The project scope included extensive interior and exterior renovations to the 1940’s section of the building on Robson Street, “to rehabilitate both the built form and internal occupancies of approximately 11,800 square meters of existing office and equipment space into office, retail/commercial and presentation space”. Telus stated that the existing building should be recycled and reused, and that green strategies be incorporated.

Building Form and Orientation

Preserving the existing building determined the basic configuration of the building. A new double glazed, fritted and frameless glazing system with operable windows is suspended from the existing building face, and thus creates the first triple-skinned green building solution in Canada.

Energy Strategies

Embodied energy is low due to the reused materials and, together with the operating energy reductions, this results in a significant reduction in life-cycle energy use compared to standard practice. Operating energy is reduced by the tempering effect of the new external glazed skin. The skin and horizontal shading devices reduce the solar load during summer and provide solar gain during winter.

Waste heat from large chillers in the adjacent telecommunications equipment building meets almost all heating requirements of the Telus building.

Structure and Building Envelope

The structure of the existing buildings was left essentially unchanged. The building’s new external cavity operates as a thermal buffer and natural ventilation intake. The curtain wall around the cavity has a ceramic fritted pattern that allows maximum daylight penetration to the interior (via lightshelves) while at the same time shading the building. The envelope has ventilating fans that are powered by photovoltaic panels. Electronic temperature sensors control the entire ventilation system to maintain the optimum temperature inside the cavity. During summer the cavity’s natural stack effect and ventilation fans lower the temperature of the perimeter walls. All perimeter windows are user operable for natural ventilation.

Mechanical Systems

The existing building serviced the city’s telephone systems, and housed communication equipment and technical staff as well as administrative staff. It was constructed in the 1940s from cast-in-place concrete. The existing exterior walls consisted of brick and punched single glazed wood sash windows covered with adhesive reflective solar film. The inside of the exterior walls and all interior partition walls consisted of plaster on terra cotta. There was a central chilled water system for the entire building, while heating was provided via central steam to the existing air conditioning units and to perimeter radiation units. Equipment rooms were provided with dedicated chilled water-cooling units located within each space.

As part of the retrofit, heating requirements are met by waste heat from an adjacent building. Typical floors now have one main air-handling unit per floor. A constant air temperature of ~17.3°C is supplied to the occupied space, distributed by an underfloor pressurized plenum. The perimeter condition is satisfied by two-pipe fan coil units (heating coil only), which draw air form the pressurized plenum, and return air from the stratified level. Primary heating is generated via heat recovery from a year-round process load.

Control and Telecommunications Systems

The building is divided with an interior zone and six perimeter zones per floor. Corner areas have separate zones.

Maximizing the Quality of Indoor Environment

Materials specified include low-VOC latex paint, no-VOC linoleum, water-based adhesive, low-pile and tight-weave construction carpet with low-emission backing. The building maintenance staff used low-VOC cleaning chemicals and techniques.

The risk of Legionella’s disease was reduced by using an air-cooled chiller, rather than a water-cooled chiller. Furthermore, the hot water system is set to 60°C to minimize bacteria growth.

Daylight bounce is maximized inside with light-shelves and whitewashed concrete ceilings.

Minimizing Impact on Ecosystems

The existing building was built to the property line, so there was no vegetation on the site. This situation has not changed.

Construction Waste and Operating Solid Wastes

Reusing the existing building, which is built out to the property line, means that the project is very efficient in its use of land and structure. Extensive care was taken to reuse and recycle materials on-site, diverting from landfill and eventual reuse.

Much of the material removed from the existing building was either toxic (contaminated with asbestos) or of little economic value in the local industries (e.g. terra cotta tiles). Material that was more economically valuable was generally retained on the building site. The ground floor Andersite stone and Granite was taken off site and recut to fit new window openings. Unused stone as salvaged and sold by the stone contractor. Because the interior renovation occurred in one floor at a time, salvaged doors and frames, lighting, mechanical equipment and furniture could be moved to unoccupied floors where no work was taking place, before being reinstalled on completed floors. The construction and demolition waste that was taken off site amounted to 70 percent by weight of the total waste.

Materials efficiency, reuse and recycling

The existing concrete structure was retained. All new concrete contains 25 percent recycled fly ash and recycled steel rebar. The existing Andersite stone and Granite was recut and reused on the exterior. Existing windows, handrails and stairs were retained. Two air-handling units were relocated and reused. Marble toilet partitions were reused. Copper bus ducts were reconfigured and reused as guardrails. Lift shafts, cabs and operating machinery were modified and retained. Existing fluorescent light fixtures were reused in basement and mechanical areas. Existing doors and fittings were relocated and reused. Existing furniture was reused. These reused and recycled materials amount 75 percentof the total material mass.

All components of the new building skin and roof screen are made with bolted steel connections. Glazing is designed with a unitized system that can be dismantled with framing and glazing intact.

Interior components and fixtures on the interior are typically left exposed, making them easily accessible to be reused. These include suspended lighting, electrical conduit, sprinklers, raised access floors and carpet tiles, floor mounted washroom fixtures, sinks, mirrors, steel studs, electrical equipment, concrete blocks, interior doors and frames and washroom cubicles.

The new chiller is located on the roof, where it can be easily removed for reuse. The existing chiller was removed and reused in another facility owned by the client. The client keeps a storage facility for stockpiling materials to be reused in their other facilities.

Recyclable exterior building materials were selected, such as structural concrete, cinder block, electrical cable, rebar, anodized aluminum mullions, clear glass, aluminum roof screen and a steel supporting structure. Interior materials include gypsum wallboard, steel suds and carpeting which will be reconditioned and reused at the end of its usable life.

Ensuring Longevity of the Building

The original concrete structure was designed to carry machinery loads so it will be flexible for other occupancies. New shear walls have been located against existing circulation cores to maintain each floor’s flexibility. The floor plate has been opened up to allow for open plan operations.

Reducing Car Use

There is a bus stop in front of the building, which is also located 100 meters from the main downtown bus depot and 200 meters from a Light Rapid Transit station on Granville Street, a busy street with commercial traffic during the day and social traffic in the evening. The transit service to Granville Street runs from 17.00 hrs. to 03:00 hrs. Changing rooms, lockers and showers (6 for women and 3 for men) are provided in the building’s fitness facility located in the basement level. Secure, covered storage for bicycles is located in the cycle park owned by the client just across the lane.

Name:	William Farrell Building
Type:	Office building
Address:	Vancouver, British Columbia
Completed:	Nearing completion
Owners:	BC Telephone Accommodation Services
Architects:	Busby + Associates Architects
Structural Engineer:	Read Jones Christoffersen
Mechanical Engineers:	Keen Engineering Co. Ltd.
Electrical Engineers:	Reid Crowther & Partners Ltd.
General Description:	8 story office building
Gross/Net Floor Area:	12,193 m2/8,654m2
Typical Building Population:	500 persons

— reprinted with permission from Issue 02-2001 of Sustainable Building, an independent, international journal on building and the environment, published by Aeneas Technical Publishers.