On a 16-month project to improve an existing five-story central heating plant on the Boston College campus, with only one allotted shutdown allowed, the team committed nearly two years to preconstruction and extensive planning. The existing plant houses three high-pressure steam boilers that provide service for up to 22 campus buildings. The upgrade and expansion project called for increasing peak load to 116,000 lb per hour from 62,000 and replacing outdated infrastructure. 

To meet the college’s needs, the construction team built a new 9,000-sq-ft addition that connects to the existing live plant and houses two new boilers. Construction of the steel-framed addition required deep excavation work and support. Water and sewer lines had to be routed around the footprint. Crews also relocated an emergency backup generator, transfer gear and fuel storage tank and removed a storage building.

Upgrades to the existing 23,000-sq-ft plant required dismantling the 145-ft-high boiler exhaust chimney. Two existing boilers were migrated out of a newly constructed exhaust stack erected atop the new structure. With hazardous materials in the chimney stack—specifically asbestos—crews capped the top and lowered a work cage inside the stack. They then demolished the chimney from the inside, containing the asbestos as sealed waste. After removing hazardous materials, the team demolished non-hazardous brick from the outside.

Prefabrication was used extensively on the new chimney, including four boiler flues and one generator flue. After completion, each large flue was picked and carefully threaded down into tightly configured structural steel stacks. 

Other equipment installed included a new 13.8-kW switchgear, an emergency generator, air handling units, a new deaerator, a VRF system and a 30,000-gallon fuel storage tank. 

Boston College accommodated only one shutdown of the existing plant during the project—a 72-hour window over a Memorial Day weekend—which required more than five months of collaboration with the facilities team and contractors to develop an hour-by-hour schedule. “During the shutdown, the steam header was tied in and high-performance valves were installed to isolate the existing header,” the submission says. While every field weld was tested, breechings for both boilers were cleaned, demolished and replaced to tie into the new stack.

The plant is visible nearly everywhere on campus, making the design aesthetic a critical component of the project. College officials insisted that the building  mimic not only the brick and stone exterior of the existing structure, but also exteriors of other current campus facilities. To ensure nearly exact imitation of the 60-year-old weathered building, masonry mock-ups were performed using mixed materials, since materials from the original structure were no longer available.

The combination of construction challenges and aesthetic demands impressed the project jury. “I know the challenges of construction on that site,” said one judge, who has worked on the campus. “I also gave it a higher score because of the architectural aesthetics associated with it and the challenges of matching the color pallet of the campus.”

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