More than 30,000 vehicles a day travel through the 1.7-mile-long twin tunnels along I-70 under Loveland Pass. Fires have been known to break out inside the tunnels two to three times a year. CDOT hired design-build firm Barnard Construction to install the country’s first comprehensive, fixed fire-suppression system. It’s also the first fire-suppression retrofit inside a tunnel, according to the contractor.

The system has sophisticated heat-detection capabilities, with a deluge mechanism that can suppress a large fire within the first two minutes of its start. The nozzles, installed in a grid fashion in the existing air plenum, provide water for 60 minutes within two of the 193 deluge sprinkler zones as well as up to 500 gallons per minute through a standpipe system. All zones are supplied by an existing water source. The deluge system also required installation of a new drainage system in the tunnels.

All of the systems had to be safely constructed within the cramped tunnel envelope. Ensuring safety while working at 11,000 ft in elevation isn’t easy, but Barnard’s team developed a strong safety culture through close communication with subcontractors, who participated in the project’s “good catch” safety incentive program.
 

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