Fire protection companies play a major role in protecting tunnels from fire disasters. Over the years there have been catastrophic events due to fires in tunnels. Although these incidents have informed best practices for global standards, it’s up to individual jurisdictions to enforce safety standards and practitioners to implement effective controls. As fire safety practitioners who design and certify buildings for fire safety, the protection of people in spaces is our top priority. The conditions found in tunnels, such as limited access, low visibility, and high temperatures, make it imperative that there are effective fire prevention and protection solutions put in place. In this blog post, we’ll explore the failures of fire protection methodologies in tunnels. We’ll look into what can be learnt and some of the ways in which tunnels can be protected from fire disasters.

Risks associated with tunnels

Fires occurring in underground tunnels encompass a variety of risks, causes and control measures. Tunnels present unique environments – underground passageways dug through surrounding soil, earth or rock for sometimes thousands of meters. There are many types of vehicles moving through tunnels, some carrying dangerous goods in an enclosed space. This puts occupants at risk. The two types of incidents within tunnels that affect people’s safety are fire and vehicles or objects that become stationary within a tunnel.

Fire detection and alarm systems

During emergency situations, tunnels pose numerous risks that require the implementation of controls in order to avoid fatalities. The combination of combustible materials within a confined space presents risks of its own for these structures. Incident detection is a mandatory control that must be put in place by fire protection companies. It is crucial to promptly identify any emergency incident, ensuring that the tunnel operator receives immediate notification and can swiftly locate fires, stationary vehicles, or objects.  Within tunnels, the risk of incidents is ever-present so it’s paramount that they’re immediately detected and the right controls are in place. The Australasian Fire and Emergency Service Authorities Council say that Closed Circuit Television (CCTV) cameras (pan-zoom type) fitted with an incident detection system are vital, together with a fire detection system in providing early detection.

Fatal tunnel incidents

Table 1: Fatal tunnel fires 1978-1999, Fire Safety for Road Tunnels Version 2.0, Australasian Fire and Emergency Service Authorities Council Limited

Year Tunnel  Length  Deaths 
1999 Mont Blanc, France / Italy 11,600 m 39
1999 Tauern, Austria 6,400 m 12
1983 Percorile, Savone, Italy 600 m 8
1979 Nihonzaka, Japan 2,045 m 7
1982 Caldecott, Oakland, USA 1,028 m 7
1978 Velsen, Netherlands 770 m 5
1996 Isola delle femmine, Italy 148 m 5
1993 Serra Ripoli, Italy 442 m 4
1995 Pfander, Austria 6719 m 3
1986 L’Arme, Nice, France 1105 m 3
1987 Gumefens, Bern, Switzerland 340 m  2
1980 Kajiwara, Japan 740 m 1
1994 Huguenot, South Africa 3914 m 1

Fire compartment systems and design

Globally, the Mont Blanc Tunnel fire is the most horrific tunnel fire to date. Its impact on tunnel safety through the lessons of the tragedy has guided tunnel design, engineering and protection since 1999. There have continued to be other fire incidents since, such as Melbourne’s 2007 Burnley Tunnel fire which resulted in three fatalities following significant fires and explosions when a truck collided with cars. Although these risks will never be entirely mitigated, it’s important to have effective controls in place to address and manage these events. Hundreds of Burnley Tunnel occupants were evacuated. In the Mont Blanc fire, most of the victims had suffocated before they burned. Fire compartment systems and design are critical to occupants of tunnels in the event of a fire. The Mont Blanc fire taught us that people don’t die first from the fire but from the fumes and smoke.

Minimising the impact of smoke on occupants

In the Mont Blanc fire, there was no fire compartment system.  This allowed the fire to spread throughout the tunnel. A poor ventilation system also accelerated the fire and caused fatal smoke inhalation among tunnel occupants. Fire and smoke can be controlled within the area of fire origin or dispersed to lower temperatures and toxicity levels. This requires adequately designed multisystem fire protection which compartmentalises areas and integrates passive fire protection.

Fire compartment system controls

Fire compartment system controls are designed to inhibit the spread of smoke, fire, and heat as well as ensure structural integrity within underground engineering. Dividing the area into a series of compartments limits the spread of fire, helps people evacuate and allows emergency services to undertake rescue operations. Examples of compartmentation controls include:

  • Fire doors – minimise the risk of smoke and/or fires spreading. They can be either self-closing or automatic.
  • Fireproof walls – made of materials that are fire resistant, preventing cracking and failure of the wall due to the fire, preventing the spread of the fire; and ensuring that an effective barrier is created to inhibit fire spread.
  • Junctions and joints – designed to control the spread of smoke and fire. Controls can include the use of fire-rated sealants and the strengthening of the tunnel lining.
  • Sealing around service penetrations – running electrical and plumbing services requires holes to be made through walls, these penetrations need to be sealed to stop the spread of fire and smoke produced as a result of a fire.

Fire resistance

From the moment a fire ignites until the completion of evacuation and firefighting efforts, fire detection and alarm systems, ventilation systems, and fire compartment system controls must have fire-resistant characteristics that perform. In the event of a fire within a tunnel, it’s imperative that the structure doesn’t collapse, and the structure and fire safety equipment doesn’t burn or produce large amounts of toxic gasses and smoke.

Engaging fire protection companies

The implementation of fire detection and fire compartment system controls is critical for fire resistance in tunnels. The latest technologies and best practices that incorporate the learnings from fatal case studies should be implemented in tunnels. This mitigates the risk of injury and fatalities, ensuring the safety and well-being of tunnel occupants and operators. A fire protection company should be engaged to ensure adherence to the highest safety standards and implement adequate risk controls.

Rely on our passive fire technicians to identify the necessary penetration type required and apply the appropriate fire-stopping techniques with expertise. Call us on (03) 5274 1226 or email estimating@profinishfire.com.au to discuss your project and passive fire protection requirements.