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Concrete to glass

There’s no question that buildings can inspire us, with both their interior and the face they present to the outside world.

There’s no question that buildings can inspire us, with both their interior and the face they present to the outside world. There are few people who could enter, say, the Sistine Chapel and remain unmoved. However, when it comes to inspirational interiors, there are probably very few decommissioned power plants that would make the list. There is at least one, though; the Water Street Coal Fired Generating Station in Halifax. By April of 2011, it will become the new headquarters for Nova Scotia Power Inc. (NSPI).

An artist’s rendering of how the building may look at night after the renovation and reskinning work is completed. Even at night, it is easy to see how the redesigned edifice will connect downtown Halifax with the historic harbour.

The Water Street Coal Fired Generating Station began its life with the installation of its first generator in 1911. Construction of the current building took place progressively with a series of modules, beginning with the northernmost one in 1944 and finishing at the south end of the site in 1959. The plant operated from 1944 to 1986 and was finally decommissioned in 1999.

The original building was composed of a concrete clad steel structure that encloses several high-volume spaces that originally housed equipment for generating electricity.
 The new building was designed by WZMH Architects, a firm with projects in Canada, the United States, Europe, Asia, and the Middle East. The original site itself has inspired the design for its new life as the headquarters of NSPI.

Early visits to the site were inspirational for the design team. The soaring interior spaces with an exposed latticework of steel framework were reminiscent of the imagery of Russian deconstructivism design. The design retains a memory of, and celebrates, the original structure.

A view of the Atrium, the core of NSPI’s new headquarters. It will become the focus of activity within the building, and will provide a place for NSPI’s staff to eat lunch and socialize, especially during the winter months.

The project is located on a five-acre site at the southern end of the Halifax downtown waterfront with access from Lower Water Street. The site steps down approximately 7.5 metres from Lower Water Street to the harbour, east of the site. To the south there has been significant redevelopment of some of existing harbour buildings, including the NASCAT and Pier 21. To the north and west, vacant lots exist that will be subject to future development.

The free-standing structure in the Atrium frames interesting views to the waterfront. Transparent stairs and bridges that thread their way through the structure provide connectivity within the building. The memory of the chimneys is recalled in the Galleria, with their bases becoming skylights. The interior finishes recall an industrial esthetic, from the polished concrete floor in the atrium to the expanded metal mesh on the balustrades.

In addition to a lot of interior work, the entire building is receiving a new skin. Formerly clad in concrete, as befits a heavy-use industrial building, the new envelope is constructed of low-iron glass, floating out from the original volume.

WZMH Architects’ design for the NSPI headquarters was a finalist for the Zerofootprint Re-Skinning Award in 2010.

A snail’s eye view of the Atrium.

The project retains and adapts the original concrete-clad steel structure by reskinning it in a tight building envelope to minimize energy loss. Existing piping from the Halifax harbour will carry seawater for cooling. The building will exemplify the first major use of “chilled beam” technology in Canada. Additional energy-saving strategies include the provision of heat recovery from HVAC systems, daylight and occupancy sensors for lighting, and solar panels for water heating and supplementary building heating. The building is a LEED Platinum Level candidate.

When it’s completed, the facility will house more than 500 staff and provide onsite parking for 150 cars.

Paul Currie is the senior project manager for NSPI. He says there were a number of reasons NSPI chose this building, and chose to reskin it in glass.

A lot of demolition work had to be done to the decommissioned power plant before the building phase could begin.

“The existing building was a barrier to the waterfront,” says Currie. “It’s over 36 metres high, and it was basically this big mass of concrete with no openings. That’s changing. The atrium will form the main entrance on Lower Water Street, and as it’s a large, transparent volume right through the centre of the building, it will provide a visual link through the building. The water on the other side will be visible from the street.”

It’s true that the building and site design reinforce the visual and pedestrian connections from city streets to the water in a very dramatic way. A portion of the existing structure at the north was demolished to allow a connection from Morris Street to the harbour. On the south, the beginning of the boardwalk is reinforced at the termination of a view and pedestrian corridor from Perimeter Road.

The use of this building isn’t just about making Halifax a more picturesque city. Make no mistake, NSPI is a power company, and understands the importance of environmental factors.

“We wanted to demonstrate environmental responsibility and show leadership in energy conservation,” says Currie. “The unique adaptive reuse of the building will be a visible statement of the corporation’s commitment to sustainability. The stated objective for the project is to achieve Gold Level LEED certification as a minimum, with a target of Platinum Level certification, subject to a detailed analysis of cost and feasibility.

A view of the building before renovations began. A lot has changed, and much more will change by the time work is completed around April of this year.

Although the building’s new skin will certainly contribute LEED points, it is the heating and cooling system that is truly innovative. Seawater cooling (and heating) is being provided utilizing existing piping from the Halifax harbour originally used to cool power-generating turbines. The building will represent the first major use of “chilled beam” technology in Canada. Although it is widely used in parts of Europe, and has seen use in parts of the United States, the new NSPI headquarters is believed to be the first large-scale use of this technology in the country. The system, which is located within the ceiling space, utilizes low-energy seawater rather than air to transport cooling, thereby lowering energy consumption.

Additional energy-saving strategies include the provision of heat recovery on HVAC, and daylight and occupancy sensors for lighting and supplemental heating for both the building and hot water with the use of solar thermal panels.

The “reskinning” of the existing building shell will result in an energy-efficient tight building envelope that will minimize energy loss/gain at the building perimeter.
Most of the demolition residue will be reused: steel will be recycled off site, and the rubble from concrete that is saw cut to make window openings will be used as fill to adjust site grades west of the building.

In addition to the environmental factors, Currie says another objective of NSPI led to the use of glass as reskinning material.

“We want to show the community we serve that we’re an accessible organization,” he says. “Transparent entries on both the boardwalk and Lower Water Street will invite the public into the facility and gives us the opportunity to showcase our environmental stewardship.”

This sense of openness is reinforced by the views between floors from either the Atrium or the Galleria. Glass elevators located on the edge of the Atrium, and adjacent “oasis” areas on each floor, make this central space into the true heart of the facility, and the focus of activity within the building. If the Atrium will be the heart of NSPI’s new headquarters, then it is the Galleria that will function as its central nervous system, serving as the main artery of internal horizontal travel.

Whether or not the completed building attains the LEED Platinum status being sought, at least one of the organization’s goals will be realized. The new headquarters of NSPI puts forward a sense of openness and connects downtown Halifax with its historic harbour.