Personnel requirements for tunnel operations

For explorations outside the danger zone, for example, outdoors in front of an emergency exit, one firefighter may suffice. At least two firefighters must be deployed in areas that are filled or can fill in future with smoke. The firefighters should reconnoitre the situation from the perspective of the incident command. Therefore, at least the head of the reconnaissance team should be an experienced firefighter, who ideally also has extensive knowledge of the tunnel system.

There are no statistical studies on how many firefighters are deployed by fire services on average to extinguish vehicle fires in tunnels. The International Fire Academy recommends the deployment of teams of five for firefighting. Thereby a line is advanced by two firefighters. They are coordinated by the team leader, who also communicates with the section or incident command and monitors the effectiveness of the measures using a thermal imaging camera.

The search tactics determine the personnel requirements for the search & rescue team: In a two-lane road tunnel, two firefighters search the vehicles on one lane. To search passenger coaches in train tunnels, two firefighters are deployed to the right, the left and within the train, making a total of six. In the case of double-decker carriages, two additional firefighters may be required for the upper carriage deck. The coordination is carried out by the team leader.

The need for reconnaissance teams is derived from the information to be procured for both railway and road tunnels, which can be distinguished into facility-specific and incident-specific information.

Facility-specific information includes, for example, tunnel length, number and arrangement of tubes, lanes, tracks, emergency exits, ventilation type, safety installations, etc. The more such information has already been collected and documented during operation planning, the less needs to be reconnoitred in the case of deployment. 

Incident-specific information is, for example, what exactly where, in which direction the smoke moves, how many people are affected, how the facility users behave and whether HAZMAT is involved. In order to obtain this information, the more reconnaissance teams are required, the more complex the tunnel system and the incident are. Direct access to surveillance cameras and video recordings of the incident sequence can significantly reduce the personnel resources required.

In road tunnels, the demand for search & rescue teams is primarily due to the number of sections that may be filled with smoked, whereby «section» refers to the area of a tunnel tube between two emergency exits. In road tunnels, according to the current European standard, these sections are a maximum of 500 m long; this corresponds to the distance that SCBA wearers with two-bottle devices, in general, can usually just cope with. In some road tunnels, the distance between emergency exits is around 100 m. Here we have to consider whether a single team should be deployed for each section; single-bottle SCBAs then would then be sufficient for these distances. Or whether a team should search two or three sections with a two-bottle SCBA.

How many sections of a road tunnel can be filled with smoke depends mainly on the type of ventilation in the event of a fire. If the smoke is extracted on both sides of the fire, the smoke is limited to a few sections. With longitudinal ventilation, the smoke in the driving area is pushed to the portal, which in the worst case can lead to smoke in the entire tube. In this case, you will want to deploy as many teams as sections have been filled with smoke.

For railway tunnels, it is challenging to assess the personnel demands. Firstly, luckily, there are hardly any empirical values that can be used as a guide. For example, it is unknown how long it takes to search a 400 m long train under operating conditions. Secondly, railway tunnels are very different. For example, there are many tunnels, several kilometres long, that have no emergency exits other than the portals. In the case of newly constructed tunnels, the distances between the emergency exits are usually 500 m. Thirdly, the personnel requirements also depend on whether firefighting and rescue trains or road-rail vehicles are available. At least for older rail tunnels, a detailed analysis of the individual case is, therefore, necessary to estimate the personnel demand.