S is for Sustainability

A Green Philosophy Sets Precedent For Suburban School Districts Expansion Plans

11/2006 By Jessica Boehland

Click here to view a slide show; Photo © Rick Keating

KEY PARAMETERS Toronto, Ontario, Canada (adjacent to Rouge River watershed) GROSS SQUARE FOOTAGE: 71,194 ft2 / 5,554 m2 COMPLETED: August 2005 COST: CAN$16 million ANNUAL ENERGY USE (BASED ON SIMULATION): 76 kBtu/ft2 (860 MJ/m2)—35% reduction from base case. ANNUAL CARBON FOOTPRINT (PREDICTED): 22 lbs. CO2/ft2 (108 kg CO2/m2). PROGRAM: Classrooms, offices, cafeteria, gymnasium, library thomas l. wells team. DATA click to View larger Heating/Cooling Temp./Dew Point Sky Conditions THOMAS L. WELLS TEAM OWNER: Toronto District School Board ARCHITECT: Baird Sampson Neuert architects COMMISSIONING AGENT:The Mitchell Partnership ENGINEER: Blackwell Bowick Partnership Ltd. (structural); Keen Engineering, now part of Stantec Consulting (mechanical); Mulvey & Banani International (electrical) LANDSCAPE ARCHITECT: Elias + Associates LIGHTING: Mulvey & Banani International ACOUSTICAL: Aercoustics Engineering BUILDING SCIENCE/SUSTAINABILITY: Ted Kesik GENERAL CONTRACTOR: Struct-Con Construction SOURCES STRUCTURAL STEEL: Vicwest CAST-IN PLACE CONCRETE: Coreslab CLADDING: Hanson Brick CURTANWALL LOW-E INSULATED GLAZING UNITS: Triple-seal doors by Doorlam WASHROOM ACCESSORIES, CABINETWORK, AND CUSTOM WOODWORK LOW-VOC CONTENT: Bobrick Washroom Equipment CARPET: Interface

The Toronto district school board had the right idea from the start. “They said, ‘don’t give us a bunch of the green design icing; give us the cake,’” says Seth Atkins, associate at Baird Sampson Neuert architects and project coordinator for the Thomas L. Wells Public School outside Toronto. “They said, we don’t want things that read as green design but don’t have a big effect. We want less green roof and more in terms of high-efficiency boilers, heat recovery, and high-performance glazing.” The resulting building, which opened in time for the 2005–2006 school year, does have a rooftop garden, but its green design sparkles mostly through less flashy features.

The two-story, 71,000-square-foot Wells school sits on three acres in the midst of a new housing development in Scarborough, a fast-growing Toronto suburb home to many Asian and Middle Eastern immigrants. It was designed to serve 670 students, in kindergarten through grade eight.

Wells was the Toronto school district’s first venture into green design, according to David Percival, an architect who serves as the district’s manager of standards compliance and environment. The school board, however, which manages nearly 600 facilities, intended Wells’ green philosophy to set a precedent for future schools. The request for proposals stressed a desire for an integrated design process and an energy-efficient building with good indoor air quality. Once Baird Sampson Neuert architects had been selected to lead the project, the board hosted several design charrettes, which involved everyone from designers and consultants to teachers, maintenance staff, and community members.

Midway through contract documents, the architects indicated the working budget was insufficient to meet the project goals, so the board increased the budget by nearly 10 percent, to Can$12.6 million (approximately $11.25 million U.S. at press time). This allowed the team to consider green alternatives that would pay for themselves after about 10 years, opening the door to innovations, such as heat-recovery ventilation, building automation, and radiant heating and cooling, that might not have been feasible within a more conventional budget.

Since the school board plans to operate Wells for at least 75 years, the team selected durable materials that would require little maintenance. “We considered durability and longevity of systems to be critical to sustainability,” says Percival. Material choices included suspended gypsum wallboard ceilings in place of less-durable acoustic tile, for example, and porcelain tile flooring, which is easy to clean with mild soap and doesn’t need to be stripped and waxed, in place of standard vinyl composition tile. Additionally, the project team used low-VOC materials throughout the project.

The school board had the right idea: “Don’t give us a bunch of the green design icing; give us the cake.”

The team was also concerned about energy efficiency. “How to use a lot of glass for daylighting yet still get energy reduction challenged our design team,” says Atkins. “For us, that meant utilizing thermal mass,” which absorbs heat during the day and releases it at night, reducing internal temperature swings and saving energy. This focus on passive solar design drove the building’s orientation and layout. Classrooms face south to harvest daylight and much of the glazing is recessed in the masonry building envelope and furnished with exterior light shelves to shade the windows in the summer, when the sun passes high overhead, and bounce daylight deep into the rooms in the winter, when the sun sits lower in the sky. All of the school’s classrooms provide daylight and views. Even the gymnasium is washed in even, diffuse daylight.

The project’s ventilation system is probably its most innovative feature. “We had three people proposing three different systems,” Atkins says, until the design team realized the disparate systems could provide superior performance when effectively combined. In the resulting fusion, ventilation air is supplied to rooms at floor level near the corridors. The air moves slowly across the floor and up along the windows to grilles in the ceiling. Then, instead of passing through ductwork above a dropped ceiling, the air moves directly through the hollow-core precast concrete slabs to ducts in the corridors. As it moves through the slabs, the return air picks up heat. In the summer that heat is expelled, and in the winter it is captured for reuse. Pleased with the results, Baird Sampson Neuert hopes to patent the system.

While the design team used both the LEED rating system and the Collaborative for High Performance Schools (CHPS) guidelines as design tools, the school board elected not to attempt LEED certification. During construction, however, it changed its mind. The team originally registered the project through the U.S. Green Building Council but shifted to the Canada Green Building Council once it became established. The school earned a LEED Canada Silver rating in September.

Since the school board plans to operate Wells for at least 75 years, the team selected durable materials that would require little maintenance.

Upon completing the project, the team carried out a comprehensive post-occupancy review, including a survey of all faculty and staff members. On a score of one to five, the overall ratings came back well above four. “The ones that really hit high marks were daylighting and views,” says Atkins. “They had fives straight across.” The only area to come in below four was acoustics, which the team has since addressed by installing acoustically absorptive wallboard in key transmission areas.

The project faced a few other difficulties as well. Percival noted that while the displacement ventilation works well in most of the school, it can be too noisy in the gym. “It’s only a problem when they’re having assemblies or other big gatherings,” he says. Maintenance personnel have struggled with the ceramic tile. While it is easier to care for than vinyl, the grout between the tiles is difficult to clean, and chairs and desks have scuffed the tile surfaces. Atkins believes terrazzo flooring would have been preferable. Ruth Jory, principal at Wells school, reported that the classrooms are sometimes too bright, but that window film and blinds have remedied the problem.

The post-occupancy review also indicated that the school could be operated more efficiently. As a result, Atkins spent two weeks observing how staff members were using the building and working with them to develop more efficient habits. He explained, for example, how turning off the mechanical ventilation when they opened the windows saves energy. “It completely changed their behavior,” he says. Jory agrees. “We have embraced the green philosophy that was inherent in the design,” she says, “and look forward to ensuring that future students and staff continue to preserve our energy-efficient school.”

Though the students are unaware of most of the school’s green features, they love the space. Atkins notes that the green design, and especially the daylighting, “seems to spark a curiosity in them.” Percival says he hopes that the teachers will incorporate some of the building’s green aspects into their lesson plans.

Before the school even opened its doors, the student body was spilling over Wells’s capacity. “Once it got out that this school would have improved indoor air quality and daylighting, everyone who could pulled their kids from other schools and enrolled them in Wells,” says Atkins, resulting in the temporary use of portable classrooms. In response, the school board is planning another K–8 school about a mile north of Wells. It too will be green.