  reduced total cost of ownership
  •  innovative solution to mitigate the issue of the escape shafts in this unique deep sub-sea tunnel project

Samruddhi tunnel in Maharashtra state, India – the first tunnel in India to be protected by a water mist system

The Samruddhi tunnel is 8.2 km long and part of the mega transportation project known as Mumbai–Nagpur expressway, with a length of 778 km. The dual tunnel is meant to facilitate India’s journey towards urbanisation and economic growth.
The entire tunnel project is built with sustainability in mind to support India’s green transition policy. The Samruddhi tunnel is one of the widest and longest tunnel in India. Danfoss Fire Safety supplies the SEM-SAFE® high-pressure water mist fire protection system, that is made up of high-pressure water mist pump units, section valves, nozzles, pipes, and fittings. In addition to supplying the system, we provide comprehensive technical design, engineering
capabilities and site supervision.

==> Click here to see the full project description and video


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Article fire protection in tunnels

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