Refuge Chambers are making a mark across the Brenner Base Tunnel (BBT) underground construction project. Multiple TunnelSAFE refuge chamber styles and fit-outs help keep the construction team safe during tunnel development.
About the Brenner Base Tunnel Project
The Brenner Base Tunnel is the main element of the new Brenner railway between Innsbruck (Austria) and Fortezza (Italy). At 64 km, it is the most extended underground railway connection in the world.
The BBT was planned primarily to relieve freight transport between Austria and Italy. Currently, it relies on roads over the Alps, or it contends with the steep uphill and downhill slopes of the old Brenner railway line, parts of which date back 140 years.
BBT SE is a European PLC created to lead the railway tunnel construction between Austria and Italy.
The BBT consists of multiple tunnels, including two primary tubes, each 8.1 m wide, running 40-70 m apart, allowing one-way train traffic. These tubes are linked every 333 m by connecting side tunnels for use as escape routes in emergencies.
A peculiar feature of the Brenner Base Tunnel (BBT) is the exploratory tunnel running from one end to another. This tunnel lies between the two main tunnels and about 12 m below them and with a diameter of 5 m, is noticeably smaller than the primary tubes.
German tunnel boring machine (TBM) manufacturer, Herrenknecht AG, has supplied the TBM scheduled to bore a 15km pilot hole at the Arge Tulfes Pfons site. This will later become the service tunnel to adjacent railway line tunnels as the project progresses. Once assembled at Herrenknecht’s facility in Schwanau, the TBM was split into modular sections for easy transportation to the site.
A joint venture of European construction companies, STRABAG and Salini Impregilo (Arge Tulfes Pfons – ATP), is responsible for constructing the Tulfes Pfons section Innsbruck in Austria.
Refuge Chambers for Tunnel Construction
Refuge Chambers for a Tunnel Boring Machine
Herrenknecht purchased a MineARC TunnelSAFE Gantry Design Refuge Chamber for use during the TBM assembly and tunnel boring phase, currently taking place several kilometres underground.
MSV Refuge Chamber Supports Injury Managment
ATP required a 24-person chamber that could be mounted onto a Multi-Service Vehicle (MSV) and allow for stretcher accessibility in the event of injury to personnel. Parked behind the TBM backup gantries, the MSV will help the crew escape in case of a fire.
In response, MineARC Engineers developed a custom TunnelSAFE MSV Design that features a unique 45° angle front entrance, enabling easy access in even the most space-restricted scenarios. The angled entry allows injured personnel to be carried into the chamber on a stretcher, even if it is mounted flush with the front/back of the MSV. The interior of the shelter provides plenty of additional space to lay a stretcher on the floor.
Another feature of ATP’s TunnelSAFE MSV Design is the high ambient air-conditioning system, designed to enable the chamber to withstand up to 50°C. The air-conditioning system is ATEX rated, meets the T4 temperature classification, and is built specifically to provide commercial-grade cooling under the harshest conditions.
Refuge Chambers for Drill and Blast Excavation
Operating concurrently to the tunnel boring phase is the drill and blast section of the BBT project, for which the site purchased two TunnelSAFE Standard Design drill and blast refuge chambers with fly rock protection and 5psi blast rating. The chambers will be positioned close to the working face of the tunnel, where they will be required to withstand multiple blasts per day.
Additional TunnelSAFE Features
Standard features to the TunnelSAFE range, although considered unique in the industry, include:
- Positive Pressure Maintenance System (PPMS) with a visual reference
- 5 psi blast rating
- 24-hour minimum duration with UPS battery back up
- Extra-low-voltage (ELV) control system with CO and CO2 scrubbing
Maintaining Positive Internal Pressure
All BBT TunnelSAFE Refuge Chambers feature the unique Positive Pressure Maintenance System (PPMS). It is designed to help maintain a safe, breathable atmosphere within the refuge chamber and allow personnel to pre-prepare for secure entry.
Once initiated via the external activation button, the PPMS dispenses measured quantities of compressed, breathable air into the chamber, maintaining a positive pressure at 200 Pa.
Ensuring that the refuge’s internal pressure is slightly higher than outside helps prevent toxic contaminants from infiltrating the chamber during personnel entry.
TunnelSAFE Commissioning At Brenner Base Tunnel
In 2015, TunnelSAFE commissioning at Brenner Base Tunnel Project began at the Austrian construction site on the first three TunnelSAFE Chambers to be used on the project.