What could be more appropriate as the headquarters of a power company.
Dating back to 1902, the Water Street plant in Halifax provided the city with power until it was decommissioned in the 1970s.
When it reopens in 2011, it will bring a new energy to the Halifax waterfront – a modern office complex built to the highest environmental standards that will revitalize the downtown neighbourhood.
For years, the old chimney stacks of the Water Street power plant, one more than 240 feet tall, dominated the Halifax skyline. The stacks have long since disappeared but a new city landmark is now set to take their place.
The old power plant is being renovated into Nova Scotia Power’s new headquarters – a 129,000 square feet building that will house more than 600 employees. And it promises to be a building like no other on the east coast.
At the heart of the building is a six-storey glazed atrium offering views from the main entrance off Lower Water Street through to the harbour beyond and providing direct access to the harbour front boardwalk. At right angles to the atrium, a full-height, sky-lit galleria brings daylight into the offices. Bridges crossing the atrium and galleria will connect the three office areas, which range from two to seven stories in height. Clear glass curtain-walls and architectural aluminum panels will give the building a sleek modern appearance.
When the building is completed later this year, Halifax will have a new architectural landmark but it is the environmental aspirations of Nova Scotia Power that set this building apart. The new office is being built to Leadership in Energy and Environmental Design platinum standards, the highest level of environmental sustainability achievable.
Central heat pumps will use Halifax harbour water to cool the building. Rainwater will be collected and used to flush the toilets. A white roof will keep the building cool while the atrium and galleria will provide natural light to the offices and common areas. Low-emitting interior finishes and furniture and a dedicated outdoor air supply will provide exceptional indoor air quality. And with all the energy efficiency designed into the building, energy consumption is expected to be as much as 50 per cent below National Energy Code.
In late December 2008, the Nova Scotia Utility and Review Board approved the redevelopment project and awarded the project management contract to Aecon Buildings Atlantic.
Aecon is managing the administration, handling general site conditions and supervising the safety program for all the trades. Nova Scotia Power is holding all the contracts with the sub-contractors.
“When the building is finished, it will have been totally transformed. You’ll never know that this was once a power plant,” says Randy Giffin, Aecon’s construction manager.
Construction Underway
On January 16, 2009, demolition of the power station was underway. By the time it had finished, more than a year later, the crews had removed about 2,000 tonnes of structural steel and replaced it with 600 tonnes of new steel. They had also demolished walls and floors, taking out about 9,000 cubic metres of concrete in the process. The steel was sent for recycling; the concrete crushed for use as backfill on site.
“Demolition was the biggest challenge on this project,” says Giffin. “This was an industrial building and with its heavy structural steel and concrete walls up to two-feet thick it was clearly built to last. But we had an additional challenge because we had to preserve the structure and reconfigure it for a totally different purpose. Typically demolition is fairly rough and ready work. This was far more precise, almost surgical.”
By September 2009, Murray Demolition had completed most of the interior work and the concrete crews were pouring the first of the new floor slabs and other subcontractors were drilling piles and installing new structural steel.
Meanwhile, the demolition crews had moved on to the exterior of the building. Workers began cutting through the concrete walls to create the window openings, each one about 10 to 12 feet wide extending from the ground to the roofline. By December, the opening for the glass atrium was complete.
“Most of the work for the first year was inside the building and hidden from view but by the spring of 2010, the transformation was starting to take shape and people watching could start getting a sense of how the building is going to look when it’s finished,” recalls Randy.
In the spring, workers started installing the massive glass panels, each one 15 feet high and eight to 10 feet wide, and by September of 2010, the entire building had been enclosed.
At the same time, the mechanical and electrical contractors were starting to install the building services. On August 31, 2010, a 300-ton crane lifted six air-handling units – the largest weighing in at 7,700 kilograms onto the building’s roof. The six units have a combined airflow capacity of more than 21,500 litres per second.
“Much of the energy efficiency of the building comes from the innovative systems that are being installed,” Randy says. “It takes more than ocean breezes to cool the building. Dexter Construction installed a 450-mm diameter pipeline that extends about 75-metres into the harbour to draw ocean water into the building. Heat exchangers will transfer energy between the cool ocean water and the buildings chilled water supply loop. The chilled water will cool the building and the heat transferred into the water will be returned to the sea.”
The Nova Scotia Power building is also one of the first in Canada to use chilled beams. Typically mounted overhead, the beam is a type of radiator that is chilled by recirculated water. Chilled beams reduce the need for ductwork and fans and improve comfort while reducing energy consumption.
By the end of the year, Randy estimates construction was about 75 percent complete and he expects the building will be completed on schedule by June of this year.
“This was not a traditional building project,” he concludes. “We are adapting an old structure and transforming it into a completely new building while staying within the original envelope. Keeping everything co-ordinated and in proper sequence was an enormous challenge, especially as the building was being fast tracked and the architect was still developing the plans after we had started work.”
But as pleased as Randy is with the progress of the job, he is just as pleased with the safety record.
“Nova Scotia Power places a great emphasis on safety, as does Aecon, and making sure that this project is completed safely has been our top priority. We have fully implemented Aecon’s safety program and all trade contractors are required to meet its provisions. We can proudly say that even with up to 100 trades people on site at peak, we have not had any lost time incidents so far.”
CAPTION – Pictures by Miriam Beach Photography