San Diego Middle School Strives for LEED Platinum

SAN DIEGO — The new $20.7 million addition to Montgomery Middle School in San Diego is set to be California’s first LEED for Schools Platinum public school building with a design that is also expected to achieve net-zero energy. The project includes 18 classrooms, a counseling center, library, cafeteria and covered lunch area.

LPA Inc., with offices in San Diego, employed several energy-efficient strategies in the design of the two-story, 900-student school. As part of the district’s Proposition O bond program, which authorized the sale of $644 million of general obligation bonds for upgrades to the district, new construction projects in the Sweetwater Union High School District are expected to acquire LEED Gold certification or better.

Though the school district was dedicated to high standards of environmentally friendly design, the new and innovative strategies used by the architectural firm still took a bit of convincing, according to Rick Musto, AIA, LEED BD+C, project director with LPA. For example, the thermal displacement ventilation system was a new endeavor for the energy conscious district.

“The thermal displacement system was new to the school district, so we had to [educate] them and show them some systems that were in operation,” Musto said. “We had to get them to buy into something that they weren’t normally used to using.”

Musto believes Montgomery’s thermal displacement ventilation system may be one of the first in public schools. Air is brought in at the floor level at a very low velocity and slowly heats as it rises and is then exhausted up at the ceiling level.

“One large diffuser in each corner of the classroom gently delivers air at a low level allowing warm air to exit at the ceiling, so it’s a much healthier way to condition a classroom,” said Wendy Rogers, AIA, principal at LPA. “You can also deliver air at a higher temperature, so it’s more energy efficient. And it’s a very quiet system, so the acoustics in the classroom are significantly better than traditional HVAC systems. Essentially, it promotes health, acoustics, and energy — a win-win-win.”

Another exciting feature of the project, Musto said, is the HVAC system. The school district requires that each classroom have its own individual packaged HVAC unit, but LPA took on a more unique delivery of this requirement.

“Typically when you see classroom buildings you see nothing but a speckled roof that’s filled up with all these little individual packaged mechanical units,” Musto said. ”We located them in these hubs to allow the roof to be completely clean for the PV system.”

The individual high-efficiency HVAC units are located in two-story mechanical distribution hubs, one at the center of each of the two classroom wings. The HVAC units feature variable speed compressors and fans that work in tandem with integrated air-side economizers. This system is tied into the campus’ energy management system, which controls the temperature.

The 217-kW rooftop photovoltaic (PV) system, which is currently under construction, is expected to provide 100 percent of the school’s energy needs. The PV system also wraps around the south façade in order to minimize solar heat gain and maximize daylighting and views.

One of the first tactics used in attempting to achieve LEED Platinum was examining the orientation of the building, Musto said. The building should be oriented in a way that avoids harsh southern exposure and that allows the direct western sunlight to be properly controlled, Musto said.

“We approach every project [the same]. The first thing you do is you look at the site and identify what we like to call the gifts of the site,” he said. “The simplest thing you can do relates to the way you orient the building.”

The firm and the school had much discussion about the issue of stormwater. Given the school’s geographical location, all water will essentially end up in the ocean, Musto said, so the issue of how to treat stormwater was significant.

“We wanted to make sure we had a feature that handled that and we used this bioswale,” Musto said. “Essentially it allows water to come in at one side, filter through and come down an outlet. Once it goes through the system it’s basically filtered.”

Other sustainable features at the 37,500-square-foot school include energy-efficient lighting systems and controls, light shelves that allow natural daylight deeper into the building, low-flow bathroom fixtures, environmentally friendly finishes, drought-resistant native landscaping and light-colored rooftop and hardscape surfaces to reduce the building’s cooling load and urban heat effect.

Collaboration with general contractor Balfour Beatty Construction, with offices in San Diego, was essential in attempting to achieve LEED Platinum, Musto said. Contractors concentrated on supplying local materials with high-recycled content.
“It took commitment on the construction side as well,” Musto said. “It was a team effort, obviously, between ourselves and the contractor to make sure everything was provided per specifications.”

Throughout the school, designers placed signage to identify the sustainable features. The signage encourages students to learn more about green design by pointing out an element that they may have simply walked passed.

“We hope that the school site can actually introduce some of these concepts into the curriculum of the school,” Musto said.

It is vital to educate clients on the benefits of new sustainable features, Musto said. The construction of the addition to Montgomery Middle School may have required a fair amount of education in order to utilize the most state-of-the-art, innovative energy efficiency strategies. However, the new building will now present an efficacious project for other schools to consider.

“I think we get better and better at educating our clients the more we encounter these features. Now that we have this building in place, with the displacement ventilation system, it becomes a laboratory that we can point to and tour to show other people that it’s successful and a nice, healthy environment,” Musto said. “It will make the next project that much simpler.”