The Puget Sound region is known for a few things—beautiful mountains, green forests and bad traffic. Holmberg Mechanical won a $6.5 million contract to build an open tunnel for a light rail system scheduled for completion in 2023 that will help fix the traffic situation.
The project involves ten ACU with roof-mounted condensing units, 13 unit/wall/ceiling mounted heaters, two stair pressurization fans, 20 exhaust/supply fans, 44 motorized dampers, several fire smoke dampers, 60 GRDs and associated ductwork.
“We have ten huge 100-horsepower jet fans we will be installing in the tunnel to clear the tunnel in case of fire or smoke from car accidents or emergencies,” says Holmberg Mechanical’s HVAC Foreman, John Crowell. “These fans are 26 feet, three inches long, six feet tall, and weigh just over 6,550 lbs. They will be mounted on a platform that runs above the tracks at the mid tunnel.”
The north and south portals both have two fans that hang from the concrete ceiling and another two fans that mount on equipment pads directly below the ceiling fans.
Crowell, a 23-year tradesman, started in 1997 at Local 105 Orange County and Los Angeles working in architectural sheet metal. A year later, he transferred to Local 206 in San Diego and started in HVAC. He now lives in the greater Seattle area.
“It’s a unique station because it’s all concrete with multiple tiers and extensive use of natural sunlight,” says Holmberg Mechanical’s Senior Project Manager, John Chapman. “The escalators and ceilings are all glass, keeping things as green as possible, and all of this runs over the top of the 405, a major freeway in our area.”
The station is located next to city hall and the police station, which meant Holmberg Mechanical’s scope was extended to include what is known as the ‘bat cave’, an underground parking area where police vehicles cars will be securely parked.
“This whole passenger station has been designed to receive passenger traffic from an underground tunnel,” Chapman says. “The Bellevue City Council chose an open-air station that would save between $19 to $33 million, compared to constructing the station inside the tunnel.”
The scheduled track open date is 2023 with a projected ridership between 43,000 to 52,000 daily. The project will prevent pollution and conserve resources by reducing waste, reusing materials, recycling, and purchasing materials with recycled content. It will be a quick 15-minute trip to Seattle from this station. In 2024, plans include extending the rail another 3.4 miles east to new stations in Southeast Redmond and downtown Redmond, WA.
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Photo courtesy of Holmberg Mechanical