MineARC News Release
- Of the 15 TBMs currently on order for the first three lines of the Doha Metro in Qatar, 11 will be fitted with custom-engineered MineARC emergency refuge chambers to provide an immediate safe-haven for workers requiring shelter in the event of a fire, a fall of ground, or a similar emergency during excavation of the TBM running tunnels.
MineARC refuge chambers to be fitted to Doha Metro TBMs
- With only one point of entry for the required TBM drives, the importance of refuge chambers on the TBM backups is evident. The refuge chambers to be fitted to 11 of the Herrenknecht TBMs on order for the project will provide a second means of safety for personnel working in the tunnel heading in the event of an emergency.
- Each of the 11 MineARC refuge chambers can shelter up to 20 people for a minimum of 30 hours. They each feature a number of life support systems, including primary and secondary oxygen supplies and a carbon monoxide/carbon dioxide scrubbing system to regenerate the air by removing the harmful chemicals produced by the breathing of the occupants as they shelter in the refuge.
- Also vital is that each chamber maintains positive internal pressure at all times. An automatic overpressure system effectively seals the chamber from any ingress of potentially compromised air from the outside. Special sensors monitor the relative pressure both inside and outside the refuge chamber constantly, and relay this information to the chamber’s internal air systems. Based on the readings, a precise amount of air is periodically released into the refuge chamber, ensuring positive internal air pressure of at least 200pascals above outside air pressure, at all times.
Each of these safety features ensure that the chambers meet the latest industry safety legislation for refuge chambers. This includes the current British Standard and the 2014 ITA Guidelines for the Provision of Refuge Chambers in Tunnels under Construction.
Interior of a MineARC refuge chamber
Rendering of the Doha TBM refuge chamber model
- Phase 1 of the Doha metro project is due for completion in 2018, and consists of four newly constructed sections: The 11km twin-running underground section of Red Line North, the 16km twin-running underground section of Green Line, the recently awarded 13.8km twin-running underground section of Red Line South, and the 13km twin-running tunnel of the Gold Line, the contract for which is expected to be awarded later this year.
- Future scope for the metro project includes the 17.5km underground section of the semicircular Blue Line that will link Airport City and West Bay Central and the extension of the Green Line, which are both yet to get under way.
Herrenknecht sweeps Doha metro Phase 1 - TunnelTalk, January 2014
Qatar begins Doha metro tunnel awards - TunnelTalk, April 2013
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